Global Warming To Increase Stroke Risk? Here’s What Study Says

Global Warming To Increase Stroke Risk? Here's What Study Says (Image Credits: iStock)

A recent study, published in the journal Neurology, examined the global impact of stroke caused by suboptimal temperatures resulting from climate change. Stroke, which disproportionately affects the elderly and often leads to severe consequences, accounted for 12.2 million new cases and 6.55 million deaths in 2019, ranking third in terms of disability-adjusted life years (DALYs). Previous research has underscored the heightened risk of stroke associated with extreme temperatures. However, there remains a scarcity of data concerning the distribution and overall burden of stroke across various countries and territories.

This study delved into the worldwide impact of stroke resulting from suboptimal temperatures. Researchers gathered data on stroke fatalities and Disability-Adjusted Life Years (DALYs) from the Global Burden of Diseases (GBD) study across various regions, countries, territories, genders, age groups, and sociodemographic index (SDI) quintiles spanning from 1990 to 2019.

Subsequently, the team analyzed the monthly average daily mean, minimum, and maximum temperatures. National indicators data were sourced from World Bank databases. Theoretical minimum risk exposure levels (TMRELs) were determined as the temperatures associated with the lowest mortality risk for each location and year.

Cause-specific death rates were calculated. Temporal trends in disease burden were determined using Joinpoint regression models, followed by computation of the annual percent change in identified trends. To forecast future trends, a Bayesian age-period-cohort model estimated the average annual percent change in rates across different age groups, period/cohort effects, and age effects.

Decomposition analysis was conducted to scrutinize the factors influencing variations in stroke burden over time. Additionally, a fixed-effect panel data analysis was employed to investigate the potential associations between national-level indicators and stroke burden linked to non-optimal temperatures. Furthermore, the study examined health inequalities related to sociodemographic index (SDI) in disease burden.

In 2019, over half a million stroke deaths and 9.42 million DALYs attributable to non-optimal temperatures were recorded worldwide. The age-standardized rates of stroke mortality (ASMR) and DALY (ASDR) attributable to non-optimal temperatures showed a continuous decline globally. The annualized rates of change in ASMR and ASDR were -0.43% and -0.45% per year, respectively.

Males had a higher burden of stroke than females. Countries with high-middle SDI consistently showed the highest burden, while those with high SDI had the least. The stroke burden declined in most regions between 1990 and 2019. The decomposition analysis revealed that population growth and ageing increased the stroke burden while epidemiological changes reduced it.

The researchers examined the worldwide, regional, and country-specific impact and dispersion of strokes linked to suboptimal temperatures. Although stroke mortality rates (ASMR) and Disability-Adjusted Life Years (DALYs) have decreased since 1990, the actual number of fatalities and DALYs rose, particularly in nations with low sociodemographic index (SDI). Older individuals and males experienced a higher burden. While low temperatures traditionally accounted for the majority of stroke burden, the contribution from high temperatures has been progressively growing, a trend expected to persist in the future.