COPD Should Not Be Overlooked in Young Adults

Key Point

Nearly 3% of adults ages 20 to 44 may have COPD.

VERONA, ITALY—Over the past several years, research by Roberto de Marco, PhD, and associates has provided evidence for an important caveat about COPD: The disease is present, most likely in its earliest stages, in a relatively substantial proportion of persons in the 20-to-44 age-group.^1,2 This theory contradicts the conventional belief held by members of the medical community, who generally do not consider young adults to be at risk for COPD. A new study by the de Marco group serves as the latest reminder of COPD’s impact on this segment of the population.³

“In a large international cohort of persons ages 20 to 44, the 10-year cumulative incidence of COPD was 2.8%,” reported Isa Cerveri, MD, a research group member who is in the Division of Respiratory Diseases at the San Matteo Hospital in Pavia, Italy. “It was 4.6% in adults ages 40 to 44,” he added.

Furthermore, the presence of chronic cough and/or phlegm accurately identified persons at high risk for COPD. On the other hand, dyspnea poorly predicted the development of airflow obstruction, the researchers found.

Cough/Phlegm Linked to Increased Risk

Using data from the second European Community Respiratory Health Survey (ECRHS II),⁴ the investigators determined COPD incidence among 5,002 subjects ages 20 to 44. Inclusion criteria for the study were participation in stage 2 of the first ECRHS, baseline FEV1/FVC ratio of at least 70%, and no reported asthma diagnosis at baseline. The study cohort was slightly older, had a lower proportion of ever smokers at baseline, and was slightly less likely to exhibit respiratory symptoms than was a control group of 4,837 persons (ie, those who met inclusion criteria for the study but who were not enrolled). However, the two groups had similar lung function.

At baseline, 2,924 of the study participants were smokers and 2,078 were nonsmokers. During 5.8 to 11.4 years of follow-up (median, 8.9 years), about 3% of nonsmokers began smoking; 28.5% of light smokers and 24.5% of heavy smokers quit.

Analysis revealed an overall annual COPD incidence rate of 2.8 cases/1,000/y. There was a positive association between annual COPD incidence and age at baseline. Rates were slightly higher in men than in women and five times higher in heavy smokers than in nonsmokers. Among subjects with chronic cough/phlegm both at baseline and at the end of follow-up, annual COPD incidence rate was 9.4 cases/1,000/y versus 2.3 cases/1,000/y among subjects who had never reported such symptoms—a fourfold difference between these two groups.

“The presence of chronic cough/phlegm remained an independent and statistically significant predictor of the occurrence of COPD after [adjustment] for smoking habits and the other potential confounders at baseline,” the study authors pointed out. Dyspnea and a low educational level were not associated with an increased risk of COPD, they noted.

The relationship between chronic cough/
phlegm and COPD risk persisted after repeat analysis under the following conditions:

• Definition of stage 0 disease as chronic symptoms plus an FEV1/FVC ratio of 70% or greater and a predicted FEV1 of 80% or greater
• Use of a more restrictive definition of COPD
• Adjustment of analysis for wheezing at baseline
• Use of a broader definition of chronic cough/
phlegm
• Exclusion from the analysis of centers with a participation rate of less than 50%.
A new case of COPD was defined as an FEV₁/FVC ratio falling below 70% by the end of follow-up. In this study, 123 new cases were observed; of these, 76.9% were ever smokers, 55.3% were men, 19.7% reported dyspnea, 23.3% had a low level of education (ie, completed full-time education before age 16), and 18.9% reported chronic cough/phlegm.

The study findings provide further evidence that smoking prevention and smoking cessation are the most effective strategies to reduce the burden of COPD and prevent new cases, the authors noted. In addition, Dr. Cerveri contended, “Our results show that the presence of chronic cough and phlegm is not an innocent symptom but is an early marker of airflow obstruction.”

Logical Results

Although COPD usually is not considered a disease of young adults, the finding of considerable COPD incidence in that group is hardly surprising, remarked Jørgen Vestbo, MD, in an accompanying editorial.⁵ “After all, COPD does not suddenly appear out of nowhere, and in order for the disease to be a major health burden in the middle-aged and elderly, significant incidence rates in young adulthood are needed!” he explained.

The main strength of the study by Dr. de Marco and colleagues was its size, and thus its ability to estimate COPD incidence with acceptable reliability, Dr. Vestbo asserted. “In this respect, it adds to previous work from the same group and indicates that the statement that ‘15% of smokers will develop COPD’ is wrong, and that lifetime risk of COPD in smokers is significantly higher, probably about 35% to 50%,” he said.

—Timothy Begany

Reference
1. de Marco R, Accordini S, Cerveri I, et al. An international survey of chronic obstructive pulmonary disease in young adults according to GOLD stages. Thorax. 2004;59:120-125.
2. Cerveri I, Accordini S, Corsico A, et al, for the ISAYA Study Group. Chronic cough and phlegm in young adults. Eur Respir J. 2003;22:413-417.
3. de Marco R, Accordini S, Cerveri I, et al. Incidence of chronic obstructive pulmonary disease in a cohort of young adults according to the presence of chronic cough and phlegm. Am J Respir Crit Care Med. 2007;175:32-39.
4. Hazenkamp-von Arx ME, Gotschi Fellmann T, Oglesby L, et al. PM2.5 assessment in 21 European study centers of ECRHS II: method and first winter results. J Air Waste Manag Assoc. 2003;53:617-628.
5. Vestbo J. Chronic cough and phlegm in young adults: should we worry? Am J Respir Crit Care Med. 2007;175:2-3.

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