Table 3.

Risk factor in lung cancer.

Risk factor	Clinical trial	Histology	TMN stage	Patients	Comparison	Risk region
UIP	Watanabe et al[113]	NSCLC	Surgically	526	Lobe distribution Location	Lower lobe region Subpleural location (peripheral type A)
Air flow limitation	Shin et al[119]	ADC SQC SCLC Others	NM	754	Location Central vs. Peripheral	Peripheral ADC and No emphysema SQC and Emphysema
IPF	Liu et al[114]	ADC SQC SCLC	NM	46	Lobe distribution Location	Peripheral and upper lobes
IPF	Lin et al[89]	ADC SQC SCLC LAC AQC	Stage I–IV	6384	Lobe distribution Location	Peripheral and lower part
IPF	Nezka et al[120]	ADC SQC AQC	IA–IIIA	641	Lobe distribution	Lower Lung lobes
IIPs	Fukui et al[117]	SQC Non-SQC	Stage I–III	1972	Lower lobectomy Upper lobectomy	Lower lobectomy

ADC: Adenocarcinoma; AQC: Adenosauamous cell carcinoma; IIPs: Idiopathic interstitial pneumonias; LAC: Large-cell carcinoma; NM: Not mentioned; NSCLC: Non-small cell lung cancer; SCLC: Small-cell lung cancer; SQC: Squamous cell carcinoma; UIP: Usual interstitial pneumonia.