Post by theshee on Sept 25, 2013 6:26:18 GMT 10
Abstract
Calcium supplements reduce bone turnover and slow the rate of bone loss. However, few studies have demonstrated reduced fracture incidence with calcium supplements, and meta-analyses show only a 10% decrease in fractures, which is of borderline statistical and clinical significance. Trials in normal older women and in patients with renal impairment suggest that calcium supplements increase the risk of cardiovascular disease. To further assess their safety, we recently conducted a meta-analysis of trials of calcium supplements, and found a 27%–31% increase in risk of myocardial infarction, and a 12%–20% increase in risk of stroke. These findings are robust because they are based on pre-specified analyses of randomized, placebo-controlled trials and are consistent across the trials. Co-administration of vitamin D with calcium does not lessen these adverse effects. The increased cardiovascular risk with calcium supplements is consistent with epidemiological data relating higher circulating calcium concentrations to cardiovascular disease in normal populations. There are several possible pathophysiological mechanisms for these effects, including effects on vascular calcification, vascular cells, blood coagulation and calcium-sensing receptors. Thus, the non-skeletal risks of calcium supplements appear to outweigh any skeletal benefits, and are they appear to be unnecessary for the efficacy of other osteoporosis treatments.
Thus, individuals considering taking or prescribing calcium supplements are left with a conundrum. There is equivocal evidence of benefit to bone health which needs to be balanced against steadily increasing evidence of adverse cardiovascular risk. This balance was assessed in the Bolland meta-analysis of calcium monotherapy, which calculated that treating 1000 people with calcium supplements for five years would cause an additional 14 myocardial infarctions, 10 strokes and 13 deaths, while preventing 26 fractures [9]. In younger subjects, the absolute numbers are smaller, but the balance remains negative [12]. Thus, the available data suggest that the widespread use of calcium supplements in older individuals is doing more harm than good and should be abandoned. The beneficial effects on bone density of calcium supplementation probably do not arise from treating a deficiency of dietary calcium, but rather the boluses act (via calcitonin and parathyroid hormone) as a weak antiresorptive therapy. Now that we have free access to much more potent antiresorptive therapies, it would seem sensible to target these to individuals at high fracture risk, and to encourage a balanced diet as the preferred way of ensuring that adequate calcium is available for normal mineralization of bone. The absence of a clinically significant association between calcium intake, bone density and fracture risk over the range seen in Western populations, suggests that calcium is not a critical determinant of bone health in most individuals taking a balanced Western diet.
The full abstract can be found here
Calcium supplements reduce bone turnover and slow the rate of bone loss. However, few studies have demonstrated reduced fracture incidence with calcium supplements, and meta-analyses show only a 10% decrease in fractures, which is of borderline statistical and clinical significance. Trials in normal older women and in patients with renal impairment suggest that calcium supplements increase the risk of cardiovascular disease. To further assess their safety, we recently conducted a meta-analysis of trials of calcium supplements, and found a 27%–31% increase in risk of myocardial infarction, and a 12%–20% increase in risk of stroke. These findings are robust because they are based on pre-specified analyses of randomized, placebo-controlled trials and are consistent across the trials. Co-administration of vitamin D with calcium does not lessen these adverse effects. The increased cardiovascular risk with calcium supplements is consistent with epidemiological data relating higher circulating calcium concentrations to cardiovascular disease in normal populations. There are several possible pathophysiological mechanisms for these effects, including effects on vascular calcification, vascular cells, blood coagulation and calcium-sensing receptors. Thus, the non-skeletal risks of calcium supplements appear to outweigh any skeletal benefits, and are they appear to be unnecessary for the efficacy of other osteoporosis treatments.
Thus, individuals considering taking or prescribing calcium supplements are left with a conundrum. There is equivocal evidence of benefit to bone health which needs to be balanced against steadily increasing evidence of adverse cardiovascular risk. This balance was assessed in the Bolland meta-analysis of calcium monotherapy, which calculated that treating 1000 people with calcium supplements for five years would cause an additional 14 myocardial infarctions, 10 strokes and 13 deaths, while preventing 26 fractures [9]. In younger subjects, the absolute numbers are smaller, but the balance remains negative [12]. Thus, the available data suggest that the widespread use of calcium supplements in older individuals is doing more harm than good and should be abandoned. The beneficial effects on bone density of calcium supplementation probably do not arise from treating a deficiency of dietary calcium, but rather the boluses act (via calcitonin and parathyroid hormone) as a weak antiresorptive therapy. Now that we have free access to much more potent antiresorptive therapies, it would seem sensible to target these to individuals at high fracture risk, and to encourage a balanced diet as the preferred way of ensuring that adequate calcium is available for normal mineralization of bone. The absence of a clinically significant association between calcium intake, bone density and fracture risk over the range seen in Western populations, suggests that calcium is not a critical determinant of bone health in most individuals taking a balanced Western diet.
The full abstract can be found here
Happy New Years Everybody!!!
