331 Cancer incidence in swedish firefighters – preliminary results of an extended follow-up of the nocca study

Introduction Firefighters may be exposed to a wide range of carcinogens by inhalation or dermal exposure. They also work shift which may disrupt the circadian rhythm. Previous studies have been inconsistent concerning cancer risks among firefighters. The aim was to evaluate the cancer incidence in Swedish firefighters. Methods This cohort study is based on the Swedish part of the Nordic Occupational Cancer (NOCCA) project, including 6 million people who participated in one or more population censuses in 1960, 1970, 1980 and 1990. Cancer diagnoses 1961–2009 were obtained from the Swedish Cancer Registry. We identified 8136 male firefighters. Female firefighters were excluded because there were too few. SIRs were calculated with the cancer incidence rates for the entire national population used as reference rates. Result There was no excess risk for all cancer sites combined (SIR=1.01, 95% CI: 0.96 to 1.06). A statistically significant excess was found only for non-melanoma skin cancer (SIR=1.48, 95% CI: 1.20 to 1.80), although the risk did not increase with duration of employment. There was a small, but statistically significant excess of prostate cancer among firefighters who had worked 30 years or more. Discussion The risk of prostate cancer was increased among long-term exposed firefighters, and a possible excess of non-melanoma skin cancer was found. An increased risk of prostate cancer has been reported in some earlier studies of firefighters, but excesses of others cancers earlier reported in association with firefighting were not confirmed. Our results do not support an overall excess risk of cancer among Swedish firefighters.