Association between life’s simple 7 (LS7) and arthritis: the mediating role of body fat percentage (BFP)

Life’s Simple 7 (LS7), developed by the American Heart Association, addresses seven key health behaviors and relationship factors. Although LS7 has been studied in relation to various chronic diseases, its association with arthritis remains unclear. This study seeks to investigate the association between LS7 and arthritis, with particular emphasis on the mediating role of body fat percentage (BFP).

Data from the 2011–2018 National Health and Nutrition Examination Survey (NHANES), including 16,332 adult participants, were analyzed. The connection between LS7 and arthritis was evaluated using multivariable logistic regression, smooth curve fitting, and subgroup analysis. Mediation analysis assessed the role of BFP in this relationship. Additionally, ROC curve analysis was used to assess the predictive performance of the model, and the Boruta algorithm identified the influential factors associated with arthritis.

After adjusting for relevant covariables, each standard deviation increase in LS7 was linked to a 13% lower likelihood of arthritis [OR = 0.87, 95% CI: 0.84, 0.89]. Participants in the highest LS7 tertile (T3) exhibited a 50% reduced likelihood of developing arthritis compared to those in the lowest tertile (T1) [OR = 0.50, 95% CI: 0.43, 0.60]. Mediation analysis confirmed that BFP significantly mediated the LS7-arthritis relationship. Furthermore, the Boruta algorithm identified LS7 and BFP as key variables associated with arthritis.

Elevated LS7 scores were associated with a lower likelihood of arthritis, with BFP serving as a mediating factor. Improving LS7 scores and managing body fat may help prevent arthritis. Due to the study’s cross-sectional design, causality cannot be confirmed. Future research should use longitudinal studies to verify these findings and target high-risk groups.