Department of Geography, McGill University, Montreal, Quebec, Canada.
Environ Health Perspect. 2010 Nov;118(11):1578-83. doi: 10.1289/ehp.1002221.
Only about 30% of cases of breast cancer can be explained by accepted risk factors. Occupational studies have shown associations between the incidence of breast cancer and exposure to contaminants that are found in ambient air.
We sought to determine whether the incidence of postmenopausal breast cancer is associated with exposure to urban air pollution.
We used data from a case-control study conducted in Montreal, Quebec, in 1996-1997. Cases were 383 women with incident invasive breast cancer, and controls were 416 women with other incident, malignant cancers, excluding those potentially associated with selected occupational exposures. Concentrations of nitrogen dioxide (NO2) were measured across Montreal in 2005-2006. We developed a land-use regression model to predict concentrations of NO2 across Montreal for 2006, and developed two methods to extrapolate the estimates to 1985 and 1996. We linked these estimates to addresses of residences of subjects at time of interview. We used unconditional logistic regression to adjust for accepted and suspected risk factors and occupational exposures.
For each increase of 5 ppb NO2 estimated in 1996, the adjusted odds ratio was 1.31 (95% confidence interval, 1.00-1.71). Although the size of effect varied somewhat across periods, we found an increased risk of approximately 25% for every increase of 5 ppb in exposure.
We found evidence of an association between the incidence of postmenopausal breast cancer and exposure to ambient concentrations of NO2. Further studies are needed to confirm whether NO2 or other components of traffic-related pollution are indeed associated with increased risks.
只有约 30%的乳腺癌病例可以用已接受的风险因素来解释。职业研究表明，乳腺癌的发病率与环境空气中存在的污染物暴露之间存在关联。
我们试图确定绝经后乳腺癌的发病率是否与接触城市空气污染有关。
我们使用了 1996-1997 年在魁北克省蒙特利尔市进行的一项病例对照研究的数据。病例为 383 名患有侵袭性乳腺癌的女性，对照为 416 名患有其他侵袭性恶性肿瘤的女性，不包括那些可能与特定职业暴露相关的肿瘤。2005-2006 年，我们在蒙特利尔全市测量了二氧化氮（NO2）的浓度。我们开发了一个基于土地利用的回归模型，以预测 2006 年蒙特利尔的 NO2 浓度，并开发了两种方法将估计值外推到 1985 年和 1996 年。我们将这些估计值与受访者在接受访谈时的住址相关联。我们使用无条件逻辑回归来调整已知和可疑的风险因素以及职业暴露。
对于 1996 年估计增加的每 5ppb 的 NO2，调整后的比值比为 1.31（95%置信区间，1.00-1.71）。尽管效应的大小在不同时期略有不同，但我们发现，暴露量每增加 5ppb，患乳腺癌的风险约增加 25%。
我们发现绝经后乳腺癌的发病率与环境空气中的二氧化氮浓度之间存在关联的证据。需要进一步的研究来证实是否是二氧化氮或其他交通相关污染成分确实与增加的风险有关。
