Familial aggregation and heritability of adult lung function: results fromthe Busselton Health Study

Decreased spirometric indices are characteristic of asthma and other respir atory diseases. The aim of this study was to investigate the genetic and en vironmental components of variance of forced expiratory volume in one secon d (FEV1) and forced vital capacity (FVC) measured in adulthood in an Austra lian population-based sample of 468 Caucasian nuclear families. The inter-r elationships of the genetic determinants of these traits with asthma and at opic rhinitis were also investigated. Serial cross-sectional studies were conducted in the town of Busselton in W estern Australia between 1966 and 1981 and follow-up of previous attendees was undertaken in 1995. Data from each subject included in this study mere from a single survey in adulthood (25-60 yrs of age) when the subject was a s close to age 45 yrs as possible. Multivariate analysis suggested that FEV1 and FVC levels were associated wi th age, sex, height, tobacco smoke exposure, asthma and atopic rhinitis, Af ter adjustment for relevant covariates, FEV1 levels had a narrow-sense heri tability (h(2)N) of 38.9% (SE 9.1 %). FVC levels had an h(2)N of 40.6% (SE 8.9%). Extended modelling demonstrated little overlap in the genetic determ inants of asthma or atopic rhinitis and either FEV1 or FVC levels. The results of this study were consistent with the existence of important g enetic determinants of adult lung function that are independent of asthma o r other atopic disease, cigarette smoking, height, age or sex.