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Bristow SM, Bolland MJ, Gamble GD, Leung W, Reid IR. Dietary calcium intake and change in bone mineral density in older adults: a systematic review of longitudinal cohort studies. Eur J Clin Nutr 2022; 76:196-205. [PMID: 34131304 DOI: 10.1038/s41430-021-00957-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 05/28/2021] [Indexed: 02/05/2023]
Abstract
Many older adults do not achieve recommended intakes of calcium and there is some concern over the potential impact of this on bone health. The objective of this review was to examine evidence from cohort studies on the relationship between calcium intake and change in bone mineral density (BMD) in older adults, something not undertaken in the last two decades. Data sources included Ovid Medline, Embase, and PubMed and references from retrieved reviews and articles. The final search was performed in February 2021. We included cohort studies of calcium intake in participants aged >50 years with change in BMD over ≥1 year as an outcome. We identified 23 studies of women and 7 of men. Most studies found no association between calcium intake and change in BMD in women (71%) or men (71%). Among women, five studies reported high rates (>30% of participants) of hormone treatment or osteoporosis therapy (HT/OT) use; 80% of these studies reported a positive association between calcium intake and change in BMD, compared with 10% of studies in which HT/OT use was low. No study in women in which the mean age was >60 years reported a positive association between calcium intake and change in BMD. We conclude that calcium intake across the ranges consumed in these studies (mean intake in all but one study >500 mg/day) is not an important determinant of bone loss, particularly among women >60 years. The positive findings in studies with high rates of HT/OT use are likely to arise from confounding as a result of co-administration of calcium supplements with these medications.
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Affiliation(s)
- Sarah M Bristow
- Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Mark J Bolland
- Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Greg D Gamble
- Department of Medicine, University of Auckland, Auckland, New Zealand
| | - William Leung
- Department of Medicine, University of Auckland, Auckland, New Zealand.,Department of Public Health, University of Otago, Wellington, New Zealand
| | - Ian R Reid
- Department of Medicine, University of Auckland, Auckland, New Zealand.
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Abstract
The maintenance of extracellular calcium levels within a narrow range is necessary for normal function of the nervous system, muscle, and coagulation, to maintain mineralization of the skeleton but to avoid calcification of soft tissues. Accordingly, absorption and excretion of calcium is closely regulated, and adult humans can adapt to a wide range of calcium intakes from 300 to 2,000 mg/day. The evidence that low calcium intakes contribute to osteoporosis development is weak, as is evidence that increasing these intakes significantly changes fracture risk. Consistent with this view, the United States Preventive Services Task Force does not support the use of calcium supplements in healthy community-dwelling adults. While some groups continue to recommend that supplements of calcium and vitamin D are given with drug treatments for osteoporosis, this view is not supported by clinical trials which demonstrate anti-fracture efficacy of estrogens and bisphosphonates in the absence of such supplementation. Thus, calcium supplements have only a minor place in contemporary medical practice.
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Affiliation(s)
- Ian R Reid
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
- Auckland District Health Board, Auckland, New Zealand.
| | - Sarah M Bristow
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Bristow SM, Horne AM, Gamble GD, Mihov B, Stewart A, Reid IR. Dietary Calcium Intake and Bone Loss Over 6 Years in Osteopenic Postmenopausal Women. J Clin Endocrinol Metab 2019; 104:3576-3584. [PMID: 30896743 DOI: 10.1210/jc.2019-00111] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/15/2019] [Indexed: 02/07/2023]
Abstract
CONTEXT Calcium intakes are commonly lower than the recommended levels, and increasing calcium intake is often recommended for bone health. OBJECTIVE To determine the relationship between dietary calcium intake and rate of bone loss in older postmenopausal women. PARTICIPANTS Analysis of observational data collected from a randomized controlled trial. Participants were osteopenic (hip T-scores between -1.0 and -2.5) women, aged >65 years, not receiving therapy for osteoporosis nor taking calcium supplements. Women from the total cohort (n = 1994) contributed data to the analysis of calcium intake and bone mineral density (BMD) at baseline, and women from the placebo group (n = 698) contributed data to the analysis of calcium intake and change in BMD. BMD and bone mineral content (BMC) of the spine, total hip, femoral neck, and total body were measured three times over 6 years. RESULTS Mean calcium intake was 886 mg/day. Baseline BMDs were not related to quintile of calcium intake at any site, before or after adjustment for baseline age, height, weight, physical activity, alcohol intake, smoking status, and past hormone replacement use. There was no relationship between bone loss and quintile of calcium intake at any site, with or without adjustment for covariables. Total body bone balance (i.e., change in BMC) was unrelated to an individuals' calcium intake (P = 0.99). CONCLUSIONS Postmenopausal bone loss is unrelated to dietary calcium intake. This suggests that strategies to increase calcium intake are unlikely to impact the prevalence of and morbidity from postmenopausal osteoporosis.
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Affiliation(s)
- Sarah M Bristow
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Anne M Horne
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Greg D Gamble
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Borislav Mihov
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Angela Stewart
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Ian R Reid
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
- Department of Endocrinology, Auckland District Health Board, Auckland, New Zealand
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Bristow SM, Gamble GD, Horne AM, Reid IR. Longitudinal changes in bone mineral density, bone mineral content and bone area at the lumbar spine and hip in postmenopausal women, and the influence of abdominal aortic calcification. Bone Rep 2019; 10:100190. [PMID: 30766896 PMCID: PMC6360344 DOI: 10.1016/j.bonr.2018.100190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 12/24/2018] [Indexed: 11/17/2022] Open
Abstract
Longitudinal studies often report that spine bone mineral density (BMD), measured by DXA, is stable in older adults, which has been attributed to osteophyte development and the presence of aortic calcification. A decline in projected spine area as a result of loss of intervertebral disc height might also contribute to higher BMD. We utilised data from 297 postmenopausal women (mean 73 years) who had DXA measurements of the lumbar spine, total hip and femoral neck 5 years apart, and abdominal aortic calcification scoring from vertebral morphometry. BMD declined by -4.4% at the total hip and -3.9% at the femoral neck (p < 0.001), but did not change at the spine (-0.5%, p = 0.12). In contrast, bone mineral content (BMC) declined by -4.0% at the total hip, -2.5% at the femoral neck and -1.7% at the spine (all p < 0.001). Bone area increased by 0.5% at the hip and 1.6% at the femoral neck but declined by -1.2% at the spine (all p < 0.001). 43% of the cohort had abdominal aortic calcification (AAC) present at baseline. The presence of AAC at baseline was not related to changes in BMD or BMC at the total hip or femoral neck, nor to BMD at the spine. However, women with AAC present had a smaller loss of BMC at the spine than those without (-0.8% versus -2.4%, p = 0.03). AAC score increased more over 5 years among those with AAC at baseline than those without (0.28 versus 0.16, p = 0.036). Thus, the stability of spine BMD is the result of both a loss of projected bone area (as a result of intervertebral disc changes and/or a decrease in projected area of the vertebral bodies) and the effects of aortic calcification. Future clinical trials should consider assessing changes in spine BMC as a more informative index of spine mineral status.
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Affiliation(s)
- Sarah M Bristow
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Greg D Gamble
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Anne M Horne
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Ian R Reid
- Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.,Department of Endocrinology, Auckland District Health Board, Auckland, New Zealand
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Billington EO, Bristow SM, Gamble GD, de Kwant JA, Stewart A, Mihov BV, Horne AM, Reid IR. Acute effects of calcium supplements on blood pressure: randomised, crossover trial in postmenopausal women. Osteoporos Int 2017; 28:119-125. [PMID: 27543500 DOI: 10.1007/s00198-016-3744-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/12/2016] [Indexed: 12/17/2022]
Abstract
UNLABELLED Calcium supplements appear to increase cardiovascular risk, but the mechanism is unknown. We investigated the acute effects of calcium supplements on blood pressure in postmenopausal women. The reduction in systolic blood pressure was smaller after calcium compared with the placebo in the hours following dosing. INTRODUCTION Calcium supplements appear to be associated with increased cardiovascular risk; however, the mechanism of this is uncertain. We previously reported that blood pressure declined over a day in older women, and that this reduction was smaller following a calcium supplement. To confirm this finding, we investigated the acute effects of calcium supplements on blood pressure. METHODS This was a randomised controlled crossover trial in 40 healthy postmenopausal women (mean age 71 years and BMI 27.2 kg/m2). Women attended on two occasions, with visits separated by ≥7 days. At each visit, they received either 1 g of calcium as citrate, or placebo. Blood pressure and serum calcium concentrations were measured immediately before, and 2, 4 and 6 h after each intervention. RESULTS Ionised and total calcium concentrations increased after calcium (p < 0.0001 versus placebo). Systolic blood pressure decreased after both calcium and placebo, but significantly less so after calcium (p = 0.02). The reduction in systolic blood pressure from baseline was smaller after calcium compared with placebo by 6 mmHg at 4 h (p = 0.036) and by 9 mmHg at 6 h (p = 0.002). The reduction in diastolic blood pressure was similar after calcium and placebo. CONCLUSIONS These findings are consistent with those of our previous trial and indicate that the use of calcium supplements in postmenopausal women attenuates the post-breakfast reduction in systolic blood pressure by around 6-9 mmHg. Whether these changes in blood pressure influence cardiovascular risk requires further study.
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Affiliation(s)
- E O Billington
- Department of Medicine, The University of Auckland, Private Bag 92019, Auckland Mail Centre 1142, Auckland, New Zealand
- Department of Medicine, University of Calgary, Calgary, Canada
| | - S M Bristow
- Department of Medicine, The University of Auckland, Private Bag 92019, Auckland Mail Centre 1142, Auckland, New Zealand.
| | - G D Gamble
- Department of Medicine, The University of Auckland, Private Bag 92019, Auckland Mail Centre 1142, Auckland, New Zealand
| | - J A de Kwant
- Department of Medicine, The University of Auckland, Private Bag 92019, Auckland Mail Centre 1142, Auckland, New Zealand
| | - A Stewart
- Department of Medicine, The University of Auckland, Private Bag 92019, Auckland Mail Centre 1142, Auckland, New Zealand
| | - B V Mihov
- Department of Medicine, The University of Auckland, Private Bag 92019, Auckland Mail Centre 1142, Auckland, New Zealand
| | - A M Horne
- Department of Medicine, The University of Auckland, Private Bag 92019, Auckland Mail Centre 1142, Auckland, New Zealand
| | - I R Reid
- Department of Medicine, The University of Auckland, Private Bag 92019, Auckland Mail Centre 1142, Auckland, New Zealand
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Abstract
There is longstanding concern that calcium supplements might increase cardiovascular risk in patients with renal impairment. The Auckland Calcium Study suggested that the same problem occurs in older people taking these supplements for prevention of osteoporosis. Our subsequent meta-analyses, (which followed protocols finalized before the data was available) confirmed that calcium supplements, with or without vitamin D, adversely affected risk of myocardial infarction and, possibly, stroke. Several groups have re-visited these data, consistently finding an adverse effect of calcium on myocardial infarction, not always statistically significant because some meta-analyses have been under-powered. Whether or not an adverse effect of calcium plus vitamin D on myocardial infarction is found depends on whether two specific groups of subjects are included-those in the Women's Health Initiative who were already taking calcium at the time of randomization, and subjects from an open, cluster-randomized study in which baseline cardiovascular risk was different between groups. Vitamin D alone does not affect vascular risk, so it is unlikely that differences between calcium alone and calcium plus vitamin D are real, and they are more likely to result from the inclusion of studies at high risk of bias. The mechanisms of the adverse cardiovascular effects are uncertain but may be mediated by the increase in serum calcium following supplement ingestion, and the effects of this on vascular function and coagulation. Available evidence suggests the risks of calcium supplements outweigh any small benefits on fracture incidence, so the case for their use is weak.
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Affiliation(s)
- Ian R Reid
- University of Auckland, Auckland, New Zealand; Department of Endocrinology, Auckland District Health Board, New Zealand
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Bristow SM, Gamble GD, Pasch A, O'Neill WC, Stewart A, Horne AM, Reid IR. 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. Osteoporos Int 2016; 27:1209-1216. [PMID: 26493812 DOI: 10.1007/s00198-015-3372-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 10/13/2015] [Indexed: 12/30/2022]
Abstract
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.
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Affiliation(s)
- S M Bristow
- University of Auckland, Auckland, New Zealand
| | - G D Gamble
- University of Auckland, Auckland, New Zealand
| | - A Pasch
- Department of Clinical Chemistry, University Hospital Bern, Inselspital, Bern, Switzerland
| | - W C O'Neill
- Renal Division, School of Medicine, Emory University, Atlanta, GA, USA
| | - A Stewart
- University of Auckland, Auckland, New Zealand
| | - A M Horne
- University of Auckland, Auckland, New Zealand
| | - I R Reid
- University of Auckland, Auckland, New Zealand.
- Department of Endocrinology, Auckland District Health Board, Auckland, New Zealand.
- Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Affiliation(s)
- Ian R Reid
- University of Auckland, Auckland, New Zealand; Department of Endocrinology, Auckland District Health Board, New Zealand.
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Abstract
Calcium is an essential element in the diet, but there is continuing controversy regarding its optimal intake, and its role in the pathogenesis of osteoporosis. Most studies show little evidence of a relationship between calcium intake and bone density, or the rate of bone loss. Re-analysis of data from the placebo group from the Auckland Calcium Study demonstrates no relationship between dietary calcium intake and rate of bone loss over 5 years in healthy older women with intakes varying from <400 to >1500 mg day(-1) . Thus, supplements are not needed within this range of intakes to compensate for a demonstrable dietary deficiency, but might be acting as weak anti-resorptive agents via effects on parathyroid hormone and calcitonin. Consistent with this, supplements do acutely reduce bone resorption and produce small short-term effects on bone density, without evidence of a cumulative density benefit. As a result, anti-fracture efficacy remains unproven, with no evidence to support hip fracture prevention (other than in a cohort with severe vitamin D deficiency) and total fracture numbers are reduced by 0-10%, depending on which meta-analysis is considered. Five recent large studies have failed to demonstrate fracture prevention in their primary analyses. This must be balanced against an increase in gastrointestinal side effects (including a doubling of hospital admissions for these problems), a 17% increase in renal calculi and a 20-40% increase in risk of myocardial infarction. Each of these adverse events alone neutralizes any possible benefit in fracture prevention. Thus, calcium supplements appear to have a negative risk-benefit effect, and so should not be used routinely in the prevention or treatment of osteoporosis.
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Affiliation(s)
- I R Reid
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Department of Endocrinology, Auckland District Health Board, Auckland, New Zealand
| | - S M Bristow
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - M J Bolland
- Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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