Research Study the Swedish Mammography Cohort and The
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Page 1 of 8 Research study The Swedish mammography cohort and the cohort of Swedish men: study design and characteristics of two population- based longitudinal cohorts H Harris1,2*, N Håkansson1, C Olofsson1, O Stackelberg1, B Julin1, A Åkesson1, A Wolk1 Study Design Abstract Cohort participants and 25% of Cohort Introduction Introduction of Swedish Men participants were cur- The Swedish Mammography Cohort The Swedish Mammography Cohort, rent smokers, and 23% and 15% were (SMC) and the Cohort of Swedish Men established in 1987, and the Cohort regular users of dietary supplements, (COSM) are two large population- of Swedish Men, established in 1997, respectively. based longitudinal cohorts established are two ongoing population-based Conclusion in Sweden. The SMC was established longitudinal cohorts designed to Recently, clinical sub-cohorts col- in 1987–1990 (together with a mam- study dietary exposures in relation to lecting more detailed information mography screening program) with chronic disease outcomes. This study including blood, urine, and adipose the aim to explore dietary exposures discusses these two cohorts. tissue collection, dual energy X-ray in relation to breast cancer risk and absorptiometry scan, and a cogni- nal manuscript. nal Materials and methods has since been expanded to assess fi Information on dietary intake includ- tive test phone interview have been risk of various health outcomes. The ing alcohol and dietary supplements established allowing for future in- COSM was established 10 years later, has been assessed by validated semi- depth analyses that examine health in 1997, with the aim to explore diet quantitative food frequency ques- outcomes in an aging population. and lifestyle in relation to chronic tionnaires at multiple time points. Questionnaires have also collected information including anthropomet- Table 1 Selected characterisƟ cs of parƟ cipants in the Swedish Mammography ric and physical activity measures Cohort (SMC) at baseline (1987) and follow-up (1997) and the Cohort of 1 across the life course, sleep habits, Swedish Men (COSM) at baseline (1997) urine and bowel habits, family his- Cohort/quesƟ onnaire year tory of selected diseases, stress and CharacterisƟ cs COSM SMC 1987 SMC 1997 social support. Annual linkage to 1997 multiple registries allows for up to date information on health status of N 61,433 38,984 45,906 all participants. Age (years) 52.9 (9.8) 62.0 (9.3) 60.3 (9.7) Results Married/living with partner (%) 76.3 — 82.4 The mean (±SD) age and body mass Body mass index (kg/m2) 24.7 (3.9) 25.0 (4.0) 25.8 (3.4) index at cohort enrolment were Height (cm) 164.1 (5.8) 164.3 (5.8) 177.2 (6.7) 52.9 (9.8) years and 24.7 (3.9) kg/ on of the manuscript, as well read and approved Ɵ m2 for the Swedish Mammography Waist circumference (cm) — 83.7 (10.8) 96.1 (11.7) Cohort and 60.3 (9.7) years and 25.8 Hip circumference (cm) — 102.7 (9.7) 101.9 (8.6) (3.4) kg/m2 for the Cohort of Swedish Men. At baseline, 76% of Swedish Postmenopausal (%) — 89.7 n/a Mammography Cohort participants Age at menopause — 49.6 (4.8) n/a and 82% of Cohort of Swedish Men Ever use of oral contracep ves (%) — 43.8 n/a participants were married. In 1997, none declared. ict of interests: Smoking status (%) fl 13% of Swedish Mammography on, design, and prepara Current — 13.1 25.0 Ɵ *Corresponding author Email: [email protected] Past — 33.0 38.9 rules of disclosure. (AME) ethical Ethics Medical on for Ɵ 1 Unit of Nutritional Epidemiology, Institute Never — 53.9 36.2 of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden Regular user of dietary supplements (%) — 22.8 14.9 2 Obstetrics and Gynecology Epidemiology Average hours of sleep per night — 7.2 (1.1) 7.2 (1.1) Center, Brigham and Women’s Hospital, 1 Boston, Massachusetts, USA Data represent mean (standard devia on) unless otherwise indicated. Licensee OA Publishing London 2013. Creative Commons Attribution Licence (CC-BY) none declared. Con ng interests: Ɵ F : Harris H, Håkansson N, Olofsson C, Stackelberg O, Julin B, Åkesson A, et al. The Swedish mammography cohort and the cohort of Swedish men: study design and characteristics of two population-based Compe longitudinal cohorts. OA Epidemiology 2013 Oct 01;1(2):16. the concep to All authors contributed All authors abide by the Associa Page 2 of 8 Research study SMC (Swedish Mammography Cohort) COSM (Cohort of Swedish Men) Source population (Born between 1914-1948, residing Source population (Born between 1918-1952, residing in Vastmanland and Uppsala counties) in Vastmanland and Orebro counties) 90,303 invited in 1987-1990 100,303 invited in 1997-1998 Respondents 66,651 (74% response rate) 1987 Diet and lifestyle questionnaire Baseline Cohort after exclusions 61,433 Contacted 56,030 SMC members 1997 Respondents alive and still residing in study Diet and lifestyle questionnaire 48,850 (49% response rate) area (70% response rate) Baseline Cohort after exclusions 1997 Cohort after exclusions 45,906 39,984 nal manuscript. nal fi Contacted 48,263 SMC members 2008 Contacted 37,861 COSM members alive and still residing in study Health questionnaire alive and still residing in study area area (63% response rate) (78% response rate) Contacted 30,134 SMC members 2009 Contacted 29,068 COSM members who completed the 2008 who completed the 2008 Diet and lifestyle questionnaire questionnaire (84% response rate) questionnaire (90% response rate) Figure 1: Description of recruitment and data collection for the Swedish Mammography Cohort (SMC; 1987–2009) and the Cohort of Swedish Men (COSM; 1997–2009). diseases. Since then, additional ques- All subjects gave full informed con- asked to return the completed ques- tionnaire data have been collected sent to participate in this study. tionnaire in-person at their mammo- and sub-cohorts with biological speci- gram appointment. Seventy-four per mens have been established making SMC cent of women returned a completed these cohorts a valuable resource for questionnaire. After excluding those Recruitment the scientific community. The aim of with an incorrect or missing national this study was to discuss the study From March 1987 to December 1990, registration number, cancer diag- design and characteristics of these all women living in Uppsala County of nosis (except non-melanoma skin on of the manuscript, as well read and approved two population-based longitudinal central Sweden and who were born cancer) before baseline, implausible Ɵ cohorts. in 1914 through 1948 (n = 48,517) total energy intake (three standard and all women living in the adjacent deviations [SD] from the mean value Västmanland County (n = 41,786) for loge-transformed energy intake), Materials and methods who were born in 1917 through those outside the age-range of 38–76 The SMC and the COSM are coor- 1948 received an invitation by mail years, or other missing data, the final dinated by the Unit of Nutritional to participate in a population-based baseline cohort consisted of 61,433 Epidemiology within the Institute mammography screening program none declared. ict of interests: women. Characteristics of the SMC at fl of Environmental Medicine at the (Figure 1). The invitation included a on, design, and prepara baseline are presented in Table 1. Ɵ Karolinska Institute, Stockholm, six-page questionnaire that sought 1 1997 SMC questionnaire rules of disclosure. (AME) ethical Ethics Medical on for Sweden . This work conforms to the information on diet and alcohol Ɵ values laid down in the Declaration of intake (67-item Food Frequency In the fall of 1997, a second extended Helsinki (1964). The protocol of this Questionnaire [FFQ]), parity, age at questionnaire was sent to all SMC mem- study has been approved by the rele- first birth, family history of breast bers (n = 56,030) who were still alive vant ethical committee related to our cancer, weight, height, education and residing in the study area (Figure 1). institution in which it was performed. level and marital status. Women were The 1997 questionnaire collected Licensee OA Publishing London 2013. Creative Commons Attribution Licence (CC-BY) none declared. Con ng interests: Ɵ F : Harris H, Håkansson N, Olofsson C, Stackelberg O, Julin B, Åkesson A, et al. The Swedish mammography cohort and the cohort of Swedish men: study design and characteristics of two population-based Compe longitudinal cohorts. OA Epidemiology 2013 Oct 01;1(2):16. the concep to All authors contributed All authors abide by the Associa Page 3 of 8 Research study information on diet and alcohol intake Table 2 Comparison of the Swedish Mammography Cohort (SMC) and (96-item FFQ), dietary supplements, the Cohort of Swedish Men (COSM) with the Swedish populaƟ on in 1997 family history of cancer and myocardial for women aged 48–83 years and men aged 45–79 years, regarding age infarction, age at menarche, history of distribuƟ on, educaƟ onal level and body mass index1 oral contraceptive use, age at meno- Female Male pause, postmenopausal hormone use, PopulaƟ on, PopulaƟ on CharacterisƟ cs SMC 1997 COSM 1997 disease diagnoses, body weight across aged 48–83 aged 45–79 the life course (birth weight through years, 19972 years, 19972 weight at age 80 years), current waist Age groups, years and hip circumferences, medication use Total, n 38,984 1,633,520 45,906 1,594,952 and lifestyle factors including history of 45–49 — — 15.9 19.5 cigarette smoking, physical activity (at 48–54 28.5 27.6 — — ages 15, 30, 50 and current) and sleep 50–54 — — 18.8 20.8 habits. The response rate for the 1997 55–59 17.9 15.0 15.9 15.6 questionnaire was 70%.