Center for Clinical Evidence Synthesis, Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA, USA.
Lung Cancer. 2012 May;76(2):150-8. doi: 10.1016/j.lungcan.2011.10.014. Epub 2011 Dec 9.
Multiple studies have assessed parity as a risk factor for lung cancer but results have been inconclusive. We searched MEDLINE (through August 2010) and the Institute of Scientific Information Web of Knowledge database (through April 2011) to identify studies investigating the association of parity with lung cancer and allowing the calculation of dose-response trends using a linear model. Between-study heterogeneity was assessed using Cochran's Q statistic and the I(2) index. Summary per-child relative risks (RRs) with their 95% confidence interval (CI) were estimated using random effects meta-analysis. Sixteen eligible studies (8077 lung cancer patients; 350,295 unaffected individuals) provided data for meta-analysis. There was significant between-study heterogeneity (p<0.001; I(2)=73%). The summary per livebirth RR was 0.98 (95% CI, 0.95-1.02), indicating no effect of parity on lung cancer risk. Results were consistent in case-control (n=11), RR=0.99 (95% CI, 0.94-1.04), and cohort studies (n=5), RR=0.97 (95% CI, 0.92-1.03). Studies not including small-cell lung cancer patients found a borderline protective effect of parity, RR=0.94 (95% CI, 0.88-1.00). In contrast, no effect was observed in studies including small-cell lung cancer patients, RR=1.00 (95% CI, 0.98-1.03); p for difference=0.05. Overall, there was little evidence of a dose-response relationship between increasing number of livebirths and lung cancer; however, studies have produced heterogeneous results. Future studies should include analyses in well-defined histological disease subgroups.
多项研究评估了生育次数作为肺癌的危险因素，但结果尚无定论。我们检索了 MEDLINE（截至 2010 年 8 月）和 Institute of Scientific Information Web of Knowledge 数据库（截至 2011 年 4 月），以确定调查生育次数与肺癌之间关联的研究，并使用线性模型计算剂量-反应趋势。使用 Cochran's Q 统计量和 I(2)指数评估研究间的异质性。使用随机效应荟萃分析估算每例儿童相对风险（RR）及其 95%置信区间（CI）。16 项符合条件的研究（8077 例肺癌患者；350295 例未受影响个体）提供了用于荟萃分析的数据。研究间存在显著的异质性（p<0.001；I(2)=73%）。每例活产 RR 的汇总值为 0.98（95%CI，0.95-1.02），表明生育次数对肺癌风险无影响。病例对照研究（n=11）RR=0.99（95%CI，0.94-1.04）和队列研究（n=5）RR=0.97（95%CI，0.92-1.03）的结果一致。未纳入小细胞肺癌患者的研究发现生育次数具有边缘保护作用，RR=0.94（95%CI，0.88-1.00）。相比之下，纳入小细胞肺癌患者的研究则未观察到这种效果，RR=1.00（95%CI，0.98-1.03）；p 值为差异=0.05。总体而言，生育次数与肺癌之间的剂量-反应关系几乎没有证据，但研究结果存在异质性。未来的研究应包括在明确的组织学疾病亚组中进行分析。
