Pulmonary Function Category

In a study of twins, Hubert et al6 concluded that while the primary genetic determinants of FVC were those that influenced height and weight, variance of FEVi was under genetic control independent of that influencing body size. Astemborski et al8 also found heritability of FEVj in a cohort of twins after adjusting for height. Twenty-five […]

Dizygotic twins are related only as full siblings and share an average of 50 percent of genes while MZ twins are genetically identical. Consequently, intrapair differences for genetically influenced traits will, on average, be smaller in monozygotes than in dizygotes. Several studies have investigated the heritability of spirometric indices by evaluating mean intrapair differences unadjusted […]

Monozygotes made up 63.5 percent of the study population. Mean ages for MZ and DZ were 19.7 and 19.5 years, respectively (Table 1). Evaluation of the assumptions required for genetic analysis revealed the following. All tested pulmonary {unction parameters, with the exception of FEV/ FVC, met the Kolmogorov-Smirnov goodness of fit test for a Gaussian […]

Pulmonary function indices were regressed against height using simple linear regression. Data for men and women were regressed separately. Data for both members of a twin set were included. Residual values were calculated as the difference between observed and expected values and used to calculate height-adjusted mean intrapair differences and heritability estimates. The influence of […]

Height and weight were measured with the subject wearing indoor clothing without shoes. Both a dry, rolling seal spirometer (model 822, Ohio Medical Products, Madison, WI) connected to an optical shaft encoder and a Collins/DS 560 automated system were used for spirometric measurements. Current ATS accuracy and methodology standards for spirometry were employed. Both spirometers […]

There is a genetic contribution to the variability of spirometric indices. It has been postulated that the resultant heritability can be attributed to the association of pulmonary function with anthropometric measures such as height which are under strong genetic control. However, several studies have demonstrated significant genetic heritability of spirometry after adjusting for individual differences […]

Furthermore, we have calculated the 95 percent confidence intervals of PD20, which permit expression of the intrasubject variability of the MIT results in individual patients, independently from fixed inhalation dose intervals. This also makes it easier to compare the reproducibility of our results to that obtained in other laboratories using different methods and inhalation dose […]