Combined healthy lifestyle score and odds of rheumatoid arthritis in Iranian adults: a nested case-control from PERSIAN Dena Cohort Study (PDCS).

Abstract

Lifestyle factors play a significant role in the development of chronic diseases. While researchers have extensively studied individual lifestyle components, the combined impact of multiple lifestyle factors on rheumatoid arthritis (RA) remains unclear. This study aimed to explore the association between a Combined Healthy Lifestyle Score (CHLS) and the odds of developing RA among Iranian adults. A nested case-control study. The study was conducted in Dena County (Sisakht region) near Yasuj city, Iran, as part of the PERSIAN Cohort Study. 130 RA cases and 260 matched controls, aged 35-70 years. Cases were identified based on biochemical tests and rheumatologist consultation. Primary outcome was the odds of RA. Secondary outcomes included anthropometric measurements (body mass index (BMI), waist circumference) and dietary quality indicators. The CHLS score was calculated based on four parameters: smoking status, physical activity level, BMI and dietary quality, as assessed by the Healthy Eating Index-2020. Scores ranged from 0 (representing the unhealthiest lifestyle) to 4 (representing the healthiest lifestyle). Multiple logistic regression analysis was used to evaluate the association between CHLS and the odds of developing RA. Participants with higher CHLS exhibited significantly lower BMI and waist circumference compared with those with lower scores. Additionally, higher CHLS was associated with greater consumption of fruits and whole grains (p<0.05). Individuals with the highest CHLS had 90% lower odds of developing RA compared with those with the lowest scores (OR 0.105; 95% CI 0.024 to 0.461, p trend=0.001), after adjusting for potential confounders. Our findings suggest that adherence to a healthy lifestyle-characterised by non-smoking, regular physical activity, maintaining a normal BMI and following a healthy dietary pattern-is associated with reduced odds of developing RA among Iranian adults. The results of this study underscore the potential importance of combined lifestyle modifications in the prevention of RA. These insights emphasise the value of promoting comprehensive lifestyle changes as a strategy to mitigate RA risk.