Objective To investigate whether calcium supplements increase the risk of cardiovascular events.Design Patient level and trial level meta-analyses.Data sources Medline, Embase, and Cochrane Central Register of Controlled Trials (1966-March 2010), reference lists of meta-analyses of calcium supplements, and two clinical trial registries. Initial searches were carried out in November 2007, with electronic database searches repeated in March 2010.Study selection Eligible studies were randomised, placebo controlled trials of calcium supplements (≥500 mg/day), with 100 or more participants of mean age more than 40 years and study duration more than one year. The lead authors of eligible trials supplied data. Cardiovascular outcomes were obtained from self reports, hospital admissions, and death certificates.Results 15 trials were eligible for inclusion, five with patient level data (8151 participants, median follow-up 3.6 years, interquartile range 2.7-4.3 years) and 11 with trial level data (11 921 participants, mean duration 4.0 years). In the five studies contributing patient level data, 143 people allocated to calcium had a myocardial infarction compared with 111 allocated to placebo (hazard ratio 1.31, 95% confidence interval 1.02 to 1.67, P=0.035). Non-significant increases occurred in the incidence of stroke (1.20, 0.96 to 1.50, P=0.11), the composite end point of myocardial infarction, stroke, or sudden death (1.18, 1.00 to 1.39, P=0.057), and death (1.09, 0.96 to 1.23, P=0.18). The meta-analysis of trial level data showed similar results: 296 people had a myocardial infarction (166 allocated to calcium, 130 to placebo), with an increased incidence of myocardial infarction in those allocated to calcium (pooled relative risk 1.27, 95% confidence interval 1.01 to 1.59, P=0.038).Conclusions Calcium supplements (without coadministered vitamin D) are associated with an increased risk of myocardial infarction. As calcium supplements are widely used these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population. A reassessment of the role of calcium supplements in the management of osteoporosis is warranted.

Objectives To investigate the effects of personal calcium supplement use on cardiovascular risk in the Women's Health Initiative Calcium/Vitamin D Supplementation Study (WHI CaD Study), using the WHI dataset, and to update the recent meta-analysis of calcium supplements and cardiovascular risk. Design Reanalysis of WHI CaD Study limited access dataset and incorporation in meta-analysis with eight other studies. Data source WHI CaD Study, a seven year, randomised, placebo controlled trial of calcium and vitamin D (1g calcium and 400 IU vitamin D daily) in 36 282 community dwelling postmenopausal women. Main outcome measures Incidence of four cardiovascular events and their combinations (myocardial infarction, coronary revascularisation, death from coronary heart disease, and stroke) assessed with patient-level data and trial-level data. Results In the WHI CaD Study there was an interaction between personal use of calcium supplements and allocated calcium and vitamin D for cardiovascular events. In the 16 718 women (46%) who were not taking personal calcium supplements at randomisation the hazard ratios for cardiovascular events with calcium and vitamin D ranged from 1.13 to 1.22 (P=0.05 for clinical myocardial infarction or stroke, P=0.04 for clinical myocardial infarction or revascularisation), whereas in the women taking personal calcium supplements cardiovascular risk did not alter with allocation to calcium and vitamin D. In meta-analyses of three placebo controlled trials, calcium and vitamin D increased the risk of myocardial infarction (relative risk 1.21 (95% confidence interval 1.01 to 1.44), P=0.04), stroke (1.20 (1.00 to 1.43), P=0.05), and the composite of myocardial infarction or stroke (1.16 (1.02 to 1.32), P=0.02). In metaanalyses of placebo controlled trials of calcium or calcium and vitamin D, complete trial-level data were available for 28 072 participants from eight trials of calcium supplements and the WHI CaD participants not taking personal calcium supplements. In total 1384 individuals had an incident myocardial infarction or stroke. Calcium or calcium and vitamin D increased the risk of myocardial infarction (relative risk 1.24 (1.07 to 1.45), P=0.004) and the composite of myocardial infarction or stroke (1.15 (1.03 to 1.27), P=0.009).Conclusions Calcium supplements with or without vitamin D modestly increase the risk of cardiovascular events, especially myocardial infarction, a finding obscured in the WHI CaD Study by the widespread use of personal calcium supplements. A reassessment of the role of calcium supplements in osteoporosis management is warranted.

Objective To systematically review and describe currently available approaches to supporting maintenance of weight loss in obese adults and to assess the evidence for the effectiveness of these interventions.Design Systematic review with meta-analysis.Data sources Medline, PsycINFO, Embase, and the Cochrane Central Register of Controlled Trials.Study selection Studies were identified through to January 2014. Randomised trials of interventions to maintain weight loss provided to initially obese adults (aged ≥18) after weight loss of ≥5% body weight with long term (≥12 months) follow-up of weight change (main outcome) were included. Study appraisal and synthesisPotential studies were screened independently and in duplicate; study characteristics and outcomes were extracted. Meta-analyses were conducted to estimate the effects of interventions on weight loss maintenance with the inverse variance method and a random effects model. Results are presented as mean differences in weight change, with 95% confidence intervals.Results 45 trials involving 7788 individuals were included. Behavioural interventions focusing on both food intake and physical activity resulted in an average difference of −1.56 kg (95% confidence interval −2.27 to −0.86 kg; 25 comparisons, 2949 participants) in weight regain compared with controls at 12 months. Orlistat combined with behavioural interventions resulted in a −1.80 kg (−2.54 to −1.06; eight comparisons, 1738 participants) difference compared with placebo at 12 months. All orlistat studies reported higher frequencies of adverse gastrointestinal events in the experimental compared with placebo control groups. A dose-response relation for orlistat treatment was found, with 120 mg doses three times a day leading to greater weight loss maintenance (−2.34 kg, −3.03 to −1.65) compared with 60 mg and 30 mg three times a day (−0.70 kg, 95% confidence interval −1.92 to 0.52), P=0.02. ConclusionsBehavioural interventions that deal with both diet and physical activity show small but significant benefits on weight loss maintenance. IntroductionObesity is one of the greatest causes of preventable morbidity and mortality worldwide, 1 with weight loss associated with reductions in risk of morbidity and mortality. 2 Evidence from systematic reviews suggests that long term weight loss through changes in eating and physical activity is possible, 3 even in adults who have already acquired obesity related illness, 4 and effective weight loss programmes are now available.5 Wardle and colleagues reported that 28% of adults in the United Kingdom claimed to be actively trying to lose weight. 6 In a population survey based in the United States, Nicklas and colleagues found that that 63% of obese participants had attempted to lose weight over the past 12 months, of whom 40% had succeeded in losing ≥5% of their initial weight and 20% had succeeded in losing ≥10%. 7 Though formal behaviour change interventions and self guided efforts at individual RESEARCHbehaviour change are successful in inducing weig...

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