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- Ljunggren Ribom, Eva, 1966-
(författare)
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Muscles, Estrogen, and Bone
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sweden has one of the highest incidences of osteoporotic fractures in the world. A more sedentary lifestyle is one of several proposed reasons for the increase in osteoporosis seen in the developed countries. The aim of this thesis was primarily to study the influence of muscle strength, and body composition, on bone mineral density, BMD, in young adults. The second aim was to evaluate the possible influence of estrogen on muscle strength in women.A population-based study of 113 subjects (53 men and 60 women) aged 22-85 showed associations for premenopausal, but not postmenopausal women, between isometric quadriceps muscle strength and BMD in the total body, lumbar spine, and femoral neck. In men there was only an association between muscle strength and BMD in the total body. Another population-based study of 125 randomly selected young adults (64 women and 61 men) showed that total body BMD, TBMD, is influenced by isokinetic knee flexion and extension strength in women but not in men where body composition influenced TBMD. In 159 randomly selected young adult women (20-39 years) knee flexion and extension strength influenced not only TBMD but also total hip BMD, and heel BMD. However, lean body mass and body weight were better predictors for BMD at these skeletal sites. An extension of this study involving 335 women again demonstrated that lean body mass is the best predictor of BMD. This study also showed that Uppsala women aged 20-39 years have a BMD that is approximately 0.1-1.2 SD (2-12 %) above international/national references. In addition marked variations in BMD T-scores between various skeletal sites were noted. In Conclusion: The association between muscle strength and BMD is evident in women in their early twenties but with age lean body mass and body weight becomes better predictors for BMD. In men lean body mass and body composition but not muscle strength predicted BMD. Hormone replacement therapy does not influence muscle strength and there is no association between allelic variations in the estrogen receptor alpha and muscle strength in women.
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- Siilin, Helene, et al.
(författare)
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Associations of primary hyperparathyroidism and physical performance, fall- and fracture risk in elderly men - Mr Os Sweden : PHPT-physical performance, falls and fractures in elderly men
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Primary hyperparathyroidism (PHPT) is an endocrine disease associated with deterioration of the skeleton and neuromuscular dysfunction. This study has explored associations between PHPT, physical function and risk of falls and fractures in elderly men. Method: Serum parameters of calcium homeostasis, physical testing of neuromuscular function (grip strength, time stands, 6 meters walking and 20 cm narrow walking tests), self reported falls during 12 months preceding the testing and self reported fractures were evaluated in 3014 men aged 69 to 81 years in the MrOS Sweden cohort. Subjects were diagnosed with PHPT (n=22) if both albumin adjusted s-calcium and plasma parathyroid hormone (p-iPTH) were above normal in absence of renal failure and vitamin-D insufficiency. To evaluate impact of minor calcium disturbance, suggesting normocalcemic HPT, the total cohort were divided into subjects with inappropriately elevated iPTH (IEP-group), based on above median value of both s-calcium (2.34mmol/L) and iPTH (4.24 pmol/L) ( n=387 minus the 22 with PHPT, in total 365) and subjects with normal calcium homeostasis (controls, n=1848). Group comparisons were made between PHPT-group and controls and IEP-group and controls. Results: The IEP-group performed inferior in all but one of the muscular functioning tests (all p <0.01, respectively) and the PHPT-group performed inferior in the time stand test (p<0.05). There were no significant group differences in fall or fracture prevalence. Conclusion: Elderly men with calcium disturbance, suggesting normocalcemic PHPT, had inferior physical performance than men with normal calcium homeostasis but it was not associated with higher fall or fracture prevalence.
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