Relation Between Lead Exposure and Trends in Blood Pressure in Children.

Obesity raises blood pressure (BP) in children and adults. Nevertheless, as obesity increased around the globe, population systolic and diastolic blood pressures were flat or fell. Examining children is insightful because pediatric trends are largely unconfounded by antihypertensive therapy. Decomposing BP into arterial types, large artery measures (pulse pressure) increased in concert with obesity while small artery measures (mean arterial pressure, [MAP]) decreased, suggesting small arteries are the locus of the countervailing temporal trends. Pediatric lead exposure decreased as pediatric obesity rose. Over the period of rising obesity, we examined the association between lead exposure and temporal trends in BP. We analyzed anthropometric, BP, and laboratory data on 8-17 year old children from the serial cross-sectional National Health and Nutrition Examination Surveys 1976 through 2008. Multivariable adjusted survey regression was used to examine temporal trends in blood pressure in relation to blood lead concentrations (N = 13,501). As obesity prevalence rose from 5.3% to 24.5%, age-sex adjusted systolic BP was flat (-0.01 [95% confidence interval (CI) -0.06, 0.04] mm Hg/yr, p = 0.8), diastolic BP and MAP decreased (respectively -0.28 [-0.32, -0.24] and -0.19 [CI -0.23, -0.15], both p<0.0001) while pulse pressure increased (0.28 [0.23, 0.32], p<0.001). Accounting for blood lead concentration attenuated the decreasing MAP trend by 67%. In conclusion, the contrary trends in pediatric BP during the rise of pediatric obesity may be substantially attributable to decreasing lead exposure acting on small resistance arteries. These results have implications for globally observed BP trends in youth and adults. Environmental policy altering lead levels may have long-lasting cardiovascular benefits.