Genetic variants and the metabolic syndrome: a systematic review

Several candidate gene studies on the metabolic syndrome (MetS) have been conducted. However, for most single nucleotide polymorphisms (SNPs) no systematic review on their association with MetS exists. A systematic electronic literature search was conducted until the 2nd of June 2010, using HuGE Navigator. English language articles were selected. Only genes of which at least one SNP–MetS association was studied in an accumulative total population =4000 subjects were included. Meta-analyses were conducted on SNPs with three or more studies available in a generally healthy population. In total 88 studies on 25 genes were reviewed. Additionally, for nine SNPs in seven genes (GNB3, PPARG, TCF7L2, APOA5, APOC3, APOE, CETP) a meta-analysis was conducted. The minor allele of rs9939609 (FTO), rs7903146 (TCF7L2), C56G (APOA5), T1131C (APOA5), C482T (APOC3), C455T (APOC3) and 174G>C (IL6) were more prevalent in subjects with MetS, whereas the minor allele of Taq-1B (CETP) was less prevalent in subjects with the MetS. After having systematically reviewed the most studied SNP–MetS associations, we found evidence for an association with the MetS for eight SNPs, mostly located in genes involved in lipid metabolis

Validity of a short questionnaire to assess physical activity in 10 European countries

To accurately examine associations of physical activity (PA) with disease outcomes, a valid method of assessing free-living activity is required. We examined the validity of a brief PA questionnaire (PAQ) used in the European Prospective Investigation into Cancer and Nutrition (EPIC). PA energy expenditure (PAEE) and time spent in moderate and vigorous physical activity (MVPA) was measured in 1,941 healthy individuals from 10 European countries using individually-calibrated combined heart-rate and movement sensing. Participants also completed the short EPIC-PAQ, which refers to past year’s activity. Pearson (r) and Spearman (s) correlation coefficients were calculated for each country, and random effects meta-analysis was used to calculate the combined correlation across countries to estimate the validity of two previously- and one newly-derived ordered, categorical PA indices (“Cambridge index”, “total PA index”, and “recreational index”) that categorized individuals as inactive, moderately inactive, moderately active, or active. The strongest associations with PAEE and MVPA were observed for the Cambridge index (r = 0.33 and r = 0.25, respectively). No significant heterogeneity by country was observed for this index (I2 = 36.3%, P = 0.12; I2 = 0.0%, P = 0.85), whereas heterogeneity was suggested for other indices (I2 > 48%, P 47%, P <0.05). PAEE increased linearly across self-reported PA categories (P for tren

Physical activity reduces the risk of incident type 2 diabetes in general and in abdominally lean and obese men and women: the EPIC-InterAct Study

Aims/hypothesis We examined the independent and combined associations of physical activity and obesity with incident type 2 diabetes in men and women. Methods The InterAct case–cohort study consists of 12,403 incident type 2 diabetes cases and a randomly selected subcohort of 16,154 individuals, drawn from a total cohort of 340,234 participants with 3.99 million person-years of follow-up. Physical activity was assessed by a four-category index. Obesity was measured by BMI and waist circumference (WC). Associations between physical activity, obesity and case-ascertained incident type 2 diabetes were analysed by Cox regression after adjusting for educational level, smoking status, alcohol consumption and energy intake. In combined analyses, individuals were stratified according to physical activity level, BMI and WC. Results A one-category difference in physical activity (equivalent to approximately 460 and 365 kJ/day in men and women, respectively) was independently associated with a 13% (HR 0.87, 95% CI 0.80, 0.94) and 7% (HR 0.93, 95% CI 0.89, 0.98) relative reduction in the risk of type 2 diabetes in men and women, respectively. Lower levels of physical activity were associated with an increased risk of diabetes across all strata of BMI. Comparing inactive with active individuals, the HRs were 1.44 (95% CI 1.11, 1.87) and 1.38 (95% CI 1.17, 1.62) in abdominally lean and obese inactive men, respectively, and 1.57 (95% CI 1.19, 2.07) and 1.19 (95% CI 1.01, 1.39) in abdominally lean and obese inactive women, respectively. Conclusions/interpretation Physical activity is associated with a reduction in the risk of developing type 2 diabetes across BMI categories in men and women, as well as in abdominally lean and obese men and women

Reproducibility and relative validity of dietary glycaemic index and glycaemic load assessed by the food-frequency questionnaire used in the Dutch cohorts of the European prospective investigation into Cancer and Nutrition

Limited information is available on the reproducibility and validity of dietary glycaemic index (GI) and glycaemic load (GL) estimated by habitual diet assessment methods such as FFQ, including the FFQ used in the Dutch cohorts of the European Prospective Investigation into Cancer and Nutrition study. To examine the reproducibility and relative validity of GI and GL, we used data from 121 Dutch men and women aged 23–72 years. They completed the FFQ three times at intervals of 6 months and twelve 24-h dietary recalls (24HDR) monthly during 1991–2. GI and GL were calculated using published values. Intra-class correlation coefficients of the three repeated FFQ were 0·78 for GI and 0·74 for GL. Pearson correlation coefficients between the first FFQ and the weighted average of the 24HDR were 0·63 for both GI and GL. Weighted ¿ values between the first FFQ and the average of the 24HDR (in quintiles) were 0·40 for GI and 0·41 for GL. Bland–Altman plots showed a proportional bias in GI (ß = 0·46), but not in GL (ß = 0·06). In conclusion, this FFQ can be used in epidemiological studies to investigate the relationship of GI and GL with disease risks, but the proportional bias should be taken into account when using this FFQ to assess the absolute GI values

Abdominal obesity and the prevalence of diabetes and intermediate hyperglycaemia in Chinese adults

Objective: To assess the association of indicators of general and abdominal obesity with the prevalence of type 2 diabetes (T2DM) and intermediate hyperglycaemia (IHG) in the Chinese population. Methods: We used data of 50 905 adults aged 18¿79 years in the 2002 China National Nutrition and Health Survey. Recommended Chinese cut-off values were used for BMI (24 kg/m2) and waist circumference (WC; 85 cm in men, 80 cm in women). Optimal cut-offs for waist:height ratio (WHtR) were determined from analyses of receiver-operating characteristic (ROC) curves. Results: The prevalence of T2DM and IHG was 2?6% and 1?9% respectively. ROC curve analyses indicated 0?5 as the optimal cut-off value for WHtR in both sexes. High BMI, WC and WHtR were all associated with the prevalence of glucose tolerance abnormalities, with the highest prevalence ratio (PR) for high WHtR (men: PR52?85, 95% CI 2?54, 3?21; women: PR53?10, 95% CI 2?74, 3?51). When combining BMI and WHtR, in men either a high BMI or a high WHtR alone was associated with increased risk. Among women, a high BMI without a concomitant high WHtR was not associated with increased glucose tolerance abnormalities risk, whereas a high WHtR was associated with risk irrespective of BMI. Conclusions: Among the Chinese adult population measures of central obesity are better predictors of glucose tolerance abnormalities prevalence than BMI. AWHtR cutoff point of 0?5 for both men and women can be considered as optimum for predicting (pre-) diabetes and may be a useful tool for screening and health education

Dairy shows different associations with abdominal and BMI-defined overweight: cross-sectional analyses exploring a variety of dairy products

Background and aims: Previous studies suggest weight-regulatory properties for several dairy nutrients, but population-based studies on dairy and body weight are inconclusive. We explored cross-sectional associations between dairy consumption and indicators of overweight. Methods and results: We included 114 682 Dutch adults, aged ≥18y. Dairy consumption was quantified by a food frequency questionnaire. Abdominal overweight was defined as waist circumference (WC) ≥88 (women) or ≥102 (men) cm (n=37 391), overweight as BMI ≥25-30 kg/m2 (n=44 772), and obesity as BMI ≥30 kg/m2 (n=15 339). Associations were quantified by logistic (abdominal overweight, no/yes), multinomial logistic (BMI-defined overweight and obesity) and linear regression analyses (continuous measures of WC and BMI), and adjusted for relevant covariates. Total dairy was positively associated with abdominal overweight (OR Q1ref vs Q5: 1.09; 95% CI: 1.04, 1.14), and BMI-defined overweight (ORQ5 1.13; 95% CI: 1.08, 1.18) and obesity (ORQ5 1.09; 95% CI: 1.02, 1.16). Positive associations were also observed of skimmed, semi-skimmed, and non-fermented dairy with overweight categories. Full-fat dairy was inversely associated with overweight and obesity (ORQ5 for obesity: 0.78; 95% CI: 0.73, 0.83). Moreover, inverse associations were observed for yogurt and custard, and positive associations for milk, buttermilk, flavoured yogurt drinks, cheese, and cheese snacks. Fermented dairy, curd cheese and Dutch cheese were not consistently associated with overweight categories. Conclusions: Total, skimmed, semi-skimmed, and non-fermented dairy, milk, buttermilk, flavoured yogurt drinks, total cheese, and cheese snacks were positively associated with overweight categories, whereas full-fat dairy, custard, and yogurt were inversely associated with overweight categories

Adherence to predefined dietary patterns and incident type 2 diabetes in European populations: EPIC-InterAct Study

Aims/hypothesis - Few studies have investigated the relationship between predefined dietary patterns and type 2 diabetes incidence; little is known about the generalisability of these associations. We aimed to assess the association between predefined dietary patterns and type 2 diabetes risk in European populations. Methods - From among a case-cohort of 12,403 incident diabetes cases and 16,154 subcohort members nested within the prospective European Prospective Investigation into Cancer and Nutrition study, we used data on 9,682 cases and 12,595 subcohort participants from seven countries. Habitual dietary intake was assessed at baseline with country-specific dietary questionnaires. Two diet-quality scores (alternative Healthy Eating Index [aHEI], Dietary Approaches to Stop Hypertension [DASH] score) and three reduced rank regression (RRR)-derived dietary-pattern scores were constructed. Country-specific HRs were calculated and combined using a random-effects meta-analysis. Results - After multivariable adjustment, including body size, the aHEI and DASH scores were not significantly associated with diabetes, although for the aHEI there was a tendency towards an inverse association in countries with higher mean age. We observed inverse associations of the three RRR-derived dietary-pattern scores with diabetes: HRs (95% CIs) for a 1-SD difference were 0.91 (0.86, 0.96), 0.92 (0.84, 1.01) and 0.87 (0.82, 0.92). Random-effects meta-analyses revealed heterogeneity between countries that was explainable by differences in the age of participants or the distribution of dietary intake. Conclusions/interpretation - Adherence to specific RRR-derived dietary patterns, commonly characterised by high intake of fruits or vegetables and low intake of processed meat, sugar-sweetened beverages and refined grains, may lower type 2 diabetes risk

Associations of 25-hydroxyvitamin D with fasting glucose, fasting insulin, dementia and depression in European elderly: the SENECA study

Purpose The classical consequence of vitamin D deficiency is osteomalacia, but recent insights into the function of vitamin D suggest that it may play a role in other body systems as well. The objective of this study was to examine the association between 25-hydroxyvitamin D (25(OH)D) and markers of glucose metabolism (n = 593), global cognitive functioning (n = 116) and depression (n = 118) in European elderly participating in the SENECA study. Moreover, we wanted to explore whether the observed associations of 25(OH)D with depression and global cognitive performance were mediated by fasting plasma glucose (FPG) levels. Methods Cross-sectional associations between 25(OH)D and FPG, fasting plasma insulin (FPI) and homeostatic model assessment-insulin resistance (HOMA-IR), a marker of insulin resistance, were estimated from multiple regression analyses. Associations of 25(OH)D with global cognitive functioning (Mini Mental State Examination) and depression (Geriatric Depression Scale) were examined using Poisson regression. Results An inverse association was observed between 25(OH)D and FPG (ß-0.001), indicating a 1 % decrease in FPG per 10 nmol/L increase in 25(OH)D, but after full adjustment for demographic factors, lifestyle factors and calcium intake, this association was not statistically significant (P = 0.07). Although participants with intermediate and high serum 25(OH)D levels showed a tendency towards a lower depression score after adjustment for demographic and lifestyle factors, RR and 95 % CI: 0.73 (0.51–1.04) and 0.76 (0.52–1.11), respectively, these findings were not statistically significant. Conclusion An inverse association of 25(OH)D with depression and FPG was observed, but this association was not statistically significant. There was no association between 25(OH)D with FPI and HOMA-IR or with global cognitive functioning. More studies are needed to further explore the possible role of vitamin D in the various body system