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Vitamin D receptor gene FokI polymorphisms and tuberculosis susceptibility: a meta-analysis

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: The association between FokI polymorphism of vitamin D receptor (VDR) and tuberculosis (TB) susceptibility has been investigated previously; however, the results were inconsistent and conflicting. In the present study, a meta-analysis was performed to assess the relationship between VDR FokI gene polymorphism and the risk of TB.

Material and methods: Databases including PubMed and Embase were searched for genetic association studies of FokI polymorphism of vitamin D receptor (VDR) and TB. Data were extracted by two independent authors and the pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to assess the strength of the association between VDR FokI gene polymorphism and TB risk. Meta-regression and subgroup analyses were performed to identify the source of heterogeneity.

Results: Thirty-four studies with a total of 5669 cases and 6525 controls were reviewed in the present meta-analysis. A statistically significant correlation was found between VDR FokI gene polymorphism and increased TB risk in two comparison models: the homozygote model (ff vs. FF: OR = 1.37, 95% CI: 1.17–1.60; Pheterogeneity = 0.001) and the recessive model (ff vs. Ff + FF: OR = 1.32, 95% CI: 1.14–1.52; Pheterogeneity = 0.006). Meta-regression found no source contributing to heterogeneity. However, sub-group analyses revealed that there was a statistically increased TB risk in the East and Southeast Asian population.

Conclusions: Synthesis of the available studies suggests that homozygosity for the FokI polymorphism of the VDR gene might be associated with an increased TB risk, especially in the East and Southeast Asian population. Additional well-designed, larger-scale epidemiological studies among different ethnicities are needed.

No MeSH data available.


Flow diagram of search strategy and study selection process (TIF)
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Figure 0001: Flow diagram of search strategy and study selection process (TIF)

Mentions: A flow chart of the study selection process is shown in Figure 1. According to the inclusion criteria, 34 qualified case-control studies were selected in the final analysis after the literature search from the PubMed (Medline), Web of Science and Embase web databases [8, 10–15, 19–45]. Twenty-four studies were based on Asian populations [8, 10–13, 19–37], seven were based on African populations [14, 15, 38–42] and the remaining three were conducted in Europe and America [43–45]. The eligible studies contained 4 “large” studies [19, 29, 40, 42] and 30 “small” studies [8, 10–15, 21–28, 30–39]. Thirty studies were genotyped by restriction fragment length polymorphism (RFLP) analysis and five were conducted by other methods [19, 23, 38, 40, 41]. The detailed characteristics of the enrolled studies are listed in Table I. A total of 5669 TB cases were obtained in the 34 studies, including 5126 (92.3%) with pulmonary TB and 426 (7.7%) with extra-pulmonary TB. The corresponding controls for the TB cases numbered 6525. Distribution of genotypes and HWE p-values in the controls are shown in Table II. Among the controls, the genotype distribution for 31 studies of the assessed polymorphisms was in HWE, except for 3 studies from India and Iran [31, 32, 35].


Vitamin D receptor gene FokI polymorphisms and tuberculosis susceptibility: a meta-analysis
Flow diagram of search strategy and study selection process (TIF)
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016579&req=5

Figure 0001: Flow diagram of search strategy and study selection process (TIF)
Mentions: A flow chart of the study selection process is shown in Figure 1. According to the inclusion criteria, 34 qualified case-control studies were selected in the final analysis after the literature search from the PubMed (Medline), Web of Science and Embase web databases [8, 10–15, 19–45]. Twenty-four studies were based on Asian populations [8, 10–13, 19–37], seven were based on African populations [14, 15, 38–42] and the remaining three were conducted in Europe and America [43–45]. The eligible studies contained 4 “large” studies [19, 29, 40, 42] and 30 “small” studies [8, 10–15, 21–28, 30–39]. Thirty studies were genotyped by restriction fragment length polymorphism (RFLP) analysis and five were conducted by other methods [19, 23, 38, 40, 41]. The detailed characteristics of the enrolled studies are listed in Table I. A total of 5669 TB cases were obtained in the 34 studies, including 5126 (92.3%) with pulmonary TB and 426 (7.7%) with extra-pulmonary TB. The corresponding controls for the TB cases numbered 6525. Distribution of genotypes and HWE p-values in the controls are shown in Table II. Among the controls, the genotype distribution for 31 studies of the assessed polymorphisms was in HWE, except for 3 studies from India and Iran [31, 32, 35].

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: The association between FokI polymorphism of vitamin D receptor (VDR) and tuberculosis (TB) susceptibility has been investigated previously; however, the results were inconsistent and conflicting. In the present study, a meta-analysis was performed to assess the relationship between VDR FokI gene polymorphism and the risk of TB.

Material and methods: Databases including PubMed and Embase were searched for genetic association studies of FokI polymorphism of vitamin D receptor (VDR) and TB. Data were extracted by two independent authors and the pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to assess the strength of the association between VDR FokI gene polymorphism and TB risk. Meta-regression and subgroup analyses were performed to identify the source of heterogeneity.

Results: Thirty-four studies with a total of 5669 cases and 6525 controls were reviewed in the present meta-analysis. A statistically significant correlation was found between VDR FokI gene polymorphism and increased TB risk in two comparison models: the homozygote model (ff vs. FF: OR = 1.37, 95% CI: 1.17–1.60; Pheterogeneity = 0.001) and the recessive model (ff vs. Ff + FF: OR = 1.32, 95% CI: 1.14–1.52; Pheterogeneity = 0.006). Meta-regression found no source contributing to heterogeneity. However, sub-group analyses revealed that there was a statistically increased TB risk in the East and Southeast Asian population.

Conclusions: Synthesis of the available studies suggests that homozygosity for the FokI polymorphism of the VDR gene might be associated with an increased TB risk, especially in the East and Southeast Asian population. Additional well-designed, larger-scale epidemiological studies among different ethnicities are needed.

No MeSH data available.