1. Higher leptin levels in girls compared to boys: Higher leptin levels were also observed in control girls compared to boys (7.5 ± 3.7 versus 4.3 ± 5.26 ng/mL). Higher leptin levels have been reported in prepubertal normal-weight girls compared to boys in a previous study(2). This gender difference in leptin levels in children might be related to the greater pubertal maturation in girls. This should be looked into in future studies.

2. The hypothesis that gender dimorphism is likely to be due to a testosterone effect may not be correct. This can be confirmed only by long-term studies on obese girls and boys. In boys, studies had shown that the leptin levels rose in parallel to weight till the age of 10 years, when a striking decrease was observed as testosterone levels rose(2). Given the proposed role of leptin in induction of puberty, higher levels are expected in girls who achieve puberty earlier than boys.

3. One wonders whether higher leptin levels were due to greater adiposity in obese girls (as a cause, not an effect): It is unclear whether elevated leptin levels are a cause or effect of obesity from the present study. Mere demonstration of elevated leptin levels in obese individuals as in our study does not prove a causative role of leptin resistance in the pathogenesis of obesity.

4. Leptin levels adjusted for body mass index (BMI) and BMI standard deviation scores (BMI SDS) may have provided further information. This may indeed be the case as leptin levels correlated well with BMI(1). Importantly the rise in leptin levels was independent of Tanner stage when controlling for adiposity. Similar observations have been reported by Hassink, et al previously(3). Long-term studies with comparison of leptin levels in obese girls and boys after adjustment of BMI as suggested would be helpful in deciding whether true leptin resistance is present in obese Indian girls. However such a study would be resource-intensive and demanding.

5. If serum leptin levels are truly low or undetectable, one must consider the possibility of leptin mutations in these children and hence proceed to leptin gene sequencing. We agree with the suggestion that leptin deficiency should be considered in obese children with low or undetectable leptin levels.