Head Circumference Versus Length and Weight Deficits up to 2 Years of Age in Bangladesh.

Abstract

Infant undernutrition, defined by length- and weight-based indices, is common in low- and middle-income countries (LMICs), but corresponding deficits in head size have received less attention. In a cohort of term newborns in Dhaka, Bangladesh, we compared the severity of deficits (vs. World Health Organization Growth Standards) in head circumference (HC), length and weight at birth and every 3 months until 2 years of age (n range across timepoints: 843-920). We estimated the mean and 25th, 50th and 75th percentiles of HC-, length- and weight-for-age z-scores (HCZ, LAZ and WAZ, respectively). Differences between HCZ and LAZ (or WAZ) were analyzed using paired t tests and quantile regression. We also derived HCZ using height-age instead of chronological age at 3-24 months. Mean HCZ was significantly higher than mean LAZ and WAZ at birth, but HCZ was significantly lower than LAZ at 6, 9 and 12 months and the HCZ and LAZ deficits were similar from 15 to 24 months. Mean HCZ was lower than WAZ at all ages beyond birth. Patterns were broadly consistent at the 25th, 50th and 75th percentiles. The HCZ deficit remained evident when HC was standardized using height-age at all ages beyond birth, indicating HC was reduced relative to body size. In conclusion, among term-born children in Dhaka, HCs were smaller than international standards at all ages up to 2 years, and there was no evidence of postnatal head sparing. Consideration should be given to routine measurement of HC in population health surveys in LMICs.