Long working hours and cancer risk: a multi-cohort study

Area of Science:

• Occupational Health
• Epidemiology
• Oncology

Background:

• Excessive working hours are linked to cardiovascular disease.
• The association between long working hours and cancer incidence is not well-established.

Purpose of the Study:

• To investigate the relationship between working hours and the risk of developing cancer.
• To examine specific cancer types including colorectal, lung, breast, and prostate cancers.

Main Methods:

• A multi-cohort study involving 116,462 cancer-free individuals.
• Ascertainment of incident cancers through national registers.
• Self-reported weekly working hours over a median follow-up of 10.8 years.

Main Results:

• No clear association found between working hours and overall cancer risk.
• Working hours were unrelated to the risk of colorectal, lung, or prostate cancers.
• Working 55+ hours/week was associated with a 1.60-fold increased risk of female breast cancer, potentially confounded by parity.

Conclusions:

• Long working hours do not appear to increase the risk of overall cancer, lung, colorectal, or prostate cancers.
• The potential association between long working hours and breast cancer risk requires further research.