Plant-based diet and risk of arthritis: a nationwide cohort study of the Chinese elderly population

<i>Background</i>. This study was aimed at investigating the association between a plant-based diet and the risk of arthritis and at identifying a strategy that achieves the ambitious goal of healthy aging. <i>Methods</i>. The nationwide cohort study included 10 059 adults aged 65 and older from the 2008-2018 waves of the Chinese longitudinal healthy longevity survey (CLHLS). Dietary intake was collected using a simplified food frequency questionnaire and used to calculate the plant-based diet index (PDI). Arthritis was defined as participants self-reporting suffering from arthritis. Time-dependent Cox regression model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the risk of arthritis. Interaction analysis was used to explore the interaction between PDI and exercise status. Stratified analyses were used to examine factors that may modify the association. <i>Results</i>. During a median follow-up period of 4.2 years, 1482 participants who were free of arthritis at baseline reported arthritis. The highest quality of plant-based diet was associated with a 16.0% decrease in the risk of suffering from arthritis (HR: 0.840, 95% CI: 0.757, 0.932). Interaction analysis showed that participants with a high PDI and exercise had a significantly lower risk of arthritis. Stratified analysis showed that the association between PDI and arthritis was significant among participants living in rural areas. <i>Conclusions</i>. Greater adherence to a plant-based diet may help delay the onset of arthritis symptoms. Promoting plant-based dietary patterns may be a strategy to reduce arthritis incidence and improve healthy life expectancy.