Cancer and Environment Group, Center for Research in Epidemiology and Population Health (CESP), INSERM, Université Paris Saclay, Université Paris-Sud, Villejuif, France.
Division of Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA.
BMC Cancer. 2018 Feb 23;18(1):220. doi: 10.1186/s12885-018-4124-0.
Obesity has been proposed as a potential protective factor against lung cancer. We examined the association between BMI and lung cancer risk in a pooled analysis based on nested case-control studies from four cohort studies.
A case-control study was nested within four cohorts in USA, Europe, China and Singapore that included 4172 cases and 8471 control subjects. BMI at baseline was calculated as weight in kilograms divided by height in meters squared (kg/m), and classified into 4 categories: underweight (BMI < 18.5), normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30) and obese (≥30). Odds ratios (ORs) and 95% confidence intervals (CIs) for BMI-lung cancer associations were estimated using unconditional logistic regression, adjusting for potential confounders.
Considering all participants, and using normal weight as the reference group, a decreased risk of lung cancer was observed for those who were overweight (OR 0.77, 95% CI: 0.68-0.86) and obese (OR 0.69, 95% CI: 0.59-0.82). In the stratified analysis by smoking status, the decreased risk for lung cancer was observed among current, former and never smokers (P for interaction 0.002). The adjusted ORs for overweight and obese groups were 0.79 (95% CI: 0.68-0.92) and 0.75 (95% CI: 0.60-0.93) for current smokers, 0.70 (95% CI: 0.53-0.93) and 0.55 (95% CI: 0.37-0.80) for former smokers, 0.77 (95% CI: 0.59-0.99), and 0.71 (95% CI: 0.44-1.14) for never smokers, respectively. While no statistically significant association was observed for underweight subjects who were current smokers (OR 1.24, 95% CI: 0.98-1.58), former smokers (OR 0.27, 95% CI: 0.12-0.61) and never smokers (OR 0.83, 95% CI: 0.5.-1.28).
The results of this study provide additional evidence that obesity is associated with a decreased risk of lung cancer. Further biological studies are needed to address this association.
肥胖被认为是肺癌的潜在保护因素。我们基于四项队列研究中的巢式病例对照研究进行了荟萃分析，以检验 BMI 与肺癌风险之间的关联。
在美国、欧洲、中国和新加坡的四项队列研究中进行了一项病例对照研究，纳入了 4172 例病例和 8471 例对照。根据体重（kg）除以身高（m）的平方（kg/m）计算 BMI，分为 4 类：体重不足（BMI<18.5）、正常体重（18.5≤BMI<25）、超重（25≤BMI<30）和肥胖（BMI≥30）。采用非条件逻辑回归模型，在调整了潜在混杂因素后，计算 BMI 与肺癌关联的比值比（OR）及其 95%置信区间（CI）。
在考虑所有参与者的情况下，将正常体重作为参照组，超重（OR 0.77，95%CI：0.68-0.86）和肥胖（OR 0.69，95%CI：0.59-0.82）与肺癌风险降低相关。按吸烟状态分层分析，无论当前、既往或从不吸烟者均观察到肺癌风险降低（交互作用 P 值=0.002）。在调整了混杂因素后，当前吸烟者中，超重和肥胖组的 OR 分别为 0.79（95%CI：0.68-0.92）和 0.75（95%CI：0.60-0.93），既往吸烟者中，OR 分别为 0.70（95%CI：0.53-0.93）和 0.55（95%CI：0.37-0.80），从不吸烟者中，OR 分别为 0.77（95%CI：0.59-0.99）和 0.71（95%CI：0.44-1.14）。而对于当前吸烟者体重不足者（OR 1.24，95%CI：0.98-1.58）、既往吸烟者（OR 0.27，95%CI：0.12-0.61）和从不吸烟者（OR 0.83，95%CI：0.58-1.28），则无统计学显著相关性。
本研究结果提供了更多证据表明肥胖与肺癌风险降低相关。需要进一步的生物学研究来探讨这种关联。
