Intensity-Specific Physical Activity Measured by Accelerometer, Genetic Susceptibility, and the Risk of Kidney Stone Disease: Results From the UK Biobank

Rationale & Objective Kidney stone disease (KSD), a significant healthcare problem within both developed and developing countries, has been associated with genetic risk factors. As well, an association between physical activity and KSD risk has been hypothesized but studies have yielded inconsistent findings. This study aimed to investigate the association between the intensity of physical activity and the incidence of KSD accounting for genetic risk. Study Design Prospective cohort study. Setting & Participants A total of 80,473 participants from the UK Biobank Study. Exposures Physical activity levels, including total physical activity (TPA), moderate-to-vigorous intensity physical activity (MVPA), and light-intensity physical activity (LPA), were measured using accelerometers and quantified using a machine learning model. A polygenic risk score (PRS) for KSD was also constructed. Outcomes Individuals with KSD were identified using the International Classification of Diseases 10th Edition, and procedure codes for KSD surgery. Analytical Approach A Fine and Gray survival model was used to estimate the associations of incident KSD with TPA, MVPA, LPA, and PRS (as categorical variables). Restricted cubic splines were used to examine potential non-linear associations within the fully adjusted models. Results During an average follow-up of 6.19 years, 421 participants developed KSD. Participants in the highest quartiles of TPA, MVPA, and LPA had lower adjusted rates of KSD compared to those in the lowest quartiles: HRs (95% confidence interval) of 0.50 (0.44, 0.56), 0.57 (0.51, 0.64), and 0.66 (0.59, 0.74), respectively. TPA, MVPA, and LPA were associated with lower risk of KSD in participants with low and high genetic predisposition for KSD. Limitations Selection bias as participants who provided accelerometry data may have been more adherent to health care. Conclusion Physical activity was negatively associated with the risk of KSD, regardless of the genetic risk. Future large studies are warranted to confirm and explain the mechanisms underlying these associations.