Preserved vegetable consumption and its association with mortality among 440,415 people in the China Kadoorie Biobank

BACKGROUND: Fresh vegetable consumption has been associated with lower incidence of cardiovascular disease (CVD). However, whether preserved vegetable consumption is linked with CVD and mortality remains unclear. This study aimed to assess the associations of preserved vegetable consumption with all-cause and cause-specific mortality. METHODS: A total of 440,415 participants free of major chronic diseases, aged 30–79 years, were enrolled from 10 diverse regions in China between 2004 and 2008 and were followed up for an average of 10 years. Preserved vegetable consumption was assessed using a validated food frequency questionnaire. Cause-specific hazard models with the consideration of competing risk from various deaths were performed to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of mortality. RESULTS: During 4,415,784 person-years of follow-up, we documented 28,625 deaths. After adjustment for major risk factors, preserved vegetable consumption was marginally associated with higher CVD mortality (P = 0.041 for trend and P = 0.025 for non-linearity) but not associated with cancer mortality and total mortality. For specific causes of death, consuming preserved vegetables was associated with higher hemorrhagic stroke mortality. The multivariable-adjusted HRs (95% CIs) of hemorrhagic stroke mortality compared with non-consumers were 1.32 (1.17–1.50) for 1–3 days/week and 1.15 (1.00–1.31) for regular consumers (≥4 days/week) (P = 0.006 for trend and P < 0.001 for non-linearity). In addition, regular preserved vegetable consumption was associated with increased risk of digestive tract cancer mortality [HR (95% CI): 1.13 (1.00–1.28); P = 0.053 for trend] and esophageal cancer mortality [HR (95% CI): 1.45 (1.17–1.81); P = 0.002 for trend]. CONCLUSIONS: Frequent consumption of preserved vegetables was associated with higher risk of mortality from hemorrhagic stroke and esophageal cancer in China. Our findings suggest limiting preserved vegetable consumption might be protective for premature death from hemorrhagic stroke and digestive tract cancer. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12916-023-02829-3.