The associations between healthful and unhealthful plant-based dietary patterns and all-cause mortality among older Chinese adults with data-adapted early-stage cardiovascular-kidney-metabolic syndrome (stages 0–2): a prospective cohort study from the CLHLS

Abstract

To examine the associations of the overall plant-based diet index (PDI), healthful plant-based diet index (hPDI), and unhealthful plant-based diet index (uPDI) with all-cause mortality in older Chinese adults with data-adapted early-stage cardiovascular-kidney-metabolic (CKM) syndrome (stages 0–2). We analyzed data from 5,872 participants aged ≥65 years from the 2008 wave of the China Longitudinal Healthy Longevity Survey (CLHLS) with data-adapted CKM stages 0–2 and no prevalent cardiovascular disease. Dietary intake was assessed using a validated food frequency questionnaire. Mortality was ascertained through March 2019. Cox proportional hazards models and restricted cubic spline analyses were used. During a median follow-up of 108 months, 2,870 deaths occurred. In multivariable-adjusted models, each 1-point increase in hPDI was associated with a 1.1% lower mortality risk (HR = 0.989, 95% CI: 0.982–0.995; p  < 0.001), whereas each 1-point increase in uPDI was associated with a 1.2% higher mortality risk (HR = 1.012, 95% CI: 1.006–1.019; p  < 0.001). Compared with the lowest quartile, the highest hPDI quartile had a 13.2% lower mortality risk (HR = 0.868, 95% CI: 0.783–0.961), and the highest uPDI quartile had a 19.2% higher risk (HR = 1.192, 95% CI: 1.060–1.340). Stratified estimates suggested numerically stronger associations in CKM stages 1–2 than in stage 0; however, formal interaction tests did not reach statistical significance ( p  = 0.062 for hPDI and p  = 0.824 for uPDI), indicating limited evidence of effect modification. Higher adherence to a healthful plant-based diet was associated with lower all-cause mortality, whereas higher adherence to an unhealthful plant-based diet was associated with higher mortality among older Chinese adults with data-adapted early-stage CKM syndrome. The overall PDI was not independently associated with mortality after adjustment, underscoring that plant-based dietary quality, rather than plant-based eating per se, is the relevant exposure.