Federally-assisted housing and blood lead levels in the United States, 1999-2016

Background/Aim: Despite declining blood lead levels (BLLs) in the US, lead exposure remains disproportionately high in older housing and for low-income and non-Hispanic Black households. Federal housing assistance is linked to lower BLLs among children, but has not been evaluated among all US residents and by program type. Methods: We used the National Health and Nutrition Examination Survey 1999-2016 data linked to the US Department of Housing and Urban Development (HUD) administrative records to identify HUD-assisted participants. We compared BLLs of those currently-assisted and those on the waitlist (will receive assistance within two years) using multivariable regressions for log-transformed and dichotomous (≥ 3 µg/dL) BLLs. We examined effect modification by program type (project-based: public and multifamily housing vs. housing choice vouchers) and race/ethnicity, and conducted subset analyses for women and children under 12. Results: Sociodemographic characteristics were similar in the currently-assisted and waitlist groups. BLL geometric means were 1.11 (SE: 1.03) and 1.41 (SE: 1.03), respectively (p<0.05). In adjusted models, HUD assistance was associated with 8% lower BLLs (95% CI: -13%, -2%). In stratified models, this association was stronger among project-based housing (-11%, 95% CI: -18%,-4%) compared to housing choice voucher (-5%, 95% CI: -12%, 2%) recipients. Non-Hispanic white participants experienced a stronger protective association (-16%, 95% CI: -25%, -6%) compared to Black participants (-3%, 95% CI: -10%, 5%) and Mexican-Americans (2%, 95% CI: -18%, 28%). The association was significant among women (-9%, 95% CI: -15%, -2%) but attenuated among children (-2%, 95% CI: -9%, 6%). Findings remained consistent for clinically-meaningful BLL cutoff ≥ 3 µg/dL. Conclusions: Housing assistance is an important social-structural determinant of health that can reduce residential environmental exposures through better quality housing, routine maintenance practices, and/or compliance with residential lead paint laws. Increasing access to affordable housing for very low-income households advances environmental health equity.