Page 274 - Contributed Paper Session (CPS) - Volume 2

CPS1855 Nobutane H.

Extended age-environment model for analysing
data on breast cancer death rates for
Japanese elderly women
Nobutane Hanayama
Shobi University, Kawagoe, Japan

Abstract
The breast cancer death rate for Japanese women aged 70-74 in 2010-14 is
almost twice of the rate in 1985-89, while the rate for women aged 50-54 has
been slightly decreased since 2000. Such trend may be due to that age and
environment factors, which include advancing medical technology,
socioeconomic condition and government policy for public health, intricately
affect Japanese women. In this study, to project such age and environmental
factors, a newly proposed statistical model, which is alternative to the age-
period-cohort model, is fitted to the data for breast cancer deaths for Japanese
women aged 50 and older in 1985-2014. The result shows that the proposed
model provides a better fit to the data than the age-period-cohort model in
terms of Akaike's Information Criterion. Besides the result of estimating
environmental factors suggests that effects of westernized food culture, low
fertility, increase of woman’s first pregnancy over 40 or working women,
westernized food culture since 1960s and low fertility rates in these several
decades in Japan. In addition, the result of comparison of estimated
environment effects on breast cancer and those on food preference rates
suggests that that change of food reference from beef stew to Hamburger or
beef stake increase the breast cancer risks.

Keywords
Age-period-cohort model; Breast cancer; Death rates given by age and period;
Environmental factor

1. Introduction
Breast cancer has become a big socio-economic problem in Japan
(Matsumoto, et al. 2015). Especially among elderly women, the death rates
from the disease have been increasing over the past three decades, though
the death rate remain relatively low compared with the United States, Canada
and England and Wales (Yang, et al., 2010). Now let’s see the Table 1 for the
numbers of deaths in 10,000 for Japanese women aged 50-79. Then it is found
the rate for women aged 70-74 in 2010-14 is almost twice of those in 1985-
89 also in Japan. However, for women aged 50-54, the rate has been slightly
decreased since 2000. More specifically, the age-specific breast cancer death
rates in 2010-14 are entirely almost double of those in 1985-89 for all age

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