Factors influencing blood pressure control in children and adolescents.

OBJECTIVE: To investigate the incidence of increased blood pressure among children and adolescents and its relation with the anthropometric indexes, fasting insulin, insulin sensitivity indexes and lipid levels.

BACKGROUND: Sufficient evidence suggests that the incidence of essential hypertension among children and adolescents is rapidly increased parallel to the incidence of obesity among these subjects.

METHODS: We investigated 154 school-aged children; 77 males and 77 females, aged 11.28+/-2.99 (4-18) years old. After an overnight (12 h) fasting, we measured the following: anthropometric parameters, insulin (micro units/ml), glucose (mg/dl), cholesterol (mg/dl), cholesterol-HDL (mg/dl), cholesterol-LDL (mg/dl), triglycerides (mg/dl), uric acid (mg/dl), systolic and diastolic blood pressure (BP) (mmHg), HOMA-R index, QUICKI index and estimated glomerular filtration rate (eGFR).

RESULTS: Boys showed greater body weight than girls as well as greater height and waist circumference. High normal systolic and diastolic BP measurements were more frequent among boys (HN-SBP: 27.2% vs. 16.8%, P=0.002. HN-DBP: 23.3% vs. 16.8%, P=0.05), but girls showed a higher frequency of systolic and diastolic high BP (H-SBP: 5.2% vs. 3.8%, P=0.6 (NS). H-DBP: 10.4% vs. 3.8%, P=0.05). Girls showed higher insulin levels and HOMA-R index values than boys, as well as higher levels of total cholesterol, triglycerides and LDL-cholesterol. Boys exhibited greater values of estimated glomerular filtration rate than girls. The most important factors influencing systolic and diastolic BP were the waist circumference (central obesity) and the body weight. Fasting insulin levels showed a biphasic effect upon systolic and, especially, diastolic BP. Normoinsulinemia exhibited a positive effect upon systolic and diastolic BP but high insulin levels exhibited a negative effect upon diastolic BP. No considerable effect of lipid parameters was found upon BP.

CONCLUSIONS: Our results suggest that anthropometric indexes, particularly central obesity and body weight play the most important role in BP control among children and adolescents. Girls exhibit greater frequency of high BP than boys, as well as greater frequency of other metabolic syndrome risk factors. Insulin levels and insulin sensitivity are important factors influencing BP control. Insulin, per se, plays a pivotal role in BP control, normoinsulinemia produce a positive effect upon BP, but high insulin levels exert a hypotensive action.