Obesity and insulin secretion in fasting high school students.

The relationship between plasma glucose, serum insulin, serum C-peptide and obesity was studied in 320 fasting high school students (13-18 years old), as part of a Busselton population study. For males and females respectively plasma glucose was 4.5 +/- 0.4 and 4.4 +/- 0.5 mmol/l (mean +/- SD), serum insulin 0.51 +/- 0.35 and 0.69 +/- 0.39 log10 (nmol/l X 100), and serum C-peptide 0.48 +/- 0.15 and 0.55 +/- 0.14 nmol/l. These sex differences were not statistically significant. Plasma glucose correlated with C-peptide (r = 0.21, p < 0.001) and insulin (r = 0.32, p < 0.001), indicating greater secretion where fasting glucose was higher. Obesity, measured as skin fold thickness, was also associated with serum C-peptide (r = 0.32, p < 0.001) and insulin (r = 0.37, p < 0.001).