Effect of breastfeeding on obesity of schoolchildren: Influence of maternal education

Abstract

Objective To evaluate the association between duration of breastfeeding (BF) and obesity in schoolchildren of Florianópolis (SC), and the role of possible effect modifiers. Methods Cross-sectional study with a random sample of 2,826 schoolchildren (7-14 years). Weight and height were measured according to standardized procedures. Data concerning BF and sociodemographic variables were obtained from a questionnaire sent to parents/guardians. Children's nutritional status was evaluated by BMI-for-age z-score for gender (WHO reference curves). Adjusted analyses were performed through logistic regression, considering a possible interaction among variables. Results Prevalence of obesity was 8.6% (95% CI: 7.6-9.7%) and 55.7% (95% CI: 53.8-57.6%) received breastmilk for ≥6 months. BF was not associated with obesity, even in the adjusted analysis. Stratified analysis according to maternal schooling showed that, in children aged 7-10 years and children whose mothers had 0-8 years of schooling, the chance of obesity was lower among those breastfeed for >1 month, especially among those who received breastmilk for 1-5 months (OR=0.22; 95% CI 0.08-0.62). Among children of women with higher educational level (>8 years), the chance of obesity was 44% lower in those who were breastfed for >12 months (p-value for interaction <0.01). This interaction was not found in older children (11-14 years). Conclusions Among children of women with lower schooling, BF for any period longer than 1 month is protective against obesity; however, for a higher maternal schooling, BF for less than 12 months increases the odds of obesity.