In 1991, the US Centers for Disease Control (CDC) defined 10 ug/dL as the blood lead level (BLL) that should prompt public health actions. This is not necessarily a no effect level and some research suggests the children’s physical and mental development might be affected at lower BLLs.
Mohan VR, Sharma S, Ramanujam K, Babji S, Koshy B, Bondu JD, John SM, Kang G. Effects of elevated blood lead levels in preschool children in urban vellore. Indian Pediatr. 2014 Aug 8;51(8):621-5.
OBJECTIVE: To study the burden and associated risk factors for elevated blood lead levels among pre-school children (15-24 months) in urban Vellore, and to study its effects on child cognition and anemia.
DESIGN: An investigative study through Mal-ED cohort.
SETTING: Eight adjacent urban slums in Vellore, Tamil Nadu.
PARTICIPANTS: 251 babies recruited through Mal-ED Network.
OUTCOME MEASURES: Blood lead levels using Graphite Furnace Atomic Absorption Spectrophotometry method at 15 and 24 mo; hemoglobin estimation by azidemethemoglobin method; cognitive levels using Bayley Scales of Infant Development III.
RESULTS: Around 45% of children at 15 months and 46.4% at 24 months had elevated blood lead levels (>10 µg/dL). Among children who had elevated blood lead levels at 15 months, 69.2% (45/65) continued to have elevated levels at 24 months. After adjusting for potential confounders, children from houses having a piped drinking water supply and houses with mud or clay floors were at significantly higher risk of having elevated blood lead levels at 15 months. Thirty one percent (21/67) of the children with elevated blood lead levels had poor cognitive scores. Children with elevated blood lead levels at 15 months had higher risk (Adjusted OR 1.80; 95% CI 0.80 – 3.99) of having poorer cognitive scores at 24 months. More than half of the children (57%) were anemic at 15 months of age, and elevated blood lead levels were not significantly associated with anemia.
CONCLUSIONS: Elevated blood lead levels are common among preschool children living in urban slums of Vellore. Poorer conditions of the living environment are associated with elevated lead levels.