A novel approach for prediction of vitamin D status using support vector regression

BACKGROUND Epidemiological evidence suggests that vitamin D deficiency is linked to various chronic diseases. However direct measurement of serum 25-hydroxyvitamin D (25(OH)D) concentration, the accepted biomarker of vitamin D status, may not be feasible in large epidemiological studies. An alternative approach is to estimate vitamin D status using a predictive model based on parameters derived from questionnaire data. In previous studies, models developed using Multiple Linear Regression (MLR) have explained a limited proportion of the variance and predicted values have correlated only modestly with measured values. Here, a new modelling approach, nonlinear radial basis function support vector regression (RBF SVR), was used in prediction of serum 25(OH)D concentration. Predicted scores were compared with those from a MLR model. METHODS Determinants of serum 25(OH)D in Caucasian adults (n = 494) that had been previously identified were modelled using MLR and RBF SVR to develop a 25(OH)D prediction score and then validated in an independent dataset. The correlation between actual and predicted serum 25(OH)D concentrations was analysed with a Pearson correlation coefficient. RESULTS Better correlation was observed between predicted scores and measured 25(OH)D concentrations using the RBF SVR model in comparison with MLR (Pearson correlation coefficient: 0.74 for RBF SVR; 0.51 for MLR). The RBF SVR model was more accurately able to identify individuals with lower 25(OH)D levels (<75 nmol/L). CONCLUSION Using identical determinants, the RBF SVR model provided improved prediction of serum 25(OH)D concentrations and vitamin D deficiency compared with a MLR model, in this dataset.Dr. Guo is funded by an Australian Postgraduate Award. Prof. Lucas is funded by a National Health and Medical Research (NHMRC) Career Development Fellowship and receives research funding from Cancer Australia, NHMRC, and MS Research Australia. Prof. Ponsonby is funded by a NHMRC Research Fellowship and receives research funding from NHMRC and MS Research Australia. The Ausimmune Study was funded by the US National Multiple Sclerosis Society, NHMRC, and MS Research Australia

Searches for Supersymmetry with compressed mass spectra using monojet events with the CMS detector at the LHC

A novel search for supersymmetric particles in events with one high transverse momentum jet and large missing transverse energy is performed using an integrated luminosity of 19.7/fb of pp collision data collected using the CMS detector at the Large Hadron Collider. By using events with an energetic radiated jet, sensitivity to supersymmetric models with compressed mass spectra is gained where the decay products have very low energy. Standard Model background estimates are evaluated with the use of data control samples. No excess over Standard Model expectations is observed, and limits are placed on third generation squark production at the 95% confidence level using supersymmetric simplified models. The development of a Level 1 trigger algorithm to reconstruct jets in the Phase 1 Upgrade of the CMS detector is presented. Utilising the full granularity of the CMS calorimeter and time-multiplexed-trigger technology, a new algorithm with increased flexibility and resolution is presented. It is possible to measure and subtract the contribution to calorimeter deposits of soft particles originating from multiple pp vertices in an event, on an event-by-event basis, in order to decrease the trigger rates associated with high luminosity future run conditions. This will enable CMS to maintain, or better, its ability to do physics as centre-of-mass energy and instantaneous luminosity of the LHC increases in the years to come.Open Acces

Vitamin D and immunity

Vitamin D deficiency has been linked to an increased risk of a wide range of adverse health outcomes. The active form of vitamin D has an important role in calcium metabolism and in bone mineralisation, but the evidence for other health outcomes is mixed, with the strongest effects seen in the weakest epidemiological study designs. There are plausible pathways whereby vitamin D deficiency can impair immune function, resulting in both overactivity and increased risk of autoimmune disease, as well as immune suppression with poorer resistance to infection. Vitamin D status may influence the bacterial flora that constitute the microbiome and affect immune function through this route. Exposure of the skin to ultraviolet radiation causes the production of a range of chemicals, including vitamin D, and new research is exploring possible vitamin D-independent immunomodulatory pathways

Reassessing Impacts of Extended Daily Exposure to Low Level Solar UV Radiation

Currently, health agencies recommend that no sun-protection is required when the UV Index (UVI) is less than 3. We use high-quality data from spectroradiometers and model calculations to demonstrate that this simplification is seriously flawed, particularly for mid-latitude conditions. For days when the peak UVI is below the threshold for advising protection, the daily dose of sun-burning UV available frequently far exceeds the threshold for damage to fair skin. This may have important health consequences, as populations at mid latitudes include a significant proportion with fair skin that is susceptible to damage

On the Nature of Evidence and ‘Proving’ Causality:Smoking and Lung Cancer vs. Sun Exposure, VitaminD and Multiple Sclerosis

If environmental exposures are shown to cause an adverse health outcome, reducing exposure should reduce the disease risk. Links between exposures and outcomes are typically based on ‘associations’ derived from observational studies, and causality may not be clear. Randomized controlled trials to ‘prove’ causality are often not feasible or ethical. Here the history of evidence that tobacco smoking causes lung cancer—from observational studies—is compared to that of low sun exposure and/or low vitamin D status as causal risk factors for the autoimmune disease, multiple sclerosis (MS). Evidence derives from in vitro and animal studies, as well as ecological, case-control and cohort studies, in order of increasing strength. For smoking and lung cancer, the associations are strong, consistent, and biologically plausible—the evidence is coherent or ‘in harmony’. For low sun exposure/vitamin D as risk factors for MS, the evidence is weaker, with smaller effect sizes, but coherent across a range of sources of evidence, and biologically plausible. The association is less direct—smoking is directly toxic and carcinogenic to the lung, but sun exposure/vitamin D modulate the immune system, which in turn may reduce the risk of immune attack on self-proteins in the central nervous system. Opinion about whether there is sufficient evidence to conclude that low sun exposure/vitamin D increase the risk of multiple sclerosis, is divided. General public health advice to receive sufficient sun exposure to avoid vitamin D deficiency (<50 nmol/L) should also ensure any benefits for multiple sclerosis, but must be tempered against the risk of skin cancers.This research received no external funding

Vitamin D sufficiency in pregnancy

One year ago, the chief medical officers of the United Kingdom recommended that “All pregnant and breastfeeding women should take a daily supplement containing 10 μg (400 IU) of vitamin D,” to counter the high prevalence of vitamin D deficiency in pregnant women. This was aimed at reducing the associated consequences of deficiency, such as rickets in children and osteomalacia in adults

Socioeconomic status and health: exploring biological pathways

The cross-sectional Biomarkers Study was undertaken in Canberra, Australia (2000-2002) to examine the role of psychosocial factors in the socioeconomic health gradient, via physiological changes consequent upon activation of the neuroendocrine stress response.¶ The study population was derived from healthy 40-44 year old men and women already participating in a longitudinal cohort study. Using data from the cohort study, four groups with similar occupational status were formed. The study sample was randomly selected within these groups, thus representing the socioeconomic spectrum.¶ A pilot study involved 60 participants with blood and saliva samples measured on two occasions. A further 302 people had blood and saliva samples taken on one occasion. Socioeconomic status was measured by occupational code and status, personal and household income, education and perceived position in the community and in Australia. Psychosocial and behavioural factors, including job strain, job security, coping style, anxiety, depression, optimism, self-esteem, sense of belonging and trust, social support, smoking, exercise and alcohol intake were assessed by selfreport. Five biological parameters: plasma fibrinogen, glycated haemoglobin, waisthip ratio, serum neopterin and salivary IgA were measured as outcome variables.Three hypotheses were tested:¶ 1. There is a socioeconomic gradient in measures of psychosocial stress, and of psychological resilience.¶ 2. There is a socioeconomic gradient in biological measures that have a plausible association with future disease. ¶ 3. Psychosocial factors mediate the demonstrated association between socioeconomic status and the biological measures.¶ ... ¶ In this sample of healthy 40-44 year olds, four out of five biological markers showed moderate socioeconomic variation with a more favourable profile associated with higher SES. The data provide limited support for the importance of psychosocial factors in the socioeconomic health gradient

Can falling infection rates in one country explain rising incidence of autoimmune and allergic diseases in other countries? Caution when (over) interpreting ecological data from disparate areas

HT is the Canada Research Chair in Neuroepidemiology and Multiple Sclerosis. She currently receives research support from the National Multiple Sclerosis Society, the Canadian Institutes of Health Research, the Multiple Sclerosis Society of Canada and the Multiple Sclerosis Scientific Research Foundation. In addition, in the last five years she has received research support from the Multiple Sclerosis Society of Canada (Don Paty Career Development Award); the Michael Smith Foundation for Health Research (Scholar Award) and the UK MS Trust. RML is supported by a National Health and Medical Research Council of Australia Senior Research Fellowship

Oregon Psychologists on Prescriptive Authority: Divided Views and Little Knowledge

With over half of all states having considered legislating prescriptive authority, an immense amount of time and money has been invested. The literature is limited in terms of understanding if opinions toward prescriptive authority are grounded in knowledge and what implications that has for altering these opinions. Following a veto of a prescriptive authority bill in Oregon, 399 licensed Oregon clinical psychologists were surveyed regarding their attitudes and knowledge. In terms of knowledge, only 6.5% knew which three states/territories currently have prescriptive authority and 70.4% were unfamiliar with any of the prerequisites for postdoctoral training in psychopharmacology. Reflecting division, 43.4% were in favor, 25.4% were undecided, and 31.2% were in opposition to broadening privileges for psychologists. Further, only 15.2% expressed interest in pursuing training or 6.7% in becoming prescribers. Data on access, training, and legislative costs were presented to participants in the education condition. These participants showed significant gains in their knowledge across all domains and their opinions shifted only in these specific areas leaving their general stance on the issue unchanged. In contrast to ardent supporters who argue that their “data should provide reassurance to psychologists spearheading legislative initiatives” because of high approval ratings (Sammons et al., 2000, p. 608), our data suggest disagreement amongst a group of professionals who are not particularly well-informed, nor interested in becoming prescribers. Future work should investigate whether expanding the data relevant to other facets of the argument contributes to further targeted change or an overall change in opinion toward prescriptive authority

Are current guidelines for sun protection optimal for health? Exploring the evidence

Exposure of the skin to ultraviolet (UV) radiation is the main risk factor for skin cancer, and a major source of vitamin D, in many regions of the world. Sun protection messages to minimize skin cancer risks but avoid vitamin D deficiency are challenging, partly because levels of UV radiation vary by location, season, time of day, and atmospheric conditions. The UV Index provides information on levels of UV radiation and is a cornerstone of sun protection guidelines. Current guidelines from the World Health Organization are that sun protection is required only when the UV Index is 3 or greater. This advice is pragmatic rather than evidence based. The UV Index is a continuous scale; more comprehensive sun protection is required as the UV Index increases. In addition, a wide range of UVA doses is possible with a UVI of 3, from which there may be health consequences, while full sun protection when the UVI is "moderate" (between 3 and 5) may limit vitamin D production. Finally, the duration of time spent in the sun is an essential component of a public health message, in addition to the intensity of ambient UV radiation as measured by the UV Index. Together these provide the dose of UV radiation that is relevant to both skin cancer genesis and vitamin D production. Further education is required to increase the understanding of the UV Index; messages framed using the UV Index need to incorporate the importance of duration of exposure and increasing sun protection with increasing dose of UV radiationProfs Lucas and Neale are funded by Senior Research Fellowships from the National Health and Medical Research Council of Australia