Cut-off values of body mass index, waist circumference, and waist-to-height ratio to identify excess abdominal fat: population-based screening of Japanese school children

Background

School-based screening and prevention programs for adiposity generally target school children in grades 4 and 6 (age 9–11 years). The aims of this study were to evaluate the validity of body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) in identifying abdominal adiposity in fifth-grade Japanese school children and to determine optimal cut-off values for anthropometric measures.

Methods

The target population was fifth-grade school children enrolled in 2 schools in Shizuoka, Japan between 2008 and 2010; 422 of the 466 children participated in the present study. Abdominal adiposity was defined as percent trunk fat in the 95th percentile or higher, as determined by dual-energy x-ray absorptiometry (DXA). We analyzed the validity of BMI, WC, and WHtR using receiver operating characteristic (ROC) curve analysis. The Youden index was used to determine cut-off values of BMI, WC, and WHtR that identify excess abdominal fat.

Results

Optimal cut-off values to identify abdominal adiposity were 20.8 kg/m² (BMI), 76.5 cm (WC), and 0.519 (WHtR) for boys, and 19.6 kg/m² (BMI), 73.0 cm (WC), and 0.499 (WHtR) for girls. Areas under the ROC curve were 0.983 (BMI), 0.987 (WC), and 0.981 (WHtR) for boys, and 0.981 (BMI), 0986 (WC), and 0.992 (WHtR) for girls.

Conclusions

BMI, WC, and WHtR successfully identified a high proportion of children with excess abdominal fat as measured by DXA, demonstrating that these measures are useful indices for school screening.Key words: child, screening, obesity, statistics as topic, reference values     

Presence of an interaction between smoking and being overweight increases risks of hypertension, diabetes, and cardiovascular disease in outpatients with mood disorders

Objective

We aimed to evaluate the hypothesis that the presence of an interaction between smoking and being overweight increases the risks of lifestyle-related diseases (hypertension, diabetes mellitus, dyslipidemia, and cardiovascular disease) in outpatients with mood disorders.

Methods

In this cross-sectional survey, using data from 213 outpatients with mood disorders (95 men, 118 women), we calculated the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for each of hypertension, diabetes, dyslipedemia, and cardiovascular disease, using a binary logistic regression model; we then calculated the adjusted OR values for smokers and non-smokers with body mass indexes (BMIs) of <25 or ≥25 kg/m². Next, we examined the data for the presence of an interaction between smoking and being overweight, using three measures of additive interaction: relative excess risk due to the interaction (RERI), attributable proportion due to the interaction (AP), and the synergy index (S).

Results

Smokers with BMI <25 kg/m² had a significantly lower risk of hypertension (OR 0.27, 95% CI 0.09–0.81) than non-smokers with BMI <25 kg/m² (reference group). Compared with the reference group, overweight non-smokers had a significantly higher risk (2.82, 1.34–6.19) of hypertension, and overweight smokers had a higher risk (4.43, 1.28–15.26) of hypertension and very high risks of diabetes (8.24, 2.47–27.42) and cardiovascular disease (13.12, 1.95–88.41). The highest RERI was derived from the relation with cardiovascular disease. The highest AP and S were derived from the relation with type 2 diabetes. There was no interaction of smoking and being overweight with dyslipidemia.

Conclusion

The presence of an interaction between smoking and being overweight exacerbates the risks of hypertension, diabetes, and cardiovascular disease in outpatients with mood disorders.     

Prevalence of Dyslipidemia and Hypertension in Indian Type 2 Diabetic Patients with Metabolic Syndrome and its Clinical Significance

Objectives

The present study was designed to estimate the prevalence of dyslipidemia and hypertension based on the National Cholesterol Educational Programme Adult Treatment Panel III definition of metabolic syndrome (MetS). The study also focuses on prevalence for MetS with respect to the duration of disease in Gwalior–Chambal region of Madhya Pradesh, India.

Methods

Type 2 diabetic patients (n = 700) were selected from a cross-sectional study that is regularly being conducted in the School of Studies in Biochemistry, Jiwaji University Gwalior, India. The period of our study was from January 2007 to October 2009. Dyslipidemia and hypertension were determined in type 2 diabetic patients with MetS as per National Cholesterol Educational Programme Adult Treatment Panel III criteria.

Results

The mean age of the study population was 54 ± 9.3 years with 504 (72%) males and 196 (28%) females. The prevalence of MetS increased with increased duration of diabetes in females; however, almost constant prevalence was seen in the males. Notable increase in the dyslipidemia (64.1%) and hypertension (49%) in type 2 diabetic patients were seen. The steep increase in dyslipidemia and hypertension could be the reason for the growing prevalence of diabetes worldwide. The study also noted a close association between age and occurrence of MetS.

Conclusion

Individual variable of MetS appears to be highly rampant in diabetic population. Despite treatment, almost half of patients still met the criteria for MetS. Effective treatment of MetS components is required to reduce cardiovascular risk in diabetes mellitus hence accurate and early diagnosis to induce effective treatment of MetS in Indian population will be pivotal in the prevention of cardiovascular disease and type 2 diabetes.     

Optimal Obesity- and Lipid-Related Indices for Predicting Metabolic Syndrome in Chronic Kidney Disease Patients with and without Type 2 Diabetes Mellitus in China

Existing obesity- and lipid-related indices are inconsistent with metabolic syndrome (MetS) in chronic kidney disease (CKD) patients. We compared seven indicators, including waist circumference (WC), body mass index (BMI), visceral fat area (VFA), subcutaneous fat area (SFA), visceral adiposity index (VAI), Chinese VAI and lipid accumulation product (LAP), to evaluate their ability to predict MetS in CKD patients with and without Type 2 diabetes mellitus (T2DM) under various criteria. Multivariate logistic regression analysis was used to investigate the independent associations between the indices and metabolic syndrome among 547 non-dialysis CKD patients, aged ≥18 years. The predictive power of these indices was assessed using receiver operating characteristic (ROC) curve analysis. After adjusting for potential confounders, the correlation between VAI and MetS was strongest based on the optimal cut-off value of 1.51 (sensitivity 86.84%, specificity 91.18%) and 2.35 (sensitivity 83.54%, specificity 86.08%), with OR values of 40.585 (8.683–189.695) and 5.076 (1.247–20.657) for males and females with CKD and T2DM. In CKD patients without T2DM, based on the optimal cut-off values of 1.806 (sensitivity 98.11%, specificity 72.73%) and 3.11 (sensitivity 84.62%, specificity 83.82%), the OR values were 7.514 (3.757–15.027) and 3.008 (1.789–5.056) for males and females, respectively. The area under ROC curve (AUC) and Youden index of VAI were the highest among the seven indexes, indicating its superiority in predicting MetS in both male and female CKD patients, especially those with T2DM.     

Relationship Between Decayed Teeth and Metabolic Syndrome: Data From 4716 Middle-Aged Male Japanese Employees

Background

Epidemiological findings regarding the relationship between decayed teeth (DT) and metabolic syndrome (MetS) are scarce. We evaluated the relationship of DT with MetS, obesity, and MetS components in early middle-aged male Japanese employees.

Methods

We cross-sectionally analyzed dental and medical health checkup results from a total of 4716 participants aged 42 or 46 years. Logistic regression models were employed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) after adjustment for age, breakfast consumption frequency, drinking habits, smoking status, and physical activity.

Results

Significant differences in the prevalence of MetS, obesity determined by body mass index, and the components of MetS between participating men with and without DT were detected (all P < 0.01). The adjusted OR of MetS was 1.41 (95% CI, 1.14–1.74) for those with 1 or 2 DT, and 1.66 (95% CI, 1.28–2.16) for those with ≥3 DT (P for trend = 0.01), and this significant relationship was observed even in those without periodontal pocket formation (P for trend = 0.03) or missing teeth (P for trend = 0.02). DT was significantly related to overweight/obesity and the MetS components of hypertension, dyslipidemia, and hyperglycemia, with adjusted ORs of 1.35 (95% CI, 1.19–1.53), 1.22 (95% CI, 1.07–1.39), 1.18 (95% CI, 1.03–1.34), and 1.33 (95% CI, 1.13–1.56), respectively. In addition, even in non-overweight/non-obese men, DT was found to be related to dyslipidemia and hyperglycemia, though with marginal significance (P < 0.05).

Conclusions

Our findings suggest that having DT is related to MetS in early middle-aged Japanese men directly and through obesity and is independent of health behaviors, periodontal condition, and tooth loss.Key words: dental caries, dyslipidemia, hyperglycemia, hypertension, obesity     

Weight gain during adulthood and body weight at age 20 are associated with the risk of endometrial cancer in Japanese women

Background

Current obesity is an established risk factor for endometrial cancer; however, the roles of weight gain during adulthood and obesity in early adulthood on endometrial cancer have not been elucidated. Here, we conducted a case-control study comprising 222 histologically diagnosed incident endometrial cancer cases and 2162 age- and menstrual-status matched non-cancer controls.

Methods

Information on current body weight, weight and height at age 20 years, and lifestyle/environmental factors was obtained from a self-administered questionnaire. Subjects were classified into 3 groups according to change in body mass index (BMI, kg/m²) from age 20 years to enrollment (≤0 [reference], 0–3, and >3 kg/m²). The effects of adult BMI change and obesity in early adulthood were evaluated using an unconditional logistic regression model adjusted for potential confounders.

Results

A high BMI at age 20 (BMI ≥25, BMI <25 as reference) was significantly positively associated with endometrial cancer risk (P = 0.005), as was a BMI increase during adulthood (0–3 BMI change, multivariate odds ratio [OR] = 1.28, 95% confidence interval [CI] = 0.88–1.87; >3 BMI change, OR = 2.02, 95% CI = 1.38–2.96; P-trend < 0.001). Parity and BMI at age 20 appeared to modify the effect of weight gain on cancer risk, albeit without statistical significance. This positive association of weight gain with risk was observed only for endometrioid adenocarcinoma.

Conclusions

The results show that endometrial cancer is positively associated with obesity at age 20 and weight gain during adulthood among Japanese women.Key words: endometrial cancer, weight gain, case-control study     

The Associations of Month of Birth With Body Mass Index,Waist Circumference,and Leg Length: Findings From the China Kadoorie Biobank of 0.5 Million Adults

Background

Season of birth (SoB) has been linked with various health outcomes. This study aimed to examine the associations between month of birth (MoB) and adult measures of leg length (LL), body mass index (BMI), and waist circumference (WC).

Methods

We analysed survey data from 10 geographically diverse areas of China obtained through the China Kadoorie Biobank. Analysis included 487 529 adults with BMI ≥ 18.5 kg/m². A general linear model was used to examine the associations between MoB and adult measures of LL, BMI, and WC, adjusted for survey site, sex, age, education level, smoking habit, alcohol consumption, physical activity level, sedentary leisure time, height (only for WC and LL), and hip circumference (only for LL).

Results

MoB was independently associated with both BMI and WC. Birth months in which participants had higher measures of adiposity were March–July for BMI and March–June for WC. The peak differences were 0.14 kg/m² for BMI and 0.47 cm for WC. The association between MoB and LL depended on survey site. Participants who were born in February–August in four sites (Harbin, Henan, Gansu, and Hunan) had the shortest LL (all P < 0.01). The peak difference in mean LL was 0.21 cm. No statistically significant association between MoB and LL was noted in the other sites (Qingdao, Suzhou, Sichuan, Zhejiang, Liuzhou, and Haikou).

Conclusions

These findings suggest that MoB is associated with variations in adult adiposity measures and LL among Chinese adults. Low exposure to ultraviolet B radiation and subsequent reduced levels of vitamin D during the late second and early third trimesters may be involved in these phenomena.Key words: month of birth, BMI, waist circumference, leg length, vitamin D deficiency     

Intraocular pressure and its determinants in subjects with type 2 diabetes mellitus in India

Objectives

This study was conducted to show the intraocular pressure (IOP) distribution and the factors affecting IOP in subjects with type 2 diabetes mellitus (DM) in India.

Methods

We measured the anthropometric and biochemical parameters for confirmed type 2 DM patients. A comprehensive ocular examination was performed for 1377 subjects aged > 40 years and residing in Chennai.

Results

A significant difference in IOP (mean ± standard deviation) was found between men and women (14.6±2.9 and 15.0±2.8 mmHg, p = 0.005). A significantly elevated IOP was observed among smokers, subjects with systemic hypertension and women with clinically significant macular edema (CSME). After a univariate analysis, factors associated significantly with higher IOP were elevated systolic blood pressure, elevated resting pulse rate and thicker central corneal thickness (CCT). In women, elevated glycosylated hemoglobin was associated with a higher IOP. After adjusting for all variables, the elevated resting pulse rate and CCT were found to be associated with a higher IOP.

Conclusions

Systemic hypertension, smoking, pulse rate and CCT were associated with elevated intraocular pressure in type 2 DM. Women with type 2 DM, especially those with CSME, were more prone to have an elevated IOP.     

Breakfast Skipping is Positively Associated With Incidence of Type 2 Diabetes Mellitus: Evidence From the Aichi Workers’ Cohort Study

Background

Skipping breakfast has been suspected as a risk factor for type 2 diabetes (T2DM), but the associations are not entirely consistent across ethnicities or sexes, and the issue has not been adequately addressed in the Japanese population.

Methods

We followed 4631 participants (3600 men and 1031 women) in a work-site cohort of participants aged 35–66 years in 2002 through 2011 for T2DM development. Frequency of eating breakfast was self-reported and was subsequently dichotomized to breakfast skippers, who eat breakfast 3–5 times/week or less, and to eaters. Cox proportional hazards models were used to adjust for potential confounding factors, including dietary factors, smoking and other lifestyles, body mass index (BMI), and fasting blood glucose (FBG) at baseline.

Results

During 8.9 years of follow-up, 285 T2DM cases (231 men and 54 women) developed. Compared to participants who reported eating breakfast every day, maximally-adjusted hazard ratios and 95% confidence intervals (CI) of those with the frequency of almost every day and 3–5, 1–2, and 0 days/week were: 1.06 (95% CI, 0.73–1.53), 2.07 (95% CI, 1.20–3.56), 1.37 (95% CI, 0.82–2.29), and 2.12 (95% CI, 1.19–3.76), respectively. In a dichotomized analysis, breakfast skipping was positively associated with T2DM incidence (maximally-adjusted hazard ratio 1.73; 95% CI, 1.24–2.42). The positive associations were found in both men and women, current and non-current smokers, normal weight and overweight (BMI ≥25 kg/m²), and normal glycemic status and impaired fasting glycemic status (FBG 110 to <126 mg/dL) individuals at baseline (Ps for interaction all >0.05).

Conclusions

The present study in middle-aged Japanese men and women suggests that skipping breakfast may increase the risk of T2DM independent of lifestyles and baseline levels of BMI and FBG.Key words: breakfast, diabetes mellitus, cohort study, Japan     

Polychlorinated biphenyls, lead, and mercury are associated with liver disease in American adults: NHANES 2003-2004

Background

High-level occupational exposures to some industrial chemicals have been associated with liver diseases, including nonalcoholic fatty liver disease (NAFLD). However, the potential role of low-level environmental pollution on liver disease in the general population has not been evaluated.

Objective

We determined whether environmental pollutants are associated with an elevation in serum alanine aminotransferase (ALT) activity and suspected NAFLD in U.S. adults.

Methods

This cross-sectional cohort study evaluated adult participants without viral hepatitis, hemochromatosis, or alcoholic liver disease from the National Health and Nutrition Examination Survey (NHANES) for 2003–2004. ALT elevation was defined in men as ≥ 37 IU/L (age18–20 years) and ≥ 48 IU/L (age ≥ 21 years) and in women as ≥ 30 IU/L (age 18–20 years) and ≥ 31 IU/L (age ≥ 21 years). Adjusted odds ratios (ORs) for ALT elevation were determined across exposure quartiles for 17 pollutant subclasses comprising 111 individual pollutants present with at least a 60% detection rate. Adjustments were made for age, race/ethnicity, sex, body mass index, poverty income ratio, and insulin resistance. Individual pollutants from subclasses associated with ALT elevation were subsequently analyzed.

Results

The overall prevalence of ALT elevation was 10.6%. Heavy metals and polychlorinated biphenyls (PCBs) were associated with dose-dependent increased adjusted ORs for ALT elevation. Within these subclasses, increasing whole-blood levels of lead and mercury and increasing lipid-adjusted serum levels of 20 PCBs were individually associated with ALT elevation.

Conclusions

PCB, lead, and mercury exposures were associated with unexplained ALT elevation, a proxy marker of NAFLD, in NHANES 2003–2004 adult participants.     

Average Volume of Alcohol Consumed,Drinking Patterns,and Metabolic Syndrome in Older Korean Adults

Background

Controversial results have been reported on the relationship between alcohol intake and metabolic syndrome (MetS). We examined the association of average volume of alcohol consumed and drinking patterns with MetS and its components.

Methods

This study was conducted as a baseline survey for the Dong-gu Study of adults aged 50 years or older. Drinking patterns were assessed using a structured interview, and average volume of alcohol consumed was calculated. MetS was defined according to the updated version of the National Cholesterol Education Program.

Results

Compared with individuals who never drank, the adjusted odds ratio (OR) for the prevalence of MetS was significantly higher in men who consumed 2.1 to 4.0 drinks/day (OR, 1.53; 95% CI, 1.17–2.00) and greater than 4.0 drinks/day (OR, 1.63; 95% CI, 1.23–2.14), whereas no significant association was observed in women. Significant dose-response relationships between average volume of alcohol consumed and all metabolic components were observed in men. A usual quantity of 5 to 6 drinks/drinking day (OR, 1.57; 95% CI, 1.19–2.09), 7 or more drinks/drinking day (OR, 1.88; 95% CI, 1.45–2.44), and binge drinking on at least 1 occasion/week (OR, 1.33; 95% CI, 1.01–1.76) were associated with a significantly higher OR for prevalence of MetS in men; however, none of these drinking patterns were associated with MetS in women.

Conclusions

Unhealthy drinking patterns such as high usual quantity and binge drinking were significantly associated with MetS, suggesting that the effect of alcohol consumption on MetS should be considered in the context of drinking pattern, particularly in men.Key words: metabolic syndrome, alcohol consumption, cross-sectional study     

Risk Factors for Cardiovascular Diseases among Diabetic Patients In Southwest Ethiopia

Background

Studies on cardiovascular risk factors among diabetic persons in Ethiopia are lacking. The objective of this study was to determine the prevalence of the cardiovascular risk factors (hypertension, obesity, physical inactivity, dyslipidemia and smoking) among diabetic patients at the diabetic clinic of Jimma University Specialized Hospital.

Methods

A cross-sectional study was conducted from October to December 2007. Three hundred one individuals were randomly selected from 950 patients on follow-up. Data were collected using a structured format and appropriate equipments and reagents. Laboratory data were recorded in a separate checklist. The data were entered into SPSS for Windows version 12. Multivariate regression analysis was carried out to identify predictors of hypertension, obesity and dyslipidemia.

Results

Two hundred and fifty six (85.1%) of the sample participated in the study. The prevalence of hypertension, obesity, dyslipidemia, physical inactivity and current smoking was 46.5%, 23.4%, 63.5%, 55.1% and 5.5% respectively. Age ≥ 45 years, type 2 diabetes and obesity were predictors of hypertension. Females were less likely to be hypertensive (OR =2.26, 3.37, 3.79 and 0.48 respectively). Type 2 diabetics and females were more while rural diabetics were less likely to be obese. (OR =6.08, 4.17 and 0.37 respectively). Female gender, hypertension and fasting blood glucose ≥ 180mg/dl were predictors of dyslipidemia. Alcohol users were less likely to be dyslipidemic. (OR =4.25, 3.5, 3.56 and 0.39, respectively)

Conclusion

Hypertension, obesity, dyslipidemia and physical inactivity were common while smoking was uncommon among diabetic patients in Jimma University Specialized Hospital. Type 2 DM was a predictor of hypertension and obesity. Diabetic women were more likely to be obese and dyslipidemic. We recommend screening and management of these risk factors.     

Postmenopausal breast cancer is associated with exposure to traffic-related air pollution in Montreal, Canada: a case-control study

Background

Only about 30% of cases of breast cancer can be explained by accepted risk factors. Occupational studies have shown associations between the incidence of breast cancer and exposure to contaminants that are found in ambient air.

Objectives

We sought to determine whether the incidence of postmenopausal breast cancer is associated with exposure to urban air pollution.

Methods

We used data from a case–control study conducted in Montreal, Quebec, in 1996–1997. Cases were 383 women with incident invasive breast cancer, and controls were 416 women with other incident, malignant cancers, excluding those potentially associated with selected occupational exposures. Concentrations of nitrogen dioxide (NO₂) were measured across Montreal in 2005–2006. We developed a land-use regression model to predict concentrations of NO₂ across Montreal for 2006, and developed two methods to extrapolate the estimates to 1985 and 1996. We linked these estimates to addresses of residences of subjects at time of interview. We used unconditional logistic regression to adjust for accepted and suspected risk factors and occupational exposures.

Results

For each increase of 5 ppb NO₂ estimated in 1996, the adjusted odds ratio was 1.31 (95% confidence interval, 1.00–1.71). Although the size of effect varied somewhat across periods, we found an increased risk of approximately 25% for every increase of 5 ppb in exposure.

Conclusions

We found evidence of an association between the incidence of postmenopausal breast cancer and exposure to ambient concentrations of NO₂. Further studies are needed to confirm whether NO₂ or other components of traffic-related pollution are indeed associated with increased risks.     

Low cholesterol is associated with mortality from stroke, heart disease, and cancer: the Jichi Medical School Cohort Study

Background

We investigated the relationship between low cholesterol and mortality and examined whether that relationship differs with respect to cause of death.

Methods

A community-based prospective cohort study was conducted in 12 rural areas in Japan. The study subjects were 12 334 healthy adults aged 40 to 69 years who underwent a mass screening examination. Serum total cholesterol was measured by an enzymatic method. The outcome was total mortality, by sex and cause of death. Information regarding cause of death was obtained from death certificates, and the average follow-up period was 11.9 years.

Results

As compared with a moderate cholesterol level (4.14–5.17 mmol/L), the age-adjusted hazard ratio (HR) of low cholesterol (<4.14 mmol/L) for mortality was 1.49 (95% confidence interval [CI]: 1.23–1.79) in men and 1.50 (1.10–2.04) in women. High cholesterol (≥6.21 mmol/L) was not a risk factor. This association was unchanged in analyses that excluded deaths due to liver disease, which yielded age-adjusted HRs of 1.38 (95% CI, 1.13–1.67) in men and 1.49 (1.09–2.04) in women. The multivariate-adjusted HRs and 95% CIs of the lowest cholesterol group for hemorrhagic stroke, heart failure (excluding myocardial infarction), and cancer mortality significantly higher than those of the moderate cholesterol group, for each cause of death.

Conclusions

Low cholesterol was related to high mortality even after excluding deaths due to liver disease from the analysis. High cholesterol was not a risk factor for mortality.Key words: low cholesterol, mortality, liver disease, stroke, heart disease, cohort study     

Prenatal organochlorine compound exposure, rapid weight gain, and overweight in infancy

Background

Although it has been hypothesized that fetal exposure to endocrine-disrupting chemicals may increase obesity risk, empirical data are limited, and it is uncertain how early in life any effects may begin.

Objectives

We explored whether prenatal exposure to several organochlorine compounds (OCs) is associated with rapid growth in the first 6 months of life and body mass index (BMI) later in infancy.

Methods

Data come from the INMA (Infancia y Medio-Ambiente) Child and Environment birth cohort in Spain, which recruited 657 women in early pregnancy. Rapid growth during the first 6 months was defined as a change in weight-for-age z-scores > 0.67, and elevated BMI at 14 months, as a z-score ≥ the 85th percentile. Generalized linear models were used to estimate the risk of rapid growth or elevated BMI associated with 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE), hexachlorobenzene, β-hexachlorohexane, and polychlorinated biphenyls in first-trimester maternal serum.

Results

After multivariable adjustment including other OCs, DDE exposure above the first quartile was associated with doubling of the risk of rapid growth among children of normal-weight (BMI < 25 kg/m²), but not overweight, mothers. DDE was also associated with elevated BMI at 14 months (relative risk per unit increase in log DDE = 1.50; 95% confidence interval, 1.11–2.03). Other OCs were not associated with rapid growth or elevated BMI after adjustment.

Conclusions

In this study we found prenatal DDE exposure to be associated with rapid weight gain in the first 6 months and elevated BMI later in infancy, among infants of normal-weight mothers. More research exploring the potential role of chemical exposures in early-onset obesity is needed.     

Particulate Air Pollution,Metabolic Syndrome,and Heart Rate Variability: The Multi-Ethnic Study of Atherosclerosis (MESA)

Background

Cardiac autonomic dysfunction has been suggested as a possible biologic pathway for the association between fine particulate matter ≤ 2.5 μm in diameter (PM_2.5) and cardiovascular disease (CVD). We examined the associations of PM_2.5 with heart rate variability, a marker of autonomic function, and whether metabolic syndrome (MetS) modified these associations.

Methods

We used data from the Multi-Ethnic Study of Atherosclerosis to measure the standard deviation of normal-to-normal intervals (SDNN) and the root mean square of successive differences (rMSSD) of 5,465 participants 45–84 years old who were free of CVD at the baseline examination (2000–2002). Data from the U.S. regulatory monitor network were used to estimate ambient PM_2.5 concentrations at the participants’ residences. MetS was defined as having three or more of the following criteria: abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol, high blood pressure, and high fasting glucose.

Results

After controlling for confounders, we found that an interquartile range (IQR) increase in 2-day average PM_2.5 (10.2 μg/m³) was associated with a 2.1% decrease in rMSSD [95% confidence interval (CI), −4.2 to 0.0] and nonsignificantly associated with a 1.8% decrease in SDNN (95% CI, −3.7 to 0.1). Associations were stronger among individuals with MetS than among those without MetS: an IQR elevation in 2-day PM_2.5 was associated with a 6.2% decrease in rMSSD (95% CI, −9.4 to −2.9) among participants with MetS, whereas almost no change was found among participants without MetS (p-interaction = 0.005). Similar effect modification was observed in SDNN (p-interaction = 0.011).

Conclusion

These findings suggest that autonomic dysfunction may be a mechanism through which PM exposure affects cardiovascular risk, especially among persons with MetS.     

Maternal body mass index and gestational weight gain and their association with perinatal outcomes in Viet Nam

Objective

To examine the association between gestational weight gain and maternal body mass index (BMI) among Vietnamese women and the risk of delivering an infant too small or too large for gestational age.

Methods

A prospective health-facility-based study of 2989 pregnant Vietnamese women was conducted in the city of Nha Trang in 2007–2008. Cubic logistic regression was used to investigate the association of interest. Infants were classified into weight-for-gestational-age categories according to weight centiles for the Asian population. Gestational age was based on the date of last menstrual period and adjusted by the results of first-trimester ultrasound.

Findings

BMI was low (< 18.5), normal (18.5–22.9) and high (≥ 23.0) in 26.1%, 65.4% and 8.5% of the women, respectively. In each of these BMI categories, the percentage of women who delivered infants too small for gestational age was 18.1, 10.0 and 9.4, respectively, and the mean gestational weight gain was 12.5 kg (standard deviation, SD: ± 3.6), 12.2 kg (SD: ± 3.8) and 11.5 kg (SD: ± 4.7), respectively. Among women with low BMI, the risk of delivering an infant too small for gestational age ranged from approximately 40% if the gestational weight gain was < 5 kg to 20% if it was 5–10 kg.

Conclusion

Having a low BMI, commonly found in Viet Nam, puts women at risk of delivering an infant too small for gestational age, especially when total maternal gestational weight gain is < 10 kg.     

Atrial fibrillation is a major risk factor for stroke, especially in women: the Jichi Medical School cohort study

Background

Only a few population-based cohort studies have investigated the impact of atrial fibrillation (AF) on stroke in Japan.

Methods

A total of 10 929 participants (4147 men and 6782 women) were included in this population-based prospective cohort study. Baseline data, including electrocardiograms (ECGs) to ascertain AF status, were obtained from April 1992 through July 1995 in 12 areas in Japan. Cox proportional hazards models were used to analyze the association of AF with stroke.

Results

A total of 54 participants had AF (0.49%). The mean follow-up period was 10.7 years, during which 405 strokes were identified; 12 of these occurred in participants with AF. The crude incidence of stroke in participants with and without AF was 14.9 and 4.5 per 1000 person-years in men, respectively, and 39.3 and 2.7 per 1000 person-years in women. After adjusting for geographical area, sex, age, smoking status, drinking status, obesity, hypertension, dyslipidemia, and diabetes mellitus, the hazard ratios (95% confidence interval) of AF in all participants and in male and female participants were 4.11 (2.28–7.41), 2.12 (0.77–5.84), and 10.6 (5.01–22.4), respectively. The population attributable fraction (PAF) of stroke caused by AF was 2.2%; the PAFs were 1.0% and 3.6% in men and women, respectively.

Conclusions

The present Japanese population-based prospective cohort study showed that AF is a major risk factor for stroke, especially in women.Key words: atrial fibrillation, stroke, women, cohort study     

Marital status, education, and risk of acute myocardial infarction in Mainland China: the INTER-HEART study

Background

We investigated the effects of marital status and education on the risk of acute myocardial infarction (AMI) in a large-scale case-control study in China.

Methods

This study was part of the INTER-HEART China case-control study. The main outcome measure was first AMI. Incident cases of AMI and control patients with no past history of heart disease were recruited. Controls were matching by age (±5 years) and sex. Marital status was combined into 2 categories: single and not single. Education level was classified into 2 categories: 8 years or less and more than 8 years.

Results

From 1999 to 2002, we recruited 2909 cases and 2947 controls from 17 cities. After adjustment for age, sex, BMI, psychosocial factors, lifestyle, other factors, and mutually for other risk factors, the odds ratio (OR) for AMI associated with being single was 1.51 (95% confidence interval: 1.18–1.93) overall, 1.19 (0.84–1.68; P = 0.072) in men and 2.00 (1.39–2.86; P < 0.0001) in women. The interaction of sex and marital status was statistically significant (P = 0.045). Compared with a high education level, a low education level increased the risk of AMI (1.45, 1.26–1.67); the odds ratios in men and women were 1.29 (1.09–1.52) and 1.55 (1.16–2.08), respectively. Single women with a low education level had a high risk of AMI (2.95, 1.99–4.37).

Conclusions

Being single was consistently associated with an increased risk for AMI, particularly in women. In addition, as compared with high education level, low education level was associated with a higher risk of AMI in both men and women.Key words: acute myocardial infarction, marital status, level of education, case control study, coronary heart disease