New Delhi. In healthy men of normal weight, relatively small increases in weight raise the risk of chronic kidney disease (CKD), said Dr KK Aggarwal, President Heart Care Foundation of India.

Quoting a study in the Journal of the American Society of Nephrology, Dr Aggarwal said that CKD should be added to the list of conditions that are associated with weight gain, including diabetes and high blood pressure. Obesity is a known risk factor for CKD, but weight gain in normal-weight individuals without high blood pressure or diabetes is now shown to be an added risk factor.

The experts followed 8792 healthy men aged 30 to 59 years with no known risk factors for CKD between 2002 and 2007. The prevalence of obesity was about 33 percent. The researchers observed a U-shaped association between changes in weight categories among normal-weight and overweight subjects and the development of CKD.

Men who lost or gained a lot of weight (more than 0.75 kilograms, or 1.7 pounds, per year) had the highest risk of developing CKD. Increased risk was seen among men with even small weight changes. The lowest risk observed was among those who gained or lost as little as 0.25 kilograms, or 0.6 pounds, per year.

The findings suggest that weight gain within 'the normal' weight range is clearly one of the risk factors in developing CKD, and initial low body mass index does not counteract the deleterious effect of weight gain. Avoidance of weight gain, even among lean individuals, is important to reduce the risk for this disease.