Association between Overall Lifestyle Changes and the Incidence of Proteinuria: A Population-based, Cohort Study

OBJECTIVE: This study aimed to examine the association between the changes in an overall healthy lifestyle, as quantified by the number of unhealthy lifestyle factors and obesity status, and the incidence of proteinuria in the general Japanese population. METHODS: A retrospective cohort study was conducted among 99,404 (men, 36.9%) participants aged from 40-74 years of age who underwent two health check-ups with a 1-year interval in Japan between 2008 and 2009. Any participants with chronic kidney disease at baseline were excluded. The smoking status, body mass index, physical activity, alcohol consumption, and healthy eating habits were combined into a simple overall healthy lifestyle score ranging from 0 to 5. The changes in overall healthy lifestyle scores from baseline (range, -5 to +5) and the incidence of proteinuria, defined by a dipstick urinalysis (score ≥1+), were assessed at the second check-up. A logistic regression analysis was used to examine the association between the changes in overall healthy lifestyle scores and the incidence of proteinuria. RESULTS: After one year of follow-up, 3.9% of men and 2.4% of women developed proteinuria. Each increase (or decrease) in the changes in overall healthy lifestyle scores was associated with a reduced (or increased) risk of proteinuria in both men (odds ratio (OR) 0.87; 95% confidence interval (CI), 0.81-0.94) and women (OR 0.87; 95%CI, 0.80-0.94) after adjusting for age, baseline lifestyle scores, hypertension, diabetes mellitus, and hypercholesterolemia. Stratified analyses based on age, the presence or absence of hypertension, or diabetes mellitus revealed similar results. CONCLUSION: Overall lifestyle changes, even within a year, were found to influence the incidence of proteinuria.