Hinchliffe A, Kogevinas M, Molina AJ, Moreno V, Aragonés N, Castaño-Vinyals G, Jiménez Moleón JJ, Gómez Acebo I, Ederra M, Amiano P, Molina-Barceló A, Fernandez-Tardon G, Alguacil J, Chirlaque MD, Hernández-Segura N, Pérez-Gómez B, Pollan M, Turner MC. Association of occupational heat exposure and colorectal cancer in the MCC-Spain study. Scand J Work Environ Health. 2023;49:211-21.


What is known about the subject?

The planet’s global warming continues its course with society doing nothing relevant to stop it, so it is expected to affect population’s health in the years to come. One of the potential consequences, which has barely received attention, is the association of temperature rise with the increased risk for cancer. There is laboratory evidence linking acute heat exposure with known cancer mechanisms such as genetic damage, oxidative stress, pro-inflammatory cytokine release, alteration of programmed cell death and of DNA repair mechanisms. In addition, the impact of heat on toxicokinetics and toxicodynamics would increase the effect of many carcinogenic agents. To this regard, studies on humans are still very limited and remain with inconclusive or contradictory findings.


What does this study add to the existing literature?

A number of researchers interested in identifying new cancer risk factors have used the occupational environment as “laboratory” to prove their hypothesis. The workplace offers a scenario of “voluntary” exposure to higher levels than those found in the environment for any type of exposures. The fact that many workers are being exposed to high temperatures similar to those expected under future scenarios will help us anticipate potential risks. Furthermore, temperature rise within the occupational environment often occur in situations that have not allowed a physiological adaptation of the worker. Our findings offer a first step that is compatible with an increased risk of certain tumours-such as colorectal tumours- only for high temperature rises, which is consistent with findings from previous studies for prostate or breast cancer.


What are the implications of the findings?

Our findings suggest the need for further in depth studies to examine the potential association between occupational heat exposure and cancer risk. Global warming is going to affect many people in the near future, especially those in the southern parts of Europe, such as the Andalusian region in Spain. The establishment of new risk factors is a slow process, but it does not exempt one from applying the precautionary principle whilst new studies are being developed to clarify the magnitude of the risks. Given the fact that the people responsible for global warming are not doing whatever necessary to prevent the latter, we must demand more proactivity from our political leaders in this regard.



Scand J Work Environ Health. 2023;49:211-21.



Juan Alguacil
Professor of Public Health
Research Group on Clinical, Environmental Epidemiology and Social Transformation (EPICAS)
University of Huelva