Twins and virtual twins: bases of relative body weight revisited.
OBJECTIVE
Application of a new investigative strategy to assess genetic and environmental influences on relative body weight.


METHODS
Covariance structure analysis of body mass index (BMI) using genetically informative samples.


METHODS
One-hundred and fourteen monozygotic (MZ) twin pairs (age 5.04-22.93 y), 81 dizygotic (DZ) twin pairs (age 6.05-16.52 y), and 98 virtual twin (VT) pairs, ie same-age unrelated siblings (3.68-54.75 y).


METHODS
Height, weight, BMI variously obtained by direct measurement and self-report.


RESULTS
In contrast with most previous studies, significant common environmental influence on BMI was observed.


CONCLUSIONS
Much past research may have underestimated common environmental effects on BMI because the designs lacked the power or ability to detect them.
Segal
N L
NL
Department of Psychology and Twin Studies Center, California State University, Fullerton 92834, USA. nsegal@fullerton.edu
Allison
D B
DB
D000300:Adoption; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight / Q000235:genetics*; D004777:Environment; D006801:Humans; D014427:Twins; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic