Prepregnancy SHBG Concentrations and Risk for Subsequently Developing Gestational Diabetes Mellitus

OBJECTIVE

Lower levels of sex hormone–binding globulin (SHBG) have been associated with increased risk of diabetes among postmenopausal women; however, it is unclear whether they are associated with glucose intolerance in younger women. We examined whether SHBG concentrations, measured before pregnancy, are associated with risk of gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

This was a nested case-control study among women who participated in the Kaiser Permanente Northern California Multiphasic Health Check-up examination (1984–1996) and had a subsequent pregnancy (1984–2009). Eligible women were free of recognized diabetes. Case patients were 256 women in whom GDM developed. Two control subjects were selected for each case patient and were matched for year of blood draw, age at examination, age at pregnancy, and number of intervening pregnancies.

RESULTS

Compared with the highest quartile of SHBG concentrations, the odds of GDM increased with decreasing quartile (odds ratio 1.06 [95% CI 0.44–2.52]; 2.33 [1.07–5.09]; 4.06 [1.90–8.65]; P for trend < 0.001), after adjusting for family history of diabetes, prepregnancy BMI, race/ethnicity, alcohol use, prepregnancy weight changes, and homeostasis model assessment of insulin resistance. Having SHBG levels below the median (<64.5 nmol/L) and a BMI ≥25.0 kg/m² was associated with fivefold increased odds of GDM compared with normal-weight women with SHBG levels at or above the median (5.34 [3.00–9.49]).

CONCLUSIONS

Low prepregnancy SHBG concentrations were associated with increased risk of GDM and might be useful in identifying women at risk for GDM for early prevention strategies.     

Differences in Maternal Circulating Fatty Acid Composition and Dietary Fat Intake in Women With Gestational Diabetes Mellitus or Mild Gestational Hyperglycemia

OBJECTIVE

We investigated the relationship between maternal circulating fatty acids (FAs) and dietary FA intake in pregnant women with gestational diabetes mellitus (GDM; n = 49), women with hyperglycemia less severe than GDM (impaired glucose challenge test [GCT] non-GDM; n = 80), and normal control subjects (n = 98).

RESEARCH DESIGN AND METHODS

A case-control design was nested within a prospective cohort of healthy pregnant women. Fasting concentrations of serum total FAs (enzymatic assay) and FA composition (gas chromatography–mass spectrometry) were determined at entry and the third trimester. Dietary fat intake data were obtained from 24-h recalls.

RESULTS

There was a graded increase among groups (control subjects, impaired GCT non-GDM, and GDM) during the third trimester for total FAs and individual FAs, including myristic, palmitic, palmitoleic, oleic, linoleic, linolenic, arachidonic, eicosapentaenoic, and docosahexaenoic acids (P for trend <0.03 to P < 0.001). Similar relationships were observed at entry in total FAs and for four FAs (myristic, palmitic, palmitoleic, and eicosapentaenoic acids). Women with impaired GCT non-GDM with BMI ≥25 kg/m² had the highest levels of FAs at entry, whereas women with GDM with BMI ≥25 kg/m² had the highest levels during the third trimester, and all grouped FAs were significantly different from lean women with impaired GCT non-GDM or control subjects (P < 0.05). Dietary intake of polyunsaturated FAs was decreased, but saturated FAs were increased in GDM compared with impaired GCT non-GDM or control subjects (P < 0.05).

CONCLUSIONS

Abnormalities in fat metabolism are present in both GDM and impaired GCT non-GDM women. Reducing pregravid weight and altering diet might prevent the associated elevation of circulating FAs.Many studies suggested that maternal circulating fatty acids (FAs) play important roles in fetal growth and development (1–2). However, elevated maternal circulating total FAs are associated with increased insulin resistance and β-cell dysfunction, which contribute to the development of gestational diabetes mellitus (GDM) and increase risk of adverse perinatal outcomes, including preterm delivery (3–4). Less attention has been focused on the relationship between FA composition and GDM. Published data (5–6) are inconclusive on which individual FAs are altered in GDM and the importance of these changes, if any. Dietary saturated fat intake is associated with increased risk of type 2 diabetes and increased polyunsaturated fat intake with a reduced risk (7). Similar results have been found in some, but not all, studies with GDM, with the difference in results probably being due to the effect of dietary counseling after GDM diagnosis (8–9).Recent studies have reported that maternal glucose intolerance less severe than overt GDM is associated with an increased risk of adverse pregnancy outcomes (10). These observations raise important questions because ∼9–19% of pregnant women have hyperglycemia during fasting or an oral glucose load but do not meet the diagnostic criteria for GDM (11). These patients generally are not provided the usual diabetes care. Consequently, there is little information on whether metabolic abnormalities in FA composition exist in these women and if their dietary fat intake differs from women with metabolically normal pregnancies.Therefore, we used a nested case-control design to investigate whether elevated concentrations of serum FA and alerted FA composition were present not only in women with overt GDM but also in those with less severe glucose intolerance. In addition, we examined whether the corresponding dietary FA intake differed among groups and correlated with serum FA concentration.     

Prospective Study of Pre-Gravid Sugar-Sweetened Beverage Consumption and the Risk of Gestational Diabetes Mellitus

OBJECTIVE

Consumption of sugar-sweetened beverages (SSBs) was related to an elevated risk of type 2 diabetes and insulin resistance in several recent studies among middle- or older-aged populations. Studies on SSB consumption and glucose intolerance among pregnant women, however, are lacking. We therefore examined the association between regular SSB consumption before pregnancy and the risk of gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

This was a prospective study among 13,475 U.S. women who reported at least one singleton pregnancy between 1992 and 2001 in the Nurses'' Health Study II. GDM was self-reported and validated by medical record review in a subsample. Cox proportional hazards models with multivariate adjustments were applied to examine the association of SSB consumption with GDM risk.

RESULTS

During 10 years of follow-up, 860 incident GDM case subjects were identified. After adjustment for age, parity, race, physical activity, smoking, alcohol intake, prepregnancy BMI, and Western dietary pattern, intake of sugar-sweetened cola was positively associated with the risk of GDM, whereas no significant association was found for other SSBs and diet beverages. Compared with women who consumed <1 serving/month, those who consumed ≥5 servings/week of sugar-sweetened cola had a 22% greater GDM risk (relative risk 1.22 [95% CI 1.01–1.47]).

CONCLUSIONS

Findings from this study suggest that prepregnancy higher consumption of sugar-sweetened cola (≥5 servings/week) is associated with an elevated GDM risk, whereas no significant association with GDM risk was observed for other SSBs and diet beverages.Gestational diabetes mellitus (GDM), defined as glucose intolerance with onset or first recognition during pregnancy, is one of the most common pregnancy complications (1). Women with GDM are at increased risk of pregnancy complications, perinatal morbidity, and type 2 diabetes in the years after pregnancy. Offspring of women with GDM have increased risk of obesity, glucose intolerance, and diabetes in childhood and early adulthood (1). Despite the maternal and infant morbidity associated with GDM, limited attention has been paid to the identification of dietary risk factors for GDM.Sugar-sweetened beverages (SSBs) are the leading source of added sugars in Americans'' diets (2). In animal models and human studies, a high-sugar diet reduces insulin sensitivity (3,4) and insulin secretion (5). Higher consumption of SSBs was associated with an elevated risk of type 2 diabetes (6–8) and insulin resistance (9) among middle- or older-aged adults in several recent epidemiological studies. Studies regarding the impact of habitual SSB consumption on glucose intolerance among pregnant women, however, are lacking. We therefore examined the association of pregravid SSB consumption with GDM risk in a large prospective cohort of U.S. women.     

Prepregnancy consumption of fruits and fruit juices and the risk of gestational diabetes mellitus: a prospective cohort study

OBJECTIVE

Examine the association of prepregnancy habitual consumption of fruits and fruit juices and gestational diabetes mellitus (GDM) risk.

RESEARCH DESIGN AND METHODS

A prospective study among women with at least one singleton pregnancy in the Nurses’ Health Study II from 1991 to 2001.

RESULTS

Among 13,475 women, 860 reported a first diagnosis of GDM. The adjusted relative risks (RRs) for GDM from the lowest to highest quintile of whole fruit consumption were 1.00 (referent), 0.80 (95% CI 0.65–0.98), 0.90 (0.73–1.10), 0.80 (0.64–1.00), and 0.93 (0.76–1.16), respectively. The corresponding RRs for fruit juice were 1.00, 0.82 (0.66–1.01), 0.78 (0.63–0.96), 0.84 (0.68–1.04), and 1.00 (0.81–1.23).

CONCLUSIONS

These data suggest that prepregnancy higher consumption of whole fruits is not associated with an increased GDM risk. The association between fruit juices and GDM risk appears to be nonlinear.Although dietary factors have long been recognized for their roles in the development of impaired glucose tolerance, the association between intakes of fruit and fruit juice and the risk of gestational diabetes mellitus (GDM) has yet to be investigated. The objective of this study was to assess the association of prepregnancy habitual consumption of fruit and fruit juices and their subgroups with GDM risk in a large prospective cohort of U.S. women.     

Pregravid Liver Enzyme Levels and Risk of Gestational Diabetes Mellitus During a Subsequent Pregnancy

OBJECTIVE

Liver enzymes are independent predictors of type 2 diabetes. Although liver fat content correlates with features of insulin resistance, a risk factor for developing gestational diabetes mellitus (GDM), the relationship between liver enzymes and GDM is unclear. The objective of this study was to assess whether pregravid liver enzyme levels are associated with subsequent risk of GDM.

RESEARCH DESIGN AND METHODS

A nested case-control study was conducted among women who participated in the Kaiser Permanente Northern California multiphasic health checkup (1984–1996) and had a subsequent pregnancy (1984–2009). Case patients were 256 women who developed GDM. Two control subjects were selected for each case patient and matched for year of blood draw, age at examination, age at pregnancy, and number of intervening pregnancies.

RESULTS

Being in the highest quartile versus the lowest quartile of γ-glutamyl transferase (GGT) levels was associated with a twofold increased risk of subsequent GDM (odds ratio 1.97 [95% CI 1.14–3.42]), after adjusting for race/ethnicity, prepregnancy BMI, family history of diabetes, and alcohol use. This result was attenuated after adjusting for homeostasis model assessment of insulin resistance (HOMA-IR), fasting status, and rate of gestational weight gain. There was significant interaction between GGT and HOMA-IR; the association with GGT was found among women in the highest tertile of HOMA-IR. Aspartate aminotransferase and alanine aminotransferase were not associated with increased GDM risk.

CONCLUSIONS

Pregravid GGT level, but not alanine aminotransferase or aspartate aminotransferase level, predicted the subsequent risk of GDM. Markers of liver fat accumulation, such as GGT level, are present years before pregnancy and may help to identify women at increased risk for subsequent GDM.     

Increased risk of cardiovascular disease in young women following gestational diabetes mellitus

OBJECTIVE—To determine whether women with gestational diabetes mellitus (GDM) have an increased risk of cardiovascular disease (CVD) following pregnancy.RESEARCH DESIGN AND METHODS—All women aged 20–49 years with live births between April 1994 and March 1997 in Ontario, Canada, were identified. Women with GDM were matched with 10 women without GDM and were followed for CVD.RESULTS—The matched cohorts included 8,191 women with GDM and 81,262 women without GDM. Mean age at entry was 31 years, and median follow-up was 11.5 years. The hazard ratio for CVD events was 1.71 (95% CI 1.08–2.69). After adjustment for subsequent type 2 diabetes, the hazard ratio was attenuated (1.13 [95% CI 0.67–1.89]).CONCLUSIONS—Young women with GDM had a substantially increased risk for CVD compared with women without GDM. Much of this increased risk was attributable to subsequent development of type 2 diabetes.Gestational diabetes mellitus (GDM) is a common condition affecting 2–4% of pregnant women (1) and is associated with adverse outcomes for both the fetus and the mother. Previous GDM is a major risk factor for type 2 diabetes, which occurs in 20–60% of affected women within 5 years of the pregnancy (2). Women with a history of GDM are also at increased risk of other cardiovascular risk factors, such as obesity, hypertension, dyslipidemia, and the metabolic syndrome (3–5), as well as subclinical atherosclerosis (6). Taken together, these findings suggest that GDM identifies a population of young women at increased risk for cardiovascular disease (CVD). We used population-based administrative data to determine whether women with GDM have a heightened risk for CVD compared with women without GDM and whether any increase in risk is independent of subsequent type 2 diabetes.     

Impact of Chronic Kidney Disease on Survival After Amputation in Individuals With Diabetes

OBJECTIVE

To identify factors that influence survival after diabetes-related amputations.

RESEARCH DESIGN AND METHODS

We abstracted medical records of 1,043 hospitalized subjects with diabetes and a lower-extremity amputation from 1 January to 31 December 1993 in six metropolitan statistical areas in south Texas. We identified mortality in the 10-year period after amputation from death certificate data. Diabetes was verified using World Health Organization criteria. Amputations were identified by ICD-9-CM codes 84.11–84.18 and categorized as foot, below-knee amputation, and above-knee amputation and verified by reviewing medical records. We evaluated three levels of renal function: chronic kidney disease (CKD), hemodialysis, and no renal disease. We defined CKD based on a glomerular filtration rate <60 ml/min and hemodialysis from Current Procedural Terminology (CPT) codes (90921, 90925, 90935, and 90937). We used χ² for trend and Cox regression analysis to evaluate risk factors for survival after amputation.

RESULTS

Patients with CKD and dialysis had more below-knee amputations and above-knee amputations than patients with no renal disease (P < 0.01). Survival was significantly higher in patients with no renal impairment (P < 0.01). The Cox regression indicated a 290% increase in hazard for death for dialysis treatment (hazard ratio [HR] 3.9, 95% CI 3.07–5.0) and a 46% increase for CKD (HR 1.46, 95% CI 1.21–1.77). Subjects with an above-knee amputation had a 167% increase in hazard (HR 2.67, 95% CI 2.14–3.34), and below-knee amputation patients had a 67% increase in hazard for death.

CONCLUSIONS

Survival after amputation is lower in diabetic patients with CKD, dialysis, and high-level amputations.Diabetes is the most common underlying cause of nontraumatic amputation in the U.S. and Europe (1–4). Of the 120,000 amputations performed in the U.S. every year, 40–70% are in individuals with diabetes. Among individuals with end-stage renal disease receiving dialysis, the incidence of amputation is about 10 times higher than in the general diabetic population (5).The in-hospital and 30-day mortality after amputation in people with diabetes is higher than in people with coronary artery bypass graft surgery, breast cancer, or stroke (6–8). However, there is little published data that report the long-term survival after amputation and even less data regarding patients with chronic kidney disease (CKD). The purpose of this study was to identify differences in the proportion of amputations and survival after lower-extremity amputation in individuals with diabetes and CKD and to identify risk factors for survival after an amputation.     

Physical Activity Before and During Pregnancy and Risk of Gestational Diabetes Mellitus: A meta-analysis

OBJECTIVE

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy and is associated with a substantially elevated risk of adverse health outcomes for both mothers and offspring. Physical activity may contribute to the prevention of GDM and thus is crucial for dissecting the vicious circle involving GDM, childhood obesity, and adulthood obesity, and diabetes. Therefore, we aimed to systematically review and synthesize the current evidence on the relation between physical activity and the development of GDM.

RESEARCH DESIGN AND METHODS

Medline, EMBASE, and Cochrane Reviews were searched from inception to 31 March 2010. Studies assessing the relationship between physical activity and subsequent development of GDM were included. Characteristics including study design, country, GDM diagnostic criteria, ascertainment of physical activity, timing of exposure (prepregnancy or early pregnancy), adjusted relative risks, CIs, and statistical methods were extracted independently by two reviewers.

RESULTS

Our search identified seven prepregnancy and five early pregnancy studies, including five prospective cohorts, two retrospective case-control studies, and two cross-sectional study designs. Prepregnancy physical activity was assessed in 34,929 total participants, which included 2,813 cases of GDM, giving a pooled odds ratio (OR) of 0.45 (95% CI 0.28–0.75) when the highest versus lowest categories were compared. Exercise in early pregnancy was assessed in 4,401 total participants, which included 361 cases of GDM, and was also significantly protective (0.76 [95% CI 0.70–0.83]).

CONCLUSIONS

Higher levels of physical activity before pregnancy or in early pregnancy are associated with a significantly lower risk of developing GDM.Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy, affecting ∼7% of all pregnancies in the U.S. (i.e., >200,000 cases annually) (1), and this number is increasing as the prevalence of obesity among women at reproductive age escalates (2–4). GDM is associated with a significantly elevated risk for short-term and long-term complications for both mothers and offspring. Women with GDM have an increased risk for perinatal morbidity and impaired glucose tolerance and type 2 diabetes in the years after pregnancy (5,6). Children of women with GDM are more likely to be obese and have impaired glucose tolerance and diabetes in childhood and early adulthood (1). In a recent meta-analysis of randomized trials on the effect of treatment for GDM, various interventions for blood glucose control, including diet, glucose monitoring, insulin use, and pharmaceutical interventions, did not significantly reduce the risk for adverse perinatal and neonatal end points, including cesarean section and perinatal or neonatal death (7). Collectively, these data indicate that prevention of GDM altogether could be crucial for avoiding its associated adverse health outcomes.Physical activity has long been known for its role in improving glucose homeostasis through its direct or indirect impact on insulin sensitivity via several mechanisms. For instance, physical activity has independent effects on glucose disposal by increasing both insulin-mediated and non–insulin-mediated glucose disposal (8,9). Physical activity can also exert long-term effects on improvement in insulin sensitivity through increased fat-free mass (10). Furthermore, the benefits of preventing or delaying the onset of type 2 diabetes among nonpregnant individuals have been reported repeatedly (11,12). Therefore, physical activity may have the potential for preventing GDM and related adverse health outcomes. However, evidence for its impact on GDM has not been systematically synthesized. The aim of this systematic review and meta-analysis was to assemble the current evidence for the relationship between physical activity and the development of GDM.     

Dialysis Treatment Is an Independent Risk Factor for Foot Ulceration in Patients With Diabetes and Stage 4 or 5 Chronic Kidney Disease

OBJECTIVE

To determine whether dialysis treatment is an independent risk factor for foot ulceration in patients with diabetes and renal impairment.

RESEARCH DESIGN AND METHODS

We performed a cross-sectional study of consecutive patients with diabetes and stage 4 or 5 chronic kidney disease (CKD) attending clinics in Manchester (U.K.). Patients were classified as either receiving dialysis therapy (dialysis) or not (no dialysis). Foot assessment included diabetic peripheral neuropathy (DPN), peripheral arterial disease (PAD), prior foot ulceration and amputation, and foot self-care. Risk factors for prevalent foot ulceration were assessed by logistic regression.

RESULTS

We studied 326 patients with diabetes and CKD (mean age 64 years; 61% male; 78% type 2 diabetes; 11% prevalent foot ulceration). Compared with no dialysis patients, dialysis patients had a higher prevalence of DPN (79 vs. 65%), PAD (64 vs. 43%), prior amputations (15 vs. 6.4%), prior foot ulceration (32 vs. 20%), and prevalent foot ulceration (21 vs. 5%, all P < 0.05). In univariate analyses, foot ulceration was related to wearing bespoke footwear (odds ratio 5.6 [95% CI 2.5–13]) dialysis treatment (5.1 [2.3–11]), prior foot ulceration (4.8 [2.3–9.8], PAD (2.8 [1.3–6.0], and years of diabetes (1.0 [1.0–1.1], all P < 0.01). In multivariate logistic regression, only dialysis treatment (4.2 [1.7–10], P = 0.002) and prior foot ulceration (3.1 [1.3–7.1], P = 0.008) were associated with prevalent foot ulceration.

CONCLUSIONS

Dialysis treatment was independently associated with foot ulceration. Guidelines should highlight dialysis as an important risk factor for foot ulceration requiring intensive foot care.The lifetime risk of an individual with diabetes developing foot ulceration has been estimated to be 25% (1). Foot ulceration is a serious problem for people with diabetes, which also results in huge economic costs (2).Causal pathways to foot ulceration are multifactorial and involve combinations of physiological and mechanical factors, self-care, and treatment factors. Diabetic nephropathy has been identified to be an important risk factor for foot ulceration and amputation (3,4). Retrospective studies in patients with diabetes have shown that incident foot ulceration increases with progressive renal impairment (5), and one study reported a close temporal relation among the onset of dialysis, foot ulceration, and amputations (6).Studies reporting an association between renal failure and foot ulceration have failed to separate dialysis-treated patients from those not receiving dialysis (5,7). We therefore aimed to determine whether dialysis treatment is an independent risk factor for foot ulceration among diabetic patients with stage 4 or 5 chronic kidney disease (CKD). We hypothesized that dialysis treatment would be associated with a higher prevalence of foot ulceration after adjustment for potential confounders.     

Parity, Breastfeeding, and the Subsequent Risk of Maternal Type 2 Diabetes

OBJECTIVE

To examine the effect of childbearing and maternal breastfeeding on a woman''s subsequent risk of developing type 2 diabetes.

RESEARCH DESIGN AND METHODS

Using information on parity, breastfeeding, and diabetes collected from 52,731 women recruited into a cohort study, we estimated the risk of type 2 diabetes using multivariate logistic regression.

RESULTS

A total of 3,160 (6.0%) women were classified as having type 2 diabetes. Overall, nulliparous and parous women had a similar risk of diabetes. Among parous women, there was a 14% (95% CI 10–18%, P < 0.001) reduced likelihood of diabetes per year of breastfeeding. Compared to nulliparous women, parous women who did not breastfeed had a greater risk of diabetes (odds ratio 1.48, 95% CI 1.26–1.73, P < 0.001), whereas for women breastfeeding, the risk was not significantly increased.

CONCLUSIONS

Compared with nulliparous women, childbearing women who do not breastfeed have about a 50% increased risk of type 2 diabetes in later life. Breastfeeding substantially reduces this excess risk.Studies suggest that breastfeeding may reduce the risk of developing type 2 diabetes (1) or the metabolic syndrome (2,3) in later life. Rates of type 2 diabetes will increase substantially throughout the developed and developing world (4). Hence, it is important to identify whether simple and accessible interventions, such as promoting breastfeeding, may reduce the incidence of diabetes, and to provide reliable estimates of the size of any benefit.     

Increased risk of hypertension after gestational diabetes mellitus: findings from a large prospective cohort study

OBJECTIVE

Whether a history of gestational diabetes mellitus (GDM) is associated with an increased risk of hypertension after the index pregnancy is not well established.

RESEARCH DESIGN AND METHODS

We investigated the association between GDM and subsequent risk of hypertension after the index pregnancy among 25,305 women who reported at least one singleton pregnancy between 1991 and 2007 in the Nurses’ Health Study II.

RESULTS

During 16 years of follow-up, GDM developed in 1,414 women (5.6%) and hypertension developed in 3,138. A multivariable Cox proportional hazards model showed women with a history of GDM had a 26% increased risk of developing hypertension compared with those without a history of GDM (hazard ratio 1.26 [95% CI 1.11–1.43]; P = 0.0004). These results were independent of pregnancy hypertension or subsequent type 2 diabetes.

CONCLUSIONS

These results indicate that women with GDM are at a significant increased risk of developing hypertension after the index pregnancy.Increasing evidence suggests the effect of gestational diabetes mellitus (GDM) extends beyond pregnancy for both the mother and child (1). For instance, women with a history of GDM are at a substantially higher risk of type 2 diabetes (2); small- and large-vessel vascular dysfunction (3); cardiovascular disease; and metabolic syndrome and its components, including hypertension (4–7). In the current study, we examined longitudinally whether GDM is associated with an increased risk of hypertension later in life independent of other known risk factors.     

Gestational Diabetes Mellitus: Simplifying the International Association of Diabetes and Pregnancy diagnostic algorithm using fasting plasma glucose

OBJECTIVE

To determine the impact of the International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria on 1) gestational diabetes mellitus (GDM) diagnosis compared with the American Diabetes Association (ADA) criteria and 2) the fasting plasma glucose (FPG) to predict GDM.

RESEARCH DESIGN AND METHODS

In 10,283 pregnant women undergoing a 75-g oral glucose tolerance test (OGTT) for universal screening of GDM, two FPG thresholds (of the OGTT) were used to rule in and to rule out GDM.

RESULTS

The IADPSG and ADA criteria identified GDM in 3,875 (37.7%) women and 1,328 (12.9%) women, respectively (P < 0.0005). FPG thresholds of ≥5.1 mmol/l ruled in GDM in 2,975 (28.9%) women with 100% specificity, while <4.4 mmol/l ruled out GDM in 2,228 (21.7%) women with 95.4% sensitivity. FPG independently could have avoided the OGTT in 5,203 (50.6%) women.

CONCLUSIONS

The IADPSG criteria increased GDM prevalence nearly threefold. By circumventing a significant number of OGTTs, an initial FPG can greatly simplify the IADPSG diagnostic algorithm.The scourge of gestational diabetes mellitus (GDM) is the lack of an international agreement on the screening and diagnosis among the pre-eminent diabetes, obstetric, and health care organizations (1). Therefore, without a globally accepted guideline, the diagnosis of GDM causes a great deal of clinical confusion (2). In March 2010, the International Association of Diabetes and Pregnancy Study Group (IADPSG) issued consensus guidelines to potentially attain a single approach for GDM diagnosis worldwide (3).The inconsistency in GDM diagnosis is evident in the United Arab Emirates (UAE), which has the second highest prevalence of type 2 diabetes (18.7%) in the world (4). GDM in the UAE varies from 7.9 to 24.9%, depending on which of the six well-accepted criteria are used for diagnosis (2). The popular American Diabetes Association (ADA) criteria (5) demonstrates a prevalence of 10.6–14.7% (2,6–8). In this population, multiple studies have confirmed that the initial fasting plasma glucose (FPG) result of the oral glucose tolerance test (OGTT) is excellent in determining the need to continue with the OGTT (6,9–10); however, its efficiency depends on the criteria used for GDM diagnosis (6). The aim of this study was to determine, in this high-risk population, the impact of the new IADPSG criteria on 1) the diagnosis of GDM compared with the ADA criteria and 2) the FPG to predict GDM in order to decide whether to proceed with the OGTT.     

Preconception Counseling in Women With Diabetes: A population-based study in the North of England

OBJECTIVE

To investigate the association of preconception counseling with markers of care and maternal characteristics in women with pregestational diabetes.

RESEARCH DESIGN AND METHODS

The study includes data from a regional multi-center survey on 588 women with pregestational diabetes who delivered a singleton pregnancy between 2001 and 2004. Logistic regression was used to obtain crude and adjusted estimates of association.

RESULTS

Preconception counseling was associated with better glycemic control 3 months preconception (odds ratio 1.91, 95% CI 1.10–3.04) and in the first trimester (2.05, 1.39–3.03), higher preconception folic acid intake (4.88, 3.26–7.30), and reduced risk of adverse pregnancy outcome (P = 0.027). Uptake of preconception counseling was positively associated with type 1 diabetes (1.87, 1.14–3.07) and White British ethnicity (2.56, 1.17–5.6) and negatively with deprivation score (0.78, 0.70–0.87).

CONCLUSIONS

Efforts are needed to improve preconception counseling rates. Uptake is associated with maternal sociodemographic characteristics.Rates of preconception counseling in women with diabetes remain low despite the recognized importance of adequate preparation for pregnancy in national guidance (1,2). This study reports the association of preconception counseling with markers of adequate preconception care and pregnancy outcome and investigates maternal characteristics related to its uptake in a population-based cohort in the North of England.     

Comparison of hemoglobin A1c with fasting plasma glucose and 2-h postchallenge glucose for risk stratification among women with recent gestational diabetes mellitus

OBJECTIVE

Postpartum testing with a 75-g 2-h oral glucose tolerance test or fasting plasma glucose (FPG) alone is often not performed among women with histories of gestational diabetes mellitus (GDM). Use of hemoglobin A_1c (A1C) might increase testing. The association between A1C and glucose has not been examined in women with histories of GDM.

RESEARCH DESIGN AND METHODS

We assessed the association of A1C ≥5.7% with FPG ≥100 mg/dL and 2-h glucose ≥140 mg/dL among 54 women with histories of GDM between 6 weeks and 36 months postpartum.

RESULTS

A1C ≥5.7% had 65% sensitivity and 68% specificity for identifying elevated FPG or 2-h glucose and 75% sensitivity and 62% specificity for elevated FPG alone. The area under the receiver operating characteristic curve for A1C was 0.76 for elevated FPG or 2-h glucose and 0.77 for elevated FPG alone.

CONCLUSIONS

The agreement between A1C and glucose levels is fair for detection of abnormal glucose tolerance among women with histories of GDM.Postpartum testing is recommended for women with histories of gestational diabetes mellitus (GDM) to diagnose diabetes and to stratify women for risk of future diabetes (1–3). Several groups have recommended postpartum testing with fasting plasma glucose (FPG) alone (1), others have recommended 2-h 75-g oral glucose tolerance tests (OGTTs) (2), and others have recommended hemoglobin A_1c (A1C) (4). Agreement between A1C and glucose has not yet been reported in this population. Our objective was to examine the agreement between A1C, FPG, and 2-h glucose among women with recent GDM.     

Trends in postpartum diabetes screening and subsequent diabetes and impaired fasting glucose among women with histories of gestational diabetes mellitus: A report from the Translating Research Into Action for Diabetes (TRIAD) Study

OBJECTIVE—The purpose of this study was to examine trends in postpartum glucose screening for women with gestational diabetes mellitus (GDM), predictors of screening, trends in postpartum impaired fasting glucose (IFG) and diabetes, and diabetes and pre-diabetes detected by postpartum fasting plasma glucose (FPG) versus a 75-g oral glucose tolerance test (OGTT).RESEARCH DESIGN AND METHODS—This was a cohort study of 14,448 GDM pregnancies delivered between 1995 and 2006. Postpartum screening was defined as performance of either an FPG or OGTT at least 6 weeks after delivery and within 1 year of delivery.RESULTS—Between 1995 and 2006, the age- and race/ethnicity-adjusted proportion of women who were screened postpartum rose from 20.7% (95% CI 17.8–23.5) to 53.8% (51.3–56.3). Older age, Asian or Hispanic race/ethnicity, higher education, earlier GDM diagnosis, use of diabetes medications during pregnancy, and more provider contacts after delivery were independent predictors of postpartum screening. Obesity and higher parity were independently associated with lower screening performance. Among women who had postpartum screening, the age- and race/ethnicity-adjusted proportion of IFG did not change over time (24.2 [95% CI 20.0–27.8] in 1995–1997 to 24.3 [22.6–26.0] in 2004–2006), but the proportion of women with diabetes decreased from 6.1 (95% CI 4.2–8.1) in 1995–1997 to 3.3 (2.6–4.0) in 2004–2006. Among women who received an OGTT in 2006, 38% of the 204 women with either diabetes or pre-diabetes were identified only by the 2-h glucose measurements.CONCLUSIONS—Postpartum screening has increased over the last decade, but it is still suboptimal. Compared with FPGs alone, the 2-h values identify a higher proportion of women with diabetes or pre-diabetes amenable to intervention.Gestational diabetes mellitus (GDM) is defined as carbohydrate intolerance with onset of or first recognition during pregnancy. Postpartum diabetes screening may detect diabetes that preceded pregnancy and therefore enable early treatment of hyperglycemia, reducing the risk of adverse fetal outcomes in subsequent pregnancies (1) and maternal microvascular complications (2). Screening can also identify women who might benefit from diabetes prevention interventions (3,4).Performance rates of postpartum diabetes screening have been low (5–7), but screening performance may have changed recently. At present, only one population-based report has examined postpartum diabetes screening practices, and this report examined fasting plasma glucose (FPG) only (8). We used data from a GDM registry in a large prepaid group practice managed health care organization (the Kaiser Permanente Medical Care Program in Northern California [KPNC]) and examined 1) postpartum diabetes screening over time, 2) predictors of postpartum screening in a detailed electronic medical record, 3) trends in impaired fasting glucose (IFG) or diabetes detected with postpartum screening, and 4) the proportion of women with diabetes or pre-diabetes identified by the FPG screen versus the proportion of women with these abnormal glucose values identified by the 75-g oral glucose tolerance test (OGTT).     

Sociodemographic correlates of the increasing trend in prevalence of gestational diabetes mellitus in a large population of women between 1995 and 2005

OBJECTIVE—Gestational diabetes mellitus (GDM) is an increasingly prevalent risk factor for the development of type 2 diabetes in the mother and is responsible for morbidity in the child. To better identify women at risk of developing GDM we examined sociodemographic correlates and changes in the prevalence of GDM among all births between 1995 and 2005 in Australia''s largest state.RESEARCH DESIGN AND METHODS—A computerized database of all births (n = 956,738) between 1995 and 2005 in New South Wales, Australia, was used in a multivariate logistic regression that examined the association between sociodemographic characteristics and the occurrence of GDM.RESULTS—Between 1995 and 2005, the prevalence of GDM increased by 45%, from 3.0 to 4.4%. Women born in South Asia had the highest adjusted odds ratio (OR) of any region (4.33 [95% CI 4.12–4.55]) relative to women born in Australia. Women living in the three lowest socioeconomic quartiles had higher adjusted ORs for GDM relative to women in the highest quartile (1.54 [1.50–1.59], 1.74 [1.69–1.8], and 1.65 [1.60–1.70] for decreasing socioeconomic status quartiles). Increasing age was strongly associated with GDM, with women aged >40 years having an adjusted OR of 6.13 (95% CI 5.79–6.49) relative to women in their early 20s. Parity was associated with a small reduced risk. There was no association between smoking and GDM.CONCLUSIONS—Maternal age, socioeconomic position, and ethnicity are important correlates of GDM. Future culturally specific interventions should target prevention of GDM in these high-risk groups.Type 2 diabetes affects an estimated 246 million individuals worldwide—a figure that is predicted to increase to 380 million by 2025, with a disproportionate number of affected individuals living in lower- and middle-income countries of the Asia-Pacific region (1). Diabetes is a major cardiovascular risk factor, more than doubling the risk of having a stroke or heart attack. Moreover, diabetes appears to be particularly hazardous in women, as there is a 50% greater risk of dying from coronary heart disease compared with that of men with the same condition (2).Gestational diabetes mellitus (GDM), defined as glucose intolerance first detected during pregnancy, is a strong predictor of type 2 diabetes. Women with GDM are up to six times more likely to develop type 2 diabetes than women with normal glucose tolerance in pregnancy (3). The incidence of GDM varies among populations, similar to the variation of type 2 diabetes, with recent prevalence estimates ranging from 2.8% of pregnant women in Washington, DC, to 18.9% in India and 22% in Sardinia, Italy (4). The risk for GDM increases with age, and incidence rates vary by ethnicity within a population, again similar to the risk for type 2 diabetes (4,5). There is also evidence that obesity, parity, smoking, and family history are risk factors for GDM (5). However, less is known regarding the sociodemographic distribution of GDM. Given the strong link between GDM and the subsequent risk of diabetes for the mother and the perinatal morbidity for mother and child—an association recently updated with findings of a continuous association of maternal glucose levels and adverse perinatal outcomes by the Hyperglycemia and Adverse Pregnancy Outcomes Study Cooperative Research Group (6)—a better understanding of the sociodemographic determinants of GDM may provide novel opportunities to reduce the incidence and to prevent the onset of type 2 diabetes in later life.Most studies that have examined the etiology of GDM have been hospital based or have been based on samples of births in a particular region (4,5). There are currently no large, comprehensive population-wide urban and rural datasets that have been collected in an attempt to examine multiple risk factors for GDM over a number of years and no population-based studies outside the U.S. The New South Wales (NSW) Midwives Dataset has information on nearly 1 million births in the state of NSW during the period from 1995 to 2005 in a health system in which there is almost universal screening for GDM. This dataset was used to study the current and changing population rates of GDM and its associated sociodemographic risk factors in a large, ethnically diverse population of women.     

Low Prepregnancy Adiponectin Concentrations Are Associated With a Marked Increase in Risk for Development of Gestational Diabetes Mellitus

OBJECTIVE

To examine whether circulating total and high–molecular weight (HMW) adiponectin concentrations, measured before pregnancy, are associated with subsequent risk of gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

This was a nested case-control study among women who participated in the Kaiser Permanente Northern California Multiphasic Health Check-up exam (1984–1996) with a serum sample obtained and who had a subsequent pregnancy (1984–2009). Eligible women were free of recognized diabetes. Case subjects were the 256 women who developed GDM. Two control subjects were selected for each case and matched for year of blood draw, age at exam, age at pregnancy, and number of intervening pregnancies.

RESULTS

Compared with the highest quartile of adiponectin, the risk of GDM increased with decreasing quartile (odds ratio [OR] 1.5 [95% CI 0.7–2.9], 3.7 [1.9–7.2], and 5.2 [2.6–10.1]; P_trend <0.001) after adjustment for family history of diabetes, BMI, parity, race/ethnicity, cigarette smoking, and glucose and insulin concentrations. Similar estimates were observed for HMW (P_trend <0.001). The combined effects of having total adiponectin levels below the median (<10.29 mg/mL) and being overweight or obese (BMI ≥25.0 kg/m²) were associated with a sevenfold increased risk of GDM compared with normal-weight women with adiponectin levels above the median (OR 6.7 [95% CI 3.6–12.5]).

CONCLUSIONS

Prepregnancy low adiponectin concentrations, a marker of decreased insulin sensitivity and altered adipocyte endocrine function, is associated with reduced glucose tolerance during pregnancy and may identify women at high risk for GDM to target for early intervention.Gestational diabetes mellitus (GDM), defined as glucose intolerance with onset or first diagnosis during pregnancy, is a common complication of pregnancy. Women with a history of GDM have a sevenfold increased risk of developing type 2 diabetes after delivery (1), and the children of women with GDM are more likely to be obese and develop diabetes (2,3). The underlying etiology of GDM appears to be similar to the physiological abnormalities that characterize diabetes outside of pregnancy and is thought to be due to an inability of the pancreatic β-cells to compensate for the increased insulin resistance induced by pregnancy (4,5). The extent to which insulin resistance or reduced insulin sensitivity leading to GDM occurs even years before pregnancy has not been determined in population-based studies. There is increasing interest in identifying prepregnancy risk factors and biomarkers for GDM to inform future preconception prevention strategies, given the proven success of specific prevention strategies for type 2 diabetes in high-risk populations (6).Adiponectin is an abundant adipocyte-derived hormone demonstrated to have actions consistent with protection against insulin resistance, inflammation, and atherosclerosis (7). Total adiponectin circulates in the bloodstream as three discrete complexes: a lower–molecular weight trimer, a mid–molecular weight hexamer, and a high–molecular weight (HMW) complex (8). Some evidence suggests that HMW adiponectin is the isoform that mediates the insulin-sensitizing and antiatherogenic effects (9,10). Prospective studies examining adiponectin and incident type 2 diabetes reported that lower circulating total adiponectin concentrations were associated with a higher risk of type 2 diabetes in a dose-response relationship (11). Both total adiponectin (12) and HMW adiponectin (13) are known to decrease significantly in normal pregnancies in response to decreased insulin sensitivity; therefore, it is important to determine whether prepregnancy levels of adiponectin are related to subsequent risk of GDM in order to clarify the temporal sequence of the association. The aim of this study is to examine the association between prepregnancy total and HMW adiponectin concentrations and the risk of developing GDM and to determine whether these associations are independent of known metabolic risk factors for GDM.     

Diabetes Trends Among Delivery Hospitalizations in the U.S., 1994�C2004

OBJECTIVE

To examine trends in the prevalence of diabetes among delivery hospitalizations in the U.S. and to describe the characteristics of these hospitalizations.

RESEARCH DESIGN AND METHODS

Hospital discharge data from 1994 through 2004 were obtained from the Nationwide Inpatient Sample. Diagnosis codes were selected for gestational diabetes mellitus (GDM), type 1 diabetes, type 2 diabetes, and unspecified diabetes. Rates of delivery hospitalization with diabetes were calculated per 100 deliveries.

RESULTS

Overall, an estimated 1,863,746 hospital delivery discharges contained a diabetes diagnosis, corresponding to a rate of 4.3 per 100 deliveries over the 11-year period. GDM accounted for the largest proportion of delivery hospitalizations with diabetes (84.7%), followed by type 1 (7%), type 2 (4.7%), and unspecified diabetes (3.6%). From 1994 to 2004, the rates for all diabetes, GDM, type 1 diabetes, and type 2 diabetes significantly increased overall and within each age-group (15–24, 25–34, and ≥35 years) (P < 0.05). The largest percent increase for all ages was among type 2 diabetes (367%). By age-group, the greatest percent increases for each diabetes type were among the two younger groups. Significant predictors of diabetes at delivery included age ≥35 years vs. 15–24 years (odds ratio 4.80 [95% CI 4.72–4.89]), urban versus rural location (1.14 [1.11–1.17]), and Medicaid/Medicare versus other payment sources (1.29 [1.26–1.32]).

CONCLUSIONS

Given the increasing prevalence of diabetes among delivery hospitalizations, particularly among younger women, it will be important to monitor trends in the pregnant population and target strategies to minimize risk for maternal/fetal complications.Diabetes is the most frequent metabolic complication of pregnancy and is associated with an increased risk of maternal and neonatal morbidity (1,2). Most diabetes in pregnancy is gestational diabetes mellitus (GDM). Depending on the population, GDM affects up to 14% of pregnancies, although most commonly reported figures range from 2 to 5% (3,4). With the rapid rise of type 2 diabetes among women in general, it is expected that this condition will also affect pregnant women at an increasing rate.A number of studies have reported increasing trends for pregestational diabetes, GDM, or both (5–7). The majority of these results, however, generally describe diabetes patterns at more localized levels in the U.S. Studies that have assessed diabetes trends in pregnancy at the national level have done so with a specific focus only on GDM, reporting marked increases in prevalence over the past 2 decades (8,9).As a comparison to these previously reported numbers and for a more comprehensive assessment of diabetes in pregnancy in the U.S., the purpose of this analysis was to examine trends and characteristics of delivery hospitalizations with a recorded diabetes diagnosis of GDM, type 1 diabetes, and type 2 diabetes between 1994 and 2004 using the Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS), a nationally representative sample of inpatient care. Given the rising background rates of type 2 diabetes, together with increases in risk factors for diabetes, which may be contributing to the trends in the general population, we expected that trends among pregnant women, particularly for GDM and type 2 diabetes, would also steadily increase, reflecting the patterns reported in localized studies.     

Serum uric acid levels and incident chronic kidney disease in patients with type 2 diabetes and preserved kidney function

OBJECTIVE

Recent studies have suggested an association between hyperuricemia and adverse renal outcomes in nondiabetic populations. Data on the relationship between hyperuricemia and the risk of incident chronic kidney disease (CKD) in type 2 diabetic patients with normal or near-normal kidney function are lacking. We determined whether baseline serum uric acid levels predict the subsequent development of CKD in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We followed 1,449 type 2 diabetic patients with normal kidney function and without overt proteinuria for 5 years for the occurrence of incident CKD (defined as overt proteinuria or estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m²).

RESULTS

During a 5-year follow-up period, 194 (13.4%) patients developed incident CKD. The cumulative incidence of CKD was significantly greater in patients with hyperuricemia than in those without hyperuricemia (29.5 vs. 11.4%, P < 0.001). In univariate logistic regression analysis, the presence of hyperuricemia roughly doubled the risk of developing CKD (odds ratio [OR] 2.55 [95% CI 1.71–3.85], P < 0.001). After adjusting for age, sex, BMI, smoking status, diabetes duration, systolic blood pressure, antihypertensive treatment, insulin therapy, HbA_1c, eGFR, and albuminuria, hyperuricemia was associated with an increased risk of incident CKD (adjusted OR 2.10 [1.16–3.76], P < 0.01). In continuous analyses, a 1-SD increment in the serum uric acid level was significantly associated with a 21% increased risk of CKD.

CONCLUSIONS

In type 2 diabetic individuals with preserved kidney function, hyperuricemia seems to be an independent risk factor for the development of incident CKD.The tide of type 2 diabetes is rising in the U.S. and all over the world, thereby becoming an increasingly powerful threat to global health (1). Type 2 diabetes also has become the leading cause of end-stage renal disease in the world, and the number of patients diagnosed each year with end-stage renal disease attributed to type 2 diabetes is rising (2).The pathophysiology of diabetic nephropathy is complex and still not fully elucidated (3). Several prospective studies have suggested that hyperuricemia is associated with an increased risk of incident cardiovascular events and death in both nondiabetic and type 2 diabetic individuals (4–9). Hyperuricemia also is largely prevalent in patients with chronic kidney disease (CKD) (10,11). However, hyperuricemia might have a pathogenic role in the development and progression of CKD, rather than solely reflecting decreased renal uric acid excretion. Indeed, several (12–17), but not all (18–20), prospective studies recently have shown a significant association between hyperuricemia and adverse renal outcomes in both the general population and other nondiabetic high-risk patient populations. However, epidemiologic data are limited about the relationship between hyperuricemia and adverse renal outcomes in patients with type 1 (21,22) or type 2 (23) diabetes.In a post hoc analysis of 1,342 patients with type 2 diabetes and nephropathy participating in the Reduction of End Points in Non–Insulin-Dependent Diabetes Mellitus With the Angiotensin II Antagonist Losartan (RENAAL) Trial, the investigators reported that the risk of adverse renal outcomes was decreased by 6% per 0.5 mg/dL decrement in serum uric acid levels during the first 6 months of treatment with losartan (23). These findings support the view that serum uric acid may be a modifiable risk factor for renal disease in type 2 diabetic patients (23).To our knowledge, however, no large prospective studies are available on the relationship between hyperuricemia and incident CKD in patients with type 2 diabetes and normal or near-normal kidney function. Thus, the purpose of this prospective, observational study was to determine whether baseline serum uric acid levels are associated with an increased incidence of CKD in a large cohort of type 2 diabetic patients with preserved kidney function at baseline and without a previous history of cardiovascular disease.     

Racial/ethnic disparities in the prevalence of gestational diabetes mellitus by BMI

OBJECTIVE

To examine whether the association between gestational diabetes mellitus (GDM) and BMI category varies by racial/ethnic group.

RESEARCH DESIGN AND METHODS

In a cohort of 123,040 women without recognized pregravid diabetes who delivered babies between 1995 and 2006 at Kaiser Permanente of Northern California, we examined racial/ethnic disparities in the prevalence of GDM by BMI category and the population-attributable risk (PAR) associated with overweight/obesity.

RESULTS

Among all racial/ethnic groups, the age-adjusted prevalence of GDM increased with increasing BMI (kg/m²) category. However, Asian and Filipina women had a prevalence of GDM of 9.9 and 8.5%, respectively, at a BMI of 22.0–24.9 kg/m², whereas in Hispanic, non-Hispanic white, and African American women, the prevalence of GDM was >8.0% at a higher BMI, such as 28–30, 34–36, and ≥37 kg/m², respectively. The estimated PARs suggest that the percentage of GDM that could be prevented if all pregnant women were of normal weight (BMI <25.0 kg/m²) ranging from 65% for African American women to only 23% among Asian women.

CONCLUSIONS

Clinicians should be aware that the BMI thresholds for increased risk of GDM varies by racial/ethnic group and that the risk is high even at relatively low BMI cutoffs in Asian and Filipina women. Asian women may benefit from different prevention strategies in addition to weight management.Gestational diabetes mellitus (GDM) is carbohydrate intolerance with onset of or first recognition during pregnancy and is one of the most common pregnancy complications in the U.S. GDM is associated with increased risk for perinatal morbidity (1,2), and, in the long-term, women with GDM have an almost sevenfold increased risk of developing type 2 diabetes after pregnancy (3). The prevalence of GDM has increased in all racial/ethnic groups, and this has been observed in several populations in recent decades (4,5). Recent data suggest that the association between glucose and risk of adverse outcomes is continuous; gestational impaired glucose tolerance (IGT) is also associated with both pregnancy complications (6) and subsequent diabetes and cardiometabolic risk (7).Race/ethnicity and obesity are the two strongest independent risk factors for GDM (8–11). However, the demographic distribution of obesity (highest among African Americans and lowest among Asians) does not mirror the demographic distribution of GDM (lowest among African Americans and highest among Asians) (12). Yet there is ongoing debate surrounding the definition of overweight and obesity in Asian populations: the World Health Organization proposed a BMI cutoff of 23.0 kg/m² for overweight among Asians in 2000 (13), compared with a cutoff of 25.0 kg/m² for non-Asian populations. More recently, the World Health Organization stated that the definition of overweight in Asians likely varies depending on the outcome of interest (14). Currently, little is known about racial disparities in the risk of GDM by BMI categories.In a cohort of 123,040 women without recognized pregravid diabetes who delivered babies between 1995 and 2006 at Kaiser Permanente of Northern California (KPNC), we examined racial/ethnic disparities in the prevalence of GDM and IGT in pregnancy by BMI category and the estimated proportion of cases that could be prevented if overweight/obesity in pregnant women were eliminated (the population-attributable risk [PAR]).