Adiposity rebound in very-low-birth-weight infants

Adiposity rebound (AR) refers to an increase in body mass index (BMI) after a nadir. Early AR, in which AR occurs earlier than five years old, is a risk factor for future obesity and metabolic syndrome, but has not been widely studied in very-low-birth-weight infants (VLBWIs).

The subjects were VLBWIs born in Dokkyo Medical University NICU from January 2008 to December 2010. Height and weight measured at birth and at intervals until seven years old were obtained from medical records. The lowest BMI after one year of age was used for the age of AR. The subjects were divided into those with early and normal AR (<5 and ≥5 years old). BMI percentile at age seven years was compared using the interquartile range (IQR). Changes in BMI were evaluated by repeated measures analysis of variance (ANOVA).

There were 38 early AR cases and 62 normal AR cases, giving a prevalence of early AR similar to that in infants with normal birth weight. BMI percentile at age seven years was significantly higher in early AR cases than in normal AR cases (44.6 [IQR: 21.0-79.2] vs. 14.4 [IQR: 3.8-40.8] kg/m²). Changes in BMI were also significantly higher in early AR cases (p=0.024 by ANOVA).

Early AR in VLBWIs is a predictor of future obesity.