Does low birth weight predict obesity/overweight and metabolic syndrome in elementary school children?

Background: We undertook this study to explore the relationship between birth weight (BW) and childhood overweight and obesity (OW/OB) and metabolic syndrome (MS).

Methods: This was a cross-sectional assessment performed in 10 elementary public schools in Buenos Aires, Argentina. Participants were 1027 students aged 9.4 +/- 2.1 years. No interventions were done. We measured the association between BW in children and OW/OB and MS at 9 years of age.

Results: Of the total number of children, 164 (16.0%) were OB (BMI >95(th) percentile) and 169 (16.5%) were OW [(body mass index (BMI) > or =85(th), <95(th) percentile); 61% were at Tanner 1. All students came from low socioeconomic families. The prevalence of low (< or =2500 g), normal, and high BW (> or =4000 g) was 7.0% (n = 72), 83.7% (n = 860), and 9.3% (n = 95), respectively. MS prevalence was 5.5%. There was a significant difference in mean BMI sd score (SDS) between low BW (0.07), normal BW (0.54) and high BW (0.99). There was a significant difference in mean BMI, BMI SDS, waist circumference (WC), WC SDS, and systolic blood pressure between low, normal, and high BW groups. In separate logistic regression models, low BW proved to be a protective factor against OW/OB [OR 0.32 (95% CI 0.16-0.63)], whereas high BW was associated with a higher OW/OB risk adjusted for age and sex [OR 2.48 (95% CI 1.62-3.81)]. The risk of MS was high for those with high BW [OR 3.16 (95% CI 1.38-7.24)] and not significant for those with low BW adjusted for age and sex.

Conclusions: Our data indicate that low BW is not associated with OW/OB or with MS in children, whereas high BW correlates with childhood OW/OB and MS.