Breakfast habits, dairy product consumption, physical activity, and their associations with body mass index in children aged 6–18

The purpose of this study was to determine breakfast habits, dairy product consumption, and physical activity and their relations with body mass index (BMI) in schoolchildren and adolescents. This cross-sectional, school-based study was performed with children aged 6–18 years. Height and weight were measured, and a BMI z-score was calculated for each child. Breakfast consumption frequency, intake of milk and other dairy products, physical activity habits, and mothers’ employment status were assessed via a self-report questionnaire. Multiple linear regression analysis was used to estimate the association between these habits and BMI z-scores. Seven thousand one hundred sixteen children were included, 3445 (48.4%) female, with a mean age of 11.7 ± 2.7 years (5.8–18.9). Of these, 62.6% had breakfast every day. Boys ate breakfast daily significantly more often than girls (64.5 and 60.7%, respectively; p < 0.001). The percentage of children eating breakfast daily decreased with age (79.1% at 6–11 vs. 52.1% at 12–18 years, p < 0.001). Sixty-four (0.9%) children consumed no dairy products. Milk intake was negatively and significantly associated with BMI z-score (β = − 0.103, p < 0.001). Cheese consumption and the mother being employed were positively and significantly associated with BMI z-score (β = 0.517, p < 0.001, and β = 0.172, p < 0.001, respectively). Children engaging in physical activity had higher BMI z-score values than others (0.22 ± 0.01 vs. 0.12 ± 0.02, p < 0.001). Prevalence of overweight/obese was higher among children of working mothers compared to those of unemployed mothers (respectively, 29.3, 23.3%, p < 0.001).

Conclusions: Skipping breakfast was associated with overweight/obesity in schoolchildren and adolescents, while milk consumption exhibited a protective effect.