Minami Yuko, Tsubono Yoshitaka, Nishino Yoshikazu, Ohuchi Noriaki, Shibuya Daisuke, Hisamichi Shigeru
Division of Epidemiology, Miyagi Cancer Center Research Institute, 47-1 Nodayama, Medeshima-Shiode, Natori 981-1293, Japan.
Int J Cancer. 2004 Mar 1;108(6):901-6. doi: 10.1002/ijc.11661.
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.
在最近几十年间，日本乳腺癌的发病率一直在上升。根据日本几个癌症登记处的最新报告，乳腺癌已成为女性癌症发病率中居首位的癌症类型。为了详细分析乳腺癌发病率的趋势，我们总结了1959年至1997年日本宫城县女性乳腺癌的发病率，并使用年龄-时期-队列模型评估了时期和队列对乳腺癌发病率的影响。特定年龄发病率和年龄标准化发病率在连续的日历时期内均有所上升。在1980年左右，这些发病率出现了加速上升。一个包含年龄、时期和队列的完整模型最能拟合发病率的趋势。在该模型中，时期和队列的影响具有统计学意义。队列的非线性效应显示出一种上升趋势，始于1888年至1897年出生的队列，而时期的非线性效应则表明随着日历时期的推移风险明显增加。此外，包含线性成分的完整模型显示队列效应呈稳步上升趋势。基于我们之前在宫城县进行的流行病学研究以及其他已发表的报告，队列效应可能与低生育和母乳喂养不足等风险因素的女性患病率变化有关。我们认为，队列效应的出现是一项重要发现，尽管时期效应可能也会持续存在。显著的队列效应可能为日本乳腺癌发病率的持续上升敲响警钟。
