Näytönastekatsaukset

Does second-hand smoke exposure increase the probability of developing COPD?

Näytönastekatsaukset

4.11.2026

Miia Aro

Level of evidence: B

Repeated second-hand smoke exposure probably increases the probability of developing chronic obstructive pulmonary disease (from 11% to 14%, OR 1.52 (1.27; 1.81)).

The evidence is based on large studies from all around the world. However, the duration, reporting, and measuring of exposure varies across studies, and there was moderate heterogeneity (I²=52%) even after adjusting. Severe heterogeneity was found in sub-group analysis. Moreover, publication bias may be present.

Table 1. Description of the included studies
Reference	Study type	Population	Intervention and comparison	Outcomes	Risk of bias «Additional comments for included studies»2
SR=systematic review
«Chen P, Li Y, Wu D, ym. Secondhand Smoke Exposure and the Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis. Int J Chron Obstruct Pulmon Dis 2023;18:1067-1076 »1	SR	25,592 adult patients around the world from 1987 to 2021. Second-hand smoke exposure: 1) Someone at home or around the workplace smokes; 2) were exposed to tobacco smoke for several hours in a week.	People who had exposed vs. not exposed	COPD diagnosed according to GOLD 2022 criteria	moderate

Table 2. Additional comments for included studies
Reference	Comments
«Chen P, Li Y, Wu D, ym. Secondhand Smoke Exposure and the Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis. Int J Chron Obstruct Pulmon Dis 2023;18:1067-1076 »1	Inclusion criteria for studies: Original cross-sectional, case-control, and cohort studies conducted, assessing the association between SHS exposure and COPD prevalence and determination of COPD followed the criteria in the 2022 Gold Report (The spirometric criterion for airflow limitation remains a post-bronchodilator fixed ratio of FEV1 (Forced Expiratory Volume in the first second) /FVC (Forced Vital Capacity) < 0.70), and the studies must include only non-smokers and ex-smokers in the population, or less than 50% of current smokers. Of these, 4 studies did not provide a specific description of SHS exposure, 7 studies described the duration of exposure, and 4 studies mentioned the number of packs or sticks of secondhand smoke inhaled per year. The duration of exposure to SHS varied greatly among different studies.

Results

Table 3. Probability of COPD after second-hand smoking
Reference	Number of studies and number of patients (I/C)	Follow-up time	Absolute number of events (%) I	Absolute number of events (%) C	Odds Ratio (95% CI)
I= intervention; C=comparison; CI=confidence interval
«Chen P, Li Y, Wu D, ym. Secondhand Smoke Exposure and the Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis. Int J Chron Obstruct Pulmon Dis 2023;18:1067-1076 »1	13 RCTs (10060/7962)	from 1 to 41 years	1415 (14)	879 (11)	1.52 (1.27;1.81)
Level of evidence: moderate The quality of evidence is downgraded due to imprecision and publication bias

References

Chen P, Li Y, Wu D, ym. Secondhand Smoke Exposure and the Risk of Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis. Int J Chron Obstruct Pulmon Dis 2023;18:1067-1076 «PMID: 37309392»PubMed