Fruit and vegetable consumption and risk of lung cancer: a dose-response meta-analysis of prospective cohort studies.
OBJECTIVE
A meta-analysis was conducted to summarize evidence from prospective cohort studies about the association of fruit and vegetable consumption with the risk of lung cancer.


METHODS
Pertinent studies were identified by a search of Embase and PubMed databases to October 2014. A random-effects model was used to combine study-specific relative risks and 95% confidence interval [RR (95% CI)]. Dose-response relationship was assessed by restricted cubic spline.


RESULTS
The RR (95% CI) of lung cancer for highest versus lowest category of fruit and vegetable (FV) consumption was 0.87 (0.79-0.95) (8 studies including 12,942 cases among 1,571,494 subjects), and the effect was 0.84 (0.79-0.90) for fruit (16 studies including 15,421 cases among 1,791,469 subjects) and 0.90 (0.84-0.96) for vegetable (19 studies including 16,422 cases among 1,877,375 subjects). The above-mentioned associations did not differed significantly in subgroup analysis by country, age, number of covariates adjusted, quality score, sex, smoking status and histological subtypes; however, studies with follow-up duration of ≥10 years and with FV assessed by interview showed a stronger association than those of <10 years and by self-administrated food frequency questionnaires, respectively. The risk of lung cancer decreased by 3% (P=0.07), 5% (P<0.01) and 3% (P=0.09) for every 1 serving/day increment in FV, fruit and vegetable consumption, respectively. There was a threshold around 2 servings/day of fruit and 2 servings/day of vegetable, respectively, after which the risk of lung cancer did not reduce further.


CONCLUSIONS
Fruit and vegetable consumption are inversely associated with risk of lung cancer.
Department of Thoracic Surgery, The Affiliated Hospital of Medical College of Qingdao University, Jiangsu Road, No. 19, Qingdao 266001, Shandong, PR China.
Yaopeng
Y
Wang
Department of Thoracic Surgery, The Affiliated Hospital of Medical College of Qingdao University, Jiangsu Road, No. 19, Qingdao 266001, Shandong, PR China.
Fei
F
Li
Department of Thoracic Surgery, The Affiliated Hospital of Medical College of Qingdao University, Jiangsu Road, No. 19, Qingdao 266001, Shandong, PR China.
Zizong
Z
Wang
Department of Thoracic Surgery, The Affiliated Hospital of Medical College of Qingdao University, Jiangsu Road, No. 19, Qingdao 266001, Shandong, PR China.
Tong
T
Qiu
Department of Thoracic Surgery, The Affiliated Hospital of Medical College of Qingdao University, Jiangsu Road, No. 19, Qingdao 266001, Shandong, PR China.
Yi
Y
Shen
Department of Thoracic Surgery, The Affiliated Hospital of Medical College of Qingdao University, Jiangsu Road, No. 19, Qingdao 266001, Shandong, PR China. Electronic address: qdwangmz1966@163.com.
Mingzhao
M
Wang
D005260:Female; D005638:Fruit; D006801:Humans; D008175:Lung Neoplasms / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D012307:Risk Factors; D014675:Vegetables
Fruit; Lung cancer; Meta-analysis; Prospective cohort studies; Vegetable