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Meta-Analysis
. 2023 Feb 22:14:1070592.
doi: 10.3389/fendo.2023.1070592. eCollection 2023.

Vitamin B12 levels in thyroid disorders: A systematic review and meta-analysis

Vicente A Benites-Zapata  1   2 , Felipe L Ignacio-Cconchoy  1 , Juan R Ulloque-Badaracco  3 , Enrique A Hernandez-Bustamante  4   5 , Esteban A Alarcón-Braga  3   6 , Ali Al-Kassab-Córdova  7 , Percy Herrera-Añazco  8
Affiliations
Meta-Analysis

Vitamin B12 levels in thyroid disorders: A systematic review and meta-analysis

Vicente A Benites-Zapata et al. Front Endocrinol (Lausanne). .

Abstract

Background and aims: Numerous studies have found an association between vitamin deficiency and thyroid disorders (TD). The presence of anti-parietal cell antibodies is indicative of reduced ability to absorb vitamin B12. Thus, this study reviewed the existing studies with the objective of assessing differences in the serum levels of vitamin B12 among patients with and without TD, the frequency of vitamin B12 deficiency in patients with TD, and the presence of anti-parietal cell antibodies in patients with TD.

Methods: A meta-analysis of random-effects model was conducted to calculate pooled frequencies, mean differences (MD), and their respective 95% confidence intervals (CI). We identified 64 studies that met our inclusion criteria (n = 28597).

Results: We found that patients with hypothyroidism had lower vitamin B12 levels than healthy participants (MD: -60.67 pg/mL; 95% CI: -107.31 to -14.03 pg/mL; p = 0.01). No significant differences in vitamin B12 levels were observed between healthy participants and patients with hyperthyroidism (p = 0.78), autoimmune thyroid disease (AITD) (p = 0.22), or subclinical hypothyroidism (SH) (p = 0.79). The frequencies of vitamin B12 deficiency among patients with hypothyroidism, hyperthyroidism, SH, and AITD were 27%, 6%, 27%, and 18%, respectively.

Conclusions: Patients with hypothyroidism had lower levels of vitamin B12 than healthy participants. No significant differences were observed between vitamin B12 levels and hyperthyroidism, AITD, or SH.

Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=324422, identifier (CRD42022324422).

Keywords: autoimmune thyroid disease; hyperthyroidism; hypothyroidism; subclinical hypothyroidism; thyroid; vitamin B12.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
PRISMA Flow Diagram.
Figure 2
Figure 2
Vitamin B12 values in patients with hypothyroidism vs healthy patients.
Figure 3
Figure 3
Vitamin B12 values in patients with hyperthyroidism vs healthy patients.
Figure 4
Figure 4
Vitamin B12 values in patients with AITD vs healthy participants.
Figure 5
Figure 5
Vitamin B12 values in patients with SH vs healthy participants.
Figure 6
Figure 6
Frequency of the presence of APCA in AITD.
See this image and copyright information in PMC

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