Childhood exposure to air pollution, noise, and surrounding greenness and incident hypertension in early adulthood in a US nationwide cohort-the Growing Up Today Study (GUTS).

Exposure to increased air pollution, noise, and reduced surrounding greenness have been suggested as potential environmental risk factors for hypertension in adults, but limited evidence exists regarding early-life exposure, particularly from prospective studies. We investigated independent and joint associations of childhood exposure to these factors with incident hypertension in early adulthood in a US nationwide cohort. Study participants were from the Growing Up Today Study (GUTS) established in 1996 (GUTSI) and 2004 (GUTSII), who were ages 9-14 (GUTSI) or 10-17 (GUTSII) at enrollment. Incident hypertension was identified by self-report on questionnaires from 2010 to 2021. We estimated residential exposures to air pollution (from spatiotemporal models), noise, and surrounding greenness throughout childhood (10-18y). We applied Cox proportional hazards models adjusted for potential confounders to assess hazard ratios (HRs) and 95% confidence intervals (CIs) associated with each interquartile range (IQR) change in exposure. We performed a quantile g-computation to assess the joint association of simultaneous exposure to the mixture. We considered potential effect modification by sex, maternal history of hypertension, overweight/obese status at age 18, urbanicity, and neighborhood socioeconomic status. Among 17,762 participants, 1530 hypertensive cases occurred during an average follow-up of 12.8 years. HRs for all exposures were small with CIs including unity. A joint HR of 1.03 (95% CI: 0.95, 1.11) was associated with a one-quartile increase across simultaneous exposure to the environmental mixture. The joint associations were stronger among non-obese participants or participants living in less advantaged neighborhoods: HRs of 1.07 (95% CI: 0.97, 1.18) and 1.08 (95% CI: 0.98, 1.18), respectively. In conclusion, we did not identify an independent or joint association between childhood exposure to air pollution, noise, and surrounding greenness and early adulthood hypertension. However, a positive joint association was suggested among non-obese participants or those living in less advantaged neighborhoods.