The aim of this study is to analyze the hereditary determinism of bone microarchitecture measured at the distal radius and distal tibia from a case control-study of mother-daughter pairs.

Many factors influence the risk of osteoporosis but one of the most important is a positive family history, emphasizing the importance of genetics in the pathogenesis of osteoporosis. Till now, most genetic studies in osteoporosis have focused on the phenotype of BMD. However, areal BMD (bone quantity per unit bone area measured) does not provide information regarding bone distribution (between cortical and cancellous compartments) or bone microarchitecture (trabecular number, thickness, spacing and distribution) and cortical (thickness, porosity). We are planning to analyze the hereditary determinism of bone microarchitecture assessed non invasively with HR pQCT at the distal radius and the distal tibia in a case-control study with fractured and not fractured mothers and their daughters. Additionally, the role of the bone turnover, hormones involved in regulating bone metabolism , bone geometry measured at the proximal femur and bone strength estimated by finite element analysis (μFE)in the hereditary determinism of bone fragility will be analyzed.

Inclusion Criteria:

• Case mothers: postmenopausal women who have at least one bone fragility fracture confirmed by radiological examination or by a surgical report. Fragility fracture is a fracture that occurs as a result of a fall from standing height or less. Fractures of the skull, fingers and toes will be excluded.
• Control mothers: menopausal women not having suffered from bone fragility fracture.
• Daughters: Women aged 20 and older (postmenopausal or not), biological daughters of participating mothers. Several daughters from the same mother may be included.

Mothers and some daughters are recruited from the OFELY (Os des FEmmes de LYon) cohort or the FMC (Filière MédicoChirurgicale).

Exclusion Criteria:

• Adoptive daughters
• Nonmenopausal mothers

1. Fractured mothers and their daughters (case group)
2. Non-fractured mothers and their daughters (control group)