Human exposure to air pollution involves complex mixtures of multiple correlated air pollutants. To date, very few studies have assessed the combined effects of exposure to multiple air pollutants on breast cancer (BC) risk. We aimed to assess the association between combined exposures to multiple air pollutants and breast cancer risk. The study was based on a case-control study nested within the French E3N cohort (5222 incident BC cases/5222 matched controls). For each woman, the average of the mean annual exposure to eight pollutants (benzo(a)oyrene, cadmium, dioxins, polychlorinated biphenyls (PCB153), nitrogen dioxide (NO), ozone, particulate matter and fine particles (PMs)) was estimated from cohort inclusion in 1990 to the index date. We used the Bayesian Profile Regression (BPR) model, which groups individuals according to their exposure and risk levels, and assigns a risk to each cluster identified. The model was adjusted on a combination of matching variables and confounders to better consider the design of the nested case-control study. Odds ratios (OR) and their 95 % credible intervals (CrI) were estimated. Among the 21 clusters identified, the cluster characterised by low exposures to all pollutants, except ozone, was taken as reference. A consistent increase in BC risk compared to the reference cluster was observed for 3 clusters: cluster 9 (OR=1.61; CrI=1.13,2.26), cluster 16 (OR=1.59; CrI=1.10,2.30) and cluster 15 (OR=1.38; CrI=1.00,1.88) characterised by high levels of NO, PMs and PCB153. The other clusters showed no consistent association with BC. This is the first study assessing the effect of exposure to a mixture of eight air pollutants on BC risk, using the BPR approach. Overall, results showed evidence of a positive joint effect of exposure to high levels to most pollutants, particularly high for NO, PMs and PCB153, on the risk of BC.

中文翻译：

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与乳腺癌风险相关的多种污染物暴露概况：法国 E3N 队列中的贝叶斯概况回归分析


人类接触空气污染涉及多种相关空气污染物的复杂混合物。迄今为止，很少有研究评估接触多种空气污染物对乳腺癌 (BC) 风险的综合影响。我们的目的是评估多种空气污染物的联合暴露与乳腺癌风险之间的关联。该研究基于法国 E3N 队列中的一项病例对照研究（5222 例 BC 病例/5222 例匹配对照）。估算了每位女性每年平均接触八种污染物（苯并（a）苯并苯、镉、二恶英、多氯联苯 (PCB153)、二氧化氮 (NO)、臭氧、颗粒物和细颗粒 (PM)）的平均值从 1990 年队列纳入到索引日期。我们使用贝叶斯概况回归 (BPR) 模型，该模型根据个人的暴露程度和风险水平对个人进行分组，并为每个识别的集群分配风险。该模型根据匹配变量和混杂因素的组合进行了调整，以更好地考虑巢式病例对照研究的设计。估计优势比 (OR) 及其 95% 可信区间 (CrI)。在确定的21个集群中，以除臭氧外所有污染物暴露量较低的集群为参考。与参考簇相比，观察到 3 个簇的 BC 风险持续增加：簇 9 (OR=1.61；CrI=1.13,2.26)、簇 16 (OR=1.59；CrI=1.10,2.30) 和簇 15 (OR= 1.38；CrI=1.00,1.88)，其特点是 NO、PM 和 PCB153 含量高。其他簇与 BC 没有一致的关联。这是第一项使用 BPR 方法评估暴露于八种空气污染物混合物对 BC 风险影响的研究。 总体而言，结果表明，暴露于高浓度的大多数污染物（特别是高浓度的 NO、PM 和 PCB153）对 BC 风险具有积极的联合影响。