Coffee Consumption, Genetic Polymorphisms, and the Risk of Type 2 Diabetes Mellitus: A Pooled Analysis of Four Prospective Cohort Studies.

The association between coffee consumption and the risk of type 2 diabetes may vary by genetic variants. Our study addresses the question of whether the incidence of type 2 diabetes is related to the consumption of coffee and whether this relationship is modified by polymorphisms related to type 2 diabetes. We performed a pooled analysis of four Korean prospective studies that included 71,527 participants; median follow-up periods ranged between 2 and 13 years. All participants had completed a validated food-frequency questionnaire (FFQ) at baseline. The odds ratios (ORs) and 95% confidence intervals (CIs) for type 2 diabetes were calculated using logistic regression models. The ORs were combined using a fixed or random effects model depending on the heterogeneity across the studies. Compared with 0 to <0.5 cups/day of coffee consumption, the OR for type 2 diabetes was 0.89 (95% CI: 0.80-0.98, p for trend = 0.01) for ≥3 cups/day of coffee consumption. We did not observe significant interactions by five single nucleotide polymorphisms (SNPs) related to type 2 diabetes (CDKAL1 rs7756992, CDKN2A/B rs10811661, KCNJ11 rs5215, KCNQ1 rs163184, and PEPD rs3786897) in the association between coffee and the risk of type 2 diabetes. We found that coffee consumption was inversely associated with the risk of type 2 diabetes.

Interactions of Habitual Coffee Consumption by Genetic Polymorphisms with the Risk of Prediabetes and Type 2 Diabetes Combined.

Habitual coffee consumption and its association with health outcomes may be modified by genetic variation. Adults aged 40 to 69 years who participated in the Korea Association Resource (KARE) study were included in this study. We conducted a genome-wide association study (GWAS) on coffee consumption in 7868 Korean adults, and examined whether the association between coffee consumption and the risk of prediabetes and type 2 diabetes combined was modified by the genetic variations in 4054 adults. In the GWAS for coffee consumption, a total of five single nucleotide polymorphisms (SNPs) located in 12q24.11-13 (rs2074356, rs11066015, rs12229654, rs11065828, and rs79105258) were selected and used to calculate weighted genetic risk scores. Individuals who had a larger number of minor alleles for these five SNPs had higher genetic risk scores. Multivariate logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (95% CIs) to examine the association. During the 12 years of follow-up, a total of 2468 (60.9%) and 480 (11.8%) participants were diagnosed as prediabetes or type 2 diabetes, respectively. Compared with non-black-coffee consumers, the OR (95% CI) for ≥2 cups/day by black-coffee consumers was 0.61 (0.38-0.95; p for trend = 0.023). Similarly, sugared coffee showed an inverse association. We found a potential interaction by the genetic variations related to black-coffee consumption, suggesting a stronger association among individuals with higher genetic risk scores compared to those with lower scores; the ORs (95% CIs) were 0.36 (0.15-0.88) for individuals with 5 to 10 points and 0.87 (0.46-1.66) for those with 0 points. Our study suggests that habitual coffee consumption was related to genetic polymorphisms and modified the risk of prediabetes and type 2 diabetes combined in a sample of the Korean population. The mechanisms between coffee-related genetic variation and the risk of prediabetes and type 2 diabetes combined warrant further investigation.

Green tea consumption and risk of stomach cancer: a meta-analysis of epidemiologic studies.

This meta-analysis investigated the quantitative association between the consumption of green tea and the risk of stomach cancer in epidemiologic studies using crude data and adjusted data. We searched MEDLINE, EMBASE and the Cochrane Review in August 2007. All the articles searched were independently reviewed and selected by 3 evaluators according to predetermined criteria. A total of 13 epidemiologic studies were included. When all the case-control and cohort studies were pooled, the odds ratios (OR) [corrected] of stomach cancer for the highest level of green tea consumption when compared with the lowest level of consumption were shown to be 1.10 (95% confidence interval (CI), 0.92-1.32) using the crude data and 0.82 (95% CI, 0.70-0.96) using the adjusted data.In the meta-analyses of case-control studies, no significant association was seen between green tea consumption and stomach cancer using the crude data (odds ratio (OR), 0.79; 95% CI, 0.58-1.07) [corrected], but green tea was shown to have a preventive effect on stomach cancer using the adjusted data (OR, 0.73; 95% CI, 0.64-0.83) [corrected]. In the meta-analyses of the recent cohort studies, the highest green tea consumption was shown to significantly increase stomach cancer risk using the crude data (RR, 1.59; 95% CI, 1.16-2.18), but no significant association between them was seen when using the adjusted data (RR, 1.04; 95% CI, 0.93-1.17). Unlike the case-control studies, no preventive effect on stomach cancer was seen for the highest green tea consumption in the meta-analysis of the recent cohort studies. Further clinical trials are needed.

Different risk factor profiles between subtypes of ischemic stroke. A case-control study in Korean men.

Ischemic stroke is composed of subtypes with variable underlying pathogenesis and studies on ischemic stroke as a whole may inadequately evaluate risk factors, being influenced by subtype distribution among studied population. This study aimed to evaluate risk factors associated with individual ischemic stroke subtypes defined by the Trial of ORG10172 in Acute Stroke Treatment. In a case-control study (290 first-ever ischemic stroke cases and 1160 individually matched controls without stroke) nested within Korean male public servants cohort, a range of potential risk factors measured at periodic health surveys prior to the onset of stroke event were examined using conditional logistic regression analysis. Increased risk for large-artery atherosclerosis was associated with hypercholesterolemia (> or = 6.2 mmol/L), hypertension, and smoking. Increased risk for small-artery occlusion was associated with hypertension, hyperglycemia (> or = 7.0 mmol/L), and frequent alcohol intake. No specific risk factor was identified for cardioembolism. For combined ischemic stroke, hypercholesterolemia, hyperglycemia, hypertension, and smoking were associated with the increased risk, but the relative odds were much smaller than those estimated from subtype analysis. Significance of risk factors evaluated for subtypes, rather than ischemic stroke as a whole, should be reflected in preventive efforts against the burden of ischemic stroke.