Cohort of Swedish Men (COSM)

The Cohort of Swedish Men was established in 1997, when all men born between 1918 and 1952 and residing in Västmanland and Örebro counties in central Sweden received a questionnaire concerning diet and other lifestyle factors. Of the 100,303 eligible men, 48,850 (49%) responded to the questionnaire. The questionnaire included items about diet, physical activity, medical history, and lifestyle factors such as cigarette smoking history and use of dietary supplements.

During 2008-09, the exposure information was updated and extended by sending out two new questionnaires - one questionnaire on health including several signs of symptoms, sleeping, social relations etc (2008) and one on diet, dietary supplement use, and lifestyle factors (2009). Majority of questions in the questionnaires have been validated.

Incident cases of cancer are ascertained by record linkages of the study population with the National Swedish Cancer Register and the Regional Cancer Registers. Cardiovascular and other diseases as well as surgeries and causes of death are identified by linkage to the National Inpatient and other registries at the Swedish Board of Health and Welfare. Ascertainment of cancer cases and other diseases is almost 100% complete. Dates of deaths are ascertained through the Swedish Death Register (100% complete), and information on date of moving out of the study area is obtained by linkage with the Swedish Population Register.