GENDER DIFFERENCE IN SMOKING EFFECTS ON LUNG-FUNCTION AND RISK OF HOSPITALIZATION FOR COPD - RESULTS FROM A DANISH LONGITUDINAL POPULATION STUDY

Recent findings suggest that females may be more susceptible than male s to the deleterious influence of tobacco smoking in developing chroni c obstructive pulmonary disease (COPD). This paper studies the interac tion of gender and smoking on development of COPD as assessed by lung function and hospital admission.A total of 13,897 subjects, born after 1920, from two population studies, 9,083 from the Copenhagen City Hea rt Study (CCHS) and 4,814 from the Glostrup Population Studies (GPS), were followed for 7-16 yrs. Data were linked with information on hospi tal admissions caused by COPD. Based on cross-sectional data, in the C CHS the estimated excess loss of forced expiratory volume in one secon d (FEV1) per pack-year of smoking was 7.4 mL in female smokers who inh aled and 6.3 mL in male smokers who inhaled. In the GPS, the correspon ding excess loss of FEV1 was 10.5 and 8.4 mL in females and males, res pectively. Two hundred and eighteen subjects in the CCHS and 23 in the GPS were hospitalized during follow-up. Risk associated with pack-yea rs was higher in females than in males (relative risks (RRs) for 1-20, 20-10 and >40 pack-years were 7.0 (3.5-14.1), 9.8 (4.9-19.6) and 23.3 (10.7-50.9) in females, and 3.2 (1.1-9.1), 5.7 (2.2-14.3) and 8.4 (3. 3-21.6) in males) but the interaction term gendenxpack-years did not r each significance (p=0.08). Results were similar in the GPS. After adj usting for smoking in more detail, females in both cohorts had an incr eased risk of hospitalization for COPD compared to males with a RR of 1.5 (1.2-2.1) in the CCHS and 3.6 (1.4-9.0) in the GPS. This was not l ikely to be caused by a generally increased rate of hospital admission for females. Results were similar when including deaths from COPD as endpoint. In two independent population samples, smoking had greater i mpact on the lung function of females than males, and after adjusting for smoking females subsequently suffered a higher risk of being admit ted to hospital for COPD. Results suggest that adverse effects of smok ing on lung function may be greater in females than in males.