Impact of insulin resistance and obesity on elevated blood pressure in Chinese children and adolescents: The BCAMS study

Abstract

Objective: Insulin resistance (IR) in the obese is closely related with cardiovascular diseases and their risk factors not only in adults but also in children and adolescents. We aimed to elucidate whether insulin resistance in non-obese children and adolescents is related with elevated blood pressure (BP). Methods: Subjects were recruited from a cross-sectional population-based survey: the Beijing Child and Adolescent Metabolic Syndrome (BCAMS) study. The present sample of 3480 students (1774 boys, 51%) was drawn from children aged 6 to 18 years who underwent physical examinations and fasted before blood testing. Obese was defined by age and gender-specific body mass index cutoffs of China. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated as fasting insulin (mU/L)×fasting glucose (mmol/L)/22.5. HOMA-IR levels above the highest quartile (>3.09 for boys and >2.83 for girls) were defined as IR. Participants were divided as four groups, i.e. normal group (non-obese and no IR, n=1923), IR group (non-obese but IR, n=338), obese group (obese but no IR, n=684) and obese combined IR group (n=535). Elevated BP was defined by systolic BP and/or diastolic BP equal to or greater than the 95th percentile for age and gender. Results: In obese combined IR groups, both systolic and diastolic BP levels were highest, followed by the obese, IR and normal groups (P<0.001 for trend) with age, gender and puberty adjusted. Prevalence of elevated BP was 8.2%, 16.1%, 29.2% and 38.3% in normal, IR, obese and obese combined IR groups, respectively (χ2=335.627, P<0.001 for trend). Adjusting for age, gender and puberty, compared with normal group, odds ratios and 95% confidence intervals of IR, obese and obese combined IR on elevated BP were 2.10 (1.50–2.96), 4.54 (3.56–5.80) and 6.21 (4.84–7.96), respectively. Conclusion: IR independently increases the risk of elevated BP not only in obese but also in non-obese children and adolescents.