Fatores associados ao sobrepeso e à hipertensão arterial em escolares do município de Viçosa-MG.

Abstract

This study was carried out to verify the association between overweight and arterial hypertension with the occurrence and duration of the breast feeding, as well as the environmental factors associated to childhood overweight and the use of the anthropometry in predicting the high body fat, arterial hypertension and inadequate biochemical profile. It is a transverse study involving 769 children at the age range from 6 to 10 years, who were enrolled in public and private in Viçosa county -MG. Thefollowing variables were analyzed: weight, height, circumferences of the waist and hip, tricipital and subescapular skinfolds, arterial pressure, serum levels of the totalcholesterol, HDL- cholesterol, LDL- cholesterol, triglycerides and glucose. The percent body fat was estimated, by using predictive equations of specific skinfolds for this age range. The nutritional state and blood pressure were classified according to the Center for Disease Control and Prevention (CDC, 2000) and Brazilian Society of Hypertension (2002), respectively. The mothers´ nutritional state was defined according to classification proposed by the World Health Organization (1998). The mothers were preferentially applied a questionnaire involving the family aspects, gestation andchildbirth conditions, breastfeeding time, and physical activity practice by the child. The overweight prevalence, both diastolic and systolic arterial hypertension and the absence of breastfeeding were 9.9, 34.1, 9.3, and 6.8%, respectively. After controlling the confusion variables, by using the multiple logistic regression, no statistical association were found between the occurrence and duration of the breastfeeding to theprevalence of overweight and arterial hypertension at the school age. Based on the multiple logistic regression analysis, the main factors associated to the childhood overweight are: maternal obesity (OR: 6.92; p < 0.001), to be single child (OR: 1.87; p = 0.03), time above three 3h daily in front of TV (OR: 1.91; p = 0.04), no accomplishment of physical education in school (OR: 4.80; p = 0.02) and to be masculine sex (OR: 2.60; p = 0.001). Either overweight and overweight risk classified by CDC (2000) were significantly associated to the highest values of systolic blood pressure (overweight: OR: 1.17; IC: 1.06 1.30; p = 0.002 / overweight risk: OR: 1.09; IC: 1.04 1.13; p < 0.001), higher percent body fat (overweight: OR: 1,41; IC: 1,11 1,79; p = 0.005 / overweight risk: OR: 1.41; IC: 1.25 1.59; p < 0.001) and higher fat accumulation in the abdominal area (overweight: OR: 1.59; IC: 1.23 2.05; p < 0.001 /overweight risk: OR: 1.31; IC: 1.17 1.47; p < 0.001), compared to eutrophy, according to the multiple logistic regression analysis. The waist circumference also showed association with either percent body fat and the systolic and diastolic blood pressure, according to the multiple linear regression analysis. No association occurred between the body mass index (BMI) and waist circumference with the biochemical profileneither the BMI with the diastolic blood pressure. The absence of either protective effect and the response-dose relationship of the breastfeeding on the overweight and on arterial hypertension rather suggests the need for new scientific researches, specially in longitudinal-type ones, because there is higher probability to obtaining more accurate estimates of the human-milk impact along the life. In addition, this study makespossible the identification of the potentially modified environmental factors associated to the overweight in children at Viçosa county-MG. The determination of these factors is important, since the increased overweight prevalence in the childhood cannot be totally explained by the genetic factors. It is important to emphasize that the cutoff points established by CDC (2000) to defining the overweight and overweight risk for BMI are accurate for classification of the children showing high percent body fat, centrally distributed fat and higher levels of systolic blood pressure. The waist circumference is an important complementary measure of the BMI in populational studies. However, further studies are necessary so that BMI and the waist circumference could be reliably adopted as reference methods for estimating adiposity, as well as for adeeper investigation about their associations with the biochemical profile and diastolic blood pressure.