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Physical activity and breast cancer risk among female physical education and language teachers: A 34‐year follow‐up
Author(s) -
Rintala Pirjo,
Pukkala Eero,
Läärä Esa,
Vihko Veikko
Publication year - 2003
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.11390
Subject(s) - poisson regression , breast cancer , demography , medicine , confidence interval , record linkage , incidence (geometry) , relative risk , cohort , cohort study , rate ratio , cancer , cancer registry , physical education , place of birth , gerontology , population , environmental health , physics , sociology , optics , medical education
The cohort consisted of 1,489 Finnish female physical education and 8,560 language teachers born after 1920 and alive in 1967. The 2 study populations were similar in social class and way of living and clearly discordant in physical activity both during their university studies and later in life. The incidence of breast cancer among these teachers up to the year 2000 was assessed through a record linkage with the Finnish Cancer Registry. The number of breast cancer cases among physical education teachers was 61 in 32,862 person‐years and among language teachers was 404 in 177,188 person‐years. In Poisson‐regression analysis, the incidence rate ratio—adjusted for age, calendar time, number of children and age at first birth—for physical education vs. language teachers was overall 0.83 (95% confidence interval 0.63–1.09). This relative rate was 0.79 (0.46–1.36) in ages <50 years and 0.86 (0.62–1.18) in ages ≥50 years. Our study is concordant with the hypothesis that life‐long physical activity may reduce the risk of breast cancer. © 2003 Wiley‐Liss, Inc.