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    Middle Eastern Women's Health Study-Phase II : the effect of monthly 50,000 IU or 100,000 IU vitamin D supplements on Vitamin D status in pre-menopausal Middle Eastern women living in Auckland : a research report presented in partial fulfilment of the requirements for the degree of Master of Sciences in Human Nutrition at Massey University, Albany, New Zealand
    (Massey University, 2014) Mazahery, Hajar
    Background: Middle Eastern women are at increased risk of vitamin D deficiency/insufficiency due to a number of specific lifestyle risk factors. Vitamin D supplements (50,000 IU/month) are prescribed by General Practitioners to correct vitamin D deficiency in this population in New Zealand. However, no research has investigated whether this dose of vitamin D supplement is useful for vitamin D deficiency treatment in Middle Eastern women or if larger doses are needed. Objectives: The primary objective of this study was to conduct a double-blind, randomised, placebo-controlled trial with vitamin D supplementation for 6 months. We aimed to assess the adequacy of supplementation with monthly 50,000 IU and 100,000 IU in optimising serum 25(OH)D concentrations (= 50 nmol/L and = 75 nmol/L) in a group of Middle Eastern premenopausal women living in Auckland. The secondary objective was to identify those factors affecting serum 25(OH)D response to the given doses of vitamin D supplements. Results from this study will help medical practitioners to provide the best options for treating vitamin D deficiency in Middle Eastern women living in New Zealand. Method: Women of Middle Eastern origin, = 20 years old and in premenopausal stage, having no major illness, living in Auckland (n=62) were recruited for the study in winter 2013. All were required to take study tablets (50,000, 100,000 IU or placebo/month) for 6 months and were required to visit the Human Nutrition Research Unit at Massey University on 3 occasions (baseline, 3-months, and 6-months). Blood samples were collected to measure serum 25(OH)D concentrations and calcium levels. Participants were required to complete questionnaires about their demographics, medical history, skin colour, lifestyle change and physical activity level. Height, weight, body fat percentage (BFP) and blood pressure were measured. Participants were also required to complete four day food dairies. The primary outcomes were the changes in serum 25(OH)D concentration and serum calcium level. Results: Mean baseline serum 25(OH)D was 46.0±15.0 nmol/L. Supplementation with 50,000 IU/month and 100,000 IU raised the mean serum 25(OH)D concentrations from a baseline of 44.0±16.0 and 48.0±11.0 nmol/L to 70.0±15.0 and 82.0±17.0 nmol/L at 6 months, respectively (P<0.001 for both treatment groups). The mean serum 25(OH)D concentration of women assigned to placebo group increased from 45.0±18.0 nmol/L at baseline to 54.0±18.0 nmol/L at 6 months (P<0.01). The mean serum 25(OH)D concentrations reached a Hajar Mazahery MEWH Study-Phase II Abstract plateau after 3 months of supplementation. Of 62 women, 59.7% had serum 25(OH)D concentrations <50 nmol/L and only 3.3% had serum 25(OH)D = 75 nmol/L. At 6 months, the proportion of subjects achieving serum 25(OH)D concentration of 75 nmol/L or more was 31.6% and 66.7% in women receiving monthly 50,000 IU and 100,000 IU, respectively (P=0.002). There were no reports of hypervitaminosis D (serum 25(OH)D >225 nmol/L) or hypercalcemia (serum calcium = 2.7 mmol/L). Response to vitamin D supplementation varied widely (increasing 1.0 to 80.0 nmol/L). In a regression analysis, dose (P<0.001), baseline serum 25(OH)D concentration (P<0.001) and baseline BFP (P=0.01) were the only variables to reach statistical significance as predictors of the change in serum 25(OH)D over 6 months. Conclusion: The prevalence of vitamin D deficiency/insufficiency was high in this study population highlighting the significance of the situation. Monthly intake of 100,000 IU vitamin D for 6 months was more effective than 50,000 IU in achieving serum 25(OH)D concentrations of 75 nmol/L, though it did not ensure a serum 25(OH)D concentration of 75 nmol/L or more in all people. Factors affecting serum 25(OH)D response to supplementation should be taken into account when an optimal dose for individuals is determined. The unexpectedly large variance in serum 25(OH)D response to a fixed dose of vitamin D highlights the importance of follow up and measurements of serum 25(OH)D when supplementation is used in clinical practice.
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    Vitamin D status of preterm infants at 4 months past hospital discharge : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand
    (Massey University, 2013) Emmett, Briar Kelly
    Preterm birth and survival rates are increasing in New Zealand and around the world. Preterm infants are subject to shorter gestational lengths and subsequently suffer from decreased nutrient accretion in utero. Vitamin D is one nutrient that is accrued in the final stages of gestation. At birth preterm infants rely on an exogenous source of this nutrient to achieve and maintain adequate stores. The vitamin D status of preterm infants after hospital discharge in New Zealand was previously unknown. The aim of this study was to investigate the serum 25-hydroxyvitamin D (25(OH)D) status of preterm infants at 4 months post hospital discharge, and describe the factors affecting these concentrations. An observational study of 49 preterm infants (<37 weeks gestation) at 4 months post hospital discharge was undertaken. A capillary blood sample was obtained from infants. Serum 25(OH)D was analysed using ADIVA Centaur Vitamin D Total immunoassay. Questionnaires were used to assess sun exposure behaviours and feeding and supplement use. In this sample of 49 preterm infants, 28.6% were classified as having insufficient vitamin D status (25(OH)D ≤50 nmol/L), of these 8.2% were further classified as having mild to moderate vitamin D deficiency (25(OH)D ≤25 nmol/L). The mean 25(OH)D concentration was 73.8 nmol/L, the range was 16 nmol/L – 314 nmol/L. Vitadol C supplementation had the most significant effect on infant 25(OH)D concentrations. All (n=14) exclusively breastfed infants who did not receive Vitadol C supplements were vitamin D insufficient or deficient on analysis. All infants who received Vitadol C or infant formula were vitamin D sufficient. Vitamin D deficiency is prevalent in exclusively breastfed preterm infants not receiving vitamin D supplements. Vitamin D supplementation should be considered for all preterm infants as part of New Zealand’s child health policy.
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    Vitamin D supplementation in adolescent female ballet dancers and gymnasts in a 12 month randomised controlled trial in Auckland, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand
    (Massey University, 2014) Jessup, Wendy
    Aim: To examine the effects of vitamin D supplementation on the bone health of female adolescent ballet dancers and gymnasts. Method: Adolescent female ballet dancers and gymnasts from Auckland, New Zealand were recruited to a 12 month randomised double-­‐blind trial. Participants were supplemented with cholecalciferol 50,000 IU per month or a placebo. At baseline detailed dietary intake was collected by a four day food record; at baseline and 12 months bone mineral density (BMD) and content were recorded by DXA as well as bone-­‐free, fat-­‐free, lean body mass, percentage body fat, height and weight. At baseline, six months and 12 months serum markers for vitamin D (oestradiol and parathyroid hormone) were collected. Results: A total of 61 adolescent girls were recruited at baseline, BMD and content by DXA was completed in 45 girls and 41 provided vitamin D serum samples. Serum vitamin D concentration was recorded for 41 female ballet dancers and gymnasts aged 12 to 18 years was 72 nmol/L and remained adequate (>50 nmol/L) in both intervention and control groups for the 12 month duration. There was no significant difference between intervention and control groups in bone mineral density and content at any bone site at 12 months. The significant predictors of increased bone mineral density at baseline were older age (P=0.002) higher bone-­‐free, fat-­‐free, lean body mass (P=0.001) and higher calcium intake (P=0.005). For higher bone mineral content the significant predictors at baseline were older age (P=0.01) and higher bone-­‐ free, fat-­‐free, lean body mass (P=0.001). In all participants (n=48) bone mineral density and content increased significantly at 12 months (total body BMD and content, areal BMD, total hip BMD and content, femoral neck BMD and content and lumbar spine BMD and content). II Discussion: More than adequate baseline serum vitamin D levels in this adolescent group may explain the lack of significant difference in any of the bone measures between intervention and control groups. As the age range of the adolescent girls varied markedly and older age predicted both an increase in BMD and content, it is likely that there was also bone accrual due to growth. The nil effect of vitamin D supplementation on bone measures was also limited by the small sample size. Conclusion: In this study vitamin D supplementation had no effect on the bone mineral density and content of female adolescent ballet dancers and gymnasts. Further investigations are needed to examine vitamin D supplementation on bone measures in a large group of adolescent girls.