The calcium supplement controversy: now what?

Associations of Habitual Calcium Supplementation With Risk of Cardiovascular Disease and Mortality in Individuals With and Without Diabetes

OBJECTIVE

To prospectively examine the associations of habitual calcium supplementation with cardiovascular disease (CVD) events and mortality in individuals with and without diabetes.

RESEARCH DESIGN AND METHODS

The main analysis included 434,374 participants from the UK Biobank. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% CIs. Interactions of calcium supplement use with diabetes status were tested on multiplicative and additive scales.

RESULTS

Over a median follow-up of 8.1 and 11.2 years, 26,374 incident CVD events and 20,526 deaths were documented, respectively. After multivariable adjustment, habitual calcium supplementation was significantly associated with higher risks of CVD incidence (HR 1.34; 95% CI 1.14, 1.57), CVD mortality (HR 1.67; 95% CI 1.19, 2.33), and all-cause mortality (HR 1.44; 95% CI 1.20, 1.72) in participants with diabetes, whereas no significant association was observed in participants without diabetes (HR 0.97 [95% CI 0.92, 1.03] for CVD incidence; HR 1.05 [95% CI 0.90, 1.23] for CVD mortality; HR 1.02 [95% CI 0.96, 1.09] for all-cause mortality). Significant multiplicative and additive interactions were found between habitual calcium supplementation and diabetes status on risks of CVD events and mortality (all Pinteraction < 0.05). In contrast, no significant interactions were observed between dietary or serum calcium and diabetes status.

CONCLUSIONS

Habitual use of calcium supplements was significantly associated with higher risk of CVD events and mortality in people with diabetes but not in people without diabetes. Further studies are needed to balance potentially adverse effects of calcium supplement against likely benefits, particularly among patients with diabetes.

Dietary Supplement Use Among Chinese Primary School Students: A Cross-Sectional Study in Hunan Province

Dietary supplement use is increasing globally, especially among children. However, few studies have been conducted to examine dietary supplement use among Chinese children. The aim of this study was to examine the prevalence of dietary supplement use and the associated factors in primary school students. A cross-sectional study was conducted in four primary schools in Hunan province, China. A total of 706 Chinese parents/caregivers of school children aged 6–12 years old were enrolled. Self-administrated questionnaires were used to collect information about the children’s dietary supplement use, and their socio-demographic characteristics. The prevalence of dietary supplement use in primary school students was 20.4%. Calcium (16.7%), vitamin C (9.2%), and vitamin D (8.5%) were the most commonly used types of dietary supplement. The main reasons for parents/caregivers to purchase dietary supplements for their children were immunity improvement (43.6%), and for growth promotion (36.5%). Some caregivers (26.4%) purchased dietary supplements online, including from dubious or unknown sellers. However, 37.5% of caregivers did not receive formal guidance on supplementation even if they purchased their supplements through formal channels. Parents/caregivers were unclear about the appropriate choices for children’s dietary supplement use. Guidelines and counseling regarding dietary supplements for children may be helpful in public health work.

Critical issues and current challenges in osteoporosis and fracture prevention. An overview of unmet needs

Osteoporosis is a silent disease with increasing prevalence due to the global ageing population. Decreased bone strength and bone quality is the hallmark of osteoporosis which leads to an increased risk of fragility fractures in elderly. It has been estimated that approximately ~50% of women will suffer during their lifetime from an osteoporotic fracture. This must be considered as a major health concern, as it has previously been established that fragility fracture has been associated with decreased quality of life due to increased disability, more frequent hospital admission and most importantly, osteoporotic fractures have been related to an augmented mortality risk. Anti-osteoporotic drugs are available for improving bone quality. Although there is access to these therapeutic options, there remain multiple unmet needs in the field of osteoporosis and fracture care, for example, the primary prevention of osteoporosis in young individuals (to reach a high peak bone mass), the optimization of the use of imaging techniques [dual-energy X-ray absorptiometry (DXA), vertebral fracture assessment (VFA) and new techniques measuring bone quality], the use of nonmedical treatment options and surgical techniques of fracture healing. In this review, we will discuss topics that play a role in the occurrence and prevention of fractures, and we give an overview of and insight into the critical issues and challenges around osteoporosis and fracture prevention.

Association of Genetic Variants Related to Serum Calcium Levels With Coronary Artery Disease and Myocardial Infarction

IMPORTANCE

Serum calcium has been associated with cardiovascular disease in observational studies and evidence from randomized clinical trials indicates that calcium supplementation, which raises serum calcium levels, may increase the risk of cardiovascular events, particularly myocardial infarction.

OBJECTIVE

To evaluate the potential causal association between genetic variants related to elevated serum calcium levels and risk of coronary artery disease (CAD) and myocardial infarction using mendelian randomization.

DESIGN, SETTING, AND PARTICIPANTS

The analyses were performed using summary statistics obtained for single-nucleotide polymorphisms (SNPs) identified from a genome-wide association meta-analysis of serum calcium levels (N = up to 61 079 individuals) and from the Coronary Artery Disease Genome-wide Replication and Meta-analysis Plus the Coronary Artery Disease Genetics (CardiogramplusC4D) consortium's 1000 genomes-based genome-wide association meta-analysis (N = up to 184 305 individuals) that included cases (individuals with CAD and myocardial infarction) and noncases, with baseline data collected from 1948 and populations derived from across the globe. The association of each SNP with CAD and myocardial infarction was weighted by its association with serum calcium, and estimates were combined using an inverse-variance weighted meta-analysis.

EXPOSURES

Genetic risk score based on genetic variants related to elevated serum calcium levels.

MAIN OUTCOMES AND MEASURES

Co-primary outcomes were the odds of CAD and myocardial infarction.

RESULTS

Among the mendelian randomized analytic sample of 184 305 individuals (60 801 CAD cases [approximately 70% with myocardial infarction] and 123 504 noncases), the 6 SNPs related to serum calcium levels and without pleiotropic associations with potential confounders were estimated to explain about 0.8% of the variation in serum calcium levels. In the inverse-variance weighted meta-analysis (combining the estimates of the 6 SNPs), the odds ratios per 0.5-mg/dL increase (about 1 SD) in genetically predicted serum calcium levels were 1.25 (95% CI, 1.08-1.45; P = .003) for CAD and 1.24 (95% CI, 1.05-1.46; P = .009) for myocardial infarction.

CONCLUSIONS AND RELEVANCE

A genetic predisposition to higher serum calcium levels was associated with increased risk of CAD and myocardial infarction. Whether the risk of CAD associated with lifelong genetic exposure to increased serum calcium levels can be translated to a risk associated with short-term to medium-term calcium supplementation is unknown.

Content Validity of a Short Calcium Intake List to Estimate Daily Dietary Calcium Intake of Patients with Osteoporosis

PURPOSE

Calcium supplements are prescribed for prevention of osteoporotic fractures, but there is controversy whether excess of calcium intake is associated with cardiovascular events. While an accurate estimation of dietary calcium intake is a prerequisite to prescribe the adequate amount of supplementation, the most adequate tools for estimating intake are time-consuming. The aim of this study is to validate a short calcium intake list (SCaIL) that is feasible in daily clinical practice.

METHODS

Based on the food groups contributing most to daily dietary calcium intake and portion sizes determined in an earlier study, a three-item, 1-min SCaIL was designed. As a reference method, an extensive dietary history (DH) with specific focus on calcium-rich foods and extra attention for portion sizes was performed. Beforehand, a difference of ≥250 mg calcium between both methods was considered clinically relevant.

RESULTS

Sixty-six patients with either primary (n = 40) or secondary (n = 26) osteoporosis were included. On average, the SCaIL showed a small and clinically non-relevant difference in calcium intake with the DH: 24 ± 350 mg/day (1146 ± 440 vs. 1170 ± 485 mg, respectively; p = 0.568). Sensitivity and specificity of the SCaIL, compared to the DH, were 73 and 80%, respectively. However, in 50% of the individuals, a clinically relevant difference of ≥250 mg calcium was observed between both methods, while in 17% this was even ≥500 mg.

CONCLUSIONS

The SCaIL is a quick and easy questionnaire to estimate dietary calcium intake at a group level, but is not sufficiently reliable for use in individual patients. Remarkably, the mean dietary calcium intake estimated by the DH of 1170 mg/day indicates that a large proportion of osteoporosis patients might not even need calcium supplementation, although more data are needed to confirm this finding.

Calcium and bone health--goodbye, calcium supplements?

This review assesses (1) the potential role of calcium supplements in the prevention and treatment of osteoporosis and osteoporotic fractures, and (2) the safety of calcium supplements with respect to cardiovascular health as well. With regard to (1), a total calcium intake of < 800 mg/day is associated with increased loss of bone mineral density in peri- and postmenopausal women with an increase in fracture risk. Hereby, the effect of calcium supplements on fracture prevention is dependent primary on baseline calcium intake. The strongest protective effect has been reported in individuals with a calcium intake < 700 mg/day and in high-risk groups. A calcium intake of about 1000-1200 mg/day seems to be sufficient for general fracture prevention. With regard to (2), an analysis of the data based on the Hill criteria does not demonstrate convincing evidence that calcium supplements increase cardiovascular risk. In the long term, total calcium intake of 2500 mg/day (from food and supplements) continues to be classified as safe. This value should not be exceeded for an extended period of time.

Increase in the serum parathyroid hormone level during a bisphosphonate drug holiday

After discontinuation of bisphosphonate therapy, an antiresorptive effect and antifracture protection persist for an undefined period. Patients are encouraged to continue calcium and vitamin D supplementation, during a bisphosphonate drug holiday. However, assessment of adequate calcium intake during the bisphosphonate drug holiday is difficult. Therefore, we measured the serum intact parathyroid hormone (PTH) level as a surrogate marker. A premenopausal woman discontinued bisphosphonate therapy, after 7.5 years of treatment. Two months later, blood calcium and phosphorus levels were normal, serum 25-hydroxyvitamin D level was 31.3 ng/mL, but serum PTH level had increased to 94.9 pg/mL. The elemental calcium supplement dose was increased to 600 mg/day, with no change in the cholecalciferol dose (400 IU). Her serum PTH levels decreased to 49.1 after 4 months and 32.9 pg/mL after 5 months. The serum PTH level may be helpful in assessing adequate calcium intake during a bisphosphonate drug holiday.

Micronutrient Needs of the Elderly

Older adults are becoming a significant percentage of the world's population. A multitude of factors, from the normal aging process to the progression of chronic disease, influence the nutrition needs of this very diverse group of people. Appropriate micronutrient intake is of particular importance but is often suboptimal. Here we review the available data regarding micronutrient needs and the consequences of deficiencies in the ever growing aged population.