Dawson-Hughes B, Harris SS, Krall EA, et al. Effect of withdrawal of calcium and vitamin D supplements on bone mass in elderly men and women. American Journal of Clinical Nutrition 2000;72:745-50
PubMed link: https://www.ncbi.nlm.nih.gov/pubmed/10966893
Full text article: https://academic.oup.com/ajcn/article/72/3/745/4729423
| Methods | Study design: Randomized placebo-controlled study with a parallel-design
Number of groups: Two groups |
| Participants | Number of participants: 295 randomized
· Active deprescribing group: 148 randomized · Control group: 147 randomized Age: 74 ± 5 years Sex: 167 female, 128 male Participants with dementia: No Inclusion criteria from the 36-month parent study: · Healthy, ambulatory men and women · 65 years of age or older Exclusion criteria from the parent study: · Current cancer · Current hyperparathyroidism · Kidney stone in the past five years · Renal disease · Bilateral hip surgery · Therapy with a bisphosphonate, calcitonin, estrogen, tamoxifen, or testosterone in the past six months · Therapy with fluoride in the past two years · Femoral neck bone mineral density more than two standard deviations below the mean for subjects of the same age and sex · Dietary calcium intake exceeding 1500 mg per day · Laboratory evidence of kidney or liver disease Country: United States of America Setting: Community |
| Interventions | Medicine: 500mg daily of calcium (as calcium citrate malate) and 17.5 mcg (700IU) vitamin D
Withdrawal Schedule: Not described Comparator: Placebo compared to continued treatment |
| Outcomes | Vertebral fractures
Non-vertebral fractures Bone Mass Density testing Laboratory measurements |
| Dates | Dates: Not described
Follow-up duration: 60 months Vitamin D and calcium for three years, then two years placebo, OR Vitamin D and calcium for five years |
| Funding sources | Grant AG10353 from the National Institutes of Health and by agreement 58-1950-001 with the US Department of Agriculture |
| Notes |
Risk of bias table
| Bias | Authors’ judgment | Support for judgment |
| Random sequence generation (selection bias) | High risk | In the previous study, subjects were randomly assigned. It seems that after that study, in the follow-upperiod, patients self-selectedwhether they would take supplements or not. This means we have the potential for four groups, only one of which is a deprescribing study (the randomly assigned intervention group who then went on to stop supplements in the follow-up). |
| Allocation concealment (selection bias) | High risk | Subjects knew whether they were taking supplements or not. |
| Blinding of participants and personnel (performance bias) | High risk | The follow-up was essentially an open trial. |
| Blinding of outcome assessment (detection bias) | High risk | The follow-up was essentially an open trial. |
| Incomplete outcome data (attrition bias) | High risk | No method described. |
| Selective reporting (reporting bias) | High risk | There were no pre-specified (primary and secondary) outcomes. |
| Other bias | High risk | See comments above on the self-selection of supplements. |
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