Vitamin D deficiency and the risk of anemia: a meta-analysis of observational studies.
OBJECTIVE
Anemia and vitamin D deficiency (VDD) are both very important health issues, recent accumulating evidence shows that VDD is prevalent in individuals with anemia. This meta-analysis aimed to detect a relationship between VDD and anemia.


METHODS
We identified eligible studies by searching the Pub Med, Embase and Cochrane Library before October 2014. Quality assessments were performed with the Newcastle-Ottawa Scale. Heterogeneity was evaluated by Cochran's Q test and source of heterogeneity was detected by subgroup analysis and sensitivity analysis.


RESULTS
A total of seven studies involving 5183 participants were included in the meta-analysis. VDD was associated with an increased incidence of anemia (OR = 2.25, 95% CI = 1.47-3.44), with significant evidence of heterogeneity among these studies (p for heterogeneity < 0.001, I(2) = 84.0%). The subgroup and sensitivity analysis confirmed the stability of the results and no publication bias was detected.


CONCLUSIONS
Our outcomes showed that VDD increased the risk of developing anemia. More researches are warranted to clarify an understanding of the association between VDD and risk of anemia.
a Department of Esophagus, Mediastinal Oncosurgery , Cancer Center of Guangzhou Medical University , Guangzhou , China .
Taisheng
T
Liu
b Department of Pediatrics , Guangzhou Women and Children's Medical Center, Guangzhou Medical University , Guangzhou , China .
Shuling
S
Zhong
c Department of Urology , the first affiliated Hospital of Guangzhou Medical University , Guangzhou , China , and.
Luhao
L
Liu
d Department of Cardiac Surgery , Guangdong General Hospital of Armed Police , Guangzhou , China.
Shenghua
S
Liu
a Department of Esophagus, Mediastinal Oncosurgery , Cancer Center of Guangzhou Medical University , Guangzhou , China .
Xiaoning
X
Li
a Department of Esophagus, Mediastinal Oncosurgery , Cancer Center of Guangzhou Medical University , Guangzhou , China .
Tianjun
T
Zhou
a Department of Esophagus, Mediastinal Oncosurgery , Cancer Center of Guangzhou Medical University , Guangzhou , China .
Jinye
J
Zhang
D000328:Adult; D017677:Age Distribution; D000740:Anemia / Q000175:diagnosis* / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064887:Observational Studies as Topic; D015995:Prevalence; D011379:Prognosis; D016016:Proportional Hazards Models; D012720:Severity of Illness Index; D017678:Sex Distribution; D014808:Vitamin D Deficiency / Q000175:diagnosis* / Q000453:epidemiology*
Anemia; meta-analysis; vitamin D