Overweight and obesity in children and adolescents: relationship with blood pressure, and physical activity

Objective: Using body mass index (BMI) quartiles, the present study's aims were (1) to describe and evaluate the relationship between overweight/obesity with cardiovascular disease (CVD) risk factors, such as systolic blood pressure (SBP), diastolic blood pressure (DBP) and physical activity; (2) to provide information on the prevalence of high blood pressure and physical activity according to BMI quartiles; and (3) to examine the relationship of risk of obesity to adverse levels of high blood pressure and physical activity. Methods: The sample consisted of 1439 children (758 males and 681 females), 8-16 years old. Participants were classified as being at 'risk of obesity' according to age- and sex-adjusted fourth quartile of BMI values. Blood pressure was measured using the Dinamap monitor. An adapted version of the Weekly Activity Checklist was applied for the diagnosis of physical activity index (PAI). Results: Systolic and diastolic blood pressures were significantly (p < 0.05) and positively related to BMI, whereas no significant associations were reported between BMI and PAI in both genders. Overall, the proportion of subjects with adverse levels of blood pressure (SBP or DBP) ranged from 21.3% in the first BMI quartile (BMI-IQ) to 30.4% in BMI-4Q (p < 0.05). The PAI ranged from 24.5% in BMI-1Q to 20.6 in BMI-4Q and no significant differences were found. Children and adolescents at 'risk of obesity' were 1.5 times as likely to have at least one risk factor (high blood pressure or low level of activity). Conclusions: Our data suggest that higher BMI is associated with higher values of SBP and DBP. Children and adolescents in the upper quartile of BMI are 1.5 times as likely to have at least one risk factor. Furthermore our data confirmed previous findings that higher levels of BMI are associated with a unfavourable risk profile for CVD risk factors.