Trends of weight gain and prevalence of overweight and obesity from birth to three years of age.

OBJECTIVE: To examine the changes in children's weight-for-height at six monthly intervals between birth and three years old (3yo) from different counties across Chile and to determine if children had overweight or obesity, and if so, whether it was a transient or persistent change.

SUBJECTS AND METHODS: Longitudinal data were obtained from routine medical check-ups and 8,373 children were selected from nine counties in Chile through a non-randomised sample design. Weight-for-height z-scores (WHZ) were generated and categorized as wasted, normal, overweight, and obese using WHO standards. Repeated-measures ANOVA were used to analyse the changes in WHZ over the seven measurements as well as based on having normal, overweight, or obese WHZ at 3yo. The number of times having overweight or obesity was counted (from 0 to 7 times). The timing of having overweight and obesity was computed as well as all combinations of the patterns.

RESULTS: Mean WHZ significantly increased up to 18months of age and declined thereafter (p<0.001). Overall mean WHZ was 0.743, prevalence of overweight 31.2% and prevalence of obesity 10.0%. Children categorised with overweight or obesity at 3yo showed significantly higher and sustained pattern of weight gain compared with children with normal WHZ. Once a child had overweight or obesity they tended to remain with it and did not return to a weight-for-height in the normal range.

CONCLUSION: The increasing prevalence of overweight and obesity in Chilean children is of concern. There is a need for greater healthcare promotion and prevention of this disease from infancy.