Exposure to tropical cyclones is associated with a higher risk of death from various causes

Exposure to tropical cyclones is associated with a higher risk of death from various causes

Beyond direct injury, exposure to tropical cyclones is associated with a higher risk of death from a range of causes, including kidney, heart and lung disease, neuropsychiatric disorders and diabetes, according to a study published inThe BMJToday's climate problem.

Risks were significantly higher in disadvantaged communities and areas that previously experienced fewer tropical cyclones, suggesting an urgent need to incorporate more evidence of tropical cyclone activity into disaster response plans, the authors say.

Tropical cyclones are among the most devastating and costly extreme weather events, affecting an average of 20.4 million people per year and causing $51.5 billion in direct economic damage over the last decade.

Although direct physical injuries are well recorded, evidence on the broader health impacts of tropical cyclones is lacking, particularly in regions with historically limited tropical cyclone experience and resilience.

To address this issue, researchers collected death certificates for 1,356 communities in nine understudied countries and territories (Australia, Brazil, Canada, South Korea, Mexico, New Zealand, the Philippines, Taiwan, and Thailand) between 2000 and 2019.

They used models to estimate wind and precipitation patterns for each tropical cyclone event and to assess the associations between exposure to tropical cyclones and the risk of death from various major causes, accounting for natural variability.

A total of 14.9 million deaths and 217 tropical cyclone events in affected communities across the nine countries and territories were included in the analysis.

The risk of death increased steadily after tropical cyclones, with peaks occurring within the first two weeks of exposure followed by a rapid decline.

During the first two weeks after exposure to a tropical cyclone, the highest increases in deaths from kidney disease (92%) and injuries (21%) were observed for each additional day of a tropical cyclone in a week.

Relatively lower risks were observed for death from diabetes (15%), neuropsychiatric diseases (12%), infectious diseases (11%), digestive diseases (6%), respiratory diseases (4%), cardiovascular diseases (2%) and neoplasia (2%).

These findings are most likely due to a combination of disrupted basic health services, limited access to medications, and increased physical and psychological stress, the authors say.

The risk of death was significantly higher in communities with greater deprivation and in those with fewer tropical cyclones in the past.

Rainfall associated with tropical cyclones appeared to be more strongly associated with deaths than wind speed, possibly due to flooding and water pollution, suggesting that rainfall should be given greater consideration in early warning systems.

Because this is an observational study, no firm conclusions can be drawn about cause and effect. The researchers acknowledge several limitations to their findings, including possible misclassification of exposure and uncertainties regarding generalizability beyond the regions analyzed.

However, they say: "Our study provides compelling and quantitative evidence of the significantly increased mortality risks from various causes following tropical cyclones at a cross-country scale."

“Overall, there is an urgent need to integrate more knowledge of tropical cyclone epidemiology into disaster response strategies to respond to the growing risks and changing activity of tropical cyclones in a warming climate,” they conclude.

“Taken together, these findings underscore the critical importance of the indirect health impacts of tropical cyclones, as many of the highest risk conditions are not due to immediate trauma, but rather to disrupted health systems, pollution, and persistent stress,” researchers explain in a linked editorial.

It is now time for action, they argue. As tropical cyclones increase in intensity due to climate change, "we must translate this research into the development of cyclone-specific health policies that protect the most vulnerable and build resilience to the direct and indirect health impacts of these devastating events."

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