Risk of heat illness in men and women: A systematic review and meta-analysis

Robert M Gifford; T Todisco; M Stacey; T Fujisawa; M Allerhand; D R Woods; R M Reynolds

doi:10.1016/j.envres.2018.10.020

Risk of heat illness in men and women: A systematic review and meta-analysis

Environ Res. 2019 Apr:171:24-35. doi: 10.1016/j.envres.2018.10.020. Epub 2018 Oct 25.

Authors

Robert M Gifford¹, T Todisco², M Stacey³, T Fujisawa², M Allerhand⁴, D R Woods⁵, R M Reynolds⁶

Affiliations

¹ University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK; Department of Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK.
² University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK.
³ Department of Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK.
⁴ Centre for Statistics, School of Mathematics, University of Edinburgh, Edinburgh, UK.
⁵ Department of Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK; Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK; Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UK; University of Newcastle, Newcastle upon Tyne, UK.
⁶ University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK. Electronic address: r.reynolds@ed.ac.uk.

PMID: 30641370
DOI: 10.1016/j.envres.2018.10.020

Abstract

Background: Heat illness (HI) is a growing global concern; its incidence has risen dramatically across the world in recent years. The individual factors whereby elevated core temperature produces HI are not well-understood. Given known physiological differences between men and women pertaining to temperature regulation, we hypothesized that women would be at increased risk of HI than men.

Objectives: We aimed to determine the relative risk of HI in women compared with men through an exhaustive literature review and meta-analysis.

Methods: We search PubMed and Ovid Medline databases from inception to Apr 2017. Search terms included all permutations of sex and heat illness (including heatstroke and exertional heat illness) with no language restrictions. We included adult or adolescent human data reporting comparable male and female HI rates. One reviewer identified and screened titles and abstracts. Two independent reviewers applied eligibility criteria. Disagreements were resolved with a third reviewer.

Results: Of 5888 articles identified by searches, 36 were included in the systematic review and 22 in the meta-analysis. The mean (standard deviation) quality score was 3.31(1.25)/5. Overall the rate among women was consistently lower than men across the lifespan. The male: female pooled IRR was 2.28 (p < 0.001, 95% CI: 1.66-3.16). There was modest heterogeneity (between-studies variance (τ²) = 0.02). The rates did not differ significantly when corrected for severity or occupation.

Discussion: The rate of HI was significantly increased in men compared with women. Risk for HI might be conferred by psychological and behavioral factors rather than physiological ones. Further research is required to delineate which groups are at greatest risk, leading to the development of mitigation strategies against HI.

Other: No funding was received. The authors acknowledge the support of the UK Women in Ground Close Combat Review. The Study was registered with PROSPREO CRD42017064739.

Keywords: Exertional heat illness; Female; Heat illness; Heatstroke; Male; Sex.

Publication types

Meta-Analysis
Systematic Review

MeSH terms

Adolescent
Adult
Environmental Exposure / statistics & numerical data*
Female
Heat Stress Disorders / epidemiology*
Hot Temperature*
Humans
Male
Men
Risk
Women