Abstract: Objective To explore the potential impact of unhealthy diets on cardiovascular diseases and all-cause mortality. Methods This study included the individuals aged 35-70 years from 45 cities and 70 rural communities across 12 provinces in China, as part of the Prospective Urban Rural Epidemiology(PURE) study. Dietary habits were assessed using a food frequency questionnaire. The dietary health status was scored using the Alternative Healthy Eating Index(AHEI), with participants in the lowest tertile of AHEI being categorized into the unhealthy diet group, while others were classified as the healthy diet group. The primary endpoints included major cardiovascular diseases(myocardial infarction, stroke, or heart failure) and all-cause mortality. Cox proportional hazard models were used to estimate hazard ratios(HR) for each group. Results A total of 40 925 participants were included in the study, with a median follow-up time of 11.9 years(interquartile range 9.6-12.6 years). During this period, 2 066 deaths and 3 099 cases of major cardiovascular diseases were reported. The results showed that unhealthy diet increased the risk of major cardiovascular diseases by 10%(HR=1.10, 95% CI:1.02-1.20, P＜0.05) and all-cause mortality by 7%(HR=1.07, 95% CI:1.00-1.18, P＜0.05). Among male residents, unhealthy diet did not increase the risk of major cardiovascular diseases or all-cause mortality. However, among female residents, those with an unhealthy diet had a higher risk of major cardiovascular diseases(HR=1.12, 95% CI:1.00-1.25, P＜0.05) and all-cause mortality(HR=1.26, 95% CI:1.08-1.46, P＜0.05) compared to those with a healthy diet. Conclusions Unhealthy diet increases the risk of major cardiovascular diseases and all-cause mortality, particularly among women. There is a need to raise awareness about healthy dietary to prevent death and the occurrence of major cardiovascular diseases.

Key words: unhealthy diet, all-cause death, cardiovascular diseases