Metal Exposure, Smoking, and the Risk of COPD: A Nested Case–Control Study in a Chinese Occupational Population

Abstract

Chronic obstructive pulmonary disease (COPD) was the third leading cause of death worldwide in 2019, with a significant disease burden. We conducted a nested case–control study using data from the China Metal-Exposed Workers Cohort Study (Jinchang Cohort) and assessed the associations of exposure to metals and tobacco smoking with the risk of COPD. We used the logistic regression model and the interaction multiplication model to assess the independent and combined effects of heavy metal and smoke exposure on COPD. The cumulative incidence of COPD was 1.04% in 21,560 participants during a median of two years of follow-up. The risk of COPD was significantly elevated with an increase in the amount of tobacco smoked daily (p < 0.05), the number of years of smoking (ptrend < 0.05), and the number of packs of cigarettes smoked per year (ptrend < 0.01). Compared with the low metal exposure group, the adjusted OR was 1.22 (95% CI: 0.85–1.76) in the medium exposure group (mining/production workers) and 1.50 (95% CI: 1.03–2.18) in the high exposure group; smoking and metal exposure had a combined effect on the incidence of COPD (pinteraction < 0.01), with an OR of 4.60 for those with >40 pack-years of smoking who also had the highest metal exposures. Both exposures to metals and smoking were associated with the risk of COPD, and there was an interaction between the two exposures for the risk of COPD.

An investigation of the risk factors of chronic obstructive pulmonary disease in natural population-based cohorts in China – a nested case-control study

“…The COPD disease burden can be decreased with early diagnosis (21). (2,3). They were all rather close to the 1.50 OR value found in our investigation.…”

“…Accelerated airway oxidative stress, airway collapse, and inadequate lung tissue repair are some of the pathophysiological processes (22). The aetiology of COPD has been steadily revealed in recent years to involve occupational exposure to substances other than tobacco smoke and air pollution (2,23). Our research, however, does not support the conception that exposure to secondhand smoke (SHS) increases the risk of developing COPD.…”

“…According to the Jinchang cohort research in Northwest China, the adjusted OR values for the metal exposure groups with moderate and high exposure were 1.22 (95%CI, 0.85-1.76) and 1.50 (95%CI, 1.03-2.18), respectively. Like the Jinchang cohort, a sizable number of our cohort's members were from northwest China, but the Jinchang cohort's members were regularly exposed to heavy metals (2). Like the Jinchang cohort, a sizable number of our cohort's members were from northwest China, but the Jinchang cohort's members were regularly exposed to heavy metals.…”

“…It may be more successful to implement interventions to improve COPD patients' adherence to smoking cessation therapy (8). It makes sense to counsel smokers to give up their habit (2,25), not only to slow down the deterioration of their lungs but also to lessen the amount of secondhand smoke that they are exposed to in the community.…”

“…The significant death rate linked with chronic obstructive pulmonary disease (COPD) has made it a global public health concern. By 2030, it is predicted to rank as the third most common cause of death globally (1,2). A survey on the prevalence of COPD in China was carried out by Zhong et al between 2002 and2004 In China, the overall COPD prevalence was 8.2% (males: 12.4%; females: 5.1%) (3).…”