Crowd Drinking And Cancer Death And Total Mortality In The Prospective Cohort Studies And Supplemental Omega-3 Fatty Acids To Improve Endothelial Function In Clinical Studies For Meta-analysis

Part One:The impact of alcohol consumption on the risk of all-cause and cancer mortality in Chinese AdultsObjectives Moderate alcohol consumption is associated with decreased risk of coronary heart disease. However, excessive alcohol consumption might lead to addiction, traffic accidents and potential fatal medical problems. It was estimated that mortality attributable to excessive alcohol intake was equivalent to that attributable to tobacco. In China, drinking alcoholic beverages is a common feature of social gatherings. In recent years, the prevalence of drinking keeps increasing, especially in women and adolescents. However, the relationships between alcohol consumption and all-cause and all-cancer mortality have not been well established in Chinese population.Materials and methods We assessed the effects of alcohol consumption on the risk of all-cause and all-cancer mortality in a large, prospective cohort study with nationally representative sample of169,871Chinese adults aged40years or older. The survey was initiated in1991, and investigators for China National Hypertension Survey collected data on alcohol consumption and other risk factors at a baseline examination using a standard protocol. Follow-up evaluation was conducted in1999and2000, with a response rate of93.4%. Alcohol consumption was ascertained at baseline by means of an interviewer-administered questionnaire. Alcohol consumption was defined as having drunk alcohol at least12times during the past year. It was assumed that12.5gram of ethanol was one drink. Participants were classified into different groups by the amount of alcohol consumed per week (drinks/week). Light to moderate drinkers were stratified into<14.0drinks/week in men and<7.0drinks/week in women. We further explored the association among the duration of alcohol consumption, total alcohol exposure, drinking age and type of alcohol consumed and all-cause death and cancer mortality risk. Cox proportional hazard regression model was used for estimation of relative risks (RRs) and corresponding confidence intervals (CIs).Results During an average8.3years of follow-up (1,055,739person-years),17,493participants (9,815men and7,678women) died,3,803of which died from cancer (2,376men and1,427women). After adjusted for baseline age, systolic blood pressure, cigarette smoking, body mass index (BMI), high school education, physical inactivity, geographic region and urbanization, U-shaped relationship was found between alcohol consumption and all-cause mortality in men (P for nonlinear trend:<0.001). The lowest all-cause mortality in men occurred with light to moderate alcohol consumption (<14.0drinks/week), with corresponding RRs (95%CIs) of0.85(0.80to0.91). Alcohol consumption was linearly associated with total death in women (P for linear trend:0.012). No benefit from light to moderate alcohol intake against all-cause mortality was observed in women, with RRs (95%CIs) of1.21(1.04,1.41). Causes of death associated with heavy drinking (>35.0drinks/week for men and>7.0drinks/week for women) were total cancers, liver cancer, lung cancer, liver cirrhosis and unexpected death in men; and all-cause mortality, digestive cancer and stroke in women. In addition, increased risk was observed in the participants who started drinking in their early life. The protective effect of alcohol intake was not restricted to any specific type for all-cause mortality in men. In stratified analyses, we found that the benefical effects of alcohol consumption on the risk of death were more apparent among participants with more than65.0years old, overweight or obesity or nonsmokers in men. After excluding the individuals who died in the first follow-up year or the participants with cardiovascular disease history at baseline, the relationships between alcohol consumption and all-cause and cancer mortality were not changed materially both in men and women. Estimates of linear relative rate model suggested that greater drinks/day for a shorter duration was more deleterious than fewer drinks/day for a longer duration. Finally, we found that4.0%of all-cancer deaths in men and6.5%all-cause deaths in women were attributable to heavy drinking in China.Conclusions Although the net benefit of moderate alcohol consumption for total mortality was observed in men, drinking of alcohol should be deliberated in public health implication considering the gender difference in alcohol metabolism and adverse effect of heavy drinking on the health of total population. Part Two:Effect of omega-3fatty acids supplementation on endothelial function: a meta-analysis of randomized controlled trialsObjective Inverse association was reported between omega-3fatty acids (FAs) supplementation and the risk of cardiovascular disease. Identifying the effect of omega-3FAs on endothelial function may contribute to explain the association. We conducted a meta-analysis to assess the effect of omega-3FAs supplementation on endothelial function, as measured by flow-mediated dilation (FMD) and endothelium-independent vasodilation (EIV).Materials and methods Randomized placebo-controlled trials (RCTs) were identified from the databases of PubMed, EMBASE and Cochrane library by two investigators and the pooled effects were measured by weighted mean difference (WMD), together with95%confidence intervals (CIs). Subgroup and meta-regression analyses were used to explore the source of between-study heterogeneity.Results Totally16eligible studies involving901participants were finally included in meta-analysis. Compared with placebo, omega-3FAs supplementation significantly increased FMD by2.30%(95%CI:0.89-3.72%, P=0.001), at a dose ranging from0.45to4.5g/d over a median of56days. Subgroup analyses suggested that the effect of omega-3FAs on FMD might be modified by the health status of the participants or the dose of supplementation. Sensitivity analyses indicated that the protective effect of omega-3on endothelial function was robust. No significant change in EIV was observed after omega-3FAs supplementation (WMD:0.57%;95%CI:-0.88-2.01%; P=0.442).Conclusion Supplementation of omega-3fatty acids significantly improves the endothelial function without affecting endothelium-independent dilation.