Medium doses of daily vitamin D decrease falls and higher doses of daily vitamin D3 increase falls: A randomized clinical trial.
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<20ng/ml (50nmol/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 <25ng/ml (<50nmol/L), 21% in the low middle quintile 32-38ng/ml (80-95nmo/L), 72% in the high middle quintile 38-46ng/ml (95-115nmo/L) and 45% in the highest quintile 46-66ng/ml (115-165nmol/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 32-38ng/ml (80-95nmol/L) and faller rates increase as serum 25OHD exceed 40-45ng/ml (100-112.5nmol/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.
Biostatistics, Public Health Department, University Nebraska Medical Center, Omaha, NE 68198, United States.
Lynette M
LM
Smith
Endocrinology, Creighton University Medical School, Omaha, NE 68131, United States. Electronic address: jcg@creighton.edu.
J Christopher
JC
Gallagher
Endocrinology, Creighton University Medical School, Omaha, NE 68131, United States.
Corinna
C
Suiter
D000058:Accidental Falls / Q000517:prevention & control*; D000368:Aged; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000097:blood / Q000627:therapeutic use; D019587:Dietary Supplements / Q000032:analysis; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008875:Middle Aged; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy; D014815:Vitamins / Q000008:administration & dosage* / Q000097:blood / Q000627:therapeutic use
D014815:Vitamins; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D
Clinical trial; Falls; Vitamin D supplementation