Environmental correlates of impaired lung function in non-smokers with severe alpha 1-antitrypsin deficiency (PiZZ)

BACKGROUND: Active smoking is the most important risk factor for pulmonary emphysema in subjects with severe alpha 1-antitrypsin (AAT) deficiency. The aim of this study was to analyse the effects of environmental risk factors other than active smoking on lung function and on respiratory symptoms in non-smoking PiZZ individuals. METHODS: Lifetime exposure to passive smoking, domiciliary use of a kerosene (paraffin) heater or gas cooker, and all occupations since leaving school were reported by 205 non-smoking PiZZ individuals (95 men and 110 women) included in the Swedish AAT deficiency register. Lung function test results and histories of respiratory symptoms (chronic bronchitis, recurrent wheezing, and exertional dyspnoea) were elicited from the AAT register records. RESULTS: After adjustment for age, agricultural employment and domiciliary kerosene heater usage, but not gas cooker usage or passive smoking, were both associated with significantly decreased lung function. Multiple linear regression analysis showed age, sex, kerosene heater usage, and agricultural employment to be independent determinants of lung function impairment. Age and passive smoking for 10 years or more, both at home and at the work place, were associated with the presence of chronic bronchitis. Age and agricultural employment for > or = 10 years were associated with recurrent wheezing and exertional dyspnoea. CONCLUSIONS: Domiciliary kerosene heater usage and an agricultural occupation therefore appear to be environmental factors associated with decreased lung function in non-smoking PiZZ individuals, and passive smoking is associated with an increased frequency of chronic bronchitis, but not with impaired lung function.