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Genetic and environmental contributions to the variance of the body mass index in a Norwegian sample of first‐ and second‐degree relatives
Author(s) -
Tambs Kristian,
Moum Torbjørn,
Eaves Lindon,
Neale Mike,
Midthjell Kristian,
LundLarsen Per G.,
Næss Siri,
Holmen Jostein
Publication year - 1991
Publication title -
american journal of human biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.559
H-Index - 81
eISSN - 1520-6300
pISSN - 1042-0533
DOI - 10.1002/ajhb.1310030305
Subject(s) - heritability , norwegian , demography , body mass index , offspring , twin study , grandparent , dominance (genetics) , population , biology , genetics , psychology , developmental psychology , gene , endocrinology , pregnancy , philosophy , linguistics , sociology
Abstract Height and weight were measured in a health screening of the population in Nord‐Trøndelag, Norway. Correlations for the body mass index were computed for 23,936 pairs of spouses, 43,586 pairs of parents and offspring, 19,151 pairs of siblings, 1,251 pairs of grandparents and grandchildren, 1,146 cognate avuncular pairs, 801 noncognate avuncular pairs, 168 pairs of same‐sexed twins, and smaller groups of other types of relatives. Correlations were largely independent of age and age difference within pairs of relatives, suggesting a stable effect of the same set of genes and familial environment throughout adulthood. No effect of convergence during marriage could be detected. Correlations were approximately .20 for parents and offspring, .26 for same‐sexed siblings, .20 for opposite‐sexed siblings, .58 for monozygotic twins, and close to zero for most second‐order relatives. Results from structural equation model‐fitting indicate a broad heritability of .4, much of which is due to genetic dominance or other genetic nonadditivity.