A genetic analysis of weight and overweight in 4-year-old twin pairs

Abstract

OBJECTIVE: Although many twin and adoption studies document genetic in¯uence on individual differences in weight, much less is known about genetic in¯uences on overweight, about the genetic links between weight and overweight, or about the origins of weight and overweight in childhood, an age that might provide a good target for prevention of obesity. We tested the hypothesis that, in early childhood, overweight is as heritable as weight and that weight and overweight are linked genetically. DESIGN: Model-®tting analyses were used to compare monozygotic (MZ) and dizygotic (DZ) twins (same-sex and oppositesex) for weight and overweight. SUBJECTS: The sample included 3636 4-y-old twins born in the UK in 1994. MEASUREMENTS: Heights and weights reported by parents were used to assess weight corrected for height, which yields results similar to body mass index (BMI) but corrects more completely for genetic effects on height. RESULTS: At 4 y of age, genetic factors contributed substantially both to individual differences in weight throughout the distribution and to the mean weight difference between overweight children and the rest of the population. Unlike results later in life, weight and overweight in 4-y-olds also suggest substantial shared family environmental in¯uence. Results are similar for boys and girls. CONCLUSIONS: Overweight is the quantitative extreme of genetic and environmental factors responsible for normal variation in weight in childhood. Genes associated with overweight are likely to be associated with variation in weight throughout the distribution, as assumed by quantitative trait locus (QTL) theory. These ®ndings linking weight and overweight in childhood have far-reaching implications for molecular genetic attempts to identify speci®c genes responsible for genetic in¯uence, for investigating pathways between genes and behaviour, and for intervention and prevention.

Development and modification of child food preferences and eating patterns: behavior genetics strategies

“…An intriguing finding from existing studies is the apparent evidence for shared environmental influences on eating behavior, which implicates the home environment vis-à-vis the development of child eating patterns. This is in contrast to most twin studies of BMI, which generally fail to find a significant effect of the home environment (although some studies do report home environmental influences on BMI in pediatric samples 40,41 ).…”

Quality of Life and Health Outcomes in Overweight and Non-Overweight Children With Asthma

“…In a large study of 3636 four year old twins, the researchers found that genetic factors contributed substantially to individual differences in weight (Koeppen-Schomerus, Wardle, & Plomin, 2001). In addition, a study of 106 overweight children age 3 to 18 years found that obesity in one or both parents correlated with a higher percentage of ideal body weight (p=0.01) (Anavian, Brenner, Fort, & Speiser, 2001).…”

Appetitive traits and child obesity: measurement, origins and implications for intervention

“…Behavioural twin studies have indicated heritability of between 14 % and 69% for indices of eating style such as daily energy intake, meal intake, energy density of the diet, pre-and postmeal hunger and pre-meal stomach contents (94)(95)(96) , while heritability for three-factor eating questionnaire and Dutch eating-behaviour questionnaire scales range from 0% to 59% depending on study population and the measure used (97)(98)(99) . However, since there is evidence for heritability of obesity in children (100) as well as adults (101) , and some suggestion that shared environmental influence may be stronger in young children, who still share the family home (102) , independent investigation of heritability of appetite in children is warranted.…”