Screen time, body mass index and neck circumference: is there an association with social class in children?

Abstract

Life habits during childhood are decisive for future health conditions. The aim of this study was to evaluate screen time and anthropometry of children enrolled in municipal schools in the interior of the State of São Paulo. A cross-sectional study was carried out with students from 9 to 10 years of age from a city in the State of São Paulo, Brazil. A socioeconomic questionnaire validated by the Brazilian Association of Research Companies was used, containing also the determination of screen time (TV, video game, computer and cell phone), recommended by the Pediatrics Society. Anthropometry data was collected according to the Lohmam Anthropometric Standardization Reference Manual and compared to the z-score level with the WHO 2007. For the statistical analysis, Kruskal-Wallis, Chi-square or Fisher’s Exact tests were used.The confidence level was at 95%. Out of the 703 schoolchildren assessed, 97.44% had adequate height, 59.17% eutrophy BMI and 30.44% overweight. There was a correlation between BMI and non-stratified social class (p=0.038) and BMI and neck circumference (NC) (p<0.001).The z-score of the BMI showed that children with weight loss stayed longer watching TV (p=0.0486). The gender comparison showed that girls of higher social class stayed longer at the computer (p=0.0351) and using the cell phone (p<0.0001), and boys playing videogame (p=0.0005). Overweight and weight loss shown in the positive correlation between BMI and NC, although on opposite sides, were associated with screen time and especially with TV in children of higher social class.