Beginning in fiscal year 1998, all surviving participants of LHS I are invited to participate in the long-term followup. The study will determine, using an intent-to-treat analysis, whether the LHS I smoking intervention significantly reduces the incidence of clinically important respiratory and cardiovascular disease over a 12- to 15-year period following study enrollment. The study will also estimate the magnitude of the effects of FEV1 and FVC on the risks of cardiovascular and respiratory morbidity and mortality, after controlling for smoking history. Studies will be conducted on the role of other factors such as gender, airways reactivity, weight gain, and co-morbidities in determining the rate of decline in pulmonary function and the risks of cardiovascular and respiratory morbidity and mortality. A determination will also be made as to whether the improvement in lung function and reduction in respiratory symptoms associated with smoking cessation result in improved health-related quality of life (HRQL) and less depression over an extended follow-up period. The LHS III, an investigator initiated long-term follow-up study, is not an NIH- defined clinical trial.