Association between vitamin D status and hyperinsulinism

Abstract

Aims: Some studies have suggested that vitamin D deficiency is associated with an increased risk of first trimester miscarriages, others have suggested that it is associated with an increased risk of hyperinsulinism/insulin resistance and the development of gestational diabetes. Hyperinsulinism is also thought to increase miscarriages. We investigated the association between vitamin D levels and hyperinsulinism in a cohort of recurrent miscarriage patients.

Methods: Patients undergoing miscarriage investigations had insulin and vitamin D levels tested. Vitamin D levels were classified as: sufficient (≥75 nmol/L), insufficient (50–74.9 nmol/L) or deficient (<50 nmol/L). Hyperinsulinism was assessed via a 75 g oral glucose tolerance test (OGTT) with insulin studies.

Results: One hundred and fifty-five patients underwent the testing. Hyperinsulinism was detected in 58.3% of the vitamin D deficient group, 38.7% of the insufficient group, and 33.3% of the sufficient group (chi-square p = .034). There were no significant associations between BMI and vitamin D levels, or BMI and hyperinsulinism. Caucasians comprised 82% of the clinic, and 67% of these women had vitamin D insufficiency/deficiency. Noncaucasians comprised 18% of the clinic but 89% of these patients had vitamin D insufficiency/deficiency.

Discussion: We found that insufficient or deficient vitamin D levels were significantly associated with hyperinsulinism in these patients. Vitamin D deficiency is also thought to contribute to an increased risk of adverse pregnancy outcomes including preeclampsia, preterm birth, small-for-gestational-age gestational diabetes mellitus, and miscarriages. Larger level one trials are needed to establish if increasing serum vitamin D levels prior to conception or in early pregnancy improves adverse pregnancy outcomes.

Keywords:

• Hyperinsulinism
• insufficiency and deficiency
• vitamin D sufficiency
• recurrent miscarriages

Acknowledgements

This study formed part of a Clinical Trial named the PAPO (Prediction of Adverse Pregnancy Outcomes) study, (Clinical trial number ACTRN12609000254291). The study was approved by the Women’s and Children’s Hospital Human Research Ethics Committee in North Adelaide South Australia, REC1481/6/09. All patients gave written informed consent.

Disclosure statement

The authors declare that there are no conflicts of interest associated with this manuscript.

Additional information

Funding

C.T. Roberts was supported by a National Health and Medical Research Council of Australia (NHMRC) Senior research fellowship [GNT1020749] (http://www.nhmrc.gov.au).