Predictors of lung function and its decline in mild to moderate COPD in association with gender: results from the Euroscop study.

BACKGROUND: There is increasing appreciation of gender differences in COPD but scant data whether risk factors for low lung function differ in men and women. We analysed data from 3 years follow-up in 178 women and 464 men with COPD, participants in the Euroscop Study who were smokers unexposed to inhaled corticosteroids.
METHODS: Explanatory variables of gender, age, starting age and pack-years smoking, respiratory symptoms, FEV(1)%FVC and FEV(1)%IVC (clinically important measures of airway obstruction), body mass index (BMI), and change in smoking were included in multiple linear regression models with baseline and change in post-bronchodilator FEV(1) as dependent variables.
RESULTS: Reduced baseline FEV(1) was associated with respiratory symptoms in men only. Annual decline in FEV(1) was not associated with respiratory symptoms in either men or women, and was 55 ml less in obese men (BMI 30 kg/m(2)) than men having normal BMI, an effect not seen in women. It was 32 ml faster in women with FEV(1)%FVC<median than women with less airway obstruction, a larger difference than in men (8 ml per year). It was 17.7 ml/year faster when increasing the daily number of cigarettes by 10 in men only, but not significantly greater than in women.
CONCLUSION: Respiratory symptoms were associated with reduced baseline FEV(1) in men with COPD. In men, obesity was associated with reduced decline and increasing the number of cigarettes smoked with increased decline in lung function. In women more severe airway obstruction was associated with accelerated decline.