Environment/Climate Change
The association between short-term wildfire smoke exposure and hospitalization among older adults with Alzheimer’s disease and related dementias Vivian Do* Vivian Do Joan A. Casey Marianthi-Anna Kioumourtzoglou Marissa Childs Jennifer J. Manly Francesca Dominici
Under climate change, wildfire smoke exposure has increased nationally in the US. Wildfire smoke-related health effects may be worse for older adults (≥65 years) due to underlying physiology and pre-existing conditions. In particular, older adults living with Alzheimer’s disease and related dementias (ADRD) may be at special risk as air pollution can trigger inflammatory responses in the brain and exacerbate other conditions. No studies have considered the impact of wildfire smoke on older adults with ADRD. We evaluated the relationship between wildfire fine particulate matter (PM2.5) and cause-specific hospitalizations among Medicare enrollees with ADRD and investigated possible effect modification by urbanicity. We identified 2,768,845 Medicare enrollees with an ADRD hospitalization between 2000-2016 and classified their zip code of residence as urban or rural based on Rural-Urban Commuting Area codes. We assigned exposure in the zip code of residence using 2006-2016 daily wildfire smoke PM2.5 predictions. We used a case-crossover design and distributed lag nonlinear models to estimate associations of wildfire PM2.5 and hospitalizations across 0-6 day lags. We observed null relationships for our main analyses but found effect modification by urbanicity. In rural zip codes, a 10g/m3 increase in wildfire smoke over a 7-day lag (lag0-lag6) was associated with an increased risk for respiratory hospitalizations (RR: 1.05, 95%CI: 1.00-1.10). In urban areas, we found a negative association for same day (lag0) depression-related hospitalizations (RR: 0.93, 95%CI: 0.88, 0.98). Adults living with ADRD, especially those in rural locations, may have elevated risk of hospitalization during wildfire smoke events. Wildfire smoke events may have also led to delayed care-seeking for mental health services among urban residents living with ADRD. Such findings are important for future strategies to protect population health in a changing climate.