Genetic regulation of body size and morphology in children: a twin study of 22 anthropometric traits.
Level 4 - case-series / case-control
Cross-sectional twin study (graded Level 4 by non-clinical design analogy)
PubMed 36635383 · doi:10.1038/s41366-023-01253-0
What was done
Researchers measured 22 anthropometric traits (height, weight, 7 skinfold thicknesses, 7 body circumferences, and 4 skeletal diameters) in 214 twin pairs aged 3–18 years (87 monozygotic pairs) in Madeira, Portugal. They applied factor analysis with Varimax rotation to determine underlying body physique dimensions and used genetic twin modeling to estimate heritability and genetic/environmental correlations.
What was found
Two latent factors explained 80% of trait variance in boys and 73% in girls. The first factor was dominated by obesity metrics (BMI, skinfolds, waist and hip circumferences) and limb circumferences, while the second factor was dominated by height and skeletal diameters. Most traits and both factors demonstrated heritability of 80% or more, with remaining variance attributed to non-shared environmental factors. Genetic correlations ranged from 0.75 to 0.98 among obesity measures and from 0.58 to 0.76 between height and body diameters. Non-shared environmental correlations were weaker than genetic correlations but remained substantial.
Why it matters
The findings demonstrate that childhood body morphology is heavily genetically determined and organized into two primary correlated clusters: one governing adiposity and soft tissue mass, and another governing linear skeletal dimensions.
Limits
The study is limited to a single geographical region (Madeira, Portugal) and a modest sample size of 214 twin pairs. The wide age bracket (3–18 years) was analyzed cross-sectionally without longitudinal tracking or accounting for specific pubertal stages, and specific causal genetic variants were not measured.
Cited by
- contradicts Research, including work by Dr. Zachary Knight, indicates that body weight and body fat are more genetically predetermined than height.