Body mass index and preclinical kidney disease in Indian adults aged 40 years and above without chronic kidney disease.

Background: Obesity is associated with diabetes and hypertension, two major risk factors for chronic kidney disease (CKD). Recently, it has been shown that obesity is associated with preclinical kidney disease defined by elevated levels of cystatin C among those without CKD in US adults. However, the association of obesity with cystatin C is not known in industrialized Asian populations.

Methods: We examined 2,052 Indian adults aged 40-80 years in Singapore who were free of CKD defined as a serum creatinine-based estimated glomerular filtration rate (eGFRcr) <60 mL/min/1.73 m(2) and/or the presence of microalbuminuria. Body mass index (BMI) values were categorized into normal (18.5-24.9), overweight (25-29.9) and obese (≥30 kg/m(2)). Elevated serum cystatin C was defined as cystatin C ≥1 mg/L.

Results: Overweight and obesity were significantly associated with elevated levels of cystatin C after adjusting for potential confounders including diabetes and hypertension and eGFRcr. Compared to those with normal weight, the odds ratio (95 % confidence interval) of elevated cystatin C was 1.49 (1.17-1.88) for overweight and 3.20 (2.33-4.39) for obese. This association was consistently present when BMI was analyzed as a continuous variable and also in subgroups of men, women and in those without diabetes mellitus or hypertension.

Conclusions: Higher BMI levels are associated with preclinical kidney disease in Indian adults aged 40 years and above without CKD.