Vitamin D and Health

Study/
country
Population/
sample size
Intervention/study design
Baseline 25OHD
(nmol/L) (SD)
Post intervention
25(OH)D (nmol/L)
Outcome Results Conclusion
Rees et al
(2013)
USA
Simpson et al
(2015)
Australia
Urashima et al
(2014)
Japan
Participants from
larger double
blind multi centre
vitamin D trial on
prevention of
large bowel
adenomas
(n=759)
Age 45-75 years
Adults (n=34)
Mean age:
1. 30y
2. 35y
Schoolchildren
(n=247)
Age: 15-18 y
1. D3 (25µg/d) + Ca
(1200 mg/d)
2. Placebo
Duration: 3y
1. 500 µg D3/week
2. Placebo
Duration: 17 wks
1. 50 µg D3/d
2. Placebo
2 months
At enrolment
1. 61.9
2. 63.1
At start of study
1. 83.1
2. 62.6
1. 60.5
2. 76.4
(p=0.04)
Not reported
1. 100.7 (23.9)
2. 56 (24.2)
Number of episodes
(winter)
URTI
1. 275 (71.1%)
2. 252 (71.8%)
Colds
1. 267 (69%)
2. 239 (68.1%)
Influenza like illness
1. 46 (11.9%)
2. 51 (14.5%)
Frequency, duration and
severity of acute
infections.
Not reported Not reported Incidence of influenza A
(diagnosed by a RIDT by
medical doctors).
URTI
RR=0.93 (5% CI, 0.79-1.09)
Colds
RR=0.93 (95% CI, 0.78-1.10)
Influenza like illness
RR=0.95 (95% CI, 0.62-1.46)
Infection risk
All participants
HR: 0.83 (95% CI, 0.53-1.31)
Participants with baseline
25(OH)D < 40 nmol/L (n=4)
HR: 0.56 (95% CI, 0.32-0.96;
p=0.007)
Clinically verified infections
HR: 0.27 (95% CI, 0.07-1.00;
p=0.05)
Total 2 month period
RR=1.11 (95% CI, 0.57-2.18;
p=0.75)
After first month
RR=0.17 (95% CI, 0.04-0.77;
p=0.009)
Vitamin D supplementation
(25µg/d) did not significantly
reduce incidence or duration
of upper RTI in adults with a
baseline serum 25 (OH)D >30
nmol/L.
No difference between
groups for infection risk,
duration or severity.
A treatment effect was
observed amongst those with
24(OH)D < 40 nmol/L at start
of study. However, this only
related to 4 participants.
Vitamin D supplementation
did not decrease the overall
incidence of RIDT-positive
influenza A.
239