NCT02185222.

Trial name or title	Effect of vitamin D on cognitive decline of patients with memory complaint (trial short name = D‐COG).
Methods	RCT, triple‐blind.
Participants	Aged 60+; both genders; "report to a memory centre with symptoms of memory complaint"; MMSE score "> the 5th percentile for sociocultural level of the patient", no dementia.
Interventions	Experimental: Cholecalciferol 100 000 IU per month as a single dose, administered as oral solution. Control: placebo. Duration: 2 years.
Outcomes	Primary outcome: change from baseline on total recall test from Free and Cued Selective Reminding Test. Secondary outcomes: multiple general and domain‐specific cognitive tests; all adverse events; several biochemical outcomes.
Starting date	July 2014
Contact information	Sponsored by University Hospital, Tours. Contact fanny.hennekinne@univ‐tours.fr
Notes	Estimated completion date July 2018.

^{MMSE: Mini‐mental state examination}