Nocturnal heat exposure and stroke risk

Area of Science:

• Environmental Health
• Cardiovascular Epidemiology
• Climate Change Impact

Background:

• Nighttime temperatures are rising faster than daytime temperatures globally.
• Increased nocturnal heat exposure is a potential cardiovascular health risk.
• This study examines the link between nighttime heat and stroke risk in Germany.

Purpose of the Study:

• To investigate the association between nighttime heat exposure and stroke risk.
• To analyze temporal variations in this association over 15 years.
• To identify subgroups with increased vulnerability to nocturnal heat.

Main Methods:

• Utilized hourly meteorological data and a dataset of 11,037 stroke cases (2006-2020).
• Employed time-stratified case-crossover analysis with a distributed lag non-linear model.
• Controlled for maximum daytime temperature and other climatic variables; performed subgroup analyses.

Main Results:

• Extreme nighttime heat (97.5th percentile of HNE) significantly increased stroke risk (OR 1.07).
• Nighttime heat-related stroke risk, especially for ischemic strokes, increased significantly in the later study period (2013-2020 vs. 2006-2012).
• Older individuals, females, and those with mild stroke symptoms showed heightened vulnerability.

Conclusions:

• Nocturnal heat exposure is linked to elevated stroke risk, independent of daytime maximum temperature.
• Susceptibility to nighttime heat has increased between 2006 and 2020.
• Nocturnal heat is a critical stroke trigger in a warming climate, necessitating targeted public health interventions.