12-year change in prevalence of respiratory symptoms in elderly Chinese living in Hong Kong.

Respiratory diseases may cause considerable disability in the elderly because of their limited respiratory reserve related to aging. This study aimed to assess the time trend of respiratory symptoms and common chronic respiratory diseases in the elderly Chinese living in Hong Kong. Two questionnaire surveys were conducted in 1991-1992 and 2003-2004. Subjects aged > or = 70 years were invited to complete a respiratory questionnaire. A total of 2032 (999 male) and 1524 (698 male) subjects completed the questionnaire surveys in 1991 and 2003, respectively. The response rates were 60% in 1991 and 78% in 2003. The prevalence of most respiratory symptoms increased over time after adjusting the data for age, sex, social status and smoking habits. Comparing the symptoms between 1991 and 2003, wheeze over the past 12 months increased from 7.5 to 12.1% (adjusted OR 2.00, 95% CI 1.54-2.61) and morning chest tightness from 4.2 to 8.8% (adjusted OR 2.48, 95% CI 1.79-3.43). The prevalence of self-reported physician-diagnosed emphysema increased over time (2.4-3.1%, adjusted OR 1.78, 95% CI 1.12-2.86), but there was no change for asthma (5.1% in 1991 and 5.8% in 2003) or chronic bronchitis (6.7% in 1991 and 7.7% in 2003). The prevalence of respiratory symptoms has increased over the past 12 years and this may be related to environmental factors especially increasing air pollution in Hong Kong.