Fifteen-year follow-up of pulmonary function in individuals heterozygous for the cystic fibrosis phenylalanine-508 deletion

Background: In a cross-sectional study, we previously showed that cystic fi brosis phenylalanine-508 deletion (Delta F508) heterozygosity may be overre presented among individuals with asthma. Objective: Using 15-year follow-up data from the Copenhagen City Heart Stud y, we now further explore this relationship. Methods: As part of 3 surveys in 1976 to 1978, 1981 to 1983, and 1991 to 19 94, we measured pulmonary function and asked all participants about asthma and pulmonary risk factors. Results: There was no difference in annual decline in lung function between Delta F508 heterozygotes and noncarriers overall; however, among individua ls with familial asthma, the annual declines in FEV1 and forced vital capac ity (FVC) were 49 and 36 mt in Delta F508 heterozygotes versus 24 and 17 mt in noncarriers (P = .01 and P = .12, respectively). Cross-sectionally base d on triple measurements, FEV1 and FVC in individuals aged 20 to 70 years w ere tower in heterozygous participants versus noncarriers (P = .02 and P = .004, respectively), The average reduction of FEV1 and FVC in Delta F508 he terozygotes versus noncarriers was 70 mt (P = .06) and 136 mt (P = .008). F inally, 10% of carriers reported asthma versus 7% of noncarriers (P = .02), resulting in an odds ratio of 2.0 (1.3-3.2) for asthma in Delta F508 heter ozygotes, Conclusion: Cystic fibrosis Delta F508 heterozygotes may be overrepresented among individuals with asthma and may have poorer lung function than nonca rriers. Furthermore, Delta F508 heterozygosity in context with familial pre disposition to asthma may be associated with a greater annual FEV1 decline.