Tarone R E, Chu K C, Gaudette L A
Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA.
J Natl Cancer Inst. 1997 Feb 5;89(3):251-6. doi: 10.1093/jnci/89.3.251.
Previous studies of regional and temporal variation in U.S. breast cancer mortality rates have been confined largely to analyses of rates for white women.
Breast cancer mortality rates from 1969 through 1992 for white women and black women in four regions of the United States and for all women throughout Canada were compared to identify racial, regional, and temporal differences. Differences and trends in the rates were evaluated in view of breast cancer risk factors and relevant medical interventions.
Age-period-cohort models were fit to the data, and changes in birth cohort trends (suggesting a change in a breast cancer risk factor or protective factor) and calendar period trends (suggesting, in part, the impact of new or improved medical interventions) were examined.
Breast cancer mortality rates for white women were significantly higher in the Northeast than in any other region of the United States (two-sided t tests; P<.005); the rates for black women were not. Birth cohort trends for all women were similar until about 1940, with a moderation of mortality risk beginning around 1924. A marked moderation of risk by 4-year birth cohorts was observed for U.S. white women born after 1950, whereas stable or slightly decreasing trends were observed for U.S. black women and Canadian women. For women born from 1924 to around 1938, fertility rates increased for all three groups; after 1950, they declined uniformly. Looking at temporal effects, we found that the slope of the mortality calendar period trend increased in the 1980s compared with the 1970s for all women. In the last calendar period, 1991-1992, a trend of decreasing mortality rates was found for white women in the United States and for Canadian women.
Widespread environmental exposures are unlikely to explain the higher relative breast cancer mortality rates observed for U.S. white women in the Northeast, since the rates for black women in this region were not higher than in other regions. The moderation of breast cancer mortality rates for women born between 1924 and 1938 coincides with increased fertility rates following World War II. Stable or decreasing mortality rates for U.S. women and Canadian women born after 1950 were not expected in view of declining fertility rates, suggesting a change in a breast cancer risk factor or protective factor. The increase in calendar period trend slope in the 1980s likely reflects the coincident rise in breast cancer diagnosis via mammography. The recent decline in calendar period trend for white women in the United States and for Canadian women may be the result of earlier detection and increased use of adjuvant therapy.
先前关于美国乳腺癌死亡率地区和时间变化的研究主要局限于对白人女性死亡率的分析。
比较1969年至1992年美国四个地区白人女性和黑人女性以及加拿大所有女性的乳腺癌死亡率，以确定种族、地区和时间差异。鉴于乳腺癌风险因素和相关医疗干预措施，对死亡率的差异和趋势进行了评估。
将年龄-时期-队列模型应用于数据，并研究出生队列趋势的变化（表明乳腺癌风险因素或保护因素的变化）和日历时期趋势的变化（部分表明新的或改进的医疗干预措施的影响）。
美国东北部白人女性的乳腺癌死亡率显著高于美国其他任何地区（双侧t检验；P<0.005）；该地区黑人女性的死亡率则不然。1940年左右之前，所有女性的出生队列趋势相似，1924年左右开始死亡风险有所降低。1950年以后出生的美国白人女性，每4年出生队列的死亡风险显著降低，而美国黑人女性和加拿大女性的死亡率呈稳定或略有下降趋势。1924年至1938年左右出生的所有三个群体的生育率都有所上升；1950年以后，生育率均下降。从时间效应来看，我们发现与20世纪70年代相比，20世纪80年代所有女性死亡率的日历时期趋势斜率有所增加。在最后一个日历时期，即1991 - 1992年，美国白人女性和加拿大女性的死亡率呈下降趋势。
广泛的环境暴露不太可能解释美国东北部白人女性相对较高的乳腺癌死亡率，因为该地区黑人女性的死亡率并不高于其他地区。1924年至1938年出生的女性乳腺癌死亡率降低与二战后生育率上升相吻合。鉴于生育率下降，预计1950年以后出生的美国女性和加拿大女性死亡率应稳定或上升，但实际却呈稳定或下降趋势，这表明乳腺癌风险因素或保护因素发生了变化。20世纪80年代日历时期趋势斜率增加可能反映了通过乳房X线摄影术诊断乳腺癌的情况同时增加。美国白人女性和加拿大女性最近日历时期趋势下降可能是早期检测和辅助治疗使用增加的结果。
