The Swedish National March Cohort (NMC)
In September 1997, the Swedish Cancer Society organized a four-day national fund-raising event, the National March, in almost 3,600 cities and villages around the country. In conjunction with this event, we established the Swedish National March Cohort (NMC).
Participants in the march were expected to be particularly motivated to provide valid information. They were invited to fill out a 32-page questionnaire, and three pages of this questionnaire were devoted to physical activity, the main focus of the project. Both previously validated and newly developed questions were used in order to estimate energy expenditure and to distinguish between constant low-level activity and short-term peak activity. We used a new rating scale for self-reports of time spent on different intensity levels of physical activity (and inactivity) during a typical day, allowing estimation of total energy expenditure on an interval scale level. This scale has been shown to be both valid and reliable. Seven pages contained questions about diet, using a 63-item validated semi-quantitative food frequency questionnaire that allows estimation of total energy intake and calorie adjustment. Supplementary questions were asked about intake of fried food, detailed pattern of alcohol intake, dietary supplements and use of health food preparations. Two pages had questions about anthropometrical measures, including height, weight (birth weight, current weight, and weight fluctuations), waist and hip measures (allowing calculations of BMI, lean body mass, waist-hip ratio). Further, three pages were allocated to questions about various background and possibly confounding factors such as country of birth, environment during childhood and adolescence, birthplace of parents, own education, type of employment. Two pages were about smoking (including passive smoking) and snuff dipping habits. One page was dedicated to vaccination history, two pages to medical history, two pages to pharmacological history. Two pages were about sun and UV exposure, possible use of sunbeds, and type of complexion. Five pages were spent on questions concerning the psychosocial history, including validated sets of questions about demands and autonomy at work, life events, self-perceived health, social support, as well as duration and quality of sleep. Sleep disturbances were assessed using a modified version of the Karolinska Sleep Questionnaire (KSQ), a widely used tool to assess quality and restorative function of sleep. One page was about the use of mobile telephones. Two pages were devoted to questions specific for women (age at menarche, parity, infertility, menstruation, menopause, use of oral contraceptives and hormone replacement therapy). Due to the open nature of the National March, the total number of individuals who in reality were given a questionnaire could not be assessed. In total, 43,880 men and women completed the questionnaire.
Essentially complete follow-up has since been attained through multiple record linkages, done approximately biannually, using the individually unique national registration numbers (NRNs) to insure exact linkages. We have linked the cohort to Statistics Swedens Register of the Total Population and Population Changes to obtain dates of death, relocations (with information about the new place of residence) and emigration, if any. Data from the Patient Register (covering all inhospital care and more recently also hospital-provided outpatient care), Cancer Register, and Causes of Death Register held by the National Board of Health and Welfare, have permitted accurate tracking of health and vital status of all cohort members. Another complete update (through 2009 in total 12 years of follow-up) was completed by the end of 2011. At the moment, a complete follow-up update (through 2016 in total 19 years of follow-up) will be done by the end of 2016.
Project leaders and research group
|Address:||Organisational Unit: Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Italy|
|Mauro Serafini||Head of Functional Food and Metabolic Stress Prevention Laboratory, CRA-NUT, Rome, Italy|
Questionnaire and Data dictionary
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