Impact of Overall Diet Quality on Association between Alcohol Consumption and Risk of Hypertension: Evidence from Two National Surveys with Multiple Ethnics

Background: Larger effect of overall diet quality on cardio-metabolic disease than individual food or nutrient, and inconsistent results regarding saturated fat and coronary heart disease in the 'French Paradox' led us to hypothesize that health effects of the same food or nutrient may be influenced by overall diet quality. To demonstrate this hypothesis, this study examined whether overall diet quality influence association between alcohol and risk of hypertension. Methods: This study used data of National Health and Nutrition Examination Survey (NHANES), China Health Nutrition Survey (CHNS) and Harbin Cohort Study, totally including 43,914 adults. Subgroup analysis included 6,984 adults from CHNS with 14-year follow-up. Alternative health eating index and diet balance index were calculated as indicators of overall diet quality. Logistic regression and Cox's proportional-hazards regression were performed to investigate the association alcohol-consumption and risk of hypertension by overall diet quality. Findings: In context of high diet quality, light to moderate alcohol consumption was significantly associated with decreased risk of hypertension in Caucasians, and heavy alcohol consumption was not associated with increased risk of hypertension in Caucasians, Asians and Hispanics. On the contrary, in context of low diet quality, light to moderate alcohol was not associated with decreased risk of hypertension, and heavy alcohol consumption was consistently significantly associated with increased risk of hypertension in Caucasians, Asians and Hispanics. Interpretation: This study firstly demonstrated that overall diet quality influenced associations between alcohol and risk of hypertension across different ethnics, emphasizing that when examining associations between individual food or nutrient, it should consider what kinds of overall diet quality are they in. Public health strategies for alcohol should be made with considering the impact of overall diet quality besides alcohol alone. Funding: This research was supported funds from National Key R&D Program of China (2017YFC1307401 to Changhao Sun). Declaration of interests: The authors declare no conflict of interests. Ethics Approval Statement: The protocol was approved by the Ethics Committee of the Harbin Medical University, and written informed consent was provided by all subjects.