The interaction of ageing and lung disease.

This article explores the structural and physiological changes that occur in the ageing lung, and the impact that lung disease and other co-morbidities may have on it. The major changes associated with ageing are reduced lung elasticity, respiratory muscle strength and chest wall compliance, all of which may be influenced by impaired lung growth in early childhood and adolescence. The resultant reduction in diffusing capacity may not be relevant in a fit older adult, but co-morbidities may interact to cause breathlessness and impairments in quality of life. Lung function declines with age, but forced vital capacity (FVC) begins to decline later than forced expiratory volume in 1 s (FEV(1)) and at a slower rate. This results in a natural fall in the FEV(1)/forced vital capacity (FVC) ratio which may result in overdiagnosis of chronic obstructive pulmonary disease, and hence the need to ensure the FEV(1) is less than 80% before confirming the diagnosis. As older adults probably have a diminished response to hypoxia and hypercapnia, they become more vulnerable to ventilatory failure during high-demand states such as heart failure and pneumonia and therefore to possible poorer outcomes. Poor nutritional status is likely to be an important factor, as is cognitive impairment. It is important to assess older patients using a range of clinical and physiological parameters rather than on the basis of age per se which is a poor predictor of outcome.