The blood biochemical parameters —  lipid profile (total cholesterol, LDL, HDL and triglycerides), plasma glucose, insulin, HbA₁c, urea, and creatinine — of Indian adolescents were measured in a large study involving over 7,600 subjects. This can now be used as reference for Indian adolescents. Till now, since biochemical parameters for Indian adolescents were not available, doctors had to rely on adult normative range, which is not scientifically correct.

For the first time, the blood biochemical parameters of Indian adolescents have been measured on a large scale and a normative range arrived at. Since biochemical parameters for Indian adolescents were not available, doctors had to rely on adult normative range. This is scientifically not correct as children are immunologically naïve and so respond quite differently compared with adults.

Some of the blood biochemical parameters studied are lipid profile (total cholesterol, LDL, HDL and triglycerides), plasma glucose, insulin, HbA₁c, urea, and creatinine. The study involved over 7,600 Indian adolescents (over 3,300 boys and about 4,300 girls) aged between 11–17 years from Delhi. Besides studying the blood biochemistry, the researchers from the Institute of Genomics and Integrative Biology (CSIR-IGIB) looked at the variation in the parameters with respect to gender and age during adolescence.

The normative range for fasting plasma glucose for Indian adolescents was found to be slightly lower than Nigerians and Croatians. Similarly, for plasma insulin, the range is less than Canadian adolescents.  The mean plasma glucose and insulin levels were found to be lower than the values measured earlier by others in a smaller number (695) of Indian adolescents.

Girls were found to be more insulin resistant than boys. “Girls were found to have more insulin but less fasting glucose than boys. The higher insulin resistance in girls is due to the hormones released during puberty. To compensate for this, there is more insulin secreted in girls. And more the insulin the less is the glucose level,” says Dr. Dwaipayan Bharadwaj from the School of Biotechnology at Jawaharlal Nehru University (JNU), who led the study.

The study found that boys have lower HbA₁c, a marker for diabetes, than girls. “Boys produce more testosterone hormone and this cause more haemoglobin production leading to lower HbA₁c value,” he says. Boys were found to have more urea and creatinine. This is because boys have more muscle mass than girls and so release more protein metabolites — urea and creatinine.

“Though our study, sponsored by CSIR-DBT, looked at adolescents belonging to an urban population in Delhi, it can still be used as normative range of commonly studied blood biochemical parameters,” says Dr. Bharadwaj. The results were published in the journal PLOS ONE.

“We used the samples collected to study childhood obesity genetics for measuring the biochemical parameters. So the samples were not collected in an epidemiologically correct way. So a little bias may be seen. But we have a huge number of samples so that bias gets nullified,” says Dr. Bharadwaj.

Published in The Hindu on March 22, 2019