Previous lung diseases (PLD) are known risk factors for lung cancer. However, it remains unclear how the association varies by lung cancer subtype and socio-demographic characteristics. We conducted a systematic literature search in three electronic databases from the inception of each database up until 13 January 2021. A total of 73 studies (18 cohort and 55 case-control studies) consisting of 97 322 cases and 7 761 702 controls were included. Heterogeneity was assessed using the I2 statistic. Based on the heterogeneity, either the fixed-effects or random-effects model was used to estimate the pooled summary estimate (PSE) and 95% confidence interval (CI) for the association between PLD and lung cancer risk. A history of asthma, chronic bronchitis, emphysema, pneumonia, tuberculosis, and chronic obstructive pulmonary disease (COPD) was associated with higher lung cancer risk, with a history of COPD and emphysema having at least twofold relative risk. A history of hay fever was associated with lower lung cancer risk (PSE= 0.66, 95% CI= 0.54-0.81), particularly among ever-smokers (PSE= 0.55, 95% CI= 0.41-0.73). Individuals with a diagnosis of asthma, emphysema, or pneumonia within 1-10 years prior to lung cancer diagnosis were observed to have a higher lung cancer risk as compared to those who were diagnosed more than 10 years prior to lung cancer diagnosis. Ever-smokers with a history of COPD or emphysema were observed to have at least twofold relative risk of lung cancer compared to those without this history. Due to the observed association between PLD with higher risk of lung cancer, it is advisable that individuals with PLD should be closely monitored and prioritised for lung cancer screening.

中文翻译：

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既往肺部疾病与肺癌风险之间的关联：系统评价和荟萃分析。

既往肺部疾病 (PLD) 是肺癌的已知危险因素。然而，目前尚不清楚这种关联如何因肺癌亚型和社会人口特征而变化。从每个数据库开始到 2021 年 1 月 13 日，我们在三个电子数据库中进行了系统的文献检索。共纳入 73 项研究（18 项队列研究和 55 项病例对照研究），包括 97 322 例病例和 7 761 702 例对照。使用 I2 统计量评估异质性。基于异质性，使用固定效应或随机效应模型来估计 PLD 与肺癌风险之间关联的汇总汇总估计 (PSE) 和 95% 置信区间 (CI)。哮喘、慢性支气管炎、肺气肿、肺炎、肺结核病史，慢性阻塞性肺病 (COPD) 与较高的肺癌风险相关，COPD 和肺气肿病史具有至少两倍的相对风险。花粉热病史与较低的肺癌风险相关（PSE= 0.66, 95% CI= 0.54-0.81），尤其是在曾经吸烟的人群中（PSE= 0.55, 95% CI= 0.41-0.73）。观察到在肺癌诊断前 1-10 年内诊断为哮喘、肺气肿或肺炎的个体与肺癌诊断前 10 年以上被诊断的个体相比具有更高的肺癌风险。据观察，有 COPD 或肺气肿病史的吸烟者患肺癌的相对风险至少是没有此病史的人的两倍。由于观察到 PLD 与较高的肺癌风险之间存在关联，