Swedish Mammography Cohort
Swedish Mammography Cohort
The Swedish Mammography Cohort began in 1987-1990, when 66,651 women living in two counties
 in central Sweden completed a mailed questionnaire that included items about their diet,
 parity, age at first child's birth, history of breast cancer in family, weight, height, and
 education. Follow-up questionnaires have been sent out in 1997 and in 2008-09.
From 1987 to 1990 a population-based mammography screening program was introduced in two
 counties in central Sweden. In Västmanland County all women born between 1917 and 1948
 received a mailed invitation to be screened by mammography between March 1987 and March 1989
 (n=41,786) together with a 6-page questionnaire; 31,735 women (76%) returned the completed
 questionnaires. In Uppsala County all women born between 1914 and 1948 were invited to the
 screening and received the same questionnaire between January 1988 and December 1990
 (n=48517); 34916 women (72%) returned the completed questionnaires. Hence, questionnaires
 completed before undergoing mammography were obtained from 66,651 women (74%) in the source
 population. These questionnaires included items about diet, parity, age at first child's
 birth, history of breast cancer in family, weight, height, and education.

 In 1997 a second questionnaire was sent to all cohort members who were still living in the
 study area. The questionnaire updated information about diet and was extended to include
 information on physical activity, medical history, age at menarche, history of oral
 contraceptive use, age at menopause, postmenopausal hormone use and lifestyle factors such as
 cigarette smoking history and use of dietary supplements. Majority of questions in the
 questionnaires have been validated.

 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).

 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.
Inclusion Criteria:

 -  All women born between 1914 and 1948, living in central Sweden

 Exclusion Criteria:

 -  None