Prenatal lead exposure and childhood blood pressure and kidney function.

BACKGROUND

Exposure to lead, a common environmental pollutant, is known to cause cardiovascular and nephrotoxic effects in adults. Potential effects of early-life lead exposure on these functions are, however, less well characterized.

OBJECTIVES

To assess blood pressure and kidney function in preschool-aged children in relation to prenatal lead exposure.

METHODS

This prospective study in rural Bangladesh measured children's systolic and diastolic blood pressure in triplicate at the follow-up at 4.5±0.11 years. Their kidney function was assessed by the estimated glomerular filtration rate (eGFR), calculated based on serum cystatin C concentrations, and by kidney volume, measured by sonography. Exposure to lead was assessed by concentrations in the mothers' blood (erythrocyte fraction; Ery-Pb) in gestational weeks (GW) 14 and 30, the effects of which were evaluated separately in multivariable-adjusted linear regression analyses.

RESULTS

We found no associations between maternal exposure to lead [n~1500 for GW14 and 700 for GW30] and children's blood pressure or eGFR. However, we found an inverse association between late gestation lead and kidney volume, although the sample size was limited (n=117), but not with early gestation lead (n=573). An increase of 85µg/kg in Ery-Pb (median concentration at GW30) was associated with a 6.0cm3/m2 decrease in kidney volume (=0.4SD; p=0.041). After stratifying on gender, there seemed to be a somewhat stronger association in girls.

CONCLUSIONS

Prenatal lead exposure may cause long-lasting effects on the kidney. This warrants follow-up studies in older children, as well as additional studies in other populations.