Overweight, Obesity, and Body Composition in 3.5-and 7-Year-Old Swedish Children Born with Marginally Low Birth Weight

Objectives To assess the prevalence of overweight/obese children and to explore body composition in a Swedish cohort of preschool children born with marginally low birth weight (MLBW, ie, 2000-2500 g). Study design We included 285 Swedish children with MLBW (44% small for gestational age), and 95 control children with normal birth weights. At 3.5 years and 7 years of age, we assessed anthropometrics, including the prevalence of overweight/obese children. At 7 years, dual-energy X-ray was used for body composition. Results There were no significant differences between groups in the prevalence of overweight/obesity or in skinfold thickness; however, at 3.5 years, mean height, weight, and BMI in children with MLBW were 2.1 cm (95% CI 1.2-3.1), 1.2 kg (95% CI 0.7-1.6), and 0.47 kg/m(2) (95% CI 0.17-0.76) lower compared with controls. The corresponding mean differences also were lower in children with MLBW compared with control children at 7 years; 2.5 cm (95% CI 0.9-4.1), 1.6 kg (95% CI 0.6-2.8), and 0.48 kg/m(2) (95% CI 0.01-0.94). The differences were greater in those born small for gestational age. Dual-energy X-ray analyses showed lower fat-free mass index in MLBW infants and a similar trend in fat mass index. Within children with MLBW, BMI at 7 years correlated positively to growth velocity in infancy. Conclusion Children with MLBW had lower BMI and did not show increased risk of overweight or obesity up to 7 years. Nevertheless, the BMI in MLBW children was positively correlated to growth-velocity in infancy.