The effectiveness of that it meta-studies is its complete characteristics
I included 59 randomised managed examples and you may reviewed the effects out of one another dietary calcium supplements supplies and you will calcium to your BMD at five skeletal sites and at three-time things. The size of brand new opinion allowed an assessment of your consequences for the BMD various resources of calcium-weight reduction provide otherwise medications-and also the outcomes inside extremely important subgroups like those laid out because of the serving out of calcium supplements, usage of co-applied vitamin D, and you may standard scientific features. The results are consistent with those from an earlier meta-studies off 15 randomised managed products out of calcium, and therefore claimed a rise in BMD of just one.6-2.0% over 2 to 4 ages.72
The average rate out-of BMD loss in old article-menopause women means step one% a year
An essential limitation would be the fact BMD is an excellent surrogate for the logical results of break. We undertook the review, yet not, as the certain subgroup analyses from the dataset of examples having fracture since the an enthusiastic endpoint don’t have a lot of electricity,ten and an assessment ranging from randomised controlled products from losing weight offer away from calcium supplements and calcium supplements that have fracture as endpoint is actually not possible as the simply a few short randomised managed examples regarding slimming down sourced elements of calcium supplements advertised fracture study.ten Several other limit is the fact inside sixty% of meta-analyses, statistical heterogeneity between the training try high (I eurodate dos >50%). It seems substantial variability in the results of included examples, although this is actually usually by the visibility out of a little quantity of outlying performance. Subgroup analyses fundamentally failed to drastically beat otherwise give an explanation for heterogeneity. I used random outcomes meta-analyses you to definitely take heterogeneity under consideration, and their show should be interpreted as the showing the average influence along the number of samples.
Implications off results
Its lack of people communications which have baseline losing weight calcium consumption otherwise a dose-response family implies that increasing consumption owing to losing weight sources or as a consequence of supplements does not right a nutritional insufficiency (in which case better outcomes is present in individuals with a decreased intakes or even the higher dosage). An alternative chance is the fact growing calcium supplements intake provides a failure anti-resorptive impression. Calcium treat indicators away from bone creation and you will resorption of the from the 20%,62 65 73 and you will broadening milk products consumption and additionally decrease limbs turount.74 Suppression away from bone turount might lead to the tiny seen expands when you look at the BMD.
Increases in BMD of about 1-2% over one to five years are unlikely to translate into clinically meaningful reductions in fractures. So the effect of increasing calcium intake is to prevent about one to two years of normal BMD loss, and if calcium intake is increased for more than one year it will slow down but not stop BMD loss. Epidemiological studies suggest that a decrease in BMD of one standard deviation is associated with an increase in the relative risk of fracture of about 1.5-2.0.75 A one standard deviation change in BMD is about equivalent to a 10% change in BMD. Based on these calculations, a 10% increase in BMD would be associated with a 33-50% reduction in risk of fracture. Therefore, the 1-2% increase in BMD observed with increased calcium intake would be predicted to produce a 5-10% reduction in risk of fracture. These estimates are consistent with findings from randomised controlled trials of other agents. The modest increases in BMD with increased calcium intake are smaller than observed with weak anti-resorptive agents such as etidronate76 and raloxifene.77 Etidronate, however, does not reduce vertebral or non-vertebral fractures, and raloxifene reduces vertebral but not non-vertebral fractures.78 In contrast, potent anti-resorptive agents such as alendronate, zoledronate, and denosumab increase BMD by 6-9% at the spine and 5-6% at the hip over three years.79 80 81 82 These changes are associated with reductions of 44-70% in vertebral fracture, 35-41% in hip fracture, and 15-25% in non-vertebral fractures.78 The magnitude of fracture reduction predicted by the small increases in BMD we observed with increased calcium intake are also consistent with the findings of our systematic review of calcium supplements and fracture.10 We observed small (<15%) inconsistent reductions in total and vertebral fracture overall but no reductions in fractures in the large randomised controlled trials at lowest risk of bias and no reductions in forearm or hip fractures.
