The high prevalence of vitamin D insufficiency across Australian populations is only partly explained by season and latitude

Background</b> Inadequate sun exposure and dietary vitamin D intake can result in vitamin D insufficiency. However, limited data are available on actual vitamin D status and predictors in healthy individuals in different regions and by season.

Methods We compared vitamin D status [25-hydroxyvitamin D; 25(OH)D] in people < 60 years of age using data from cross-sectional studies of three regions across Australia: southeast Queensland (27&deg;S; 167 females and 211 males), Geelong region (38&deg;S; 561 females), and Tasmania (43&deg;S; 432 females and 298 males).

Results The prevalence of vitamin D insufficiency (≤ 50 nmol/L) in women in winter/spring was 40.5% in southeast Queensland, 37.4% in the Geelong region, and 67.3% in Tasmania. Season, simulated maximum daily duration of vitamin D synthesis, and vitamin D effective daily dose each explained around 14% of the variation in 25(OH)D. Although latitude explained only 3.9% of the variation, a decrease in average 25(OH)D of 1.0 (95% confidence interval, 0.7&ndash;1.3) nmol/L for every degree increase in latitude may be clinically relevant. In some months, we found a high insufficiency or even deficiency when sun exposure protection would be recommended on the basis of the simulated ultraviolet index.

Conclusion Vitamin D insufficiency is common over a wide latitude range in Australia. Season appears to be more important than latitude, but both accounted for less than one-fifth of the variation in serum 25(OH)D levels, highlighting the importance of behavioral factors. Current sun exposure guidelines do not seem to fully prevent vitamin D insufficiency, and consideration should be given to their modification or to pursuing other means to achieve vitamin D adequacy.

Prevalence of vitamin D deficiency and its determinants in Australian adults aged 25 years and older : a national, population-based study

Objective  Vitamin D deficiency is recognized as a global public health problem, but the population-based prevalence of deficiency and its determinants in Australian adults is not known. This study evaluated the vitamin D status of Australian adults aged ≥25 years and risk factors associated with vitamin D deficiency in this population.

Design and Patients  We studied a national sample of 11 247 Australian adults enrolled in the 1999/2000 Australian Diabetes, Obesity and Lifestyle (AusDiab) study drawn from 42 randomly selected districts throughout Australia.

Measurements  Serum concentrations of 25-hydroxyvitamin D [25(OH)D] were measured by immunoassay. Vitamin D deficiency was defined as a concentration <50 nmol/l. Information on demographic and lifestyle factors was derived from interview-administered questionnaires.

Results  The mean serum 25(OH)D concentration was 63 nmol/l (95% CI: 59&ndash;67 nmol/l). Only 4% of the population had a level <25 nmol/l, but the prevalence of vitamin D deficiency (<50 nmol/l) was 31% (22% men; 39% women); 73% had levels <75 nmol/l. The prevalence of vitamin D deficiency increased significantly with age, was greater in women, in those of non-Europid origin, in the obese and those who were physically inactive and with a higher level of education. Deficiency was also more common during winter and in people residing in southern Australia (latitude >35&deg;S); 42% of women and 27% of men were deficient during summer&ndash;autumn, which increased to 58% and 35%, respectively, during winter&ndash;spring.

Conclusion  Vitamin D deficiency is common in Australia affecting nearly one-third of adults aged ≥25 years. This indicates that strategies are needed at the population level to improve vitamin D status of Australians.

Assessing the reading and writing of EAL/D students: issues and implications

This paper reports on the preliminary findings of a study on literacy strategies for learners in established English as an Additional Language (EAL) classes in Years 7-10 in three Victorian secondary schools. The paper draws on baseline reading and writing assessment results (N=45). <div>
The findings showed that within a single classroom, around 70% of students were operating at well below their high school year level, and that teachers faced a six-year spread of literacy levels in each class. At the lower levels, students were weak in both reading and writing. At higher levels, students were stronger in reading than in writing.

The reading assessments have several implications for teaching. They point to a need for instruction in decoding skills, especially semantic and syntactic cueing systems. Because decoding is necessary but not sufficient for comprehension of academic texts, knowledge about vocabulary, grammar and genre needs to be embedded in the curriculum in a systematic way for literacy development to be maximised. The study also shows how ongoing formative assessment is required to ground literacy pedagogy.div>

Effects of vitamin D supplementation on neuroplasticity in older adults: a double-blinded, placebo-controlled randomised trial

Summary - Vitamin D can improve muscle function and reduce falls, but whether it can strengthen neural connections within the brain and nervous system is not known. This 10-week randomised controlled trial indicates that treatment with 2,000 IU/day vitamin D3 does not significantly alter neuroplasticity relative to placebo in older adults.
Introduction - The purpose of this study was to examine the effects of vitamin D supplementation on neuroplasticity, serum brain-derived neurotrophic factor (BDNF) and muscle strength and function in older adults.
Methods - This was a 10-week double-blinded, placebo-controlled randomised trial in which 26 older adults with 25-hydroxyvitamin D [25OHD] concentrations 25&ndash;60 nmol/L were randomised to 2,000 IU/day vitamin D3 or matched placebo. Single- and paired-pulse transcranial magnetic stimulation applied over the motor cortex was used to assess changes in motor-evoked potentials (MEPs) and short-interval intracortical inhibition (SICI), as measures of corticospinal excitability and inhibition respectively, by recording electromyography (EMG) responses to stimulation from the wrist extensors. Changes in muscle strength, stair climbing power, gait (timed-up-and-go), dynamic balance (four square step test), serum 25(OH)D and BDNF concentrations were also measured.
Results - After 10 weeks, mean 25(OH)D levels increased from 46 to 81 nmol/L in the vitamin D group with no change in the placebo group. The vitamin D group experienced a significant 8&ndash;11 % increase in muscle strength and a reduction in cortical excitability (MEP amplitude) and SICI relative to baseline (all P < 0.05), but these changes were not significantly different from placebo. There was no effect of vitamin D on muscle power, function or BDNF.
Conclusions - Daily supplementation with 2,000 IU vitamin D3 for 10 weeks had no significant effect on neuroplasticity compared to placebo, but the finding that vitamin D treatment alone was associated with a decrease in corticospinal excitability and intracortical inhibition warrants further investigation as this suggests that it may improve the efficacy of neural transmission within the corticospinal pathway.

Environmental and genetic determinants of vitamin D insufficiency in 12-month-old infants

We aimed to investigate the relationship between genetic and environmental exposure and vitamin D status at age one, stratified by ethnicity. This study included 563 12-month-old infants in the HealthNuts population-based study. DNA from participants' blood samples was genotyped using Sequenom MassARRAY MALDI-TOF system on 28 single nucleotide polymorphisms (SNPs) in six genes. Using logistic regression, we examined associations between environmental exposure and SNPs in vitamin D pathway and filaggrin genes and vitamin D insufficiency (VDI). VDI, defined as serum 25-hydroxyvitamin D3(25(OH)D3) level ≤50 nmol/L, was measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Infants were stratified by ethnicity determined by parent's country of birth. Infants formula fed at 12 months were associated with reduced odds of VDI compared to infants with no current formula use at 12 months. This association differed by ethnicity (P;bsubesub;= 0.01). The odds ratio (OR) of VDI was 0.29 for Caucasian infants (95% CI, 0.18-0.47) and 0.04 for Asian infants (95% CI, 0.006-0.23). Maternal vitamin D supplementation during pregnancy and/or breastfeeding were associated with increased odds of infants being VDI (OR, 2.39; 95% CI, 1.11-5.18 and OR, 2.5; 95% CI, 1.20-5.24 respectively). Presence of a minor allele for any GC SNP (rs17467825, rs1155563, rs2282679, rs3755967, rs4588, rs7041) was associated with increased odds of VDI. Caucasian infants homozygous (AA) for rs4588 had an OR of 2.49 of being associated with VDI (95% CI, 1.19-5.18). In a country without routine infant vitamin D supplementation or food chain fortification, formula use is strongly associated with a reduced risk of VDI regardless of ethnicity. There was borderline significance for an association between filaggrin mutations and VDI. However, polymorphisms in vitamin D pathway related genes were associated with increased likelihood of being VDI in infancy. © 2014 Elsevier B.V. All rights reserved.

Examining the prevalence of type-D personality in an Australian population

© 2015 The Australian Psychological Society. Objective: Type-D personality is a construct that describes a tendency to simultaneously experience negative emotions and inhibit self-expression for fear of negative social judgement. The link between type-D and poor health outcomes may be partly mediated by two prominent psychosocial mechanisms, poor-quality health-related behaviour and poor perceived-social support. Method: The present study replicated and extended a 2008 UK and Irish prevalence study, utilising a sample from the Australian general population. The study aimed to investigate the relationship between type-D personality and subjective levels of social support, health-related behaviours and neuroticism, as well as examining the estimated prevalence rate of type-D in the general Australian population. Nine hundred and fifty five Australian participants over the age of 18 (194 male and 761 female) completed four measures assessing levels of type-D personality, quality of health-related behaviours, perceived-social support and neuroticism. Results: As hypothesised, the estimated prevalence rate was not found to be significantly different from the rate obtained by Williams etal. (2008). In addition, type-D individuals reported significantly lower perceived-social support and poorer-quality health behaviours than non-type-D individuals. Conclusions: The results of this study provide further support for the association of type-D personality with poor health-related behaviours and poor perceived-social support, as well as demonstrating the applicability of the type-D construct to the Australian general population for the first time. General healthcare applications are discussed, as well as the potential for type-D personality research to influence public illness prevention in general.