Calcium & Osteoporosis

Note: The following abstracts are written in extremely technical language and include technical research and case studies. References are provided. For 'user-friendly' informative reading, check out the health topics presented by Dr. Martin and Dr. Davenport. Feel free to contact us for more information or if you have any questions.

Calcium for prevention of osteoporotic fractures in postmenopausal women

A systematic review of the literature was conducted to assess the effectiveness of calcium supplements and/or dietary calcium for the prevention of osteoporotic fractures in postmenopausal women. Studies were identified by conducting a Medline search using the text words "fracture" and "calcium" for the period 1966 to March 1997 and by reviewing articles known to the authors. Only studies with fracture outcomes were eligible. There were 14 studies of calcium supplements (including 4 randomized trials), 18 studies of dietary calcium and hip fracture (no randomized trials), and 5 studies of dietary calcium and other fracture sites (no randomized trials). The 4 randomized trials of calcium supplements (mean calcium dose: 1050 mg) found relative risk (RR) reductions between 25% and 70%. Meta-analytic techniques for dose-response data were used to investigate and pool the findings of 16 observational studies of dietary calcium and hip fracture. These hip fracture studies were not consistent and heterogeneity of study findings (p = 0.02) was not easily explained by subject characteristics or study design. Pooling study results gave an odds ratio (OR) of 0.96 (95% confidence interval, (CI) 0.93-0.99) per 300 mg/day increase in calcium intake (the equivalent of one glass of milk). This is likely to be an underestimate of calcium's true effect because of inaccurate measurement of dietary calcium in observational studies. This review supports the current clinical and public health policy of recommending increased calcium intake among older women for fracture prevention.

Cumming-RG; Nevitt-MC
J-Bone-Miner-Res. 1997 Sep; 12(9): 1321-9

Osteoporosis: new hope for the future

This article will review established and newer approaches to osteoporosis. With greater awareness of this major public health problem and highly sensitive, safe, and accurate measures of bone mass, it is now possible to identify women with osteoporosis well before they begin to suffer some of its devastating consequences. One of the most important approaches to therapy is prevention. Measures of importance relate to the establishment of peak bone mass in young adulthood. Along with issues of life style, adequate calcium intake looms as one of the important nutritional features of a program designed to establish peak bone mass. Calcium is also important later on in life to prevent bone loss and to help restore bone that might have been lost due to osteoporosis. Sufficient calcium intake is an essential component of any preventive regimen. New guidelines for optimal calcium intake are based upon the Consensus Development Conference that was held at the National Institutes of Health in June 1994. These guidelines recommended calcium intake somewhat higher than the official recommended dietary allowances (RDA) as published by the Food and Drug Administration. For women who are not yet menopausal as well as for those who are taking hormone replacement therapy (up to the age of 65) an intake of 1,000 mg daily is recommended. For women beyond the age of 65, as well as for women over 50 who choose not to take hormone replacement therapy, 1,500 mg of calcium a day are recommended. Along with sufficient calcium, it is important that vitamin D be sufficient in supply. Adequate vitamin D is essential for optimal dietary calcium absorption. In the United States, many factors are predisposing women to become less sufficient with respect to vitamin D stores. These factors include routine avoidance of sun, which is a major source of vitamin D; avoidance of milk, which is fortified with vitamin D; and physiological factors that make it more difficult for an older individual to activate vitamin D and to respond to it. Thus, along with adequate calcium, it is important that vitamin D stores are adequate. If vitamin D stores are inadequate or if they are marginal, a supplement regimen is usually advisable. Another helpful preventive measure is an exercise program. It is also important to minimize the likelihood of falling because hip fractures do not generally occur among those who do not fall. Attention to factors that may predispose an individual to fall, such as her balance, eyesight, stairs, and bathtubs that are difficult to get into and out of, are all items that need attention. The controversy surrounding hormone replacement therapy in postmenopausal women continues to be active. On the other hand, there is no question that estrogen replacement therapy in the menopausal years is a highly effective means to prevent bone loss. In its absence, women experience a 5- to 8-year period of accelerated bone loss-beyond what would be expected to occur as a function of age alone. Estrogen essentially prevents this bone loss, and it continues to be prevented for as long as estrogens are taken. Estrogen therapy has also been strongly associated with preventing deaths due to cardiovascular disease. In fact, recommendations for hormone replacement therapy are more compelling when cardiovascular risks are considered than those for osteoporosis alone. More women die of cardiovascular causes than any others, far exceeding the mortality associated with hip fracture. The controversy around estrogen replacement therapy specifically related to the increased risk of uterine cancer is essentially negated because a progestational agent is part of the regimen when the uterus is present. Breast cancer, however, continues to be a potential risk for those who take long-term estrogen therapy. (ABSTRACT TRUNCATED)

Masi-L; Bilezikian-JP
Int-J-Fertil-Womens-Med. 1997 Jul-Aug; 42(4): 245-54

Abnormalities in skeletal growth in children with juvenile rheumatoid arthritis

A review of the acquisition of peak skeletal mass in normal children and studies that have been reported for children with JRA lead to the following tentative conclusions: (1) The appendicular skeleton is predominantly the overall status of skeletal mineralization; (2) a failure to develop adequate bone mineralization is virtually universal in children with JRA and is characterized by a failure of bone formation. A failure to undergo the normal increase in bone mass during puberty is common in children with JRA and markedly decreases their potential to achieve an adequate peak skeletal mass; (3) the onset of accelerated skeletal maturation with puberty is a critical period of potential intervention in JRA. Conversely, therapeutic interventions later during adolescence offer less promise of reversal of inadequate bone mineralization; and (4) the most important therapeutic maneuver is likely to be control of the inflammation process, although there is hope, at present unsubstantiated, that supplemental dietary calcium and vitamin D, and normalization of physical activity, many lead to some "catch-up" mineralization.

Cassidy-JT; Hillman-LS
Rheum-Dis-Clin-North-Am. 1997 Aug; 23(3): 499-522

Effect of calcium and vitamin D supplementation on bone density in men and women 65 years of age or older

BACKGROUND: Inadequate dietary intake of calcium and vitamin D may contribute to the high prevalence of osteoporosis among older persons. METHODS: We studied the effects of three years of dietary supplementation with calcium and vitamin D on bone mineral density, biochemical measures of bone metabolism, and the incidence of nonvertebral fractures in 176 men and 213 women 65 years of age or older who were living at home. They received either 500 mg of calcium plus 700 IU of vitamin D3 (cholecalciferol) per day or placebo. Bone mineral density was measured by dual-energy x-ray absorptiometry, blood and urine were analyzed every six months, and cases of nonvertebral fracture were ascertained by means of interviews and verified with use of hospital records. RESULTS: The mean (+/-SD) changes in bone mineral density in the calcium-vitamin D and placebo groups were as follows: femoral neck, +0.50+/-4.80 and -0.70+/-5.03 percent, respectively (P=0.02); spine,+2.12+/-4.06 and +1.22+/-4.25 percent (P=0.04); and total body, +0.06+/-1.83 and -1.09+/-1.71 percent (P<0.001). The difference between the calcium-vitamin D and placebo groups was significant at all skeletal sites after one year, but it was significant only for total-body bone mineral density in the second and third years. Of 37 subjects who had nonvertebral fractures, 26 were in the placebo group and 11 were in the calcium-vitamin D group (P=0.02). CONCLUSIONS: In men and women 65 years of age or older who are living in the community, dietary supplementation with calcium and vitamin D moderately reduced bone loss measured in the femoral neck, spine, and total body over the three-year study period and reduced the incidence of nonvertebral fractures.

Dawson-Hughes-B; Harris-SS; Krall-EA; Dallal-GE
N-Engl-J-Med. 1997 Sep 4; 337(10): 670-6

Calcium supplementation

Calcium is necessary for the prevention and treatment of diseases such as osteoporosis, hypertension, and, possibly, colon cancer. Supplementation is useful when dietary calcium intake is low, as is the current situation in North America. There are many factors to consider before recommending any one form of supplement. A consideration for calcium carbonate tablets is whether the tablet disintegrates and whether or not a lack of food or acid in the stomach will hinder utilization. Other forms of calcium, particularly the chelated calcium salts, are better absorbed in fasting achlorhydric subjects but have less calcium per gram of supplement. Interaction of calcium with other mineral nutrients and the presence of contaminating metals has focused attention on safety. Based on present evidence, chelated calcium and refined calcium carbonate tablets (including those labeled as antacids) may be safely and effectively ingested by most people at doses generally recommended for treatment or prevention of osteoporosis. One should not exceed 2,000 mg of calcium, except at the advice of their health care provider, as inadvertent mineral deficiencies may arise. Persons at risk for developing milk-alkali syndrome, such as thiazide users and persons with renal failure, should be identified and monitored for alkalosis and hypercalcemia when using calcium supplements.

Whiting-SJ; Wood-R; Kim-K
J-Am-Acad-Nurse-Pract. 1997 Apr; 9(4): 187-92

Dietary prevention of osteoporosis

Osteoporosis is a major health problem facing women and men, and the number of people affected is likely to increase substantially as the population ages. The gold standard for treatment has always been prevention. This article reviews therapeutic options, with an emphasis on nutrition; outlines current recommendations for calcium and vitamin D throughout the life span; and discusses food and supplemental sources of calcium. Guidelines are given for identifying high- and low-risk patients, and appropriate interventions are highlighted.

Lippincotts-Prim-Care-Pract. 1997 Jul-Aug; 1(3): 307-19

Osteoporosis: prevention, diagnosis, and management

Osteoporosis is a public health scourge that is usually eminently preventable. Some risk factors, such as low calcium intake, vitamin D deficiency, and physical inactivity, are amenable to early interventions that will help maximize peak bone density. Other risk factors subject to modification are cigarette smoking and excessive consumption of protein, caffeine, and alcohol. Hip fractures are the most serious outcome of osteoporosis, with enormous personal and public health consequences. The ongoing Study of Osteoporotic Fractures has identified additional independent predictors of hip fracture risk, including maternal hip fracture, absence of significant weight gain since age 25, height, hyperthyroidism, use of long-acting benzodiazepines or anticonvulsants, spending < 4 hours a day on one's feet, inability to rise from a chair without using one's arms, poor visual depth perception and contrast sensitivity, and tachycardia. In an individual perimenopausal woman, the risk of osteoporotic fracture and the urgency of estrogen replacement therapy can be best estimated on the basis of bone mineral density, as measured by dual-energy x-ray absorptiometry, coupled with the presence or absence of existing fractures and clinical risk factors evident from the history and physical examination. Estrogen, calcitonin, and bisphosphonates have all been proved effective in retarding postmenopausal bone loss and therefore reducing the risk of fracture. The use of sodium fluoride is more controversial, although a recent study has suggested a possible role for slow-release fluoride combined with high-dose calcium supplementation.

Am-J-Med. 1997 Jan 27; 102(1A): 35S-39S

Importance of diet and sex in prevention of coronary artery disease, cancer, osteoporosis, and overweight or underweight: a study of attitudes and practices of Danish primary care physicians

General practitioners (GPs) in Denmark (n = 374) answered a questionnaire on attitudes toward including information on diet and sex in the prevention of coronary artery disease, cancers, osteoporosis, and weight problems. Risk factors for disease were ranked as follows: smoking, alcohol, stress, diet, physical exercise, heredity, and hygiene. Patients' lack of motivation, insufficient time for each patient, and inadequate knowledge about nutrition were listed by GPs as barriers to dietary counseling. GPs stated that the sex of the patient was important only for counseling on osteoporosis. Lack of time and insufficient knowledge were perceived as barriers to including sex-specific issues in prevention. One-half of the GPs were questioned about the issue of prevention on the basis of female case stories and the other half on the basis of male case stories with identical wording. Responses to the case stories indicated that GPs would give dietary guidance and recommend loss of weight to slightly overweight male patients to a much greater degree than to overweight female patients for prevention of coronary artery disease, give dietary counseling and recommend loss of weight and exercise to female patients more than to male patients for prevention of cancers, recommend a supplement of calcium and vitamin D for prevention of osteoporosis to female patients, and recommend weight gain and discuss psychosocial issues more with underweight female patients than with underweight male patients. Female GPs included measures of prevention such as dietary counseling, exercise prescription, dietary supplement prescription, and discussion of psychosocial issues to a greater extent than did male GPs.

Holund-U; Thomassen-A; Boysen-G; Charles-P; Eriksen-EF; Overvad-K; Petersson-B; Sandstrom-B; Vittrup-M
Am-J-Clin-Nutr. 1997 Jun; 65(6 Suppl): 2004S-2006S

Long-term vegetarian diet and bone mineral density in postmenopausal Taiwanese women

This study examined bone density among postmenopausal Buddhist nuns and female religious followers of Buddhism in southern Taiwan and related the measurements to subjects characteristics including age, body mass, physical activity, nutrient intake, and vegetarian practice. A total of 258 postmenopausal Taiwanese vegetarian women participated in the study. Lumbar spine and femoral neck bone mineral density (BMD) were measured using dual-photon absorptimetry. BMD measurements were analyzed first as quantitative outcomes in multiple regression analyses and next as indicators of osteopenia status in logistic regression analyses. Among the independent variables examined, age inversely and body mass index positively correlated with both the spine and femoral neck BMD measurements. They were also significant predictors of the osteopenia status. Energy intake from protein was a significant correlate of lumbar spine BMD only. Other nutrients, including calcium and energy intake from nonprotein sources, did not correlate significantly with the two bone density parameters. Long-term practitioners of vegan vegetarian were found to be at a higher risk of exceeding lumbar spine fracture threshold (adjusted odds ratio = 2.48, 95% confidence interval = 1.03-5.96) and of being classified as having osteopenia of the femoral neck (3.94, 1.21-12.82). Identification of effective nutrition supplements may be necessary to improve BMD levels and to reduce the risk of osteoporosis among long-term female vegetarians.

Chiu-JF; Lan-SJ; Yang-CY; Wang-PW; Yao-WJ; Su-LH; Hsieh-CC
Calcif-Tissue-Int. 1997 Mar; 60(3): 245-9

A 4-year follow-up study of the effects of calcium supplementation on bone density in elderly postmenopausal women

To determine the long-term effect of calcium supplementation on bone density, 84 elderly women (54-74 years) more than 10 years past the menopause were studied for 4 years as part of a follow-up study of a randomized, double-masked, placebo-controlled trial. The placebo group who did not take calcium supplements at all during the 4-year study (control group, n = 21) served as a comparison with the treated group who took calcium supplements for 4 years (calcium supplement group, n = 14). We also studied subjects who were treated for 2 years with calcium supplements and then ceased taking them (non-compliant group, n = 49). The changes in bone density at the lumbar spine, hip and ankle sites, current calcium intake and activity were monitored. Over the 4 years the calcium supplement group (mean calcium intake 1988 +/- 90 mg/day) did not lose bone at the hip and ankle site. The control group (mean calcium intake 952 +/- 109 mg/day) lost significantly more bone than the calcium supplement group at all sites of the hip and ankle. No overall bone loss was seen at the spine, in either group, over the 4 years of this study. Between years 2 and 4 the non-compliant group (mean calcium intake 981 +/- 75 mg/day) lost significantly more bone at all sites of the ankle than the calcium supplement group. Therefore, calcium supplementation produces a sustained reduction in the rate of loss of bone density at the ankle and hip sites in elderly postmenopausal women. Increasing dietary calcium intake in women should be the aim of a public health campaign.

Devine-A; Dick-IM; Heal-SJ; Criddle-RA; Prince-RL
Osteoporos-Int. 1997; 7(1): 23-8

Do men suffer with osteoporosis?

Osteoporotic fractures in men are a neglected public health problem. The pathogenesis of bone loss is incompletely understood but is probably due to reduced bone formation rather than increased bone resorption. Primary or secondary hypogonadism is a common and treatable cause of osteoporosis and should be excluded in all men presenting with spine or hip fractures. Alcohol excess, with or without hypogonadism, is a most important attributable risk factor for osteoporosis in men. There is no known treatment for osteoporosis in men (as there have been no clinical trials using anti fracture efficacy as an endpoint in men) and few well designed trials examining the effects of drugs on bone mineral density (BMD). Bisphosphonates, while reducing fracture rates in women, have only been shown to increase BMD in men Calcium supplementation may slow bone loss. Anabolic agents, such as nandrolone have not been adequately studied. Fluoride therapy cannot be recommended as bone strength does not appear to increase despite the well documented increase in BMD. Risk factors such as alcohol excess and tobacco use should be corrected.

Aust-Fam-Physician. 1997 Feb; 26(2): 135-43

Osteoporosis. Current pharmacologic options for prevention and treatment

For virtually all asymptomatic postmenopausal women, moderate exercise and supplementation with calcium and vitamin D are recommended. In addition, most postmenopausal women without contraindications would benefit from estrogen replacement therapy, primarily because of its cardiovascular benefits. In patients with contraindications or an aversion to hormone therapy, bone densitometry should be performed to determine risks before expensive nonhormonal treatment is initiated. Therapy with alendronate sodium (Fosamax) or calcitonin (Calcimar, Miacalcin) is clearly indicated in women with established osteoporosis and may be appropriate for early postmenopausal women with osteopenia. Calcitonin is a good option in patients with disabling spinal bone pain. Slow-release sodium fluoride, although still considered experimental, may eventually be given for vertebral fracture in patients with mild to moderate disease.

Isenbarger-DW; Chapin-BL
Postgrad-Med. 1997 Jan; 101(1): 129-32, 136-7, 141-2

Clinical practice guidelines for the diagnosis and management of osteoporosis. Scientific Advisory Board, Osteoporosis Society of Canada

OBJECTIVE: To recommend clinical practice guidelines for the assessment of people at risk for osteoporosis, and for effective diagnosis and management of the condition. OPTIONS: Screening and diagnostic methods: risk-factor assessment, clinical evaluation, measurement of bone mineral density, laboratory investigations. Prophylactic and corrective therapies: calcium and vitamin D nutritional supplementation, physical activity and fall-avoidance techniques, ovarian hormone therapy, bisphosphonate drugs, other drug therapies. Pain-management medications and techniques. OUTCOMES: Prevention of loss of bone mineral density and fracture; increased bone mass; and improved quality of life. EVIDENCE: Epidemiologic and clinical studies and reports were examined, with emphasis on recent randomized controlled trials. Clinical practice in Canada and elsewhere was surveyed. Availability of treatment products and diagnostic equipment in Canada was considered. VALUES: Cost-effective methods and products that can be adopted across Canada were considered. A high value was given to accurate assessment of fracture risk and osteoporosis, and to increasing bone mineral density, reducing fractures and fracture risk and minimizing side effects of diagnosis and treatment. BENEFITS, HARMS AND COSTS: Proper diagnosis and management of osteoporosis minimize injury and disability, improve quality of life for patients and reduce costs to society. Rationally targeted methods of screening and diagnosis are safe and cost effective. Harmful side effects and costs of recommended therapies are minimal compared with the harms and costs of untreated osteoporosis. Alternative therapies provide a range of choices for physicians and patients. RECOMMENDATIONS: Population sets at high risk should be identified and then the diagnosis confirmed through bone densitometry. Dual-energy x-ray absorptiometry is the preferred measurement technique. Radiography can be adjunct when indicated. Calcium and vitamin D nutritional supplementation should be at currently recommended levels. Patients should be counseled in fall-avoidance techniques and exercises. Immobilization should be avoided. Guidelines for management of acute pain are listed. Ovarian hormone therapy is the therapy of choice for osteoporosis prevention and treatment in postmenopausal women. Bisphosphonates are an alternative therapy for women with established osteoporosis who cannot or prefer not to take ovarian hormone therapy.

CMAJ. 1996 Oct 15; 155(8): 1113-33

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