Child’s body mass index and mother’s obesity: the moderating role of physical fitness

Abstract

The aim of this study was to verify the association between children’s body mass index and their mother’s obesity, considering children’s physical fitness as a possible moderator. Cross-sectional study developed with 1842 children and adolescents, aged seven to 17 years, from Santa Cruz do Sul-RS, Brazil. Body weight and height were assessed to determine body mass index. Cardiorespiratory fitness was determined by the 6-min walk/run test and muscular strength through the lower limb strength test. Mother’s perception of obesity was self-assessed. Moderation was tested through a SPSS program extension. Results indicated that higher children’s body mass index (p < 0.001) and lower levels of cardiorespiratory fitness (p = 0.001) and muscular strength (p = 0.035) were associated with mother’s obesity. Likewise, higher body mass index (p < 0.001) and lower cardiorespiratory fitness (p < 0.001) in adolescents were associated with maternal obesity. Moreover, physical fitness moderates the relationship between body mass index and mother’s obesity in children (cardiorespiratory fitness: β = − 0.006; 95% CI = (− 0.010, − 0.001); muscular strength: β = − 8.415; 95% CI = (− 12.526, − 4.304)) and in adolescents (cardiorespiratory fitness: β = − 0.004; 95% CI = (− 0.008, − 0.0008); muscular strength: β − 2.958; 95% CI = (− 5.615, − 0.030)). Conclusion: increasing physical fitness is an important strategy to protect youths from high body mass index, when their mothers are obese.