The level of FEV1 at a given time point in an individual depends on two potentially independent processes: the maximum lung function obtained during development, and the rate of decline of lung function with age. Lung function reaches a maximum by age 25–35 years35. The populations studied in SpiroMeta cover a wide range of ages except the very elderly; as expected, FEV1 and FVC values were much lower in children. At least for the loci we identify, there was little evidence for age-specific effects, suggesting that the genetic risk factors identified operate across the age ranges; these findings again are in keeping with those of previous epidemiological studies7. Our analyses were based on cross-sectional measures of lung function; additional studies in cohorts with longitudinal data will be needed to identify determinants of the gradients of development and decline in lung function with age.
