Cancer incidence in Stockholm firefighters 1958–2012: an updated cohort study

OBJECTIVES Previous studies on firefighters indicate an increased risk of cancer although findings regarding which cancer sites are in excess have been inconsistent. The aim of this study was to investigate the cancer incidence among Swedish firefighters. METHODS This updated cohort study included 1080 men who worked at least 1 year as a firefighter in the city of Stockholm, Sweden during 1931-1983. First-time diagnoses of cancer were identified through the Swedish Cancer Registry from 1958 until 2012. Employment as a firefighter was determined from the annual fire station enrolment records. Standardized incidence ratios were calculated using the Stockholm population as reference. RESULTS Firefighters in Stockholm had a low overall risk of cancer (SIR = 0.81 95% CI 0.71-0.91). However, firefighters were at an increased risk of stomach cancer (SIR = 1.89 95% CI 1.25-2.75). Firefighters had significantly low risks for prostate cancer (SIR = 0.68 95% CI 0.52-0.87) and malignant melanoma of the skin (SIR = 0.30 95% CI 0.06-0.88). There was a statistically significant trend of increasing overall risk of cancer with increasing employment duration, although there was still no excess of cancer overall in any of the categories of employment duration. CONCLUSION Stockholm firefighters had an increased risk of stomach cancer but a low overall risk of cancer. The trend of increasing overall risk of cancer with increasing employment duration could potentially be related to the carcinogenic exposures at work.