Students' Perceived Heat-Health Symptoms Increased with Warmer Classroom Temperatures

Our plain-English summary of Students' Perceived Heat-Health Symptoms Increased with Warmer Classroom Temperatures, by S. Bidassey-Manilal, C.Y. Wright, J.C. Engelbrecht, et al (International Journal of Environmental Research and Public Health, 2016).

The study

• Authors: S. Bidassey-Manilal, C.Y. Wright, J.C. Engelbrecht, P.N. Albers, R.M. Garland, M. Matooane
• Journal: International Journal of Environmental Research and Public Health
• Published: 2016;13(6)
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Temperatures in Africa are expected to increase by the end of the century. Heat-related health impacts and perceived health symptoms are potentially a problem, especially in public schools with limited resources. Students (n = 252) aged ~14-18 years from eight high schools completed an hourly heat-health symptom log over 5 days. Data loggers measured indoor classroom temperatures. A high proportion of students felt tired (97.2%), had low concentration (96.8%) and felt sleepy (94.1%) during at least one hour on any day. There were statistically significant correlations, when controlling for school cluster effect and time of day, between indoor temperatures ≥32 °C and students who felt tired and found it hard to breathe. Consistently higher indoor classroom temperatures were observed in classrooms constructed of prefabricated asbestos sheeting with corrugated iron roof and converted shipping container compared to brick classrooms. Longitudinal studies in multiple seasons and different classroom building types are needed.

In plain English

This study was about classroom heat; asbestos appears only as the wall material of one classroom. In February and March 2014, 252 students at eight Johannesburg government high schools logged 14 symptoms each school hour for five days while loggers recorded classroom temperature. 248 of 252 students (98.4%) reported at least one symptom; 97.2% felt tired. Against outdoor readings from Johannesburg's airport, the largest maximum-temperature gaps were in the one classroom of prefabricated asbestos sheeting with a corrugated iron roof (all days) and a converted shipping container (days 1 and 2), where the highest temperature, 47.5 °C, was measured. In models for hours at 32 °C or higher, with temperature as a continuous variable, feeling tired (odds ratio 1.10, 95% CI 1.04 to 1.16) and finding it hard to breathe (odds ratio 1.29, 95% CI 1.16 to 1.44) were statistically significantly associated with temperature. The authors concluded that asbestos-sheeting and container classrooms are more likely than brick ones to get hot when occupied by similar numbers of students; the study had one of each. They stated that their results cannot prove causation.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Panel study: students kept an hourly symptom log for 5 school days (Monday to Friday) while data loggers measured indoor classroom temperature
• Who was studied: 252 students from one class at each of eight randomly selected government high schools in Regions B, F and G of the City of Johannesburg, South Africa, studied between 10 February and 7 March 2014. Students were mostly aged about 14 to 18 years; the age table also lists 31 students older than 18.
• Exposure: Indoor classroom temperature, recorded every 5 minutes by Lascar data loggers and averaged per hour, and analysed both overall and for temperatures of 32 °C or higher. Classroom building types were brick (6 schools), prefabricated asbestos sheeting with a metal corrugated iron roof (School 3), and a converted metal shipping container (School 7). Asbestos itself was not studied as an exposure.
• Main results:
  • 248 of 252 students (98.4%) reported at least one heat-health symptom during at least one hour on a study day
  • Most common symptoms across all students were tired (245/252, 97.2%), low concentration (244/252, 96.8%) and sleepy (237/252)
  • The highest classroom temperature, 47.5 °C, was measured in the converted shipping container classroom (School 7)
  • Outdoor (ambient) temperatures were taken from the Oliver R. Tambo International Airport, 18 to 38 km from the schools
  • Compared with the airport's maximum temperatures, the largest differences were in the prefabricated (asbestos sheeting) classroom at School 3 on all days and in the container classroom at School 7 on days 1 and 2. Brick classrooms were slightly lower than, or 2 to 3 °C warmer than, the outdoor maximum.
  • In the controlled models for hourly classroom temperatures of 32 °C or higher, 'tired' (p = 0.001, OR 1.10, 95% CI 1.04 to 1.16) and 'hard to breathe' (OR 1.29, 95% CI 1.16 to 1.44) were statistically significantly associated with temperature
  • The table note for these 32 °C or higher models states that temperature was treated as a continuous variable with no reference group
  • With temperature as a continuous value, a rise in temperature was statistically significantly associated with most symptoms, but most of these associations weakened after adjustment for other factors
  • The authors reported no statistically significant differences in symptoms by gender, age, alcohol use, smoking or exercise
• The authors' conclusion: The authors concluded that classrooms made of prefabricated asbestos sheeting with metal roofs, or of converted shipping containers, are more likely than brick classrooms to experience high indoor temperatures when occupied by a similar number of students. They called for a larger longitudinal study with validation methods to confirm their findings.
• Limitations the authors state:
  • The results cannot prove that temperature caused the symptoms
  • Symptoms were self-reported and not verified, and other factors such as illness, sleep deprivation and stress may have contributed
  • Completion of the symptom log was likely affected by a Hawthorne effect, by teacher instruction, and by recall bias
  • There were too few schools of each building type (five brick, one asbestos sheeting, one container) to detect differences in symptoms by classroom type
  • Outdoor temperatures were not measured at the schools themselves
  • A week of self-reporting may have reduced compliance
  • School 8 was studied in autumn rather than summer, and only 8 of its students took part
  • The principal questionnaire was not detailed enough to analyse building differences, and principals' reports of open windows may be inaccurate

Related studies

• Socio-economic, infrastructural and health-related risk factors associated with adverse heat-health effects reportedly experienced during hot weather in South Africa — C.Y. Wright, F. Dominick, et al. (2019)
• Reaction mechanism for the aqueous-phase mineral carbonation of heat-activated serpentine at low temperatures and pressures in flue gas conditions — L.C. Pasquier, G. Mercier, et al. (2014)
• Exploration of the role of heat activation in enhancing serpentine carbon sequestration reactions — M.J. McKelvy, A.V. Chizmeshya, et al. (2004)
• Free radical activity of natural and heat treated amphibole asbestos — C. Otero Areán, F. Barceló, et al. (2001)
• Ablation mechanism of polymer layered silicate nanocomposite heat shield — A.R. Bahramian, M. Kokabi (2009)
• Effect of heat on the identification of asbestos by x-ray diffraction — C. Plowman (1973)

Browse more research in International Journal of Environmental Research and Public Health, or return to medical research.