Combined effect of inflammatory gene polymorphisms and the risk of ischemic stroke in a prospective cohort of subjects with type 2 diabetes: a Go-DARTS study.

OBJECTIVE: We have previously observed that genetic profiles determined by the combination of five functionally significant single nucleotide polymorphisms (SNPs) (rs1800795, rs5498, rs5361, rs1024611, and rs679620) of genes encoding prototypical inflammatory molecules are associated with history of ischemic stroke. Here we tested the ability of this multigenic model to predict stroke risk in a large population-based prospective cohort of subjects with type 2 diabetes. RESEARCH DESIGN AND METHODS: This study was conducted using a prospective cohort of individuals with type 2 diabetes participating in the Go-DARTS (Genetics of Diabetes Audit and Research in Tayside Scotland) study, which includes genetic and clinical information of patients with diabetes within the Tayside region of Scotland, U.K. The above-mentioned inflammatory SNPs were investigated in 2,182 Go-DARTS participants. We created an inflammatory risk score (IRS), ranging from 0 to 5, according to the number of "at-risk" genotypes concomitantly carried by a given individual. The primary outcome was the occurrence of fatal or nonfatal stroke of any kind. Mean follow-up time was 6.2 ± 1.1 years. RESULTS: The incidence of stroke increased according to the IRS. The IRS was significantly and independently associated with increased stroke risk after adjustment for other conventional risk factors (hazard ratio 1.34 [95% CI 1.1-1.7]; P = 0.009). The highest hazard ratio for stroke was found in subjects concomitantly carrying > 3 proinflammatory variations and in subjects without previous cardiovascular diseases. CONCLUSIONS: This large prospective cohort study provides evidence that SNPs of genes encoding prototypical inflammatory molecules may be used to create multigenic models that predict stroke risk in subjects with type 2 diabetes.

The FTO gene is associated with an atherogenic lipid profile and myocardial infarction in patients with type 2 diabetes: a Genetics of Diabetes Audit and Research Study in Tayside Scotland (Go-DARTS) study.

BACKGROUND: Common variation in the fat mass and obesity (FTO)-related gene is associated with increased body fat and susceptibility to type 2 diabetes. We hypothesized that this would also associate with metabolic phenotypes of insulin resistance and increased risk of cardiovascular morbidity and mortality. METHODS AND RESULTS: FTO rs9939609 genotype was determined in 4897 patients with type 2 diabetes in the prospective Genetics of Diabetes Audit and Research Study in Tayside Scotland study. The A allele was associated with lower plasma high-density lipoprotein cholesterol (mean difference, 0.03 mmol/L; P=0.008), higher triglycerides (0.1 mmol/L, P=0.007), higher atherogenic index of plasma (0.03, P=0.003), and, as expected, increased body mass index (0.77 kg/m(2), P=8.8 x 10(-6)). During a mean follow-up of 3.6 years, the A allele was also associated with increased risk (hazard ratio, 2.36; CI, 1.49 to 3.74; P=0.0002) of fatal and nonfatal myocardial infarction (total of 324 events) in a model, including baseline age, gender, prevalent myocardial infarction, smoking status, statin, and insulin use. This association diminished but remained significant when obesity-related traits, such as body mass index, glycohemoglobin, and lipid parameters, were also included (hazard ratio, 2.01; CI, 1.18 to 3.45, P=0.011). There was a strong interaction of FTO genotype and statin use and cardiovascular outcome (P=0.001), such that cardiovascular morbidity and mortality was completely abrogated in individuals who were prescribed statins. CONCLUSIONS: The increased fat mass in carriers of the A allele of rs9939609 of FTO is associated not only with increased risk of type 2 diabetes, but also with an increase in atherogenic lipid profile and myocardial infarction in these patients. This variant may, therefore, in the future contribute to more effective targeting of specific preventative therapy.

Reduced-function SLC22A1 polymorphisms encoding organic cation transporter 1 and glycemic response to metformin: a GoDARTS study.

OBJECTIVE: Metformin is actively transported into the liver by the organic cation transporter (OCT)1 (encoded by SLC22A1). In 12 normoglycemic individuals, reduced-function variants in SLC22A1 were shown to decrease the ability of metformin to reduce glucose excursion in response to oral glucose. We assessed the effect of two common loss-of-function polymorphisms in SLC22A1 on metformin response in a large cohort of patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: The Diabetes Audit and Research in Tayside Scotland (DARTS) database includes prescribing and biochemistry information and clinical phenotypes of all patients with diabetes within Tayside, Scotland, from 1992 onwards. R61C and 420del variants of SLC22A1 were genotyped in 3,450 patients with type 2 diabetes who were incident users of metformin. We assessed metformin response by modeling the maximum A1C reduction in 18 months after starting metformin and investigated whether a treatment target of A1C <7% was achieved. Sustained metformin effect on A1C between 6 and 42 months was also assessed, as was the time to metformin monotherapy failure. Covariates were SLC22A1 genotype, BMI, average drug dose, adherence, and creatinine clearance. RESULTS: A total of 1,531 patients were identified with a definable metformin response. R61C and 420del variants did not affect the initial A1C reduction (P = 0.47 and P = 0.92, respectively), the chance of achieving a treatment target (P = 0.83 and P = 0.36), the average A1C on monotherapy up to 42 months (P = 0.44 and P = 0.75), or the hazard of monotherapy failure (P = 0.85 and P = 0.56). CONCLUSIONS: The SLC22A1 loss-of-function variants, R61C and 420del, do not attenuate the A1C reduction achieved by metformin in patients with type 2 diabetes.

Two variants on chromosome 17 confer prostate cancer risk, and the one in TCF2 protects against type 2 diabetes.

We performed a genome-wide association scan to search for sequence variants conferring risk of prostate cancer using 1,501 Icelandic men with prostate cancer and 11,290 controls. Follow-up studies involving three additional case-control groups replicated an association of two variants on chromosome 17 with the disease. These two variants, 33 Mb apart, fall within a region previously implicated by family-based linkage studies on prostate cancer. The risks conferred by these variants are moderate individually (allele odds ratio of about 1.20), but because they are common, their joint population attributable risk is substantial. One of the variants is in TCF2 (HNF1beta), a gene known to be mutated in individuals with maturity-onset diabetes of the young type 5. Results from eight case-control groups, including one West African and one Chinese, demonstrate that this variant confers protection against type 2 diabetes.