Reduced serum concentrations of vitamin B12 and folate and elevated thyroid-stimulating hormone and homocysteine levels in first-trimester pregnant Saudi women with high A1C concentrations

Abstract

Better understanding of the risk factors for diabetes can lead to proper prevention of this devastating metabolic abnormality. It is hypothesized that diabetes pathogenesis is linked to complex metabolic abnormalities involving homocysteine (HCY) pathways and affecting B12, folate, and thyroid-stimulating hormone (TSH) concentrations. This study was conducted to determine the associations between serum concentrations of vitamin B12, folate, TSH, and HCY in pregnant women with normal glycemic control, diabetes, or prediabetes. This cross-sectional study included 1159 healthy first-trimester pregnant women who were randomly selected from antenatal clinics in 2 hospitals and 21 health care centers across Al-Madinah, Saudi Arabia. Data collected included clinical history and blood sample analyses for serum folate, vitamin B12, TSH, HCY, and glycated hemoglobin (A1C). Participants were classified with normal A1C (<5.7%), prediabetes (≥5.7 and <6.5%), or undiagnosed type 2 diabetes (≥6.5%). Results revealed that 79.5% of the participants had normal A1C levels, whereas 19.3% and 1.21% had A1C levels in prediabetic and diabetic ranges, respectively. Serum concentrations of vitamin B12 and folate were lower in prediabetes subjects than in participants with normal A1C concentrations, whereas serum concentrations of TSH and HCY were significantly higher. There was a strong negative correlation among the concentrations of A1C, vitamin B12, and folate, whereas positive correlations among A1C, TSH, and HCY were reported. Regression analysis identified TSH as having the strongest impact on A1C concentrations. These complex metabolic changes that occur at the prediabetic stage that involve TSH, HCY, folate, and vitamin B12 might direct research on diabetes prevention.