Article Text

Download PDFPDF

841 People at elevated risk of developing heat-related illness at workplace: a case-control study
  1. S Horie1,
  2. N Gommori2,
  3. S Tabuchi1,
  4. J Inoue1,
  5. S Kawanami1
  1. 1University of Occupational and Environmental Health, Kitakyushu, Japan
  2. 2JFE Steel Corporation, Kawasaki, Japan


Introduction Primary causes of heat-related illness (HRI) at work are:

  • extreme heat and humidity,

  • heavy work load,

  • continuous exertion and infrequent rest,

  • clothes with poor vapor–permeability, and

  • personal health condition.

Empirical research has not been performed to investigate the effect of underlying health problems to HRI.

Methods A case-control study was performed by asking occupational health staffs to report all HRI cases occurred at their workplaces in 2015 and 2016. One co-worker control of the same gender at the closest in age was also reported for each case. Target population included:

  • 26 large manufacturing factories,

  • 15 major construction companies,

  • all traffic guard companies in Japan, and

  • a fire stations in Kitakyushu city.

Their results of the periodic health examination were collected to evaluate the underlying health problems of obesity (BMI >25), impaired glucose tolerance, IGT (HbA1c≥6.5%, fast blood sugar ≥126 mg/dL, and/or casual blood sugar ≥200 mg/dL), high blood pressure, HBP (≥140/90 mmHg), and dyslipidemia (LDL-C ≥140 mg/dL, HDL-C <40 mg/dL, or TG ≥150 mg/dL). Data were statistically compared between the case and the control using JMP Pro 13.

Results Overall incidence rate of HRI at the examined workplaces was 0.065% (114 cases/1 76 094 person-year). A total of 102 pairs (n=204) could be compared. Cases showed higher BMI (p=0.046) and visceral circumference (p=0.045). Cases and controls included 12 and 2 persons with IGT, respectively (p=0.005). Multiple logistic regression analysis revealed increase of HbA1c elevated the risk of developing HRI (OR 16.76 [95% CI: 2.44 to 165.5], p=0.0014), whereas LDL-cholesterol showed protective effect (OR 0.97 [0.95–0.99], p<0.001).

Conclusion Significantly elevated risk of developing heat-related illness was observed among workers with IGT. Impaired endothelium-dependent vasodilatation among workers with IGT may decrease heat dissipation by conduction, convection, radiation, and sweat evaporation and may pose a risk to develop HRI.

  • Heat stroke
  • Diabetes mellites
  • Obesity

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.