Weight loss reduces the incidence of dipstick proteinuria: a cohort study from the Japanese general population.

ABSTRACT

BACKGROUND: Though elimination of obesity is one of main therapeutic goal for lifestyle-related diseases, the impact of appropriate weight loss on reduction of the incidence of proteinuria in the general population is still unclear. METHODS: The study cohort was based on a general population of 9,33,490 from 40 to 74 years of age who had undergone annual specific health checkups. The subjects who were finally included were the 2,74,598 people for whom all the data necessary for this study were available. The incidence of proteinuria in this study was defined as negative proteinuria at the primary and secondary survey years, and newly developed proteinuria during subsequent follow-up years. RESULTS: Whereas people with rapidly decreased weight tended to have a high incidence of proteinuria in the underweight (BMI < 18.5 kg/m2) and normal weight (18.5-24.9 kg/m2) groups, the obese group (≥ 25.0 kg/m2) with rapidly decreased weight had a lower incidence compared to those with stable weight. In the obese population, a rapid decline of BMI (- 1 to - 5 kg/m2 per year) was associated with a reduced risk (hazard ratio [95% confidence interval]; 0.89 [0.80-0.98], P = 0.02) of proteinuria. CONCLUSIONS: Weight reduction can lead to a risk reduction of 11% in the incidence of proteinuria in obese Japanese adults. This is the first study to report the effects of weight reduction on the early phase of chronic kidney disease in obesity relevant to the characteristics of the Japanese general population. The present findings might have a role in renal health promotion in Japan.