Familial resemblance in trabecular and cortical volumetric bone mineral density and bone microarchitecture as measured by HRpQCT.

To estimate the heritability of bone geometry, volumetric bone mineral density (vBMD) and microarchitecture of trabecular (Tb) and cortical (Ct) bone measured by high resolution peripheral quantitative computerised tomography (HRpQCT) at the distal radius and tibia and to investigate the genetic correlations of these measures. Participants were 177 mother-offspring pairs from 162 families (mothers, mean age (SD) = 52.1 (4.7) years; offspring, 25.6 (0.73) years). Trabecular and cortical bone measures were obtained by HRpQCT. Multivariable linear regression was used to analyse the association of bone measures between mother and offspring. Sequential Oligogenic Linkage Analysis Routines (SOLAR) software was utilised to conduct quantitative genetic analyses. All maternal bone measures were independently associated with the corresponding bone measures in the offspring before and after adjustment for age, sex, weight and height. Heritability estimates ranged from 24% to 67% at the radius and from 42% to 74% at the tibia. The relationship for most bone geometry measures was significantly stronger in mother-son pairs (n = 107) compared with mother-daughter pairs (n = 70) (p < 0.05). In contrast, the heritability for most vBMD and microarchitecture measures were higher in mother-daughter pairs. Bivariate analyses found moderate to strong genetic correlations across all measures between radius and tibia (R = 0.49 to 0.93). Genetic factors have an important role in the development of bone geometry, vBMD and microarchitecture. These factors are strongly shared for the radius and tibia but vary by sex implying a role for imprinting.