Table 1.

Summary of Trial Characteristics.

Participant Characteristics	Frequency, n/30 (%)
Age
Mean or Median ≥70	25 (83.3)
All participants ≥70 *	12 (40.0)
% women
Median, % (IQR)	80.3 (61–100)
100% women *	13 (43.3)
Trial size, median (IQR)	337 (170–1864)
Recruitment with falls history *	9 (30.0)
Non-exclusion of individuals taking ≥200 IU *,†	14 (46.7)
Vitamin D Measurement and Intervention
Laboratory Assessment of vitamin D Levels
Not assessed at any time point, n (%)	1 (3.3)
Assessed at follow-up, n (%)	28 (93.3)
Assay Type, n/29 ‡ (%)
Radioimmunoassay	14 (48.3)
Protein binding assay	2 (6.9)
High-performance liquid chromatography	2 (6.9)
Immunoenzymometric assay	1 (3.4)
Liquid chromatography with tandem mass spectrometry	4 (13.8)
Enzyme linked immunoassay	1 (3.4)
Chemiluminescent immunoassay	1 (3.4)
Not reported	3 (10.3)
Baseline 25(OH)D
Baseline mean or median <30 ng/mL, n/25 § (%)	24 (96.0)
<20 ng/mL, n/25 § (%)	15 (60.0)
All participants with baseline <30 ng/mL *, n/30 (%)	4 (13.3)
<20 ng/mL *, n/30 (%)	3 (10.0)
Intervention, n/46 treatment arms (%)
Daily, oral	31 (67.4)
Non-daily, oral	11 (23.9)
Intramuscular	4 (8.7)
Concomitant calcium	12 (26.1)
Principal Outcomes Assessment Method
Falls as primary outcome	17 (56.7)
Event Ascertainment
At-event reporting	16 (53.3)
Falls Diary	8 (26.7)
Postcard/Calendar	3 (10.0)
Nurse report	5 (16.7)
Interview/Questionnaire	14 (43.3)
Nursing Home Chart Review	1 (3.3)

* trial enrollment criteria; ^† explicit dose exclusion was not reported; multivitamin use was permitted (Broe et al. 2009); ^‡ among trials that measured 25(OH)D either at baseline and/or follow-up; ^§ trials were excluded from the denominator if they did not assess baseline 25(OH)D (3 trials) or the median/mean baseline level was not clear from the primary publication (2 trials).