Smoking before age 15 significantly increases risk of chronic lung disease

By Priyanjana Pramanik, MSc.Reviewed by Lily Ramsey, LLMJan 9 2025

A recent study using national data highlights the strong association between smoking in childhood and increased COPD prevalence in adulthood, emphasizing the urgent need for prevention strategies targeting young smokers.

Study: Childhood Cigarette Smoking and Risk of COPD in Older U.S. Adults: A Nationally Representative Replication Study. Image Credit: Sophon Nawit/Shutterstock.com

In a recent article in Chronic Obstructive Pulmonary Diseases, researchers used nationally representative data from the United States to assess how smoking cigarettes in childhood affects the chance of developing chronic obstructive pulmonary disease (COPD) in late adulthood.

Their findings reinforce the link between early smoking and COPD risk, emphasizing the need for targeted prevention strategies.

Background

Cigarette smoking has been declining across the U.S. since the 1960s. However, it continues to cause preventable deaths and is a key driver of COPD. Most adults who currently smoke start before age 26, with many beginning in adolescence.

Smoking initiation in early adolescence, i.e. between 12 and 16 years, was common before 1980, and those individuals are now 55 or older. Lung development continues through adolescence, and smoking during this period has been linked to reduced lung function and increased COPD risk later in life.

Previous studies showed that early smoking initiation raises COPD risk but has limitations, such as focusing only on males or not adjusting for factors like smoking duration and intensity.

A recent study using 2020 National Health Interview Survey data found that starting smoking before age 15 significantly increases COPD risk, even when adjusting for these factors. The risk remains high for those who started smoking between 15-19 years.

The study suggests early smoking disrupts lung development, leading to long-term health issues. However, it did not account for exposure to secondhand smoke, which is also linked to higher COPD risk.

About the study

This study expanded on previous research by examining the relationship between childhood smoking and COPD risk while accounting for exposure to secondhand smoke.

Using data from the Population Assessment of Tobacco and Health (PATH) study, researchers aimed to replicate findings from the National Health Interview Survey (NHIS) and test if the association between childhood smoking and COPD is independent of various smoking-related factors.

The PATH study, a national longitudinal survey, included adults aged over 40 from Wave 5 (2018-2019) and used computer-assisted interviews.

The study analyzed COPD prevalence based on self-reported diagnoses and categorized initiation to cigarette smoking into three groups: never smoked, started before age 15, and started after age 15.

Smoking covariates like current smoking status, years spent smoking packs, and exposure to secondhand smoke were included, along with sociodemographic factors.

Statistical analysis involved weighted Poisson regressions to examine associations between childhood smoking and COPD, adjusting for age, sex, race, income, and smoking-related variables.

Findings

Most participants were urban (77%), female (53%), and White (80%). Lower childhood smoking rates were observed among Black adults, females, and older participants (60+ years), while those with household incomes under $25,000 had higher childhood smoking rates.

COPD prevalence was higher among those who started smoking before age 15 (29%) than those who started later (21%) or never smoked (7.5%). Early smokers had higher current smoking rates, longer smoking durations, and more cigarette pack years.

The study found that early smoking initiation, i.e., before the age of 15, significantly increased COPD risk, even after accounting for secondhand smoke and other factors. Multivariable analyses showed that starting smoking before age 15 significantly increased the risk of COPD with an adjusted risk ratio (aRR) of 1.27.

Current smoking, cigarette pack years, and exposure to secondhand smoke also raise COPD risk. In a model comparing early smoking (under 15) with later initiation (after the age of 20), the risk remained significant with an aRR of 1.4.

A third analysis incorporating smoking intensity found that medium-intensity smokers who started before age 15 had a significantly higher COPD risk.

Sensitivity analyses showed that using smoking duration instead of pack years slightly weakened the association but still indicated a significant link between childhood smoking and COPD when smoking lasted over 25 years.

Adding hypothetical increases to years spent smoking packs for early smokers showed that a large adjustment (85%) was needed to nullify the childhood smoking effect on COPD risk.

Conclusions

This study examined the link between childhood smoking and COPD risk, finding that starting smoking before age 15 significantly increases COPD risk, independent of smoking amount, current status, and exposure to secondhand smoke.

The findings, based on PATH study data (2018-2019), aligned with a previous NHIS study but showed higher overall COPD prevalence, likely due to cumulative data collection over multiple waves in PATH.

Both studies identified a clear risk increase for COPD when smoking started before age 15, with an inflection point around the age of 20. The study highlighted that smoking duration was a stronger COPD risk predictor than cigarette pack years.

The results underscore the importance of preventing early smoking to protect lung development. The study supports the federal law raising the tobacco sales age to 21 and suggests using these findings to inform public health campaigns.

Limitations include reliance on self-reported data and potential unmeasured variables, but the study’s strengths lie in its large sample and comprehensive analysis.