Stunting is associated with blood lead concentration among Bangladeshi children aged 2-3 years

Kelsey M. Gleason, Linda Valeri, A. H. Shankar, Md Omar Sharif Ibne Hasan, Quazi Quamruzzaman, Ema G. Rodrigues, David C. Christiani, Robert O. Wright, David C. Bellinger, Maitreyi Mazumdar

Lead toxicity is of particular public health concern given its near ubiquitous distribution in nature and established neurotoxicant properties. Similar in its ubiquity and ability to inhibit neurodevelopment, early childhood stunting affects an estimated 34 % of children under 5 in low- and middle-income countries. Both lead and stunting have been shown to be associated with decreased neurodevelopment, although the relationship between these childhood burdens is underexplored. The association between lead exposure and stunting has been previously established, yet limited data are available on susceptibility windows. Whole blood lead samples were collected from rural Bangladeshi children at delivery (umbilical cord blood) and at age 20-40 months (fingerstick blood). Stunting was determined using the Child Growth Standards developed from the World Health Organization Multicentre Growth Reference Study. Children with height for age < -2 z-scores below the median of the WHO Child Growth Standards were classified as stunted in all analyses. Median (IQR) umbilical cord and fingerstick blood lead levels were 3.1 (1.6-6.3) μg/dl and 4.2 (1.7-7.6) μg/dl, respectively. In adjusted multivariable regression models, the odds of stunting at 20-40 months increased by 1.12 per μg/dl increase in blood lead level (OR = 1.12, 95 % CI: 1.02-1.22). No association was found between cord blood lead level and risk of stunting (OR = 0.97, 95 % CI: 0.94-1.00). There is a significant association between stunting and concurrent lead exposure at age 20-40 months. This association is slightly attenuated after controlling for study clinic site. Additional research including more precise timing of lead exposure during these critical 20-40 months is needed.