The dose-response relationship between body mass index and the risk of incident stage ≥3 chronic kidney disease in a General Japanese Population: The ibaraki prefectural health study (IPHS)

Abstract

Purpose: To examine the relationship between body mass index (BMI) and the risk of stage ≥3 chronic kidney disease (CKD) in a general Japanese population. Methods: A total of 105 611 participants aged 40-79 years who completed health checkups in Ibaraki Prefecture, Japan, and were free of CKD in 1993 were followed-up through 2006. Stage ≥3 CKD was defined by an estimated glomerular filtration rate <60 mL/min/1.73m2 reported during at least 2 successive annual surveys or as treatment for kidney disease. Hazard ratios (HRs) for the development of stage ≥3 CKD relative to the BMI categories were calculated using the Cox proportional hazards regression model, which was adjusted for possible confounders and mediators. Results: During a mean follow-up of 5 years, 19 384 participants (18.4%) developed stage ≥3 CKD. Compared to a BMI of 21.0-22.9 kg/m2, elevated multivariable-adjusted HRs were observed among men with a BMI =23.0 kg/m2 and women with a BMI =27.0 kg/m2. Significant dose-response relationships between BMI and the incidence of stage ≥3 CKD were observed in both sexes (P for trend <0.001). Conclusions: Obesity was associated with the risk of developing stage ≥3 CKD among men and women.