Pulmonary Aging

Acute respiratory symptoms are among the most common reasons why older persons seek medical attention. In addition, clinical manifestations of the more chronic respiratory diseases play a major role in reduced function, acute hospitalizations, and increased mortality seen in older persons. Despite decades of research in respiratory physiology and lung biology, there is still difficulty in isolating age-related changes in lung structure and function from the many other confounding risk factors encountered by most individuals during 70 or more years of living. These “cohort effect” uncertainties should perhaps not be surprising. The current generation of persons over 65 years of age was born and raised in the preantibiotic era, when the devastating effects on lung development of formerly common childhood respiratory viral infections, such as pertussis and measles, were rampant. Tuberculosis was the most common cause of death during the teens and early adulthood of this cohort, and exposure as measured by the common tuberculosis skin test was nearly 100%. As a whole, there has probably been a higher prevalence of cigarette smoking in the generation born between 1910 and 1930 than at any time in the history of the human race. As adults during the post–World War II era, they have had the longest potential exposure to high levels of particulate air pollution ever experienced to date.

The health impact of chronic obstructive pulmonary disease (COPD) in elderly patients is enormous. The fourth leading cause of death among persons age 65 years and older, COPD in its various clinical forms is relatively common in older adults and probably underdiagnosed. For example, chronic bronchitis, defined as production of phlegm for at least 3 months of the year for at least 2 consecutive years, is present in 15% of community-dwelling persons age 65 years and older. The presence of chronic bronchitis is associated with more acute respiratory infections and hospitalizations. In addition to being very common in older adults, chronic bronchitis has strong prognostic implications. In fact, this symptom complex of cough and phlegm production is associated with a 30% excess mortality over a 10-year period. For at least the past 25 years, there has been a steady increase in age-adjusted office visits, hospitalizations, and mortality for COPD in both men and women. There is a particularly high symptom burden in community-dwelling older adults with advanced COPD. Individuals with COPD have 71% more moderate or severe symptoms than do participants with advanced congestive heart failure. As is often the case in geriatric care, the frequency and range of symptoms associated with COPD may be distinct from those experienced by younger patients. For example, predominating presenting symptoms, such as limited activity, fatigue, and physical discomfort, are nearly as prevalent as shortness of breath. Compared with the general population, older patients with COPD are twice as likely to rate their health as fair or poor, are nearly twice as likely to report limitations in their usual activities, and visit physicians for medical care more frequently.

Asthma is a relatively common and potentially serious disease in older persons. Moreover, asthma is frequently underdiagnosed in older age groups. Various studies cite an asthma prevalence rate of 7% to 9% in persons over 65 years of age compared with prevalence rates of 6% to 7% in the general population. Rates of hospitalization for asthma are highest in the age groups over 65 years. Asthma death rates also rise dramatically with advancing age. Although many older patients with asthma have clear lifelong clinical histories of symptomatic bronchospasm, there is growing appreciation that asthma may commonly become manifest after 65 years of age. In some surveys of older asthmatics attending a pulmonary referral clinic, 48% had developed asthma after 65 years of age.

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