Poster Presentation 29th Australian and New Zealand Bone and Mineral Society Annual Scientific Meeting 2019

Glycaemic control in pregnancy and offspring bone measures: The Vitamin D in Pregnancy Study   (#160)

Natalie K Hyde 1 , Mia A Percival 1 , John D Wark 2 , Sarah M Hosking 1 , Kara L Holloway 1 , Julie A Pasco 1
  1. School of Medicine, Deakin University, Geelong, Victoria, Australia
  2. Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Parkville, Victoria, Australia

Associations between maternal vitamin D status (maternal-25(OH)D) and gestational diabetes mellitus (GDM) have been observed and, in studies of child health outcomes, interactions have been reported between maternal-25(OH)D and GDM. We previously reported an association between maternal-25(OH)D during pregnancy and child bone1. Evidence has also demonstrated associations between GDM and infant bone2. Thus, we investigated associations between gestational glycaemic control and childhood bone measures and explored interactions with maternal 25(OH)D.

 

Women (n=475) were recruited before 16 weeks gestation from Geelong Hospital. At recruitment, and 28-32 weeks gestation, maternal-25(OH)D was determined from maternal serum samples by radioimmunoassay (Immunodiagnostic Systems) . At 28-32 weeks gestation, glucose challenge tests (GCT) were performed (≥6.8nmol/L considered high) to screen for further GDM testing. 195 offspring underwent dual energy X-ray absorptiometry (GE Lunar Prodigy) at the spine and total body (less head; TBLH) of which 177 had a maternal GCT recorded. Regression models predicting offspring bone outcomes were adjusted for maternal-25(OH)D, BMI and child lean and fat mass, sex and pubertal status.

 

There was a trend for maternal-25(OH)D at recruitment to be lower in mothers who had a high GCT result (n=28, 15.2%) compared to women with a normal GCT (median:49.6 vs 56.5 nmol/L, p=0.16), but no difference at 28-32 weeks (p=0.77).  Children of mothers with a high GCT had higher TBLH-BMD (β0.02 95%CI:0.01-0.04) and spine-BMC (β1.8 95%CI:0.07,3.6) and tended to have a higher TBLH-BMC (β49.3 95%CI:-2.6,101.2). There were significant 25(OH)D*GCT interactions; the association between maternal-25(OH)D and offspring bone was only observed in women with normal GCT.

 

Poor glycaemic control in pregnancy may be associated with higher bone density in offspring and appears to moderate maternal-25(OH)D-offspring bone associations. These findings warrant investigation with confirmed diagnoses of GDM. Future investigations using fracture and microarchitecture endpoints will help clarify whether observed changes in bone are favourable or detrimental.

  1. Hyde NK et al. Bone 2019; 124:126-131
  2. Regev RH et al. J Pediatr Endocrinol Metab 2004; 17(8):1083-8