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Item Relationship between vitamin D, iron, and hepcidin in premenopausal females, potentially confounded by ethnicity.(Springer Nature, 2023-08-29) Greenwood A; Von Hurst PR; Beck KL; Mazahery H; Lim K; Badenhorst CEPURPOSE: To investigate the associations between vitamin D, hepcidin, and iron status in premenopausal females of different ethnic cohorts residing in Auckland, New Zealand (NZ). METHODS: A total of 160 females aged 18-45 years participated in a cross-sectional study. Demographics, body composition, serum 25(OH)D, inflammatory markers (C-reactive protein and interleukin-6, IL-6), and iron biomarkers (serum ferritin, haemoglobin, soluble transferrin receptor, and hepcidin) were measured. Comparisons between parametric, non-parametric, and categorical variables were completed by using one-way ANOVA, Kruskal-Wallis, and Chi-squared tests, respectively. ANCOVA was used to compare serum 25(OH)D across iron parameter categories. RESULTS: Of the 160 participants, 60 were NZ European, 67 were South Asian, and 33 were from the 'other' ethnic groups. South Asians had significantly higher body fat percentage (BF%) and IL-6 concentration (38.34% and 1.66 pg·mL-1, respectively), compared to NZ Europeans (27.49% and 0.63 pg·mL-1, respectively, p < 0.001). South Asians had significantly lower 25(OH)D concentrations compared to NZ Europeans (33.59 nmol·L-1 vs 74.84 nmol·L-1, p < 0.001). In NZ Europeans, higher 25(OH)D concentration was seen in those with lower (≤ 3.5 nM) hepcidin concentration, p = 0.0046. In South Asians, higher 25(OH)D concentration was seen in those with higher (> 3.5 nM) hepcidin concentrations, p = 0.038. There were no associations between serum 25(OH)D and serum ferritin. CONCLUSION: Within South Asian women, an unexpected positive relationship between 25(OH)D and hepcidin concentration was observed which may be due to significantly higher IL-6 concentrations, BF%, and lower 25(OH)D concentrations. Future research is required to confirm these observations in this ethnic cohort.Item Knowledge, attitudes and behaviours towards vitamin D and sun exposure of parents of infants and young children and health professionals in New Zealand.(SAGE Publications, 2023-07-02) Von Hurst P; Mazahery H; Reynolds E; Thomson A; Franklin M; Conlon CBACKGROUND: Vitamin D deficiency may result in adverse long-term health consequences in adulthood if it occurs during fetal development, infancy and childhood. To effectively improve vitamin D status of infants/toddlers, there needs to be knowledge and awareness of vitamin D among parents and health professionals. AIMS: The aim of this study was to investigate parents' and health professionals' knowledge, attitudes and behaviours towards vitamin D and sun exposure over two timepoints. METHODS: The study was an ecological study over two timepoints (Parents 2009 and 2021; Health professionals 2010 and 2019) and used an online questionnaire. RESULTS: The analysis included 9834 parents (2009 n = 8032; 2021 n = 1802) and 283 health professionals (2010 n = 193; 2019 n = 90). Parents and health professionals had good knowledge of vitamin D sources, roles and risk factors for deficiency over two timepoints. There were however some confusions regarding the vitamin D content of breast milk, exclusive breastfeeding as a risk factor for deficiency, and ineffectiveness of sun exposure through glass windows in relation to vitamin D synthesis. In 2019, only 37% of health professionals indicated giving advice on supplements for infants/toddlers. Most parents and health professionals believed there was not enough information available to parents regarding vitamin D (>90%) and that skin cancer prevention messages make it difficult to get information about vitamin D across (>70%). CONCLUSION: Although parents and health professionals had good knowledge in most areas, knowledge of some specific sources and risk factors for vitamin D deficiency was poor.Item Vitamin D and omega-3 fatty acid supplements in children with autism spectrum disorder: a study protocol for a factorial randomised, double-blind, placebo-controlled trial.(23/06/2016) Mazahery H; Conlon C; Beck KL; Kruger MC; Stonehouse W; Camargo CA; Meyer BJ; Tsang B; Mugridge O; von Hurst PRBACKGROUND: There is strong mechanistic evidence to suggest that vitamin D and omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFAs), specifically docosahexaenoic acid (DHA), have the potential to significantly improve the symptoms of autism spectrum disorder (ASD). However, there are no trials that have measured the effect of both vitamin D and n-3 LCPUFA supplementation on autism severity symptoms. The objective of this 2 × 2 factorial trial is to investigate the effect of vitamin D, n-3 LCPUFAs or a combination of both on core symptoms of ASD. METHODS/DESIGN: Children with ASD living in New Zealand (n = 168 children) will be randomised to one of four treatments daily: vitamin D (2000 IU), n-3 LCPUFAs (722 mg DHA), vitamin D (2000 IU) + n-3 LCPUFAs (722 mg DHA) or placebo for 12 months. All researchers, participants and their caregivers will be blinded until the data analysis is completed, and randomisation of the active/placebo capsules and allocation will be fully concealed from all mentioned parties. The primary outcome measures are the change in social-communicative functioning, sensory processing issues and problem behaviours between baseline and 12 months. A secondary outcome measure is the effect on gastrointestinal symptoms. Baseline data will be used to assess and correct basic nutritional deficiencies prior to treatment allocation. For safety measures, serum 25-hydroxyvitamin D 25(OH)D and calcium will be monitored at baseline, 6 and 12 months, and weekly compliance and gastrointestinal symptom diaries will be completed by caregivers throughout the study period. DISCUSSION: To our knowledge there are no randomised controlled trials assessing the effects of both vitamin D and DHA supplementation on core symptoms of ASD. If it is shown that either vitamin D, DHA or both are effective, the trial would reveal a non-invasive approach to managing ASD symptoms. TRIAL REGISTRATION: Australian New Zealand Clinical Trial Registry, ACTRN12615000144516 . Registered on 16 February 2015.Item Vitamin D and Autism Spectrum Disorder: A Literature Review.(21/04/2016) Mazahery H; Camargo CA; Conlon C; Beck KL; Kruger MC; von Hurst PRLow vitamin D status in early development has been hypothesised as an environmental risk factor for Autism Spectrum Disorder (ASD), given the concurrent increase in the prevalence of these two conditions, and the association of vitamin D with many ASD-associated medical conditions. Identification of vitamin D-ASD factors may provide indications for primary and secondary prevention interventions. We systematically reviewed the literature for studies on vitamin D-ASD relationship, including potential mechanistic pathways. We identified seven specific areas, including: latitude, season of conception/birth, maternal migration/ethnicity, vitamin D status of mothers and ASD patients, and vitamin D intervention to prevent and treat ASD. Due to differences in the methodological procedures and inconsistent results, drawing conclusions from the first three areas is difficult. Using a more direct measure of vitamin D status--that is, serum 25(OH)D level during pregnancy or childhood--we found growing evidence for a relationship between vitamin D and ASD. These findings are supported by convincing evidence from experimental studies investigating the mechanistic pathways. However, with few primary and secondary prevention intervention trials, this relationship cannot be determined, unless randomised placebo-controlled trials of vitamin D as a preventive or disease-modifying measure in ASD patients are available.