The researchers noted that moderate to high amounts of precipitation had a positive effect on public health, apparently due to a decrease in air pollution and people staying at home. However, extreme rainfall, beyond certain levels, caused damage to infrastructure, water pollution and exposure to harmful microorganisms, leading to an increased risk to health
A recent comprehensive global study published in the BMJ reveals the link between extreme rainfall events and different mortality rates around the world. The researchers collected data from 645 different sites across the globe, including East Asia, Europe and North America, in order to examine how these events affect mortality rates. The study looked at mortality effects in the ranges of one, two and five years after extreme rain events and took into account factors such as local climate, variability in precipitation and vegetation cover.
During the study period, 50,913 rain events with recurrence chances, 8,362 events with a two-year recurrence chance, and 3,301 events with a five-year recurrence chance were identified. It was found that on a day of extreme rain with a five-year chance of recurrence, general mortality increased by 8%, mortality from causes related to heart or blood vessel diseases or cardiovascular problems increased by 5%, while mortality from causes related to the respiratory system increased by 29 % for the following 14 days. Events with a chance of recurrence (recurrence?) of XNUMX years mainly affected deaths related to respiratory failure, while events with a chance of recurrence of XNUMX year had no effect on mortality due to heart disease or respiratory failure.
Another factor that the researchers found was a connection between low variability in the amount of precipitation or a lack of vegetation and an increase in the risk of mortality after extreme rain, which indicates the importance of vegetation cover in the natural environment.
Protection from the rains: moderate precipitation effects
The researchers also noted that moderate to high amounts of precipitation had a positive effect on public health, apparently due to a decrease in air pollution and people staying at home. However, extreme rainfall, beyond certain levels, caused damage to infrastructure, water pollution and exposure to harmful microorganisms, leading to an increased risk to health.
Research limitations and significance for public health
The study is observational, therefore absolute causal conclusions cannot be drawn from it, and it was also brought up that most of the data was collected from certain geographic areas only. Also, variables such as age, sex, origin or urban or rural residence were not taken into account.
However, these findings highlight the need for coordinated public strategies to reduce the health effects of extreme rainfall, especially in light of their increasing frequency due to climate change. In an accompanying article, John Ji of Tsinghua University in China noted that "health professionals are in a perfect position to promote climate action by educating communities to prepare for the health impacts of climate change."
מקור:
He et al. "Rainfall events and daily mortality across 645 global locations: two stage time series analysis." *BMJ* 2024, DOI: 10.1136/bmj-2024-080944
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