Videman T et al. (2007) Heritability of BMD of femoral neck and lumbar spine: a multivariate twin study of Finnish men. J Bone Miner Res 22: 1455–1462

The estimated influence of genetic heritability on bone mineral density (BMD) varies markedly; intergenerational studies have attributed 50–70% of BMD variation to genetic factors, and twin studies have suggested a total heredity of 80–90%. These estimates are affected by adjusting for the heritability of other factors related to BMD, such as lean body mass and leg strength; therefore, Videman and colleagues conducted a twin study to evaluate the influences of heritability and anthropometric factors on BMD of the femoral neck and lumbar spine. The study included data from a representative sample of 147 monozygotic and 153 dizygotic twins (age 35–70 years) from the Finnish Twin Cohort.

Genetic heritability was estimated to account for 75% of the variance of femoral neck BMD and 83% of lumbar spine BMD (L1–L4 lumbar vertebrae). Isokinetic lifting force and lean body mass/height significantly influenced the heritability of BMD. Lifting force explained 9% and lean body mass/height explained 18% of the total genetic variation of femoral BMD; for lumbar spine BMD, these proportions were 9% and 11% for lifting force and lean body weight/height, respectively.

These results indicate that body weight was important only for lumbar BMD, while lifting force accounted for an important portion of both femoral and lumbar BMD. The authors conclude that muscle-strengthening exercises might have more practical importance for BMD modification (particularly at the femoral neck) than other life-style factors.