B97-03 Associations of Short-term Heat Exposure and Lung Function in Older U.S. Adults

Abstract Rationale Exposure to high temperatures is associated with respiratory symptoms, such as breathlessness and wheeze, as well as respiratory hospitalizations and respiratory mortality. Yet, the effect of heat on lung function, an important marker of respiratory health, is not well-described. The aim of this study was to determine associations of acute exposure to high temperatures with lung function in older US adults. Methods We included a subset (n = 1,923) of study participants who were invited to undergo spirometry testing from Lung VITAL, an ancillary study of VITAL (VITamin D and OmegA-3 TriaL), a nationwide, randomized, placebo-controlled trial of vitamin D and marine omega-3 fatty acids supplements. We obtained repeated measures of forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) at the baseline and 2-year follow-up visits (2 per participant) between 2010-2018 across 11 US urban sites. We assigned daily mean temperature, relative humidity, and air pollution to geocoded participant home addresses. We used distributed lag nonlinear models to examine potentially nonlinear associations of temperature with FEV1 and FVC. We express effect estimates as estimated mean difference in lung function for a contrast of 30oC versus 20oC. All models adjusted for age, sex, height, weight, trial intervention arm, current tobacco use, season, social vulnerability, relative humidity, PM2.5, and O3, and testing site. Results Median (IQR) daily mean temperature was 13.6 oC (17.1 oC) for the study population. Daily exposures were moderately correlated with pairwise Spearman correlations ranging from -0.31 to 0.34. Cumulative short-term exposure to high temperature (lag 1-7 days) was associated with a 49.9mL (95% CI: -96.8, -2.9) lower FEV1 and 85.4 mL (95% CI: -152.5, -18.2) lower FVC, compared to reference temperature (30 oC vs 20 oC). CONCLUSIONS Short-term exposure to high temperatures over the preceding seven days was associated with lower lung function in older US adults. As the number of high heat days increases in the US, there is a need for interventions to prevent heat-related respiratory effects, particularly in elderly populations. This abstract is funded by: This work was supported by grants from the NIH/NIEHS (NIH K23 ES035863), the Harvard-NIEHS Center (P30-ES000002), and the Eleanor and Miles Shore Faculty Development Program. The VITAL study was funded by the National Center for Complementary and Integrative Health (R01 AT011729) and the NCI (R01 CA138962). The Lung VITAL study was funded by NIH grants (R01 HL101932, R01 AT011729, U01 CA138962, R01 CA138962, R01 AI093723) and the National Institute of Neurological Disorders and Stroke, and the National Center for Complementary and Integrative Health, which have been sources of support for relevant work by Drs. Buring, Manson, Gold, and Luttmann-Gibson. This work was conducted with support from the Harvard Catalyst CTSC (NCRR and NCATS, NIH Award UL1TR001102) and the Office of Dietary Supplements.