Evaluating adherence, tolerability and safety of oral calcium citrate in elderly osteopenic subjects: a real-life non-interventional, prospective, multicenter study.

BACKGROUND: Osteoporosis is a common concern in the elderly that leads to fragile bones. Calcium supplementation plays a crucial role in improving bone health, reducing fracture risk, and supporting overall skeletal strength in this vulnerable population. However, there is conflicting evidence on the safety of calcium supplements in elderly individuals. AIM: The aim of this study was to evaluate the adherence, safety and tolerability of calcium citrate supplementation in elderly osteopenic subjects. METHODS: In this non-interventional, prospective, multicenter study, subjects received daily 500 mg calcium citrate supplementation for up to one year. Adherence was calculated based on compliance and persistence. Safety was assessed through adverse reactions (ARs), deaths, and clinical laboratory evaluations. RESULTS: A total of 268 Caucasian subjects (91.4% female, mean age 70 ± 4.5 years) participated in the study. Mean adherence to treatment was 76.6 ± 29.5% and half of subjects had an adherence of 91% and ~ 33% of participants achieved complete (100%) adherence. ARs were reported by nine (3.9%) subjects, primarily gastrointestinal disorders, with no serious ARs. The frequency of all adverse events (including ARs) was significantly higher in subjects with adherence of < 80% (41.6%; 32/77) vs. those with adherence ≥ 80% (11%; 16/145, p < 0.0001). Both systolic and diastolic blood pressure decreased from baseline to follow-up visit (change of -2.8 ± 13.9 mmHg, p = 0.0102 and -2.1 ± 10.4 mmHg, p = 0.0116, respectively). CONCLUSION: This study demonstrated favorable adherence to calcium citrate supplementation in elderly osteopenic subjects. The occurrence of ARs, though generally mild, were associated with lower adherence to calcium supplementation.

Acute and 3-month effects of calcium carbonate on the calcification propensity of serum and regulators of vascular calcification: secondary analysis of a randomized controlled trial.

SUMMARY: Calcium supplements have been associated with increased cardiovascular risk, but the mechanism is unknown. We investigated the effects of calcium supplements on the propensity of serum to calcify, based on the transition time of primary to secondary calciprotein particles (T50). Changes in serum calcium were related to changes in T50. INTRODUCTION: Calcium supplements have been associated with increased cardiovascular risk; however, it is unknown whether this is related to an increase in vascular calcification. METHODS: We investigated the acute and 3-month effects of calcium supplements on the propensity of serum to calcify, based on the transition time of primary to secondary calciprotein particles (T50), and on three possible regulators of calcification: fetuin-A, pyrophosphate and fibroblast growth factor-23 (FGF23). We randomized 41 postmenopausal women to 1 g/day of calcium as carbonate, or to a placebo containing no calcium. Measurements were performed at baseline and then 4 and 8 h after their first dose, and after 3 months of supplementation. Fetuin-A, pyrophosphate and FGF23 were measured in the first 10 participants allocated to calcium carbonate and placebo who completed the study. RESULTS: T50 declined in both groups, the changes tending to be greater in the calcium group. Pyrophosphate declined from baseline in the placebo group at 4 h and was different from the calcium group at this time point (p = 0.04). There were no other significant between-groups differences. The changes in serum total calcium from baseline were significantly related to changes in T50 at 4 h (r = -0.32, p = 0.05) and 8 h (r = -0.39, p = 0.01), to fetuin-A at 3 months (r = 0.57, p = 0.01) and to pyrophosphate at 4 h (r = 0.61, p = 0.02). CONCLUSIONS: These correlative findings suggest that serum calcium concentrations modulate the propensity of serum to calcify (T50), and possibly produce counter-regulatory changes in pyrophosphate and fetuin-A. This provides a possible mechanism by which calcium supplements might influence vascular calcification.

Acute effects of calcium supplements on blood pressure and blood coagulation: secondary analysis of a randomised controlled trial in post-menopausal women.

Recent evidence suggests that Ca supplements increase the risk of cardiovascular events, but the mechanism(s) by which this occurs is uncertain. In a study primarily assessing the effects of various Ca supplements on blood Ca levels, we also investigated the effects of Ca supplements on blood pressure and their acute effects on blood coagulation. We randomised 100 post-menopausal women to 1 g/d of Ca or a placebo containing no Ca. Blood pressure was measured at baseline and every 2 h up to 8 h after their first dose and after 3 months of supplementation. Blood coagulation was measured by thromboelastography (TEG) in a subgroup of participants (n 40) up to 8 h only. Blood pressure declined over 8 h in both the groups, consistent with its normal diurnal rhythm. The reduction in systolic blood pressure was smaller in the Ca group compared with the control group by >5 mmHg between 2 and 6 h (P≤0·02), and the reduction in diastolic blood pressure was smaller at 2 h (between-groups difference 4·5 mmHg, P=0·004). Blood coagulability, assessed by TEG, increased from baseline over 8 h in the calcium citrate and control groups. At 4 h, the increase in the coagulation index was greater in the calcium citrate group compared with the control group (P=0·03), which appeared to be due to a greater reduction in the time to clot initiation. These data suggest that Ca supplements may acutely influence blood pressure and blood coagulation. Further investigation of this possibility is required.

Incidence of hypercalciuria and hypercalcemia during vitamin D and calcium supplementation in older women.

OBJECTIVE: This study aims to prospectively assess the incidence of hypercalciuria and hypercalcemia with different doses of vitamin D and with a calcium intake of approximately 1,200 mg/day. METHODS: This was a 1-year randomized placebo-controlled study of vitamin D (400-4,800 IU/d) in 163 white women aged 57 to 90 years. Calcium citrate tablets (200 mg) were added to the diet to achieve a total calcium intake of approximately 1,200 mg/day in all groups. All women had vitamin D insufficiency at baseline, with serum 25-hydroxyvitaminD levels lower than 20 ng/mL (50 nmol/L). Serum and 24-hour urine calcium were collected every 3 months on supplementation, any test result above the upper reference range represented an episode of hypercalcemia or hypercalciuria. Mixed-effects models and multivariate logistic regression were used in the analysis. RESULTS: Hypercalcemia (>10.2 mg/dL [2.55 mmol/L]) occurred in 8.8% of white women. Hypercalciuria (>300 mg/d [7.5 mmol]) occurred in 30.6% of white women. Episodes of hypercalciuria were transient in half of the group and recurrent in the other half. No relationship between hypercalcemia or hypercalciuria and vitamin D dose was found, and hypercalciuria was equally common in the placebo group. CONCLUSIONS: Hypercalciuria and hypercalcemia commonly occur with vitamin D and calcium supplements. Whether hypercalciuria and hypercalcemia are caused by calcium, vitamin D, or both is unclear. These findings may have relevance to the reported increase in kidney stones in the Women's Health Initiative trial. Because calcium 1,200 mg and vitamin D 800 IU/day are widely recommended in postmenopausal women, systematic evaluation of the safety of supplements is warranted in clinical management and in future studies.

Thiazide-induced severe hypercalcemia: a case report and review of literature.

Most common causes of hypercalcemia are hyperparathyroidism, malignancy, vitamin D-mediated conditions such as sarcoidosis, and vitamin D toxicity. Less commonly, hypercalcemia can be caused by drugs such as thiazide diuretics and lithium. Mild hypercalcemia is usually asymptomatic but severe hypercalcemia is associated with nausea, vomiting, abdominal pain, excessive thirst, muscle weakness, lethargy, confusion, and fatigue. We are reporting a case of abdominal pain and altered mental status caused by thiazide-induced severe hypercalcemia of 19.8 mg/dL. This is the most severe case of thiazide-induced hypercalcemia that we have seen reported. Patients on thiazide diuretics should have their electrolytes frequently checked, especially patients on calcium supplements. Management usually includes hydration and discontinuation of drugs causing hypercalcemia.

Effects of nano calcium carbonate and nano calcium citrate on toxicity in ICR mice and on bone mineral density in an ovariectomized mice model.

Taking calcium supplements can reduce the risk of developing osteoporosis, but they are not readily absorbed in the gastrointestinal tract. Nanotechnology is expected to resolve this problem. In the present study, we examined whether the bioavailability of calcium carbonate and calcium citrate can be improved by reducing the particle size. The morphology of nano calcium carbonate and nano calcium citrate was characterized by dynamic laser-light scattering (DLS), field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The measurements obtained from DLS, FE-SEM and TEM were comparable. Acute and sub-chronic toxicity tests were performed to establish the safety of these products after oral administration. The no-observed-adverse-effect levels of nano calcium carbonate and nano calcium citrate were 1.3 and 2.3 g kg(-1) body weight, respectively. The results of our in vivo studies indicate that administering nano calcium carbonate and nano calcium citrate can enhance the serum calcium concentration and maintain the whole-body bone mineral density in ovariectomized mice. These data suggest that nano calcium carbonate and nano calcium citrate are more bioavailable than micro calcium carbonate and micro calcium citrate, respectively.

Reduction of adipose tissue and body weight: effect of water soluble calcium hydroxycitrate in Garcinia atroviridis on the short term treatment of obese women in Thailand.

Fifty obese women with a body mass index (BMI) over 25 kg/m(2) were randomly allocated into two groups, 25 in each. Group 1, with a mean (+/-SEM) age of 40.0+/-2 years, received water soluble calcium hydroxycitrate (HCA) as Garcinia atroviridis. Group 2, with a mean age of 35.6+/-1.8 years, received placebo. All subjects were recommended a similar diet with 1000 Kcal/day. The trial lasted for 2 months. At baseline the means BMI of Group 1 and Group 2 were 27.5+/-0.2 kg/m(2) and 26.7+/-0.5 kg/m(2), respectively. Group 1 lost significantly more weight (2.8 vs. 1.4 kg, p<0.05) and at a greater rate than Group 2 throughout the study. The decrease in their body weight was due to a loss of fat storage as evidenced by a significant decrease in the triceps skin fold thickness. On a short-term basis, HCA in Garcinia atroviridis was an effective for weight management.

Severe hypercalcemia after transition from calcium carbonate to calcium citrate in an elderly woman treated with ergocalciferol 50,000 IU per day.

BACKGROUND: Absorption of calcium carbonate in the fasting state has been reported to be significantly compromised in subjects with achlorhydria. Although calcium carbonate malabsorption in the fasting state cannot be predicted, it might be corrected if the compound is administered with meals. However, administering calcium carbonate with meals is logistically challenging in long-term care facilities. OBJECTIVE: The aim of this study was to report the case of a woman who was transitioned to calcium citrate and subsequently experienced symptomatic severe hypercalcemia. METHODS: An 89-year-old female resident of the Wisconsin Veterans Home, a skilled nursing facility in King, Wisconsin, was receiving long-term treatment with ergocalciferol (vitamin D2) 50,000 IU/d. The patient also was receiving calcium carbonate supplements in the morning, and she rarely ate breakfast (fasting state). The patient was transitioned from 2000 mg/d of elemental calcium as carbonate to 1230 mg/d as citrate. RESULTS: After being switched from calcium carbonate to calcium citrate, the patient developed severe symptomatic hypercalcemia (16.8 mg/dL), the primary cause of which was the administration of an inappropriately high dose of vitamin D. CONCLUSIONS: We report a case of symptomatic severe hypercalcemia in a skilled nursing facility resident treated with an inappropriately high daily dose of vitamin D. Hypercalcemia manifested when calcium carbonate was replaced with calcium citrate.

Stone forming risk of calcium citrate supplementation in healthy postmenopausal women.

PURPOSE: We evaluated the effect of calcium citrate supplementation alone or in combination with potassium citrate on the stone forming propensity in healthy postmenopausal women. MATERIALS AND METHODS: A total of 18 postmenopausal women without stones underwent a randomized trial of 4 phases comprised of 2 weeks of treatment with placebo, calcium citrate (400 mg calcium twice daily), potassium citrate (20 mEq twice daily), and calcium citrate and potassium citrate (at same doses). During the last 2 days of each phase urine was collected in 24-hour pools for complete stone risk analysis. RESULTS: Compared to placebo, calcium citrate increased urinary calcium and citrate but decreased urinary oxalate and phosphate. Urinary saturation of calcium oxalate, brushite and undissociated uric acid did not change. Potassium citrate decreased urinary calcium, and increased urinary citrate and pH. It decreased urinary saturation of calcium oxalate and undissociated uric acid, and did not change the saturation of brushite. When calcium citrate was combined with potassium citrate, urinary calcium remained high, urinary citrate increased even further and urinary oxalate remained reduced from the calcium citrate alone, thereby marginally decreasing the urinary saturation of calcium oxalate. Urinary pH increased, decreasing urinary undissociated uric acid. The increase in pH increased the saturation of brushite despite the decrease in urinary phosphorus. CONCLUSIONS: Calcium citrate supplementation does not increase the risk of stone formation in healthy postmenopausal women. The co-administered potassium citrate may provide additional protection against formation of uric acid and calcium oxalate stones.

Acute effects of calcium sodium citrate supplementation of a test meal on mineral homeostasis, oxalate, and calcium oxalate crystallization in the urine of healthy humans--preliminary results in patients with idiopathic calcium urolithiasis.

Calcium, in the form of regular food supplementation, can improve bone metabolism, but it can also increase the risk for renal calcium stones, and may aggravate pre-existing calcium urolithiasis. To study the first of these two aspects, ten healthy volunteers were given a conventional test meal (breakfast; calcium content 28 mg) with or without two dosages of calcium (as calcium-sodium citrate, CSC 1, 680 mg; CSC 2 1,360 mg), taken after an overnight 12 h fast. To study the latter aspect, patients with idiopathic recurrent calcium urolithiasis (ICU) received a balanced test meal of fixed composition, containing 1,000 mg calcium either as CSC (Meal + CSC3; n = 6) or as calcium gluconate (Mcal; n = 8). In normals, CSC induced a dose-dependent increasing intestinal absorption of calcium, and a decrease in oxalate absorption; in serum, CSC increased calcitonin and suppressed parathyroid hormone, but left unchanged the markers of bone turnover, serum osteocalcin and bone alkaline phosphatase. In urine, CSC decreased bone resorption markers (collagen crosslinks) and phosphaturia increased citrate, created signs of metabolic alkalosis, and inhibited several parameters of CaOx crystallization. In ICU, the CSC3 load failed to promote the crystallization of CaOx and calcium phosphate. It was concluded that CSC supplementation of a meal: (1) is well tolerated by healthy subjects and ICU patients, renders calcium highly available to bone, and prevents post-prandial oxaluria from rising; and, (2) is followed by the inhibition of crystallization of renal stone forming calcium-containing substances. Long-term studies aimed at evaluating the usefulness of CSC in preserving healthy bone, and in the metaphylaxis of renal stones would appear justified.