Cancer Causes & Control

, Volume 7, Issue 5, pp 507–512 | Cite as

Lifestyle changes during adolescence and risk of breast cancer: an ecologic study of the effect of World War II in Norway

  • Steinar Tretli
  • Maria Gaard
Research Papers

There are biologic reasons to believe that the period between thelarche and the first full-term pregnancy is a particularly sensitive period in a woman's life regarding the development of breast cancer. In this ecologic study, data provided by the Norwegian Cancer Registry were analyzed to compare risk of breast cancer among women who experienced this sensitive period before, during, or after World War II. An ordinary age-cohort model and a model where the cohort was described by exposure by calendar period and sensitivity to this exposure at different ages, were fitted to the data. The incidence of breast cancer was lower than expected among women who experienced puberty during the war. The estimated configuration of the exposure variable showed an increase in exposure up to the start of WWII to twice the levelin 1916, dropped by 13 percent during the war, and increased again after the war. The levelin 1975 was approximately 2.7 times higher than the level in 1916. The results indicate that one or more lifestyle factors that changed among adolescent women during the war, influenced their risk of breast cancer. Dietary intake of energy, fat, meat, milk, fish, fresh vegetables, and potatoes, in addition to physical activity level and height, are important factors to consider in relation to breast cancer risk.

Key words

Breast cancer diet height Norway physical activity World War II 


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  1. 1.
    Moolgavkar SH, Day NE, Stevens RG. Two-stage model for carcinogenesis: Epidemiology of breast cancer in females. JNCI 1980; 65: 559–69.Google Scholar
  2. 2.
    Tokunaga M, Norman JE, Asano M, et al. Malignant tumors among atomic bomb survivors, Hiroshima and Nagasaki 1950–74. JNCI 1979; 62: 1347–59.Google Scholar
  3. 3.
    MacMahon B. Reproduction and cancer of the breast. Cancer 1993; 71: 3185–8.Google Scholar
  4. 4.
    Tomatis L, Aito A, Day NE, et al. Cancer: Cause, Occurrence and Control. Lyon, France: International Agency for Research on Cancer, 1990; IARC Sci. Pub. No. 100.Google Scholar
  5. 5.
    Buell P, Dunn JE. Cancer mortality amongst Japanese Issii and Nissei of California. Cancer 1965; 18: 656–64.Google Scholar
  6. 6.
    Doll R, Peto R. The causes of cancer: quantivetive estimates of avoidable risks of cancer in the United States today. JNCI 1981; 66: 1191–308.Google Scholar
  7. 7.
    Armstrong B, Doll R. Environmental factors and cancer incidence and mortality in different countries with special reference to dietary practices. Int J Cancer 1975; 15: 617–31.Google Scholar
  8. 8.
    Block G, Patterson B, Subar A. Fruit, vegetables, and cancer prevention: a review of the epidemiological evidence. Nutr Cancer 1992; 18: 1–29.Google Scholar
  9. 9.
    Howe GR, Hirohata T, Hislop TG, et al. Dietary factors and risk of breast cancer: combined analysis of 12 casecontrol studies. JNCI 1990; 82: 561–9.Google Scholar
  10. 10.
    Willett WC, Hunter DJ, Stampfer MJ, et al. Dietary fat and fiber in relation to risk of breast cancer. An 8-year follow-up. JAMA 1992; 268: 2037–44.Google Scholar
  11. 11.
    van den Brandt PA, van't Veer P, Goldbohm RA, et al. A prospective cohort study on dietary fat and the risk of postmenopausal breast cancer. Cancer Res 1993; 53: 75–82.Google Scholar
  12. 12.
    Toniolo P, Riboli E, Shore RE, Pasternack BS. Consumption of meat, animal products, protein, and fat and risk of breast cancer: a prospective cohort study in New York. Epidemiology 1994; 5: 391–7.Google Scholar
  13. 13.
    Jones DY, Schatzkin A, Green SB, et al. Dietary fat and breast cancer in the National Health and Nutrition Examination Survey I Epidemiologic Follow-up Study. JNCI 1987; 79: 465–71.Google Scholar
  14. 14.
    Gaard M, Tretli S, Løken EB. Dietary fat and the risk of breast cancer: a prospective study of 25,892 Norwegian women. Int J Cancer 1995; 63: 13–7.Google Scholar
  15. 15.
    Bernstein L, Henderson BE, Hanisch R, Sullivan Halley J, Ross RK. Physical exercise and reduced risk of breast cancer in young women. JNCI 1994; 86: 1403–8.Google Scholar
  16. 16.
    Brundtland GH, Liestøl K, Walløe L. Height and weight and menarchal age of Oslo schoolchildren during the last 60 years. Ann Hum Biol 1980; 7: 307–22.Google Scholar
  17. 17.
    Tretli S. Height and weight in relation to breast cancer morbidity and mortality. A prospective study of 570,000 women in Norway. Int J Cancer 1989; 44: 23–30.Google Scholar
  18. 18.
    Numerical Algorithms Group Ltd. The Generalized Interactive Modeling (GLIM) System. Oxford, UK: Royal Statistical Society, 1987.Google Scholar
  19. 19.
    Galtung-Hansen O. Food conditions in Norway during the war 1939–45. Proc Nutr Soc 1947; 5: 263–70.Google Scholar
  20. 20.
    Freedman LS, Clifford C, Messina M. Analysis of dietary fat, calories, body weight, and the development of mammary tumors in rats and mice: a review. Cancer Res 1990; 50: 5710–9.Google Scholar
  21. 21.
    Albanes D, Winick M. Are cell number and cell profile ratio risk factors for cancer?. JNCI 1988; 80: 772–5.Google Scholar
  22. 22.
    Kritchevsky D. The effect of over-and undernutrition on cancer. Europ J Cancer Prev 1995; 4: 445–51.Google Scholar
  23. 23.
    Micozzi MS. Nutrition, body size and breast cancer. Year-book Ph Phys Anthropol 1985; 28: 175–206.Google Scholar
  24. 24.
    Vatten LJ, Kvinnsland S. Body height and risk of breast cancer. A prospective study of 23, 831 Norwegian women. Br J Cancer 1990; 61: 881–5.Google Scholar
  25. 25.
    Strøm A. Examination into the diet of Norwegian families during the war-years 1942–1945. Acta Med Scand 1948; Suppl 214.Google Scholar
  26. 26.
    Johansson L, Drevon CA, Bjørneboe G-Aa. The Norwegian diet during the last hundred years in relation to coronary heart disease. Eur J Clin Nutr 1996; in press.Google Scholar
  27. 27.
    Mittendorf R, Matthew P, Longnecker MP, et al. Strenuous physical activity in young adulthood and risk of breast cancer (United States). Cancer Causes Control 1995; 6: 347–53.Google Scholar
  28. 28.
    Liestøl K. Social conditions and menarchal age. The importance of early years of life. Ann Hum Biol 1982; 9: 521–37.Google Scholar
  29. 29.
    Brunborg H, Kravdal Ø. Fertility by birth order in Norway. A register based analysis. Oslo, Norway: Statistics Norway, 1986; Report 27.Google Scholar
  30. 30.
    MacMahon B, Cole P, Lin TM, et al. Age at first birth and cancer of the breast. A summary of an international study. Bull World Health Organ 1970; 43: 209–21.Google Scholar
  31. 31.
    Tretli S, Haldorsen T. A cohort analysis of breast cancer, uterine corpus cancer, and childbearing pattern in Norwegian women. J Epidemiol Comm Health 1990; 44: 215–9.Google Scholar

Copyright information

© Rapid Science Publishers 1996

Authors and Affiliations

  • Steinar Tretli
  • Maria Gaard

There are no affiliations available

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