De La Biblioteca Cochrane Plus, número 3, 2008. Oxford, Update Software Ltd. Todos los derechos están reservados.

Suplementos de calcio para la pérdida ósea en mujeres postmenopáusicas (Revisión Cochrane traducida)

Shea BJ, Adachi JD, Cranney A, Griffith L, Guyatt G, Hamel C, Ortiz Z, Peterson J, Robinson VA, Tugwell P, Wells G, Zytaruk N

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Fecha de la modificación significativa más reciente: 13 de noviembre de 2003. Las revisiones Cochrane se revisan regularmente y se actualizan si es necesario.

RESUMEN EN TÉRMINOS SENCILLOS

HOW WELL DOES CALCIUM SUPPLEMENTS WORK TO PREVENT BONE LOSS IN WOMEN AFTER MENOPAUSE?

To answer this question, scientists analysed 15 high quality studies. These studies tested over 1800 women after menopause. Women received either a placebo (sugar pill) or 500 to 2000 mg of calcium supplements daily, including calcium gluconate, calcium carbonate, calcium citrate or salt with or without vitamin D. These studies provide the best evidence we have today.

Why does bone loss occur and how can calcium supplements help?Bone loss may occur more quickly in women after menopause due to hormonal changes and occurs when calcium leaks out the bones. Bone loss leads to bones that are not dense and can lead to osteoporosis, a condition of weak brittle bones that break easily. Calcium is found in many foods and available as a pill for people who would like to add more calcium to their diet. It is thought that taking calcium supplements may help prevent bone loss (osteoporosis) and fractures.

How well did calcium supplements prevent bone loss and decrease fractures? A bone mineral density test that measures how dense bones are, showed that the amount of bone lost in women taking calcium supplements taken for 2 or more years was less than the amount of bone lost in women who took a placebo.

There are not many studies or large studies that measure whether calcium supplements prevent fractures. But the results from the small studies show a trend towards a decrease in spine fractures with calcium supplements and a smaller trend for non-spinal fractures, such as hip and wrist.

Were there any side effects? Side effects were not analysed in this review. But side effects, such as stomach upset and constipation may occur.

What is the bottom line? There is "silver" level evidence that in women after menopause, calcium supplements taken for two or more years prevents bone loss.

Calcium supplements may decrease the chances of spine fractures, but it is not known whether calcium decreases non-spinal fractures. It is important to have an adequate amount of calcium. Calcium supplements, such as calcium gluconate, calcium carbonate, calcium citrate or salt with or without vitamin D at 500 to 2000 mg daily, are the simplest and least expensive way to prevent bone loss.



RESUMEN

Antecedentes:

Although calcium is one the simplest and least expensive strategies for preventing osteoporotic fractures calcium supplementation is nevertheless not without controversy (Kanis 1989; Nordin 1990). The Food and Drug Administration in the US has permitted a bone health claim for calcium-rich foods, and the NIH in its Consensus Development Process approved a statement that high calcium intake reduces the risk of osteoporosis.

Objectivos:

To assess the effects of calcium on bone density and fractures in postmenopausal women.

Estrategia de búsqueda:

We searched Cochrane Controlled Register, MEDLINE and EMBASE up to 2001, and examined citations of relevant articles and proceedings of international meetings.

Criterios de selección:

Trials that randomized postmenopausal women to calcium supplementation or usual calcium intake in the diet and reported bone mineral density of the total body, vertebral spine, hip, or forearm or recorded the number of fractures, and followed patients for at least one year were considered for inclusion.

Recopilación y análisis de datos:

Three independent reviewers assessed the methodologic quality and extracted data for each trial. For each bone density site (lumbar spine, total body, combined hip and combined forearm), we calculated the weighted mean difference in bone density between treatment and control groups using the percentage change from baseline. We constructed regression models in which the independent variables were year and dose, and the dependent variable was the effect size. This regression was used to determine the years across which pooling was appropriate. Heterogeneity was asssesed. For each fracture analysis we calculated a risk ratio.

Resultados principales:

Fifteen trials, representing 1806 participants, were included. Calcium was more effective than placebo in reducing rates of bone loss after two or more years of treatment. The pooled difference in percentage change from baseline was 2.05% (95% CI 0.24 to 3.86) for total body bone density, 1.66% (95% CI 0.92 to 2.39) for the lumbar spine at 2 years, 1.60% (95% CI 0.78 to 2.41) for the hip, and 1.91% (95% CI 0.33 to 3.50) for the distal radius. The relative risk of fractures of the vertebrae was 0.79 (95% CI 0.54 to 1.09); the relative risk for non-vertebral fractures was 0.86 (95% CI 0.43 to 1.72).

Conclusiones de los revisores:

Calcium supplementation alone has a small positive effect on bone density. The data show a trend toward reduction in vertebral fractures, but it is unclear if calcium reduces the incidence of non vertebral fractures.

Esta revisión debería citarse como: Shea BJ, Adachi JD, Cranney A, Griffith L, Guyatt G, Hamel C, Ortiz Z, Peterson J, Robinson VA, Tugwell P, Wells G, Zytaruk N. Suplementos de calcio para la pérdida ósea en mujeres postmenopáusicas (Revisión Cochrane traducida). En: La Biblioteca Cochrane Plus, número 3, 2008. Oxford, Update Software Ltd. Disponible en: http://www.update-software.com. (Traducida de The Cochrane Library, Issue . Chichester, UK: John Wiley & Sons, Ltd.).



Éste es el resumen de una revisión Cochrane traducida. La Colaboración Cochrane prepara y actualiza estas revisiones sistemáticas. El texto completo de la revisión traducida se publica en La Biblioteca Cochrane Plus (ISSN 1745-9990).

El Centro Cochrane Iberoamericano traducen, Infoglobal Suport edita, y Update Software Ltd publica La Biblioteca Cochrane Plus.