Type 2 diabetes risk in persons with dysglycemia: the Framingham Offspring Study

Aims

Detection of risk of type 2 diabetes mellitus (T2DM) among adults with dysglycemia.

Methods

We used a nested case-cohort prospective design to estimate risk of new diabetes (diabetes treatment or FPG ≥7.0 mmol/L) among 1004 Framingham Heart Study Offspring with baseline dysglycemia [fasting plasma glucose (FPG) 5.4-6.9 mmol/L and/or 2-h post glucose load level 7.8-11.0 mmol/L]. Using clinical characteristics previously shown to predict incident T2DM, we used logistic regression to estimate odds ratios (OR), p-values for predictors, and assessment of model discrimination.

Results

At the end of 7 years follow-up there were 118 incident T2DM cases. In a model that included age, sex, elevated blood pressure or blood pressure treatment, lipid-lowering treatment and elevated triglycerides, we found the following additional characteristics to be independently associated with new T2DM: parental history of diabetes (OR 2.28, p = 0.004); excess adiposity (BMI ≥ 30 kg/m² or waist circumference ≥101.6 cm) (OR 2.04, p = 0.0005), and low HDL-C [<1.0 (men) or <1.3 mmol/L (women)] (OR 2.77, p < 0.0001). The multivariable C-statistic for this model was 0.701, and with glycemic category information included, c = 0.751.

Conclusions

The key non-glycemic traits that predicted later T2DM in adults with dysglycemia were parental history of diabetes, excess adiposity and low HDL-C.     

The PlA1/A2 polymorphism of platelet glycoprotein IIIa is not associated with deep venous thrombosis.

BACKGROUND: Platelet glycoprotein (GP) IIb/IIIa, a fibrinogen and von Willebrand factor binding membrane receptor, has an important role in platelet aggregation. A common leucine33-proline polymorphism (PlA1/A2) of the gene encoding the GP IIIa subunit is associated with platelet reactivity and has been proposed as a risk factor for atherothrombotic disease. The aim of this study was to investigate the role of this polymorphism for deep venous thrombosis (DVT). METHODS: We performed a case-control study including 206 patients with documented DVT and a sex- and age-matched group of 310 control subjects. GP IIIa genotypes were determined by restriction fragment analysis of amplimers containing the polymorphic site. RESULTS: A1/A1, A1/A2 and A2/A2 genotypes were found in 67.0, 31.6 and 1.5 percent of patients and 72.3, 25.8 and 1.9 percent of controls (p=0.35), PlA2 allele frequencies were 0.17 in patients and 0.15 in controls (p=0.92). Odds ratio of the PlA2 allele for DVT was 1.21 (95 percent CI 0.85-1.71, p=0.29) and remained insignificant after adjustment for factor V Leiden and prothrombin 20210A genotypes (1.22, 95 percent CI 0.86-1.75, p=0.27). CONCLUSIONS: Our data suggest that the PlA1/A2 polymorphism of GP IIIa is not associated with DVT.     

Alcohol consumption and platelet activation and aggregation among women and men: the Framingham Offspring Study

BACKGROUND: Alcohol intake has been associated with lower platelet activity; however, few large-scale studies have included women, and to our knowledge, the relationship of alcohol intake with measures of platelet activation has not been studied. METHODS: We performed a cross-sectional analysis of adults free of cardiovascular disease enrolled in the Framingham Offspring Study. Study physicians assessed alcohol consumption with a standardized questionnaire. We measured platelet activation in response to 1 and 5 microm of adenosine diphosphate (ADP) with a P-selectin assay among 1037 participants and platelet aggregability in response to ADP, epinephrine, and collagen among 2013 participants. RESULTS: Alcohol consumption was inversely associated with P-selectin expression in response to 1 microm ADP (p = 0.007) and 5 microm ADP (p = 0.02) among men but not women. Alcohol consumption was also inversely associated with platelet aggregation induced by ADP among both women (p = 0.04) and men (p trend = 0.008) and by epinephrine among men (p = 0.03) CONCLUSIONS: Alcohol consumption is inversely associated with both platelet activation and aggregation, particularly in men. Additional research is needed to determine whether these findings contribute to the contrasting associations of alcohol consumption with risk of thrombotic and hemorrhagic cardiovascular events.     

The GPIIIa (beta3 integrin) PlA polymorphism in the early development of coronary atherosclerosis

The GPIIIa (beta3 integrin) is an integral part of two glycoprotein receptors - the GP(IIb/IIIa) fibrinogen receptors in platelets and the GP(V/IIIa) vitronectin receptors in endothelium and vascular smooth muscle cells (vSMC). The PlA polymorphism of the gene for GPIIIa (beta3 integrin) has been suggested to play an important role in the progression of coronary artery disease (CAD) and in coronary thrombosis. Whether the action of the PlA polymorphism is due to differences in platelet aggregability or function of the vSMC and endothelial GPIIIa is not known. The association of the PlA polymorphism with the early, non-complicated atherosclerosis and CAD was studied in the Helsinki Sudden Death Study (HSDS) comprising two independent, autopsy series of altogether 700 middle-aged Caucasian Finnish men (33-70 year) suffering sudden out-of-hospital death. The burden of complicated lesions was greater in men with the A2 allele (heterozygotes or homozygotes for A2) (P=0.01) compared with PlA1/A1 homozygotes in the entire series. To further estimate the role of platelet-independent GPIIIa receptors, we excluded all cases with coronary thrombosis and thrombus-overlaid complicated lesions. In this subset of men, fibrous coronary lesions were more frequent (OR 2.9; P<0.01) in the coronary arteries of PlA1/A1 homozygotes compared with men with the PlA2 allele. Moreover, men with the PlA1/A1 genotype also had more stenotic coronary arteries (P<0.05) compared with men with the A2 allele at this early, non-complicated stage of atherosclerosis. The findings of this study suggest that Pl(A1/A1) homozygotes may be prone to early atherosclerosis and more rapid progression of stable CAD whereas carriers of the PlA2 allele are more prone to thrombotic complications. We hypothesize that the PlA polymorphism may account for the early atherosclerosis by affecting the function of endothelial and vSMC GP(V/IIIa) receptors, whereas the PlA polymorphism on platelet GP(IIb/IIIa) receptors may play a major role in coronary thrombosis.     

The platelet polymorphism PlA2 is a genetic risk factor for myocardial infarction

OBJECTIVES: Platelet glycoprotein (GP) receptor IIb/IIIa plays a key role in the development of myocardial infarction (MI), and Pl(A2) is a polymorphism in the gene encoding this receptor. The prevalence of Pl(A2) shows pronounced geographical variation and has to our knowledge not been presented for a Scandinavian population before. Platelets from Pl(A2)-positive individuals show increased aggregability compared with platelets from Pl(A2)-negative individuals, and Pl(A2) genotypes might be associated with MI. The purpose of this study was to investigate the relation between the Pl(A2) polymorphism and MI in a large Scandinavian population. DESIGN: Case-control study. We included patients with angiographically verified CAD with and without previous MI and a group of healthy individuals matched for age, race, and sex. RESULTS: We studied the frequency of Pl(A2) in 1191 healthy individuals and 1019 patients with coronary artery disease (CAD). Amongst these patients, 529 subjects had suffered an MI previously. Pl(A2) was present in 28% of healthy individuals, 28% of patients with CAD but no MI, and in 35% of patients with CAD and MI. The difference between healthy individuals and MI patients was significant (P = 0.002). Furthermore, a graded relationship between the number of Pl(A2) alleles and the risk of MI was seen (P = 0.011). Associations between Pl(A2) and traditional cardiovascular risk factors as well as mean platelet volume were investigated. We found a significant interaction between Pl(A2) and serum cholesterol. CONCLUSION: In our Scandinavian study population the common platelet polymorphism Pl(A2) is significantly associated with an increased risk of MI, but not of CAD. Clinically, typing for Pl(A2) might have implications for antiplatelet therapy of patients with MI.     

Association between the PPARA L162V polymorphism and plasma lipid levels: the Framingham Offspring Study

Peroxisome proliferator activated receptor (PPAR) alpha is a member of the nuclear receptor superfamily that regulates key proteins involved in fatty acid oxidation, extracellular lipid metabolism, hemostasis, and inflammation. A L162V polymorphism at the PPARA locus has been associated with alterations in lipid and apolipoprotein concentrations. We studied the association among lipids, lipoproteins, and apolipoproteins and the presence of the L162V polymorphism in 2373 participants (1128 men and 1244 women) in the Framingham Offspring Study. The frequency of the less common allele (V162) was 0.069. The V162 allele was associated with increased serum concentrations of total and LDL cholesterol in men (P=0.0012 and P=0.0004, respectively) and apolipoprotein B in men (P=0.009) and women (P=0.03 after adjustment for age, body mass index, smoking, and use of beta-blockers, diuretics or estrogens). Apolipoprotein (apo) C-III concentrations were higher in carriers of the V162 allele. The association of the L162V polymorphism on LDL cholesterol concentration was greatest in those who also carried the E2 allele at the APOE locus and the G allele at the APOC3 3238C>G polymorphism. This suggests that alterations in triglyceride-rich lipoprotein metabolism may be involved in the generation of the increase in LDL cholesterol observed with the L162V PPARA polymorphism.     

Meta-analysis of the association of platelet glycoprotein IIIa PlA1/A2 polymorphism with myocardial infarction

This meta-analysis examined all the published reports up to October 1999 that studied the association between PlA2 polymorphism of platelet glycoprotein IIIa gene and myocardial infarction. The PlA2 polymorphism was not found to be associated with an increased risk of myocardial infarction, either overall or in selected subgroups, which were patients with premature disease onset (age < or = 60 years), first acute myocardial infarction, and patients who were men, women, and exclusively Caucasian.     

Lifetime risk for developing dyslipidemia: the Framingham Offspring Study

Background

High serum low-density lipoprotein (LDL) cholesterol and low high-density lipoprotein (HDL) cholesterol are major vascular risk factors. National surveys indicate that 40% of individuals in the United States have borderline-high LDL cholesterol, and 13-34% have low HDL. The lifetime risk of developing dyslipidemia is unknown, however.

Methods

We estimated the 10- to 30-year long-term risks of developing “borderline-high” LDL cholesterol (≥130 mg/dL [3.4 mmol/L]), “high” LDL cholesterol (≥160 mg/dL [4.1 mmol/L]) and “low” HDL cholesterol (<40 mg/dL [1.0 mmol/L]) in 4701 Framingham Offspring Study participants (53% women) who attended at least 2 examinations between 1971 and 2000. We performed sex-specific analyses (for age groups 30-34, 40-44, 50-54 years), and estimated risks conditional on surviving without the lipid abnormality up to the baseline age. We also estimated risks accounting for baseline prevalence of dyslipidemia (elevated LDL, low HDL).

Results

Over a 30-year period, approximately 6 of 10 participants developed borderline-high LDL, 4 of 10 people developed high LDL, and 2 (women) to 4 (men) of 10 individuals developed low HDL levels; estimates were generally similar for different age groups. Adjustment for baseline prevalence of dyslipidemia increased these estimates: 30-year risks exceeded 80% for borderline-high LDL, 50% for high LDL, and 25% (women) to 65% (men) for low HDL; 20-50% had or developed a low HDL along with a high LDL level. The 30-year estimates approximate the lifetime risk in 50-year-olds.

Conclusions

The long term risks of developing dyslipidemia are substantial in both sexes, and considerably exceed prevalence estimates from cross-sectional surveys.     

The PlA1/A2 polymorphism of platelet glycoprotein IIIa is not associated with the risk of type 2 diabetes. The Ludwigshafen Risk and Cardiovascular Health Study

Aims/hypothesis The PlA1/A2 polymorphism of platelet glycoprotein IIIa (GPIIIa) has been implicated in the pathogenesis of type 2 diabetes. We studied this polymorphism in a homogenous, extensively phenotyped cohort using the candidate gene approach.Methods The PlA1/A2 polymorphism was determined in 1051 patients with type 2 diabetes and in 2247 individuals without type 2 diabetes.Results In patients with type 2 diabetes, genotype frequencies were as follows: PlA1/A1 71.4%, PlA1/A2 26.0%, and PlA2/A2 2.7%. In individuals without type 2 diabetes, genotype frequencies were 71.6%, 25.7% and 2.8%, respectively. The PlA2 allele was not associated with fasting and postprandial glucose, glycated haemoglobin, insulin, proinsulin, C-peptide and calculated indices of insulin resistance or pancreatic beta cell function. The PlA2 allele was also not significantly associated with angiographic CHD (adjusted odds ratio [OR] 1.13; 95% CI, 0.93–1.39) or with a history of previous myocardial infarction (adjusted OR 1.09; 95% CI, 0.87–1.37).Conclusions/interpretation The GPIIIa PlA1/A2 polymorphism is not associated with type 2 diabetes, glucose metabolism, angiographic CHD or myocardial infarction.     

The Framingham Offspring Study: a commentary. 1980

Forty-three of 1,312 men aged 35 to 54 years in the Framingham Offspring Study had clinically recognized coronary heart disease at the initial examination. Twenty-six men in this group had previously had a myocardial infarction. Of 1,296 women in the same age range, only 11 had coronary disease and 3 a prior myocardial infarction. The prevalence of coronary heart disease in men was strongly associated with age, smoking, high density lipoprotein (HDL), low density lipoprotein (LDL) and total cholesterol using univariate analyses. When multivariate logistic regression analysis was used, age, smoking and HDL and LDL cholesterol retained their significant association with coronary heart disease. The total cholesterol/HDL cholesterol ratio was also strongly associated with coronary heart disease in the multivariate analysis. It is concluded that both HDL and LDL cholesterol are strongly and independently associated with the prevalence of coronary heart disease, whereas the level of very low density lipoprotein cholesterol makes no statistically significant independent contribution.     

Association of apo A-IV 360 (Gln --> His) polymorphism with plasma lipids and lipoproteins: the Framingham Offspring Study

The effect of a common apolipoprotein (apo) A-IV polymorphism (substitution of histidine for glutamine at position 360) on plasma lipid, lipoprotein cholesterol and lipoprotein(a) (Lp(a)) levels, and on low-density lipoprotein (LDL) particle size was examined by genotyping in 2322 Caucasian men and women (mean age: 48.9+/-10.1 years) participating in the Framingham Offspring Study (FOS). The relative frequencies of the apo A-IV-Gln (apo A-IV-1) and the apo A-IV-His (apo A-IV-2) alleles were 0.932 and 0.068, respectively, and were in Hardy-Weinberg equilibrium. No effect of the apo A-IV-2 genotype was observed on plasma triglyceride, total and lipoprotein cholesterol, and LDL particle size in either men or women after adjustment for age and body mass index. To avoid a possible interaction between the apo E genotype and the apo A-IV genotype, subgroup analyses were undertaken in 1,414 male and female subjects with the apo E3/3 genotype. Among women in this group there was a significant effect of the apo A-IV-2 allele on triglyceride levels (p=0.046). This effect was no longer significant after adjustment for age and BMI (p=0.074). No significant allele effect on other lipoprotein levels, including Lp(a), was noted in apo E3/3 men or women. We have also conducted a meta-analysis of our own data and of other studies found in the literature, indicating a significant lowering effect of apo A-IV-2 on plasma triglycerides, but no effects on other parameters. In conclusion, the apo A-IV-2 allele is associated with a modest reduction in plasma triglyceride levels in the general population.     

Association of the C-514T polymorphism in the hepatic lipase gene with variations in lipoprotein subclass profiles: The Framingham Offspring Study

Hepatic lipase is involved in the metabolism of several lipoproteins and has a key role in reverse cholesterol transport. A common C-to-T substitution at position -514 of the hepatic lipase promoter has been associated with variations in plasma high density lipoprotein cholesterol (HDL-C) levels and hepatic lipase activity. The aim of the current study was to investigate the association of this polymorphism to lipoprotein levels in a population-based sample of 1314 male and 1353 female Framingham Offspring Study participants. In men and women, carriers of the -514T allele had higher HDL-C and apolipoprotein A-I (apoAI) concentrations compared with noncarriers. The higher HDL-C levels associated with the -514T allele was due to an increase in the HDL(2)-C subfraction, and this association was stronger in women compared with men (P=0.0043 versus 0.0517). To gain further understanding about the metabolic basis of these effects, HDL and low density lipoprotein (LDL) subclass profiles were measured by using automated nuclear magnetic resonance spectroscopy and gradient gel electrophoresis, respectively. The association of the -514T allele with higher HDL-C levels seen in men and women was primarily due to significant increases in the large HDL subfractions (size range 8.8 to 13.0 nm). In contrast, there was no relationship between the hepatic lipase polymorphism at position -514 and the LDL particle size distribution after adjustment for familial relationships, age, body mass index, smoking, alcohol intake, use of beta-blockers, apoE genotype, and menopausal status and estrogen therapy in women. Moreover, multiple regression analyses suggested that the C-514T polymorphism contributed significantly to the variability of HDL particle size in men and women (P<0.04). Thus, our results show that the C-514T polymorphism in the hepatic lipase gene is associated with significant variations in the lipoprotein profile in men and women.     

Autoantibodies to oxidized LDL and cardiovascular risk: the Framingham Offspring Study

BACKGROUND: The relation between measures of oxidation of lipid particles and cardiovascular disease has not been extensively investigated prospectively on a population basis. METHODS: A community cohort of 1192 men and 1427 women with measures of IgG antibodies to oxidized LDL were followed 8 years for the development of initial coronary heart disease (CHD) and cardiovascular disease (CVD) events. RESULTS: Levels of IgG autoantibodies to a form of oxidized LDL were significantly associated with age in both sexes, positively with fibrinogen in men and negatively with HDL cholesterol in women. In sex-specific models that adjusted for age alone or those that adjusted for age, cholesterol, HDL cholesterol, smoking, and diabetes mellitus, there was no relation between level of antibodies to oxidized LDL and the development of CHD or CVD. CONCLUSION: Autoantibodies to oxidized LDL were strongly related to age and were not related to incident CHD or CVD over 8 years of follow up.     

Relationship between bleeding time, aspirin and the PlA1/A2 polymorphism of platelet glycoprotein IIIa

A single nucleotide T to C transition of the gene encoding glycoprotein IIIa leads to a common diallelic polymorphism Leu-33-->Pro (PLA1/A2). We studied the relationship between the PlA1/A2 polymorphism and platelet function in 80 healthy men, aged 20-25 years. Before aspirin ingestion, bleeding time (BT) was shorter in carriers of the PlA2 than in carriers of the PlA1/A1 allele. At 4 h after ingestion of 300 mg of aspirin, BT became prolonged, and the intergroup difference was enhanced. In seven out of 26 PLA2 allele carriers, aspirin shortened BT on average by 30 s, compared with only one among 54 subjects with the PlA1/A1 genotype. Thus, BT both at baseline and after aspirin depends on the PlA1/A2 polymorphism of glycoprotein IIIa. Carriers of the PlA2 allele appear to be more resistant to the antithrombotic action of aspirin.     

Metabolic syndrome compared with type 2 diabetes mellitus as a risk factor for stroke: the Framingham Offspring Study

BACKGROUND: Metabolic syndrome (MetS) has been recognized as a prediabetic constellation of symptoms and an independent risk factor for cardiovascular disease. METHODS: To evaluate the age-adjusted risk of stroke and population-attributable risk associated with MetS and compare with those of overt type 2 diabetes mellitus (hereinafter, "diabetes"), we determined the prevalence of MetS alone, diabetes alone, and both in 2097 subjects in the Framingham Offspring Study, aged 50 to 81 years and free of stroke. Age-adjusted risk ratios, 10-year incidence, and population-attributable risks of stroke were estimated for men and women with MetS alone, diabetes alone, and both. RESULTS: Criteria for MetS were met in 30.3% of men and 24.7% of women. Twenty-four percent of men had MetS alone; 7% had diabetes alone; and 6% had both. Twenty percent of women had MetS alone; 3% had diabetes alone; and 5% had both. Over 14 years of follow-up, 75 men and 55 women developed a first stroke; all but 4 events were ischemic. Relative risk (RR) of stroke in persons with both diabetes and MetS (RR, 3.28; confidence interval [CI], 1.82-5.92) was higher than that for either condition alone (MetS alone: RR, 2.10; CI, 1.37-3.22; diabetes alone: RR, 2.47; CI, 1.31-4.65). The population-attributable risk, owing to its greater prevalence, was greater for MetS alone than for diabetes alone (19% vs 7%), particularly in women (27% vs 5%). CONCLUSIONS: Metabolic syndrome is more prevalent than diabetes and a significant independent risk factor for stroke in people without diabetes. Prevention and control of MetS and its components are likely to reduce stroke incidence.     

The type 2 deiodinase (DIO2) A/G polymorphism is not associated with glycemic traits: the Framingham Heart Study.

BACKGROUND: Type 2 deiodinase plays a critical role in thyroid hormone homeostasis. A single nucleotide polymorphism in DIO2 gene (A/G) in humans has been associated with a approximately 20% lower glucose disposal rate and greater insulin resistance in type 2 diabetes (DM2) patients. OBJECTIVE: This study was designed to test whether homozygosity for the DIO2 A/G polymorphism would be associated with risk of DM2 or elevated levels of diabetes intermediate traits. DESIGN AND SETTING: Community-based, longitudinal study. Participants were withdrawn from a subset of unrelated individuals from the Offspring Cohort of the Framingham Heart Study who had DNA collected between 1995 and 1998. METHODS: DNA samples from 1633 participants (mean age, 62 years) underwent genotyping of the DIO2 A/G polymorphism. Incident DM2 and diabetes-related traits (fasting plasma glucose, mean fasting plasma glucose, 2-hour glucose, hemoglobin A(1c), fasting insulin, insulin resistance) were measured. RESULTS: The minor allele (G) frequency was 0.37. Using multivariable regression for intermediate traits and Cox proportional hazards regression for DM2, p values were calculated for two models: Model 1: age, age-squared, sex, and smoking; Model 2: Model 1 + body mass index. There were no significant associations (all p > 0.20) for any trait examined. For DM2 risk, the hazard ratios associated with A/G or G/G relative to the A/A genotype were 1.0 (95% confidence interval [CI] 0.7-1.3) and 1.2 (95% CI 0.7-1.9), respectively. CONCLUSIONS: Our results indicate that in this community-based sample, there is no association of the DIO2 A/G polymorphism with diabetes intermediate trait levels or DM2 risk.