Register for BMI shows strong heritability among male family members
Obesity Genomics and GeneticsDecember 16, 2002
by Maria G. Essig, MS, ELS, senior medical writer - Strong similarities in body mass index found among biologically unrelated members of the same family indicate that factors in addition to simple heritability can influence obesity patterns in families, according to a report in the International Journal of Obesity.
P.K. Magnusson, at the Columbia Genome Center of Columbia University in New York, and F. Rasmussen, at the Karolinska University Hospital in Stockholm, studied the correlations in body mass index (BMI) among male members of 92,869 families in Sweden. BMI data from Sweden's Military Service Conscription Register was available for 196,743 sons and 19,972 fathers.
The investigators found very significant correlations in BMI among the biologically related family members, which was strongest for full brothers (0.36) and then for fathers and sons (0.28).
Interestingly, the correlation for maternal half-brothers (0.21) was almost twice that found for paternal half-brothers (0.11). A correlation of 0.06 existed between fathers and sons who were not related biologically.
BMI values at the high and the low ends of the scale were equally likely to be correlated among the subject pairs (Familial resemblance of body mass index and familial risk of high and low body mass index. A study of young men in Sweden. International Journal of Obesity, 2002;26(9):1225-1231).
"The almost twice as strong BMI correlation between maternal half-brothers as between paternal half-brothers illustrates the importance of factors of nonadditive genetic origin, to the familial aggregation of BMI," reported Magnusson and Rasmussen. "The significant BMI association found between biologically unrelated individuals from the same family emphasizes that assortative mating (and regional clustering) should be taken into account when the heritability of BMI is estimated."
The corresponding author for this study is F. Rasmussen, Division of Epidemiology, Norrbacka, Karolinska University Hospital, SE-17176 Stockholm, Sweden. E-mail: finn.rasmussen@imm.ki.se.
A search at www.NewsRx.net using the search term "obesity genomics and genetics" yielded 54 articles in 14 specialized reports.
Key points reported in this study include:
* BMI was highly correlated among related male family members
* The BMI correlation coefficient was almost two times higher for maternal half-brothers than for paternal half-brothers
* A significant correlation in BMI was found even between fathers and sons who were not biologically related This article was prepared by Genomics & Genetics Weekly editors from staff and other reports.
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