Average Temperature, Diurnal Temperature Variation, and Stroke Hospitalizations

Abstract

Background: Studies assessing the relationship between meteorological factors and stroke incidence are inconsistent. We assessed the associations of average temperature and diurnal temperature fluctuations with ischemic stroke hospitalizations in a nationally representative sample of patients in the United States.

Methods: Hospitalizations were identified for adults aged 18 years or older in the 2009-2011 Nationwide Inpatient Sample and linked with county-level monthly average temperatures from the United States National Climatic Data Center. Logistic regression models assessed the relationships of 5°F increases in average temperature and diurnal temperature variation (difference between high- and low-daily temperatures) with the odds of ischemic stroke hospitalization (International Classification of Diseases, Ninth Revision, Clinical Modification codes 433, 434, and 436), adjusting for patient characteristics and dew point. Models were stratified by age (18-64, ≥65 years), season, and region, with analysis at the hospitalization level.

Results: Increased average temperature was associated with decreased odds of stroke hospitalization among both age groups and across seasons in the Northeast, and among the elderly in the West. Increased diurnal temperature variation was associated with increased odds of stroke hospitalization for nearly all regions in the spring to fall seasons; associations were most pronounced in the Northeast and strongest in the spring.

Conclusions: Lower average temperature and larger diurnal temperature variations were associated with stroke hospitalizations. Associations were strongest in the Northeast and largely similar across seasons and age. Further research is needed to explore the mechanisms underlying these associations. Understanding these patterns may lead to targeted prevention strategies for vulnerable populations during periods of extreme weather conditions.

Keywords: Temperature; hospitalization; ischemic stroke; risk factor; weather.