Osteoporosis. Frequency, consequences, and risk factors

Ross, Philip D.

doi:10.1001/archinte.156.13.1399

Cited by 147 publications

(125 citation statements)

References 175 publications

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“…(1,2) The causes of osteoporotic fractures are multifactorial. Among all the known risk factors, (3) estrogen deficiency is considered the most important because bone loss accelerates 2 to 3 years after menopause at a rate of 1% to 1.5% annually.…”

Section: Introductionmentioning

confidence: 99%

Inhibitory effects of iron on bone morphogenetic protein 2–induced osteoblastogenesis

Yang

Jian

Abramson

et al. 2011

Journal of Bone and Mineral Research

111

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Postmenopausal osteoporosis is characterized by an imbalance of bone resorption exceeding bone formation, resulting in a net loss of bone mineral density (BMD). Estrogen deficiency is known to promote bone resorption. However, the causative factors that impair bone formation have not been identified. Women after menopause experience not only estrogen deficiency but also iron accumulation as a result of cessation of menstruation. In this study we investigated whether increased iron plays a role in osteoporosis. By growing primary mouse osteoclast and osteoblast progenitor cells as well as immortalized cell lines in the presence of iron, we found that increased iron had minimal effects on osteoclast cell differentiation. Interestingly, iron, particularly in its inorganic form, and to a lesser extent ferritin and transferrin all suppressed alkaline phosphatase (ALP) activities in osteoblasts. Moreover, iron downregulated mRNA levels of several other osteoblastogenic markers such as Runx2, osterix, osteopontin, and osteocalcin. To further show that this in vitro finding is relevant to the in vivo condition, we demonstrated that iron-accumulated mice with intact ovaries exhibited a significant decrease in BMD. Although iron inhibited preosteoblast cell differentiation, it did enhance preosteoblast cell proliferation, as evidenced by increased cell growth and expression of cell cycle regulator genes such as CDK4, CDK6, cyclin D1, and cyclin D3 and G 2 /M phase cell population. Taken together, our results suggest that increased iron could be a factor that slows down bone formation in postmenopausal women. ß

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Section: Introductionmentioning

confidence: 99%

Inhibitory effects of iron on bone morphogenetic protein 2–induced osteoblastogenesis

Yang

Jian

Abramson

et al. 2011

Journal of Bone and Mineral Research

111

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“…Prospective studies have reported that physical activity reduces the risk of coronary heart disease (Paffenbarger et al, 1984;Lakka et al, 1994), diabetes mellitus (Manson et al, 1992;Moy et al, 1993), essential hypertension (Paffenbarger et al, 1983;Arroll and Beaglehole, 1992), colon cancer (Lee and Paffenbarger, 1994) and osteoporosis (Nelson et al, 1991;Gutin and Kasper, 1992). The importance of establishing and maintaining optimal bone mass to guard against the debilitating results of osteoporosis is well documented (Ross, 1996).…”

Section: Introductionmentioning

confidence: 99%

Bone mineral density in triathletes over a competitive season

McClanahan¹,

Ward²,

Vukadinovich³

et al. 2002

Journal of Sports Sciences

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There is evidence from previous cross-sectional studies that high volumes of certain sports, including running, swimming and cycling, may have a negative impact on bone mineral density. The aim of the present study was to evaluate prospectively the effects of high athletic training in individuals who engage in high volumes of all three of these activities (triathletes). Bone mineral density for the total body, arms and legs was determined by dual-energy X-ray absorptiometry in 21 competitive triathletes (9 men, 12 women) at the beginning of the training season and 24 weeks later. Age, body mass index, calcium intake and training volume were also recorded to examine potential mediators of bone mineral density change. Men had greater bone mineral density at all sites than women. No significant changes were observed over the 24 weeks for either total body or leg bone mineral density. Bone mineral density in both arms increased by approximately 2% in men (P < 0.03), but no change was observed for women. Change in bone mineral density at all sites was unrelated to age, body mass index, calcium intake and training volume. The results suggest that adverse changes in bone mineral density do not occur over the course of 6 months of training in competitive triathletes.

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“…41,43,44 Immobility is a significant risk factor for osteoporosis, with up to 40% loss of BMD reported. 45 Many investigators have found that weight-bearing exercises are beneficial in the maintenance of bone mass 46,47 in addition to retarding bone loss 48 and reducing the fracture rate. 46,49 -51 However, some other investigators have not found any such association.…”

Section: Discussionmentioning

confidence: 99%

Factors affecting bone mineral density in patients with prostate carcinoma before and after orchidectomy

Agarwal

Khandelwal

Mandal

et al. 2005

Cancer

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BACKGROUNDOrchidectomy is an accepted form of androgen‐deprivation therapy (ADT) for prostate carcinoma. Osteoporosis is common in elderly individuals and is accelerated by ADT. The authors studied changes in bone mineral density (BMD) after ADT and factors that affected those changes.METHODSFifty patients with prostatic adenocarcinoma who opted to undergo orchidectomy were studied prospectively. All patients completed 6 months of follow‐up, and 20 of those patients completed 12 months of follow‐up. Patients' age, weight, height, body mass index (BMI), physical activity, addiction (smoking, alcohol), dietary calcium intake, and lactose tolerance status were noted. Lumbar spinal (L1–L3) trabecular BMD was measured with quantitative computed tomography (QCT) at baseline and every 6 months for 1 year and was compared with preoperative values. The effects of various patient characteristics on preoperative BMD and changes in BMD also were analyzed.RESULTSThe mean ± standard deviation (SD) age of the patients was 69.5 ± 8.1 years, BMI was 23.5 ± 3.9 kg/m2, dietary calcium intake was 1066.1 ± 443.3 mg per day. Thirty‐eight percent of patients were lactose intolerant. Sixty‐two percent of patients were in the light weight‐bearing activity group. The mean ± SD preoperative BMD was 119.2 ± 34.9 mg/cc, with T‐scores of − 1.77 ± 1.22 and Z‐scores of 0.43 ± 1.27. A decrease in BMD during the first 6 months (≈ 13%) was statistically significant (P = 0.0001) and continued further during next 6 months (BMD loss of ≈ 18% at 12 months). Patients with osteoporosis, as defined by T‐scores ≤ − 2.5, increased from 24% at baseline to 48% at 6 months. Nonsmokers, nonalcoholics, patients with higher physical activity, and patients with a BMI > 25 kg/m2 had statistically significant higher BMD compared with their counterparts (P < 0.05). Body weight < 60 kg and BMI < 25 kg/m2 were significant risk factors for loss of BMD (P < 0.05). Dietary calcium had a discernible but statistically insignificant effect on BMD (P = 0.16). Lactose intolerance had no significant effect on BMD or bone loss.CONCLUSIONSOsteoporosis was common in the population affected by prostate carcinoma. Orchidectomy led to accelerated bone loss. Periodic measurement of BMD after ADT would help in the early detection of osteoporosis. Maintenance of high BMI, weight‐bearing physical activity, avoidance of alcohol and smoking, and possibly high dietary calcium intake help in maintaining bone mass. Cancer 2005. © 2005 American Cancer Society.

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Osteoporosis. Frequency, consequences, and risk factors

Cited by 147 publications

References 175 publications

Inhibitory effects of iron on bone morphogenetic protein 2–induced osteoblastogenesis

Inhibitory effects of iron on bone morphogenetic protein 2–induced osteoblastogenesis

Bone mineral density in triathletes over a competitive season

Factors affecting bone mineral density in patients with prostate carcinoma before and after orchidectomy

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