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Robust inference for variance components models in families ascertained through probands: II. Analysis of spirometric measures
Author(s) -
Beaty T. H.,
Liang K. Y.,
Seerey S.,
Cohen B. H.,
Rao D. C.
Publication year - 1987
Publication title -
genetic epidemiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.301
H-Index - 98
eISSN - 1098-2272
pISSN - 0741-0395
DOI - 10.1002/gepi.1370040306
Subject(s) - proband , vital capacity , spirometry , pulmonary function testing , statistics , medicine , mathematics , demography , asthma , lung function , biology , genetics , lung , sociology , gene , diffusing capacity , mutation
Three spirometric measures of pulmonary function were used to estimate genetic and nongenetic components of variance for 781 members of 158 families ascertained through a proband with obstructive pulmonary disease. Forced expiratory volume in 1 sec (FEV 1 ), forced vital capacity (FVC), and the ratio of these two (FEV 1 /FVC) were adjusted for age, sex, race, smoking, and height and used in a robust approach to estimate variance components after conditioning on the proband's observed value. The best fitting model for both residual FEV 1 /FVC and FEV 1 included an additive genetic component representing 25% and 9% of the variation in these two traits, respectively. In addition, there was a significant correlation between parents in residual FEV 1 /FVC, and a component shared among full sibs was statistically significant for residual FEV 1 . No evidence of a genetic component for residual FVC was found in this analysis. Although these results agree with previous reports based on other populations in showing a substantial degree of direct genetic control over spirometric measures of pulmonary function, they also raise the possibility of etiologic heterogeneity.