[Estimating family correlation of quantitative traits using generalized estimating equation].
OBJECTIVE
To study the method for measuring familial correlations of quantitative trait and analyzing family data set of body height.


METHODS
Generalized estimating equation 2 (GEE2) was employed to estimating both regression coefficients and the familial correlation. Analyses was carried out on software MAREG. A example from height pedigrees illustrated the method.


RESULTS
GEE2 provided robust estimations of regression coefficients and familial correlations simultaneously. In body height the correlations between parents and offspring (r = 0.459) and between siblings (r = 0.671) were significantly higher than those between two parents (r = 0.184) after adjusting gender, residence and birth age. Of the same types of relative pairs, the correlation between pairs with individuals of the same gender (eg. father-son r = 0.603, mother-daughter r = 0.456, male sibling r = 0.947, female sibling r = 0.681) was higher than those individuals of different gender (eg father-daughter r = 0.431, mother-son r = 0.364, sibling with different gender r = 0.530).


CONCLUSIONS
GEE2 should be considered a standard method for the investigation of familial aggregation due to its flexibility and robustness.
Gao
Yan-hui
YH
Department of Epidemiology, College of Public Health, Fudan University, Shanghai 200032, China.
Jiang
Qing-wu
QW
D000328:Adult; D001827:Body Height / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D015233:Models, Statistical; D020412:Multifactorial Inheritance; D009679:Nuclear Family; D010375:Pedigree; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D012044:Regression Analysis; D012307:Risk Factors; D012737:Sex Factors