Objective To examine and quantify the potential dose-response relation between fruit and vegetable consumption and risk of all cause, cardiovascular, and cancer mortality.Data sources Medline, Embase, and the Cochrane library searched up to 30 August 2013 without language restrictions. Reference lists of retrieved articles.Study selection Prospective cohort studies that reported risk estimates for all cause, cardiovascular, and cancer mortality by levels of fruit and vegetable consumption.Data synthesis Random effects models were used to calculate pooled hazard ratios and 95% confidence intervals and to incorporate variation between studies. The linear and non-linear dose-response relations were evaluated with data from categories of fruit and vegetable consumption in each study.Results Sixteen prospective cohort studies were eligible in this meta-analysis. During follow-up periods ranging from 4.6 to 26 years there were 56 423 deaths (11 512 from cardiovascular disease and 16 817 from cancer) among 833 234 participants. Higher consumption of fruit and vegetables was significantly associated with a lower risk of all cause mortality. Pooled hazard ratios of all cause mortality were 0.95 (95% confidence interval 0.92 to 0.98) for an increment of one serving a day of fruit and vegetables (P=0.001), 0.94 (0.90 to 0.98) for fruit (P=0.002), and 0.95 (0.92 to 0.99) for vegetables (P=0.006). There was a threshold around five servings of fruit and vegetables a day, after which the risk of all cause mortality did not reduce further. A significant inverse association was observed for cardiovascular mortality (hazard ratio for each additional serving a day of fruit and vegetables 0.96, 95% confidence interval 0.92 to 0.99), while higher consumption of fruit and vegetables was not appreciably associated with risk of cancer mortality.Conclusions This meta-analysis provides further evidence that a higher consumption of fruit and vegetables is associated with a lower risk of all cause mortality, particularly cardiovascular mortality.

Although both SLC30A8 rs13266634 single nucleotide polymorphism and plasma zinc concentrations have been associated with impaired glucose regulation (IGR) and type 2 diabetes ( T2D), their interactions for IGR and T2D remain unclear. Therefore, to assess zinc-SLC30A8 interactions, we performed a case-control study in 1,796 participants: 218 newly diagnosed IGR patients, 785 newly diagnosed T2D patients, and 793 individuals with normal glucose tolerance. After adjustment for age, sex, BMI, family history of diabetes, and hypertension, the multivariable odds ratio (OR) of T2D associated with a 10 mg/dL higher plasma zinc level was 0.87 (95% CI 0.85-0.90). Meanwhile, the OR of SLC30A8 rs13266634 homozygous genotypes CC compared with T T was 1.53 (1.11-2.09) for T2D. Similar associations were found in IGR and IGR&T2D groups. Each 10 mg/dL increment of plasma zinc was associated with 22% Our study suggested that the C allele of rs13266634 was associated with higher odds of T2D, and higher plasma zinc was associated with lower odds. The inverse association of plasma zinc concentrations with T2D was modified by SLC30A8 rs13266634. Further studies are warranted to confirm our findings and clarify the mechanisms underlying the interaction between plasma zinc and the SLC30A8 gene in relation to T2D.

BackgroundConsiderable controversy exists regarding the association between dietary calcium intake and risk of mortality from cardiovascular disease and all causes. Therefore, we performed a meta-analysis of prospective cohort studies to examine the controversy.MethodsWe identified relevant studies by searching MEDLINE, Embase, and the Cochrane Library databases between 1 September 2013 and 30 December 2013. Reference lists of relevant articles were also reviewed. Observational prospective studies that reported relative risks and 95% confidence intervals for the association of calcium intake with cardiovascular and all-cause mortality were eligible. Study-specific relative risks were pooled using a random-effects model.ResultsIn this meta-analysis, 11 prospective studies with 12 independent cohorts, involving 757,304 participants, were eligible. There was evidence of a non-linear association between dietary calcium intake and risk of mortality from cardiovascular disease (P for non-linearity <0.01) and all causes (P for non-linearity <0.01). A dose-response analysis showed a U-shaped relationship between dietary calcium intake and cardiovascular mortality. Intakes that were lower and higher than around 800 mg/day were gradually associated with a higher risk of cardiovascular mortality. For all-cause mortality, we also observed a threshold effect at intakes around 900 mg/day. The risk of all-cause mortality did not decrease further at intakes above 900 mg/day.ConclusionsThis meta-analysis of prospective cohort studies suggests that dietary calcium intake is associated with cardiovascular mortality in a U-shaped manner and that high dietary calcium intake (>900 mg/day) is not associated with a decreased risk of all-cause mortality.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-014-0158-6) contains supplementary material, which is available to authorized users.