PhD Study : Maternal obesity and vitamin D supplementation: implications for maternal and fetal bone health.

Summary

​Pregnant women who are overweight or obese are particularly vulnerable to vitamin D insufficiency owing to the higher physiological requirement and lower status (25-hydroxyvitamin D, 25(OH)D concentrations) associated with obesity (1,2). Vitamin D is involved in calcium and phosphate homeostasis and is essential for the maintenance of bone health (3).  Maternal vitamin D supply is the main source of fetal vitamin D and vitamin D status of the neonate has been shown to be highly correlated with maternal vitamin D status, accounting for 42-80% of infants’ status at delivery. Vitamin D deficiency during pregnancy is associated with poor fetal and postnatal growth and it has been observed that neonates of obese mothers had significantly lower vitamin D status in cord blood compared to neonates of normal weight mothers despite no difference in maternal 25(OH)D status (4). During pregnancy, the maternal physiology adapts to meet the increased calcium demands of the fetus.

The effect of this adaptation on maternal and fetal bone status, particularly in the context of obesity, combined with a low vitamin D status is not fully understood. While numerous studies have examined vitamin D supplementation in pregnancy, none have examined the impact of obesity on bone turnover markers in response to vitamin D supplementation throughout pregnancy. We have recently completed a large double-blind randomised vitamin D intervention study (MO-VITD) to assess the effect of supplementation (10μg-vs-20μg vitamin D3/d) throughout pregnancy on vitamin D status of normal weight, overweight and obese pregnant women (from 12 weeks gestation until delivery) and on infant cord blood (5). Based on our findings of the high prevalence of vitamin D insufficiency in early pregnancy, maternal vitamin D supplementation of 20µg/d may be advisable to maintain maternal vitamin D status in pregnant women in Northern Ireland.

This PhD will be a continuation of our work and will aim to investigate the impact of obesity and vitamin D supplementation on the associated maternal and fetal bone turnover markers and on bone health in early childhood.

This aim will be addressed through the completion of the following analysis:

The association between maternal adiposity, vitamin D status and bone turnover markers: a systematic review

To investigate the impact of maternal adiposity on bone turnover marker status in early pregnancy.

To investigate the effect of supplementation of 10μg vs 20μg vitamin D3/d on maternal and fetal bone turnover markers in normal weight, overweight and obese pregnant women

To assess the impact of supplementation of 10μg vs 20μg vitamin D3/d during pregnancy on bone density in the offspring (MOVITD follow-up study). ​

The proposed work is subject to external funding and the aims of the work may be subject to amendment.

Please note: Applications for more than one PhD studentships are welcome, however if you apply for more than one PhD project within Biomedical Sciences, your first application on the system will be deemed your first-choice preference and further applications will be ordered based on the sequential time of submission. If you are successfully shortlisted, you will be interviewed only on your first-choice application and ranked accordingly. Those ranked highest will be offered a PhD studentship. In the situation where you are ranked highly and your first-choice project is already allocated to someone who was ranked higher than you, you may be offered your 2nd or 3rd choice project depending on the availability of this project.

AccessNI clearance required

Please note, the successful candidate will be required to obtain AccessNI clearance prior to registration due to the nature of the project.

Essential criteria

Applicants should hold, or expect to obtain, a First or Upper Second Class Honours Degree in a subject relevant to the proposed area of study.

We may also consider applications from those who hold equivalent qualifications, for example, a Lower Second Class Honours Degree plus a Master’s Degree with Distinction.

In exceptional circumstances, the University may consider a portfolio of evidence from applicants who have appropriate professional experience which is equivalent to the learning outcomes of an Honours degree in lieu of academic qualifications.

• Sound understanding of subject area as evidenced by a comprehensive research proposal
• Clearly defined research proposal detailing background, research questions, aims and methodology

Desirable Criteria

If the University receives a large number of applicants for the project, the following desirable criteria may be applied to shortlist applicants for interview.

• Completion of Masters at a level equivalent to commendation or distinction at Ulster
• Experience using research methods or other approaches relevant to the subject domain
• Sound understanding of subject area as evidenced by a comprehensive research proposal
• Work experience relevant to the proposed project
• Publications record appropriate to career stage
• Experience of presentation of research findings
• A comprehensive and articulate personal statement
• Relevant professional qualification and/or a Degree in a Health or Health related area

Funding and eligibility

The University offers the following levels of support:

Vice Chancellors Research Studentship (VCRS)

The following scholarship options are available to applicants worldwide:

• Full Award: (full-time tuition fees + £19,000 (tbc))
• Part Award: (full-time tuition fees + £9,500)
• Fees Only Award: (full-time tuition fees)

These scholarships will cover full-time PhD tuition fees for three years (subject to satisfactory academic performance) and will provide a £900 per annum research training support grant (RTSG) to help support the PhD researcher.

Applicants who already hold a doctoral degree or who have been registered on a programme of research leading to the award of a doctoral degree on a full-time basis for more than one year (or part-time equivalent) are NOT eligible to apply for an award.

Please note: you will automatically be entered into the competition for the Full Award, unless you state otherwise in your application.

Department for the Economy (DFE)

The scholarship will cover tuition fees at the Home rate and a maintenance allowance of £19,000 (tbc) per annum for three years (subject to satisfactory academic performance).

This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.

• Candidates with pre-settled or settled status under the EU Settlement Scheme, who also satisfy a three year residency requirement in the UK prior to the start of the course for which a Studentship is held MAY receive a Studentship covering fees and maintenance.
• Republic of Ireland (ROI) nationals who satisfy three years’ residency in the UK prior to the start of the course MAY receive a Studentship covering fees and maintenance (ROI nationals don’t need to have pre-settled or settled status under the EU Settlement Scheme to qualify).
• Other non-ROI EU applicants are ‘International’ are not eligible for this source of funding.
• Applicants who already hold a doctoral degree or who have been registered on a programme of research leading to the award of a doctoral degree on a full-time basis for more than one year (or part-time equivalent) are NOT eligible to apply for an award.

Due consideration should be given to financing your studies. Further information on cost of living