Effect of Smoking and Gender on Pulmonary Function and Clinical Features in Sarcoidosis

Background

The effect of cigarette smoking on the clinical manifestations and progression of sarcoidosis is not well characterized. We sought to determine the effects of smoking in sarcoidosis patients and to evaluate for gender-specific differences.

Methods

We examined the effects of cigarette smoking in 518 patients seen at the Sarcoidosis and Interstitial Lung Disease Center at Wayne State University using radiographic pattern, pulmonary function testing, and clinical features of the disease. We performed a separate analysis to evaluate for gender-specific differences based on smoking history.

Results

We found that smokers had significantly lower FEV₁ and FEV₁/FVC values. Total lung capacity was not significantly different between smokers and nonsmokers, but diffusion capacity for carbon monoxide (DL_CO) was significantly reduced in smokers. Gender-based statistical analysis showed a marked decrease in DL_CO values among female smokers. Smokers were also found to have a higher incidence of extrapulmonary involvement as multivariate regression analysis demonstrated that both smoking and female gender are significantly associated with the development of extrapulmonary manifestations.

Conclusions

Our data indicate that both cigarette smoking and gender are important in shaping the clinical manifestations of sarcoidosis. The nature of the gender difference requires further study and may be related to differences in inflammatory response.