Lower Circulating B12 Is Associated with Higher Obesity and Insulin Resistance during Pregnancy in a Non-Diabetic White British Population.
OBJECTIVE
Vitamin B12 and folate are critical micronutrients needed to support the increased metabolic demands of pregnancy. Recent studies from India have suggested that low vitamin B12 and folate concentrations in pregnancy are associated with increased obesity; however differences in diet, antenatal vitamin supplementation, and socioeconomic status may limit the generalisability of these findings. We aimed to explore the cross-sectional relationship of circulating serum vitamin B12 and folate at 28 weeks' gestation with maternal adiposity and related biochemical markers in a white non diabetic UK obstetric cohort.


METHODS
Anthropometry and biochemistry data was available on 995 women recruited at 28 weeks gestation to the Exeter Family Study of Childhood Health. Associations between B12 and folate with maternal BMI and other obesity-related biochemical factors (HOMA-R, fasting glucose, triglycerides, HDL and AST) were explored using regression analysis, adjusting for potential confounders (socioeconomic status, vegetarian diet, vitamin supplementation, parity, haemodilution (haematocrit)).


RESULTS
Higher 28 week BMI was associated with lower circulating vitamin B12 (r = -0.25; P<0.001) and folate (r = -0.15; P<0.001). In multiple regression analysis higher 28 week BMI remained an independent predictor of lower circulating B12 (β (95% CI) = -0.59 (-0.74, -0.44) i.e. for every 1% increase in BMI there was a 0.6% decrease in circulating B12). Other markers of adiposity/body fat metabolism (HOMA-R, triglycerides and AST) were also independently associated with circulating B12. In a similar multiple regression AST was the only independent obesity-related marker associated with serum folate (β (95% CI) = 0.16 (0.21, 0.51)).


CONCLUSIONS
In conclusion, our study has replicated the previous Indian findings of associations between lower serum B12 and higher obesity and insulin resistance during pregnancy in a non-diabetic White British population. These findings may have important implications for fetal and maternal health in obese pregnancies.
Exeter NIHR Clinical Research Facility, University of Exeter Medical School, Exeter, England; Royal Devon and Exeter NHS Foundation Trust, Exeter, England.
Bridget Ann
BA
Knight
Exeter NIHR Clinical Research Facility, University of Exeter Medical School, Exeter, England.
Beverley M
BM
Shields
Exeter NIHR Clinical Research Facility, University of Exeter Medical School, Exeter, England; Royal Devon and Exeter NHS Foundation Trust, Exeter, England.
Adam
A
Brook
Royal Devon and Exeter NHS Foundation Trust, Exeter, England.
Anita
A
Hill
Diabetes Unit, KEM Hospital and Research Centre, Pune, India.
Dattatray S
DS
Bhat
Exeter NIHR Clinical Research Facility, University of Exeter Medical School, Exeter, England.
Andrew T
AT
Hattersley
Diabetes Unit, KEM Hospital and Research Centre, Pune, India.
Chittaranjan S
CS
Yajnik
D050154:Adiposity / Q000502:physiology; D003430:Cross-Sectional Studies; D004032:Diet; D014676:Diet, Vegetarian; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000097:blood*; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008019:Life Style; D008075:Lipoproteins, HDL / Q000097:blood; D009765:Obesity / Q000097:blood* / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood; D014280:Triglycerides / Q000097:blood; D006113:United Kingdom / Q000453:epidemiology; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000097:blood*; D044465:White People
D008075:Lipoproteins, HDL; D014280:Triglycerides; D005492:Folic Acid; D014805:Vitamin B 12