title: Abdominal Obesity and Lung Cancer Risk: Systematic Review and Meta-Analysis of Prospective Studies.
abstract: Several meta-analyses of observational studies have been performed to examine the association between general obesity, as measured by body mass index (BMI), and lung cancer. These meta-analyses suggest an inverse relation between high BMI and this cancer. In contrast to general obesity, abdominal obesity appears to play a role in the development of lung cancer. However, the association between abdominal obesity (as measured by waist circumference (WC) (BMI adjusted) and waist to hip ratio (WHR)) and lung cancer is not fully understood due to sparse available evidence regarding this association. PubMed and Web of Science databases were searched for studies assessing the association between abdominal obesity and lung cancer up to October 2016. The summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated with a random-effects model. Six prospective cohort studies with 5827 lung cancer cases among 831,535 participants were included in our meta-analysis. Each 10 cm increase in WC and 0.1 unit increase in WHR were associated with 10% (RR 1.10; 95% CI 1.04, 1.17;I² = 27.7%,p-heterogeneity = 0.198) and 5% (RR 1.05; 95% CI 1.00, 1.11;I² = 25.2%,p-heterogeneity = 0.211) greater risks of lung cancer, respectively. According to smoking status, greater WHR was only positively associated with lung cancer among former smokers (RR 1.11; 95% CI 1.00, 1.23). In contrast, greater WC was associated with increased lung cancer risk among never smokers (RR 1.11; 95% CI 1.00, 1.23), former smokers (RR 1.12; 95% CI 1.03, 1.22) and current smokers (RR 1.16; 95% CI 1.08, 1.25). The summary RRs for highest versus lowest categories of WC and WHR were 1.32 (95% CI 1.13, 1.54;I² = 18.2%,p-heterogeneity = 0.281) and 1.10 (95% CI 1.00, 1.23;I² = 24.2%,p-heterogeneity = 0.211), respectively. In summary, abdominal obesity may play an important role in the development of lung cancer.
authors.affiliation: Department of Endocrinology and Metabolism, the First Affiliated Hospital of Soochow University, Suzhou 215006, China. khemzie_khem@yahoo.com.
authors.forename: Khemayanto
authors.initials: K
authors.lastname: Hidayat
authors.affiliation: Department of Endocrinology and Metabolism, the First Affiliated Hospital of Soochow University, Suzhou 215006, China. cathy-dx0630@163.com.
authors.forename: Xuan
authors.initials: X
authors.lastname: Du
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Soochow University, Suzhou 215123, China. lsguorong@126.com.
authors.forename: Guochong
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of Respiratory Medicine, the Second Affiliated Hospital of Soochow University, Suzhou 215000, China. shiminhua@163.com.
authors.forename: Minhua
authors.initials: M
authors.lastname: Shi
authors.affiliation: Department of Endocrinology and Metabolism, the First Affiliated Hospital of Soochow University, Suzhou 215006, China. shibimin@163.com.
authors.forename: Bimin
authors.initials: B
authors.lastname: Shi
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D056128:Obesity, Abdominal / Q000150:complications* / Q000503:physiopathology; D064887:Observational Studies as Topic; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D055105:Waist Circumference; D049629:Waist-Hip Ratio
keywords: abdominal obesity; central obesity; dose-response; lung cancer; waist circumference; waist to hip ratio