Trewin Cassia B, Strand Bjørn Heine, Weedon-Fekjær Harald, Ursin Giske
Department of Research, Cancer Registry of Norway, Oslo, Norway.
Norwegian Advisory Unit for Women's Health, Oslo University Hospital, Oslo, Norway.
Eur J Public Health. 2017 Feb 1;27(1):160-166. doi: 10.1093/eurpub/ckw148.
In the last century, breast cancer incidence and mortality was higher among higher versus lower educated women in developed countries. Post-millennium, incidence rates have flattened off and mortality declined. We examined breast cancer trends by education level, to see whether recent improvements in incidence and mortality rates have occurred in all education groups.
We linked individual registry data on female Norwegian inhabitants aged 35 years and over during 1971–2009. Using Poisson models, we calculated absolute and relative educational differences in age-standardised breast cancer incidence and mortality over four decades. We estimated educational differences by Slope and Relative Index of Inequality, which correspond to rate difference and rate ratio, comparing the highest to lowest educated women.
Pre-millennium, incidence and mortality of breast cancer were significantly higher in higher versus lower educated women. Post-millennium, educational differences in breast cancer incidence and mortality attenuated. During 2000–2009, breast cancer incidence was still 38% higher for higher versus lower educated women (Relative Index of Inequality: 1.38, 95% confidence interval: 1.31–1.44), but mortality no longer varied significantly by education level (Relative Index of Inequality: 1.09, 95% confidence interval: 0.99–1.19). Among women below 50 years, however, the education gradient for mortality reversed, and mortality was 28% lower for the highest versus lowest educated women during 2000–2009 (Relative Index of Inequality: 0.72, 95% confidence interval: 0.51–0.93).
Post-millennium improvements in breast cancer incidence and mortality have primarily benefited higher educated women. Breast cancer mortality is now highest among the lowest educated women below 50 years.
在上个世纪，发达国家中受教育程度较高的女性与受教育程度较低的女性相比，乳腺癌发病率和死亡率更高。进入千禧年后，发病率趋于平稳，死亡率有所下降。我们按教育水平研究了乳腺癌趋势，以了解发病率和死亡率的近期改善是否在所有教育群体中都有出现。
我们将1971年至2009年期间35岁及以上挪威女性居民的个人登记数据进行了关联。使用泊松模型，我们计算了四十年来年龄标准化乳腺癌发病率和死亡率的绝对和相对教育差异。我们通过斜率和不平等相对指数估计教育差异，这分别对应于率差和率比，比较受教育程度最高与最低的女性。
千禧年前，受教育程度较高的女性乳腺癌发病率和死亡率显著高于受教育程度较低的女性。千禧年后，乳腺癌发病率和死亡率方面的教育差异有所减弱。在2000年至2009年期间，受教育程度较高的女性乳腺癌发病率仍比受教育程度较低的女性高38%（不平等相对指数：1.38,95%置信区间：1.31 - 1.44），但死亡率不再因教育水平而有显著差异（不平等相对指数：1.09,95%置信区间：0.99 - 1.19）。然而，在50岁以下的女性中，死亡率的教育梯度发生了逆转，在2000年至2009年期间受教育程度最高的女性死亡率比受教育程度最低的女性低28%（不平等相对指数：0.72,95%置信区间：0.51 - 0.93）。
千禧年后乳腺癌发病率和死亡率的改善主要惠及了受教育程度较高的女性。现在50岁以下受教育程度最低女性的乳腺癌死亡率最高。
