Medium doses of daily vitamin D decrease falls and higher doses of daily vitamin D3 increase falls: A randomized clinical trial

Lynette M. Smith, John Christopher G. Gallagher, Corinna Suiter

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47 Scopus citations


Falls are a serious health problem in the aging population. Because low levels of vitamin D have been associated with increased fall rates, many trials have been performed with vitamin D; two meta-analyses showed either a small effect or no effect of vitamin D on falls. We conducted a study of the effect of vitamin D on serum 25 hydroxyvitamin D (25OHD) and data on falls was collected as a secondary outcome. In a 12-month double blind randomized placebo trial, elderly women, mean age 66 years, were randomized to one of seven daily oral doses of vitamin D or placebo. The main inclusion criterion for study was a baseline serum 25OHD. <. 20. ng/ml (50. nmol/L). A history of falls was collected at baseline and fall events were collected every 3 months. Results showed that the effect of vitamin D on falls followed a U-shaped curve whether analyzed by dose or serum 25OHD levels. There was no decrease in falls on low vitamin D doses 400, 800 IU, a significant decrease on medium doses 1600, 2400,3200 IU (p = 0.020) and no decrease on high doses 4000, 4800 IU compared to placebo (p = 0.55). When compared to 12-month serum 25OHD quintiles, the faller rate was 60% in the lowest quintile <25. ng/ml (<50. nmol/L), 21% in the low middle quintile 32-38. ng/ml (80-95. nmo/L), 72% in the high middle quintile 38-46. ng/ml (95-115. nmo/L) and 45% in the highest quintile 46-66. ng/ml (115-165. nmol/L). In the subgroup with a fall history, fall rates were 68% on low dose, 27% on medium doses and 100% on higher doses. Fall rates on high doses were increased compared to medium doses (Odds Ratio 5.6.95% CI: 2.1-14.8). In summary, the maximum decrease in falls corresponds to a 12- month serum 25OHD of 32-38. ng/ml (80-95. nmol/L) and faller rates increase as serum 25OHD exceed 40-45. ng/ml (100-112.5. nmol/L). The Tolerable upper limit (TUL) recently increased in 2010 from 2000 to 4000 IU/day may need to be reduced in elderly women especially in those with a fall history.

Original languageEnglish (US)
JournalJournal of Steroid Biochemistry and Molecular Biology
StateAccepted/In press - Aug 3 2016

All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Medicine(all)
  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Endocrinology
  • Clinical Biochemistry
  • Cell Biology

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