Sex Difference and Smoking Effect of Lung Cancer Incidence in Asian Population.

Boyoung Park,Jaeho Lee,Seung Hun Jang,Nayoung Lee,Yeol Kim

doi:10.3390/cancers13010113

Abstract

Simple SummaryThis study analyzed the sex difference in the effect of smoking exposure on lung cancer in terms of absolute and relative risks despite the increasing lung cancer incidence in Asian female never smokers. Lung cancer risk is positively associated with the duration of smoking, quantity of smoking, and pack-years of smoking, and negatively associated with the number of years since smoking cessation for both sexes. However, higher lung cancer incidence in men than in women with the same level of smoking exposure was observed, suggesting a higher susceptibility for lung cancer in men. Sex should be considered in combination with smoking history in the selection of a lung cancer screening target population.This study analyzed the sex difference in the effect of smoking exposure on lung cancer in terms of absolute and relative risks despite the increasing lung cancer incidence in Asian female never smokers. A retrospective cohort study was conducted on individuals aged 40–79 years who participated in the national health screening program in 2007 and 2008 with linkage to the Korea Central Cancer Registry records. We evaluated sex differences in the age-standardized incidence rate (ASR) of lung cancer by smoking history and the hazard ratio (HR) after adjusting for potential confounders. ASRs for male and female never smokers were 92.5 and 38.3 per 100,000 person-years, respectively (rate ratio (RR) = 2.4; 95% confidence interval (CI) = 2.3–2.5). ASRs for male and female current smokers with a 30 pack-year smoking history were 305.3 and 188.4 per 100,000 person-years, respectively (RR = 1.6; 95% CI = 1.3–2.0). Smoking was significantly associated with lung cancer risk for both sexes. HRs for former smokers versus never smokers were 1.27 (95% CI = 1.23–1.33) for men and 1.43 (95% CI = 1.16–1.81) for women. HRs for current smokers versus never smokers were 2.71 (95% CI = 2.63–2.79) for men and 2.70 (95% CI = 2.48–2.94) for women. HRs for lung cancer increased similarly in both men and women according to smoking status. However, among Korean individuals with comparable smoking statuses, lung cancer incidence is higher in men than in women. Sex should be considered in combination with smoking history in the selection of a lung cancer screening target population.

Highlights

Lung cancer is a leading cause of cancer incidence and mortality worldwide [1], and its incidence is higher in men than in women
For men is approximately 31.5 per 100,000 person-years, which is twice as high as that for women (14.6 per 100,000 person-years) [1]. In recent studies, this sex difference in lung cancer incidence has remarkably decreased in developed countries
We evaluated sex differences in both the absolute risk in terms of age-standardized incidence rates (ASRs) and relative risk for given exposure levels of smoking

Summary

Introduction

Lung cancer is a leading cause of cancer incidence and mortality worldwide [1], and its incidence is higher in men than in women. In recent studies, this sex difference in lung cancer incidence has remarkably decreased in developed countries. One suggested reason for this is the changes in smoking habits between sexes, which has been declining in men, but continuously increasing in women [1]. Another trend in lung cancer incidence over the past decades is the increasing number of non-smoking-associated lung cancers, which was more prominent in women previously [2]. One study even proposed that female sex itself is an independent risk factor of lung cancer [3]. Lung cancer in never smokers accounts for 10–25% of all lung cancers, with significant geographical variations [4,5], as high as 30–50% in Southeast and East Asia [6,7]

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