Familial comparison of bone mineral density at the proximal femur and lumbar spine

• Published in: Bone and mineral Vol. 24; no. 2; pp. 95 - 107
• Main Authors: McKay, H.A., Bailey, D.A., Wilkinson, A.A., Houston, C.S.
• Format: Journal Article
• Language: English
• Published: London Elsevier Inc 01.02.1994; Amsterdam Elsevier; New York, NY
• Subjects: Adolescent; Adult; Aged; Biological and medical sciences; Bone Density - genetics; Bone mineral density; Child; Children; Familial resemblance; Female; Femur; Fundamental and applied biological sciences. Psychology; Humans; Male; Middle Aged; Postmenopause; Pre-menopausal mothers; Premenopause; Puberty; Skeleton and joints; Spine; Vertebrates: osteoarticular system, musculoskeletal system; Bone mineral density; Pre-menopausal mothers; Children; Familial resemblance; Human; Family study; Spine; Sex; Radiologic investigation; Density; Inorganic element; Osteoarticular system; X ray absorption spectrometry; Family resemblance; Dual energy; Development; Bone; Age; Comparative study
• ISSN: 0169-6009
• DOI: 10.1016/S0169-6009(08)80148-1

Familial resemblance of bone mineral density (BMD) was studied in the lumbar spine and three regions of the proximal femur in 41 biological mother-daughter (M-D), 42 mother-son (M-S), 24 mother-grandmother (M-G) pairs and 18 mother-grandmother-daughter (M-G-D) triads. Children were placed into three maturity categories based on an assessment of secondary sex characteristics and growth velocities. Two sets of standardized BMD Z-scores were derived for the children based on either their chronological age or their maturational status. These scores were compared with maternal Z-scores derived from age-specific norms. Similar comparisons were made between the Z-scores of the mothers and grandmothers. For all three regions of the proximal femur and for the total AP lumbar spine the correlations between Z-score values were similar and significant ( P < 0.05) between the M-G and M-D pairs ranging from 0.41 to 0.57. In general, the familial correlations improved when maturity-status based Z-scores were used for comparison. The absolute BMD values measured in the grandmothers and the three maturity groups of the children — expressed as a percentage of the BMD of the mothers — showed that at the neck and the trochanteric regions of the proximal femur the late-pubescent girls and boys had a significantly ( P < 0.05) greater bone density than their mothers (115–123%), whereas at the AP spine these groups averaged only 88% of their mothers BMD. This site differential was not apparent when comparing the post-menopausal grandmothers with the pre-menopausal mothers (80% at both sites). Three generation comparisons demonstrated a strong familial resemblance in bone mineral density. The value of incorporating maturity-based versus chronological-based parameters for comparison with adult measures in studies that involve growing children at different stages of development was also demonstrated.