Association of exposure to extreme rainfall events with cause-specific mortality in North Carolina, US

Abstract

Extreme rainfall events could influence human health. However, the associations between extreme rainfall events and mortality remain rarely explored. Here, we conducted a time-series study using county-level mortality data in North Carolina during 2015–2018 to estimate the associations between extreme rainfall events and cause-specific mortality. We defined an extreme rainfall event as a day when a county’s daily total precipitation exceeded the 95th percentile of daily rainfall measurements from all of North Carolina’s counties during the study period. We employed a two-stage analysis where we first estimated the associations for each county and then used the estimates to obtain the state-wide associations by meta-analysis. Exposure to an extreme rainfall event was significantly associated with an increase in total, non-accidental, cardiovascular disease, respiratory disease, and external mortality by 2.24% (95% CI: 0.67%, 3.83%), 2.38% (95% CI: 0.76%, 4.03%), 3.60% (95% CI: 0.69%, 6.60%), 6.58% (95% CI: 1.59%, 11.82%), and 6.92% (95% CI: 1.28%, 12.86%), respectively. We did not find significant differences in the mortality risks within age, sex, or race groups or by seasonality. Our findings suggest that extreme rainfall events may trigger the risk of mortality, especially from non-accidental diseases such as respiratory mortality.