The increase of female breast cancer incidence in Japan: Emergence of birth cohort effect

During recent decades, breast cancer incidence has been increasing in Japan. According to the latest reports from several cancer registries in Japan, the breast has become the leading cancer site in female cancer incidence. To analyze the trend of breast cancer incidence in detail, we summarized female breast cancer incidence in Miyagi Prefecture, Japan during 1959–1997, and evaluated the period and cohort effect on breast cancer incidence using the age‐period‐cohort model. Age‐specific and age‐standardized rates have increased over successive calendar periods. Around 1980, an accelerated increase in these incidence rates took place. A full model including age, period and cohort was best fitted to the trend of incidence. In the model, the effects of period and cohort were statistically significant. The nonlinear effect for cohort indicates an increasing trend, beginning with the cohort in 1888–1897, and the nonlinear effect for period showed a clear increase in risk with calendar period. Furthermore, the full model including a linear component showed a steadily upward trend in the cohort effect. Based on our own epidemiologic studies previously conducted in Miyagi Prefecture, and other published reports, the cohort effect is likely to be related to the change in prevalence of women with risk factors such as low parity and insufficient breastfeeding. We believe that the emergence of the cohort effect is an important finding, although the period effect may also persist. The significant cohort effect may give a caution for continuous increase of breast cancer incidence in Japan. © 2003 Wiley‐Liss, Inc.

[1]  J L Kelsey,et al.  Reproductive factors and breast cancer. , 1993, Epidemiologic reviews.

[2]  T. Holford.  Understanding the effects of age, period, and cohort on incidence and mortality rates. , 1991, Annual review of public health.

[3]  H. Adami,et al.  Trends in breast cancer incidence in Sweden 1958-1988 by time period and birth cohort. , 1993, British Journal of Cancer.

[4]  M. Vinceti,et al.  Changes in breast cancer incidence and stage distribution in Modena, Italy: the effect of a mammographic screening program , 2002, Cancer Causes & Control.

[5]  T. Tango,et al.  Age, period and cohort analysis of trends in mortality from major diseases in Japan, 1955 to 1979: peculiarity of the cohort born in the early Showa Era. , 1987, Statistics in medicine.

[6]  J. Kelsey.  Breast cancer epidemiology: summary and future directions. , 1993, Epidemiologic reviews.

[7]  P. Boyle,et al.  Age-period-cohort models: a comparative study of available methodologies. , 1999, Journal of clinical epidemiology.

[8]  T R Holford,et al.  The estimation of age, period and cohort effects for vital rates. , 1983, Biometrics.

[9]  Y. Nomura,et al.  Occurrence of breast cancer in relation to diet and reproductive history: a case-control study in Fukuoka, Japan. , 1985, National Cancer Institute monograph.

[10]  W. Willett,et al.  Diet, body size, and breast cancer. , 1993, Epidemiologic reviews.

[11]  S. Duffy,et al.  Incidence of female breast cancer in relation to prevalence of risk factors in Denmark. , 1994, International journal of cancer.

[12]  Michael Green,et al.  The GLIM system : release 4 manual , 1993 .

[13]  C. Nagata,et al.  Effects of Menstrual and Reproductive Factors on the Risk of Breast Cancer: Meta‐analysis of the Case‐Control Studies in Japan , 1995, Japanese journal of cancer research : Gann.

[14]  D Clayton,et al.  Models for temporal variation in cancer rates. I: Age-period and age-cohort models. , 1987, Statistics in medicine.

[15]  J. Ranstam,et al.  Breast cancer and breastfeeding: collaborative reanalysis of individual data from 47 epidemiological studies in 30 countries, including 50 302 women with breast cancer and 96 973 women without the disease , 2002, The Lancet.

[16]  L. Lipworth,et al.  History of breast-feeding in relation to breast cancer risk: a review of the epidemiologic literature. , 2000, Journal of the National Cancer Institute.

[17]  M. Singer,et al.  Nutritional Epidemiology , 2020, Definitions.

[18]  N. Ohuchi,et al.  Risk factors for breast cancer: A case-control study of screen-detected breast cancer in Miyagi Prefecture, Japan , 1997, Breast Cancer Research and Treatment.

[19]  Y. Minami,et al.  Trends in the Incidence of Female Breast and Cervical Cancers in Miyagi Prefecture, Japan, 1959–1987 , 1996, Japanese journal of cancer research : Gann.

[20]  J. Ferlay,et al.  Cancer Incidence in Five Continents , 1970, Union Internationale Contre Le Cancer / International Union against Cancer.

[21]  Eric R. Ziegel,et al.  Generalized Linear Models , 2002, Technometrics.

[22]  D Clayton,et al.  Models for temporal variation in cancer rates. II: Age-period-cohort models. , 1987, Statistics in medicine.

[23]  N. Ohuchi,et al.  Determinants of infant feeding method in relation to risk factors for breast cancer. , 2000, Preventive medicine.

[24]  M. Inoue,et al.  A Large‐scale, Hospital‐based Case‐Control Study of Risk Factors of Breast Cancer According to Menopausal Status , 1995, Japanese journal of cancer research : Gann.

[25]  R. Abe,et al.  A case-control study of breast cancer among Japanese women: with special reference to family history and reproductive and dietary factors , 2005, Breast Cancer Research and Treatment.

[26]  Norman E. Breslow,et al.  The design and analysis of cohort studies , 1987 .

[27]  Cancer incidence and incidence rates in Japan in 1997: estimates based on data from 12 population-based cancer registries. , 2002, Japanese journal of clinical oncology.

[28]  N. Breslow,et al.  Statistical methods in cancer research. Volume II--The design and analysis of cohort studies. , 1987, IARC scientific publications.

[29]  R. W. Wedderburn.  Quasi-likelihood functions, generalized linear models, and the Gauss-Newton method , 1974 .

[30]  Norman E. Breslow,et al.  Statistical Methods in Cancer Research, Vol. II: The Design and Analysis of Cohort Studies. , 1990 .

[31]  Richard Doll,et al.  Cancer incidence in five continents : a technical report , 1966 .

[32]  P. Boyle,et al.  Age-period-cohort analysis of chronic disease rates. I: Modelling approach. , 1998, Statistics in medicine.

[33]  T. Holford,et al.  Trends in female breast cancer in Connecticut and the United States. , 1991, Journal of clinical epidemiology.

[34]  A. Oshima,et al.  Cancer incidence in Japan in 1990: estimates based on data from Population-based Cancer Registries. The Research Group for Population-based Cancer Registration in Japan. , 1998, Japanese journal of clinical oncology.