In combination with vitamin D substitution, calcium supplements have proven anti-fracture efficacy when targeted to persons at risk of calcium and/or vitamin D insufficiency, including elderly or institutionalized individuals, osteoporosis patients on antiresorptive or anabolic medication and persons receiving glucocorticoids [4–8]. Benefits are most apparent when a daily dose of 1,000–1,200 mg calcium is complemented with 800 IU vitamin D [6, 8]. This section reviews the evidence for the positive and negative non-skeletal effects of calcium [9]. Calcium as potentially protective against cardiovascular
events Observational research has suggested an inverse relationship between calcium intake and selleck products vascular diseases. In the Iowa Women’s Health Study in 34,486 postmenopausal women aged 55 to 69 years, Bostick and colleagues found that the highest quartile of total calcium selleck compound intake (>1,425 mg/day), when compared to the lowest quartile (<696 calcium/day), was associated with a 33% reduction in ischaemic heart disease mortality (risk ratio (RR) 0.67, 95% confidence interval
(CI) 0.47 to 0.94). According to the analysis, this risk reduction was dependent of the high total intake of calcium and could be attained by diet, supplements or both [10]. Similarly, Knox found a strong negative correlation between dietary calcium intake and mortality ratios for ischemic heart GW-572016 molecular weight disease [11]. In the Nurses’ Health Study cohort of 85,764 women aged 39 2-hydroxyphytanoyl-CoA lyase to 59 years followed for 14 years, women in the highest quintile of total calcium intake (median calcium 1,145 mg/day) had a lower risk of stroke (RR 0.69, 95% CI 0.50–0.95) than those in the lowest quintile (median calcium 395 mg/day) [12]. To explain this observed protection against vascular diseases, potential beneficial effects of calcium on a number of vascular risk factors have been postulated. In particular, reductions in blood pressure, serum lipid concentration and body
weight might be involved, although the data, to some extent, remain inconsistent [9]. An inverse relationship between calcium and blood pressure has been observed in several studies. In a meta-analysis of randomised controlled trials, both dietary calcium intake and calcium supplements were associated with reduced blood pressure, with a trend towards larger effects with dietary intake. However, the effect size was relatively small, with a mean reduction in systolic and diastolic blood pressure of −1.44 mmHg (95% CI −2.20 to −0.68) and −0.84 mmHg (95% CI −1.44 to −0.24), respectively [13]. In line with these findings, a recent trial showed significantly lower rates of hypertension amongst women aged over 45 years with a dietary calcium intake of at least 679 mg/day.