Childhood Cigarette Smoking and Risk of Chronic Obstructive Pulmonary Disease in Older U.S. Adults

Abstract

Rationale: It is not certain the extent to which childhood smoking adds chronic obstructive pulmonary disease (COPD) risk independent of lifetime cigarette exposure. Objectives: We examined the association between age started smoking cigarettes regularly, current smoking status, smoking history, and risk of COPD. Methods: Cross-sectional survey of U.S. adults ⩾40 years old in the 2020 National Health Interview Survey. Respondents who were ever cigarette smokers were asked when they began smoking regularly. Multivariable analysis assessed self-report of COPD diagnosis as a function of age started smoking (<15 yr vs. ⩾15 yr) adjusting for current smoking, cigarette pack-years, and covariates. Measurements and Main Results: Overall, 7.1% reported that they had COPD, 2.6% for never-smokers compared with 23.1% and 11.6% for smoking onset <15 and ⩾15 years, respectively. Persons who began smoking regularly at <15 years of age had higher pack-years of smoking (median, 29 vs. 15, respectively), and higher smoking intensity (median, 20 cigarettes/d for <15 yr vs. 10 cigarettes/d for ⩾15 yr for current smokers). In the multivariable analysis, the relative risk for COPD among childhood smokers was 1.41 (95% confidence interval, 1.22-1.63) compared with later-onset smokers. Substituting smoking duration for pack-years confounded the association between current smoking and COPD but did not change the childhood smoking estimate. In a stratified analysis, higher risk for childhood smoking was found at all current smoking intensity levels. Conclusions: Among adults aged ⩾40 years, one-fifth of childhood smokers have COPD. Lifetime cigarette smoking explained some but not all of the higher risk. If replicated, this suggests a lung development window of enhanced vulnerability to cigarette smoking.

Keywords: COPD; adolescence; cigarette; lung development; smoking.

Figure 1.

Lowess smoothed plot showing the relation between age started smoking regularly and COPD prevalence. COPD = chronic obstructive pulmonary disease.

Figure 2.

Prevalence of COPD by childhood smoking. COPD = chronic obstructive pulmonary disease.

Figure 3.

Percentage of former smokers by childhood smoking. Percentages significantly different at P < 0.001.

Figure 4.

Box plots describing (A) cigarette smoking history and (B) current smoking by childhood smoking. Upper and lower bounds of the box are the interquartile range, and the line in the middle is the median. There is no median line in B for age started smoking <15 years, because the median = 75th percentile.