Incidence of milk alkali syndrome in the Women's Health Initiative clinical trial and cohort study: response to Neupane

Calcium supplementation in osteoporosis: useful or harmful?

Osteoporosis and fragility fractures are important social and economic problems worldwide and are due to both the loss of bone mineral density and sarcopenia. Indeed, fragility fractures are associated with increased disability, morbidity and mortality. It is known that a normal calcium balance together with a normal vitamin D status is important for maintaining well-balanced bone metabolism, and for many years, calcium and vitamin D have been considered crucial in the prevention and treatment of osteoporosis. However, recently, the usefulness of calcium supplementation (alone or with concomitant vitamin D) has been questioned, since some studies reported only weak efficacy of these supplementations in reducing fragility fracture risk. On the other hand, besides the gastrointestinal side effects of calcium supplements and the risk of kidney stones related to use of co-administered calcium and vitamin D supplements, other recent data suggested potential adverse cardiovascular effects from calcium supplementation. This debate article is focused on the evidence regarding both the possible usefulness for bone health and the potential harmful effects of calcium and/or calcium with vitamin D supplementation.

Interactions between dietary supplements in hospitalized patients

Inpatient consumption of dietary and herbal supplements (DHS) has recently received research attention, particularly due to potential DHS-drug interactions. Nevertheless, DHS-DHS interactions have seldom been evaluated among hospitalized patients. We evaluated potential DHS-DHS interactions among inpatients. The study was a cross-sectional prospective study, conducted at Bnai Zion Medical Center (Haifa, Israel) in 2009-2014. A multi-disciplinary team of researchers constructed a questionnaire aimed at detecting DHS use among inpatients. The Natural Medicine Database was used to examine identified DHS for potential DHS-DHS interactions. Then, medical files were reviewed to identify side effects potentially caused by such interactions and rate of documentation of DHS use. Univariate and multivariate logistic regression analyses were conducted to characterize potential risk factors for DHS-DHS interactions among hospitalized DHS users. Of 927 patients who agreed to answer the questionnaire, 458 (49.4 %) reported the use of 89 different DHS. Potential DHS-DHS interactions were identified in 12.9 % of DHS users. Three interactions were associated with the actual occurrence of adverse events. Patients at risk of DHS-DHS interactions included females (p = 0.026) and patients with greater numbers of concomitant medications (p < 0.0001) and of consumed DHS (p < 0.0001). In 88.9 % of DHS users, DHS use was not reported in medical files and only 18 % of the DHS involved in interactions were documented. Potential DHS-DHS interactions are common in inpatients, and may lead to hospitalization or worsen existing medical conditions. The causal relationship between potential interactions and actual adverse events requires further study.

Should we prescribe calcium or vitamin D supplements to treat or prevent osteoporosis?

Systematic reviews of randomized, controlled trials (RCTs) are considered the highest level of evidence to inform clinical practice. Meta-analyses of large RCTs of calcium and/or vitamin D supplements completed in the last 15 years provide strong evidence for clinical recommendations. These meta-analyses with data for > 50,000 older adults reported that calcium with or without vitamin D has only weak, inconsistent effects on fracture, and that vitamin D without calcium has no effect on fracture. Only one RCT of co-administered calcium and vitamin D in frail, institutionalized, elderly women with low dietary calcium intake and vitamin D levels showed significant reductions in fracture risk. These RCTs have also reported previously unrecognized adverse events of calcium supplements including kidney stones, myocardial infarction, hypercalcemia, and hospitalization with acute gastrointestinal symptoms. The small risk of these important adverse effects, together with the moderate risk of minor side-effects such as constipation, probably outweighs any benefits of calcium supplements on fracture. These data suggest the role for calcium and vitamin D supplements in osteoporosis management is very limited. Neither calcium nor vitamin D supplements should be recommended for fracture prevention in community-dwelling adults, although vitamin D should be considered for prevention of osteomalacia in at-risk individuals.