A new study suggests that poorer lung function in early adulthood may be enough to predispose a person to COPD later in life. The study, which included more than 2,500 individuals from Danish and US populations, found that about half of those who ultimately developed COPD had a low forced expiratory volume in 1 second (FEV1) before the age of 40 years, but a normal decline in this measure thereafter, according to Medscape. Data was analyzed from three cohorts: the Lovelace Smokers Cohort, the Copenhagen City Heart Study, and the Framingham Offspring Cohort.
The results of the study showed that the incidence of COPD was notably higher among individuals who had an FEV1 of less than 80% of the predicted value before 40 years of age compared with those who had a higher FEV1 during that time of their life (26% vs 7%; P < 0.001), as indicated on the Medscape news report. Additionally, 48% of the participants who developed COPD had had a normal FEV1 before age 40 years and experienced a rapid drop in FEV1 thereafter, with a mean decline of 53 mL per year.
The Medscape news report also notes that the other 52% had had a low FEV1 before age 40 years and experienced a significantly smaller subsequent mean decline in FEV1 of 27 mL per year, even though they had similar smoking exposure.
Peter Lange, MD, says, “The results of this study suggest that the classic trajectory of an accelerated decline in FEV1 from a normal level is not an obligate feature of COPD and that a substantial proportion of the persons in whom COPD develops have a low FEV1 level in early adulthood.”
According to an accompanying editorial, factors unrelated to smoking, such as asthma and environmental pollution, may affect pulmonary function in early adulthood as well as its decline thereafter. Also, some of the rate of change of FEV1 may reflect disease activity, rather than disease severity.
The authors write, “To sort out these additional components of COPD risk definitively will require large data sets with repeated measurements of diverse population groups across the life course. Few groups of investigators or institutions have or can make the commitment to carry out such studies.”