Sepúlveda, S. et al. Low spinal and pelvic bone mineral density among individuals with Down syndrome. Am. J. Ment. Retard. 100, 109-114
ABSTRACT The bone mineral density of 15 adults with Down syndrome was compared to 25 control subjects without Down syndrome. Bone mineral density was measured by dual x-ray absorptiometry with a Lunar DPX scanner. Arm, leg, pelvic, and spine bone mineral density was tested. Analysis of covariance was conducted for each variable; Down syndrome was the independent variable, and the covariates were height, lean body mass, fat mass, age, and gender. No significant group differences were found for arm or leg bone mineral density. Individuals with Down syndrome had significantly lower pelvic and spinal bone mineral density. Before adjustment for covariates, percentage difference between group means for spine was 14.5% and for pelvis, 11.6%. Adjusted percentage was 11.1% and 13.9%, respectively. Suggestions for further research were made.
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ABSTRACT: Together, osteoporosis and osteopetrosis comprise a substantial proportion of the bone diseases that severely affect humans. In order to understand and effectively treat these disorders, an understanding of the mechanisms controlling bone remodelling is essential. While numerous animal models of bone disease have been generated, the lack of correlation between these animal models and human disease has limited their utility in terms of defining therapeutic strategies. The generation and analysis of cathepsin K knockout mice has resulted in a model for pycnodysostosis, a rare human osteopetrotic disease, and is now providing considerable insights into both osteoclast function and potential therapeutic strategies for the treatment of bone disease. This review highlights the importance of genes such as cathepsin K in understanding bone remodelling and illustrates a new trend towards understanding bone disease as a complete entity rather than as a series of unrelated disorders.Human Molecular Genetics 02/1999; 8(10):1839-46. · 6.68 Impact Factor
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ABSTRACT: During 3.5 years, 182 fractures occurred among 994 residents of a developmental center. The fracture rate was 5.2 per 100 person-years (1.7 times greater than the rate in the US population). Fracture rate was significantly greater in residents with: epilepsy, older age, male gender, white race, independent ambulation, osteoporosis, and residence in intermediate care (versus skilled nursing) units; it was not affected by severity of mental retardation. Hand and foot bones were fractured in 58% of cases. Femur fracture occurred in 13 cases (7%). Fracture was caused by a fall in 41 cases (23%); its cause was indeterminable in 105 cases (58%). Fractures, occurring without significant injury, may be an important cause of preventable disability in this population. Control measures are suggested.Western Journal of Medicine 05/1999; 170(4):203-9.
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ABSTRACT: The objective of this study was to compare the bone mineral density (BMD) of men with Down syndrome (DS) to otherwise mentally retarded (MR) men and to investigate whether leg muscle strength of these patients is related to BMD. Two groups with MR (with and without DS) participated in the study, having met the following criteria: similar age, moderate to mild mental retardation, Tanner stage V of sexual development, similar age of beginning to walk, and equal motor activities. The DS group consisted of 8 men 23.9 +/- 4.2 years, and the MR group without DS consisted of 8 men 23.5 +/- 3.6 years. The two groups were compared with 10 sedentary students of the same age range (25.9 +/- 2.9 years) attending our University. The BMD of the 2(nd) to 4(th) lumbar vertebrae was measured in the PA projection and the mean density was expressed as g/cm(2). The isokinetic muscle strength of the right quadriceps femoris and hamstrings muscles was measured on a Cybex II isokinetic dynamometer. The value measured was peak torque at angular velocities at 60, 120, and 300 degrees.sec(-1). The results showed that BMD in DS individuals versus young adults (reference group of the scanner) was lower at the 26% level (T-score - 2.66 +/- 0.29) and significantly lower (P = 0.002) than that of the MR group. Significantly different muscle strength was observed between the DS and non-DS MR group (in quadriceps at 300 degrees.s(-1): P < 0.01, at 120 and 60 degrees. s(-1): P < 0.05; in hamstrings at 300 degrees.s(-1): P < 0.05). Higher differences in muscle strength were found between MR and control men, but no significant difference existed in BMD between them. Bivariate correlation showed that quadriceps strength significantly predicted the BMD in the DS patients. Active lifestyle and increased physical exercise to improve muscular strength should be instituted to avoid the development of osteoporosis in DS patients.Calcified Tissue International 03/2000; 66(3):176-80. DOI:10.1007/s002230010035 · 2.75 Impact Factor