Page 280 - Contributed Paper Session (CPS) - Volume 2

CPS1855 Nobutane H.

Effect of Environment effect Effect of
incorporation of
westernized food 0.15 mammography to
culture, low 0.1 health check for
fertility, increase 0.05
public
of woman’s first 0
pregnancy over -0.05
40 or working -0.1
women -0.15

year
Figure 10. Estimates of environment effects

4. Discussion and Conclusion
In the above, a newly proposed model was fitted to the data given by age
and period for breast cancer deaths obtained from the Japan Vital Statistics.
The result of fitting the model to the data showed that the proposed model
provides a better fit to the data than the age-period-cohort model in terms of
AIC. The proposed model can be applied to data given by the same format,
that is, age-by-period data. Because of that, we can compare trends in
environment effects estimated from data for people’s traits or features. In this
section, we focused on breast cancer and food preferences, and show the
result of analysing causal relations between the food preferences and breast
cancer based on estimated environment effects for breast cancer and food
preferences. As described in the Introduction, the socio-economic factors for
breast cancer are associated, for example, with westernized food culture, low
fertility, increase of working women, increasing of pregnancies over
incorporation of mammography to public health check is also considered as
socioeconomic factors. Because changing of food culture might be considered
independent from other factors for breast cancer, it may be appropriated to
consider a regression model where the environment effect on breast cancer is
a regressand and those on food preferences are regressors (Figure 11). From
the result of regression analysis for the environment effect on breast cancer
and food preferences (Table 3), it is found that change of food reference from
beef stew to Hamburger or beef stake increase the breast cancer risks.

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