Linearity assessment: deviation from linearity and residual of linear regression approaches.

In this computer simulation study, we examine four different statistical approaches of linearity assessment, including two variants of deviation from linearity (individual (IDL) and averaged (AD)), along with detection capabilities of residuals of linear regression (individual and averaged). From the results of the simulation, the following broad suggestions are provided to laboratory practitioners when performing linearity assessment. A high imprecision can challenge linearity investigations by producing a high false positive rate or low power of detection. Therefore, the imprecision of the measurement procedure should be considered when interpreting linearity assessment results. In the presence of high imprecision, the results of linearity assessment should be interpreted with caution. Different linearity assessment approaches examined in this study performed well under different analytical scenarios. For optimal outcomes, a considered and tailored study design should be implemented. With the exception of specific scenarios, both ADL and IDL methods were suboptimal for the assessment of linearity compared. When imprecision is low (3 %), averaged residual of linear regression with triplicate measurements and a non-linearity acceptance limit of 5 % produces <5 % false positive rates and a high power for detection of non-linearity of >70 % across different types and degrees of non-linearity. Detection of departures from linearity are difficult to identify in practice and enhanced methods of detection need development.

Ensuring quality in 17OHP mass spectrometry measurement: an international study assessing isomeric steroid interference.

OBJECTIVES: Interference from isomeric steroids is a potential cause of disparity between mass spectrometry-based 17-hydroxyprogesterone (17OHP) results. We aimed to assess the proficiency of mass spectrometry laboratories to report 17OHP in the presence of known isomeric steroids. METHODS: A series of five samples were prepared using a previously demonstrated commutable approach. These samples included a control (spiked to 15.0 nmol/L 17OHP) and four challenge samples further enriched with equimolar concentrations of 17OHP isomers (11α-hydroxyprogesterone, 11ß-hydroxyprogesterone, 16α-hydroxyprogesterone or 21-hydroxyprogesterone). These samples were distributed to 38 participating laboratories that reported serum 17OHP results using mass spectrometry in two external quality assurance programs. The result for each challenge sample was compared to the control sample submitted by each participant. RESULTS: Twenty-six laboratories (68 % of distribution) across three continents returned results. Twenty-five laboratories used liquid chromatography-tandem mass spectrometry (LC-MS/MS), and one used gas chromatography-tandem mass spectrometry to measure 17OHP. The all-method median of the control sample was 14.3 nmol/L, ranging from 12.4 to 17.6 nmol/L. One laboratory had results that approached the lower limit of tolerance (minus 17.7 % of the control sample), suggesting the isomeric steroid caused an irregular result. CONCLUSIONS: Most participating laboratories demonstrated their ability to reliably measure 17OHP in the presence of the four clinically relevant isomeric steroids. The performance of the 12 (32 %) laboratories that did not engage in this activity remains unclear. We recommend that all laboratories offering LC-MS/MS analysis of 17OHP in serum, plasma, or dried bloodspots determine that the isomeric steroids are appropriately separated.

Quantifying resistance to myxomatosis in wild rabbits produces novel evolutionary insights.

Wild rabbits in Australia developed genetic resistance to the myxoma virus, which was introduced as a biological control agent. However, little is known about the rate at which this evolutionary change occurred. We collated data from challenge trials that estimated rabbit resistance to myxomatosis in Australia and expressed resistance on a continuous scale, enabling trends in its development to be assessed over 45 years up to 1995. Resistance initially increased rapidly, followed by a plateau lasting ten years, before a second rapid increase occurred associated with the introduction of European rabbit fleas as myxoma virus vectors. By contrast, in the United Kingdom, where rabbit flea vectors were already present when the myxoma virus initially spread, resistance developed more slowly. No estimates of rabbit resistance to myxomatosis have been made for almost 30 years, despite other highly lethal rabbit pathogens becoming established worldwide. Continued testing of wild-caught rabbits in Australia to determine current levels of resistance to myxomatosis is recommended to assess its current effectiveness for managing pest rabbits. Given the economic and environmental significance of invasive rabbits, it would be remiss to manage such biological resources and ecosystem services poorly.

Method evaluation in the clinical laboratory.

Method evaluation is one of the critical components of the quality system that ensures the ongoing quality of a clinical laboratory. As part of implementing new methods or reviewing best practices, the peer-reviewed published literature is often searched for guidance. From the outset, Clinical Chemistry and Laboratory Medicine (CCLM) has a rich history of publishing methods relevant to clinical laboratory medicine. An insight into submissions, from editors' and reviewers' experiences, shows that authors still struggle with method evaluation, particularly the appropriate requirements for validation in clinical laboratory medicine. Here, we consider through a series of discussion points an overview of the status, challenges, and needs of method evaluation from the perspective of clinical laboratory medicine. We identify six key high-level aspects of clinical laboratory method evaluation that potentially lead to inconsistency. 1. Standardisation of terminology, 2. Selection of analytical performance specifications, 3. Experimental design of method evaluation, 4. Sample requirements of method evaluation, 5. Statistical assessment and interpretation of method evaluation data, and 6. Reporting of method evaluation data. Each of these areas requires considerable work to harmonise the practice of method evaluation in laboratory medicine, including more empirical studies to be incorporated into guidance documents that are relevant to clinical laboratories and are freely and widely available. To further close the loop, educational activities and fostering professional collaborations are essential to promote and improve the practice of method evaluation procedures.

The LEAP checklist for laboratory evaluation and analytical performance characteristics reporting of clinical measurement procedures.

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers, and editors in deciding the quality of a submitted manuscript. The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the LEAP checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

The LEAP checklist for Laboratory Evaluation and Analytical Performance Characteristics reporting of clinical measurement procedures.

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers, and editors in deciding the quality of a submitted manuscript.The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the LEAP checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

Testosterone and exercise: effects on fitness, body composition, and strength in middle-to-older aged men with low-normal serum testosterone levels.

As men age, serum testosterone (T) concentrations decrease, as do fitness, strength, and lean mass. Whether testosterone treatment confers additive benefit to reverse these changes when combined with exercise training in middle-to-older aged men remains unclear. We assessed the effects of T treatment and exercise, alone and in combination, on aerobic capacity (V̇o2peak), body composition, and muscular strength in men 50-70 yr, waist circumference ≥95 cm and low-normal serum T (6-14 nmol·L-1). Participants (n = 80) were randomized to AndroForte5 (testosterone 5.0% wt/vol, 100 mg/2 mL) cream (T), or matching placebo (P), applied transdermally daily, and supervised center-based exercise (Ex) or no additional exercise (NEx), for 12-wk. Exercise increased V̇o2peak and strength versus nonexercise (V̇o2peak: T + Ex: +2.5 mL·kg-1·min-1, P + Ex: +3.2 mL·kg-1·min-1, P < 0.001; leg press: T + Ex: +31 kg, P + Ex: +24 kg, P = 0.006). T treatment did not affect V̇o2peak or strength. Exercise decreased total (T + Ex: -1.7, P + Ex: -2.3 kg, P < 0.001) and visceral fat (T + Ex: -0.1 kg, P + Ex: -0.3 kg, P = 0.003), and increased total (T + Ex: +1.4 kg, P + Ex: +0.7 kg, P = 0.008) and arm lean mass (T + Ex: +0.5 kg, P + Ex: +0.3 kg, P = 0.024). T treatment did not affect total or visceral fat, but increased total (T + Ex: +1.4 kg, T + NEx: +0.7 kg, P = 0.015), leg (T + Ex: +0.3 kg, T + NEx: +0.2 kg, P = 0.024), and arm lean mass (T + Ex: +0.5 kg, T + NEx: +0.2 kg, P = 0.046). T + Ex increased arm lean mass (T + Ex: +0.5 kg vs. P + NEx: -0.0 kg, P = 0.001) and leg strength (T + Ex: +31 kg vs. P + NEx: +12 kg, P = 0.032) compared with P + NEx, with no other additive effects. Exercise training was more effective than T treatment in increasing aerobic capacity and decreasing total and visceral fat mass. T treatment at therapeutic doses increased lean mass but conferred limited additional benefit when combined with exercise. Exercise should be evaluated as an antiaging intervention in preference to testosterone treatment in men.NEW & NOTEWORTHY We illustrate that exercise training generates superior outcomes to testosterone treatment for improving aerobic fitness, muscular strength, and total and visceral fat mass in men 50-70 yr with low-normal serum testosterone concentrations. Adding testosterone treatment to exercise did not provide any additive benefit for these variables. Testosterone treatment alone and exercise alone had similar impacts on lean mass. Therefore, men unable to exercise may obtain benefit from testosterone treatment alone to improve lean mass.

Effects of testosterone treatment, with and without exercise training, on ambulatory blood pressure in middle-aged and older men.

CONTEXT: With age, testosterone (T) and physical activity levels often decline in parallel. The effect of combining T treatment and exercise training on ambulatory blood pressure (ABP) is unclear. OBJECTIVE: To assess T and exercise effects, alone and in combination, on ABP in men aged 50-70 years, waist circumference ≥ 95 cm and low-normal serum T (6-14 nmol/L), without organic hypogonadism. DESIGN: A 2 × 2 factorial randomised, placebo-controlled study. INTERVENTION: Randomization to daily transdermal AndroForte5® (Testosterone 5.0%w/v, 100 mg in 2 ml) cream (T), or matching placebo (P) (double-blind), and to supervised exercise (Ex) or no additional exercise (NEx), for 12 weeks. RESULTS: Average 24-h systolic blood pressure (SBP) increased with T treatment (testosterone*time, p = .035). Average 24-h SBP increased in T+Ex (T+Ex:+3.0 vs. P+NEx: -3.0 mmHg, p = .026) driven by day-time changes (T+Ex:+3.5 vs. P+NEx: -3.0 mmHg, p = .026). There was an effect of T for 24-h average diastolic blood pressure (DBP, testosterone*time, p = .044) driven by the decrease in P+Ex (P+Ex: -3.9 vs. T+NEx: -0.5 mmHg, p = .015). Night-time DBP was lower with exercise (P+Ex: -4.0 vs. P+NEx: +0.7 mmHg, p = .032). The effect of exercise to lower night-time DBP was not apparent in the presence of T (T+Ex: -0.4 vs. P+NEx: +0.7 mmHg, p > .05). Ex increased average 24-h pulse pressure (PP, exercise*time, p = .022), largely during daytime hours (exercise*time, p = .013). CONCLUSIONS: There was a main effect of T to increase 24-h SBP, primarily seen when T was combined with Ex. Exercise alone decreased 24-h and night-time DBP; an effect attenuated by T. BP should be carefully assessed and monitored, when prescribing T treatment to middle-aged and older men, especially when combined with exercise training.

Forecast increase in invasive rabbit spread into ecosystems of an oceanic island (Tenerife) under climate change.

The European rabbit (Oryctolagus cuniculus) is a pest and a conservation problem on many islands, where its heavy grazing pressure threatens many endemic plants with extinction. Previous studies in its native and introduced range have highlighted the high spatial variability of rabbit abundance at local and landscape scales, depending on many factors such as the existence of different habitats. Modeling of the species can be useful to better understand spatial patterns and to prioritize actions, especially in those regions in which rabbits have become invasive. Here, we investigate the distribution of the European rabbit in Tenerife (Canary Islands, Spain), where the species was introduced during the 15th century and has subsequently changed vegetation composition. Added to the direct effects of rabbits on vegetation, climate change could also have implications for rabbit populations, especially in the alpine ecosystem. To evaluate that, we estimated rabbit abundance in 216 plots randomly distributed on Tenerife island (61 in the alpine ecosystem), modeled the potential current spatial abundance of the species and considered how it might vary under different climate change scenarios. We associated rabbit abundance to a wide selection of abiotic, biotic, and human variables expected to influence rabbit abundance on the island. We found a positive correlation between rabbit abundance and temperature and a negative correlation in the case of precipitation. Hence, according to the models' projections, climate change is expected to enhance rabbit populations in the future. Current higher densities were related to land disturbance and open areas, and a remarkable increase is expected to occur in the alpine ecosystem. Overall, we consider that this study provides valuable information for land managers in the Canary archipelago as it reveals how global warming could indirectly exacerbate the conservation problems of the endemic flora in oceanic islands.

Identification of essential exported Plasmodium falciparum protein kinases in malaria-infected red blood cells.

FIKK kinases in the human malaria parasite Plasmodium falciparum are attractive targets for new anti-malaria drugs, as they have no orthologues in humans and have been linked to disease severity. Six FIKKs are known to be exported into red blood cells (RBCs) where they mediate dramatic structural and functional changes to RBCs that are central to pathogenesis. Eleven members of this family, which are predicted to be exported into infected RBCs (iRBCs), remain uncharacterised. Using a targeted gene-knockout approach, we have characterised these FIKKs and discovered that five are essential for parasite survival. Three of these five FIKKs (FIKK9.1, FIKK10.1, FIKK10.2) were exported from the parasite into iRBCs and for two of these (FIKK9.1 and FIKK10.1), export was via Maurer's clefts (parasite-derived structures involved in protein trafficking and pathognomonic of falciparum malaria). Of the remaining two essential kinases, FIKK3 was associated with rhoptries (specialised protein secretory organelles in the parasite) and FIKK9.5 was localised in the parasite nucleus. The diverse localisation and essentiality of these FIKKs demonstrate that they play different but essential roles in the survival of P. falciparum in RBCs and therefore are attractive new drug targets for the prevention or treatment of falciparum malaria.

Vibrational Spectroscopic Based Approach for Diagnosing Babesia bovis Infection.

Babesia bovis parasites present a serious and significant health concern for the beef and dairy industries in many parts of the world. Difficulties associated with the current diagnostic techniques include the following: they are prone to human error (microscopy) or expensive and time-consuming (polymerase chain reaction) to perform. Little is known about the biochemical changes in blood that are associated with Babesia infections. The discovery of new biomarkers will lead to improved diagnostic outcomes for the cattle industry. Vibrational spectroscopic technologies can record a chemical snapshot of the entire organism and the surrounding cell thereby providing a phenotype of the organism and the host infected cell. Here, we demonstrate the applicability of vibrational spectroscopic imaging techniques including Atomic Force Microscopy Infrared (AFM-IR) and confocal Raman microscopy to discover new biomarkers for B. bovis infections. Furthermore, we applied Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) to detect B. bovis in red blood cells (RBCs). Based on changes in the IR spectral bands, with ATR-FTIR in combination with Partial Least Squares-Discriminant Analysis we were able to discriminate infected samples from controls with a sensitivity and specificity of 92.0% and 91.7%, respectively, in less than 2 min, excluding sample extraction and preparation. The proposed method utilized a lysis approach to remove hemoglobin from the suspension of infected and uninfected cells, which significantly increased the sensitivity and specificity compared to measurements performed on intact infected red blood cells (intact infected RBC, 77.3% and 79.2%). This work represents a holistic spectroscopic study from the level of the single infected RBC using AFM-IR and confocal Raman to the detection of the parasite in a cell population using ATR-FTIR for a babesiosis diagnostic.

Adaptive changes in the genomes of wild rabbits after 16 years of viral epidemics.

Since its introduction to control overabundant invasive European rabbits (Oryctolagus cuniculus), the highly virulent rabbit haemorrhagic disease virus (RHDV) has caused regular annual disease outbreaks in Australian rabbit populations. Although initially reducing rabbit abundance by 60%, continent-wide, experimental evidence has since indicated increased genetic resistance in wild rabbits that have experienced RHDV-driven selection. To identify genetic adaptations, which explain the increased resistance to this biocontrol virus, we investigated genome-wide SNP (single nucleotide polymorphism) allele frequency changes in a South Australian rabbit population that was sampled in 1996 (pre-RHD genomes) and after 16 years of RHDV outbreaks. We identified several SNPs with changed allele frequencies within or close to genes potentially important for increased RHD resistance. The identified genes are known to be involved in virus infections and immune reactions or had previously been identified as being differentially expressed in healthy versus acutely RHDV-infected rabbits. Furthermore, we show in a simulation study that the allele/genotype frequency changes cannot be explained by drift alone and that several candidate genes had also been identified as being associated with surviving RHD in a different Australian rabbit population. Our unique data set allowed us to identify candidate genes for RHDV resistance that have evolved under natural conditions, and over a time span that would not have been feasible in an experimental setting. Moreover, it provides a rare example of host genetic adaptations to virus-driven selection in response to a suddenly emerging infectious disease.

Models of spatiotemporal variation in rabbit abundance reveal management hot spots for an invasive species.

The European rabbit (Oryctolagus cuniculus) is a notorious economic and environmental pest species in its invasive range. To better understand the population and range dynamics of this species, 41 yr of abundance data have been collected from 116 unique sites across a broad range of climatic and environmental conditions in Australia. We analyzed this time series of abundance data to determine whether interannual variation in climatic conditions can be used to map historic, contemporary, and potential future fluctuations in rabbit abundance from regional to continental scales. We constructed a hierarchical Bayesian regression model of relative abundance that corrected for observation error and seasonal biases. The corrected abundances were regressed against environmental and disease variables in order to project high spatiotemporal resolution, continent-wide rabbit abundances. We show that rabbit abundance in Australia is highly variable in space and time, being driven primarily by internnual variation in temperature and precipitation in concert with the prevalence of a non-pathogenic virus. Moreover, we show that internnual variation in local spatial abundances can be mapped effectively at a continental scale using highly resolved spatiotemporal predictors, allowing "hot spots" of persistently high rabbit abundance to be identified. Importantly, cross-validated model performance was fair to excellent within and across distinct climate zones. Long-term monitoring data for invasive species can be used to map fine-scale spatiotemporal fluctuations in abundance patterns when accurately accounting for inherent sampling biases. Our analysis provides ecologists and pest managers with a clearer understanding of the determinants of rabbit abundance in Australia, offering an important new approach for predicting spatial abundance patterns of invasive species at the near-term temporal scales that are directly relevant to resource management.

Influence of isotopically labeled internal standards on quantification of serum/plasma 17α-hydroxyprogesterone (17OHP) by liquid chromatography mass spectrometry.

Objectives Our recent survey of 44 mass spectrometry laboratories across 17 countries identified variation in internal standard (IS) choice for the measurement of serum/plasma 17α-hydroxyprogesterone (17OHP) by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The choice of IS may contribute to inter-method variations. This study evaluated the effect of two common isotopically labeled IS on the quantification of 17OHP by LC-MS/MS. Methods Three collaborating LC-MS/MS laboratories from Asia, Europe and Australia, who routinely measure serum 17OHP, compared two IS, (1) IsoSciences carbon-13 labeled 17OHP-[2,3,4-13C3], and (2) IsoSciences deuterated 17OHP-[2,2,4,6,6,21,21,21-2H]. This was performed as part of their routine patient runs using their respective laboratory standard operating procedure. Results The three laboratories measured 99, 89, 95 independent samples, respectively (up to 100 nmol/L) using the 13C- and 2H-labeled IS. The slopes of the Passing-Bablok regression ranged 0.98-1.00 (all 95% confidence interval [CI] estimates included the line of identity), and intercept of <0.1 nmol/L. Average percentage differences of -0.04% to -5.4% were observed between the two IS materials, which were less than the optimal bias specification of 7% determined by biological variation, indicating no clinically significant difference. The results of 12 Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) proficiency samples (1-40 nmol/L) measured by the laboratories were all within the RCPAQAP analytical performance specifications for both IS. Conclusions Overall, the comparison between the results of 13C- and 2H-labeled IS for 17OHP showed good agreement, and show no clinically significant bias when incorporated into the LC-MS/MS methods employed in the collaborating laboratories.

U-shaped association of vigorous physical activity with risk of metabolic syndrome in men with low lean mass, and no interaction of physical activity and serum 25-hydroxyvitamin D with metabolic syndrome risk.

BACKGROUND: There is uncertainty over how lean mass, physical activity (PA) and 25-hydroxyvitamin D (25-OH-D) status interact on metabolic syndrome (MetS) risk in adults. AIMS: To test the hypothesis that these factors additively influence MetS risk. METHODS: Four thousand eight hundred and fifty-eight adults (54.6% female) mean ± SD age 58.0 ± 5.8 years, body mass index 28.1 ± 4.8 kg/m2 , resident in Busselton, Western Australia. PA assessed by questionnaire (all/total and vigorous), lean mass using dual energy X-ray absorptiometry (% total body mass), serum 25-OH-D via immunoassay, analysed using multivariable logistic regression. RESULTS: In men, lower total PA was associated with MetS (no vs >24 h/week odds ratio (OR) = 3.1; ≤8 vs >24 h/week OR = 1.8, both P < 0.001), as was lower lean mass (low vs high OR = 20.4; medium vs high OR = 7.4, both P < 0.001). Men with low lean mass exhibited a U-shaped relationship of vigorous PA with MetS risk (covariate-adjusted: 0 vs 4-8 h/week OR = 2.1, P = 0.037; >12 vs 4-8 h/week OR = 4.3, P = 0.002; interaction P = 0.039). In women, low PA (0 vs >24 h/week OR = 2.1, P = 0.003) and lean mass (low vs high OR = 13.1; medium vs high OR = 7.2, both P < 0.001) were associated with MetS risk. Low 25-OH-D status was associated with MetS in men (low vs high OR = 4.1; medium vs high OR = 2.3, both P < 0.001) and women (OR = 3.5 and 2.1 respectively, both P < 0.001) with no PA interaction. CONCLUSIONS: Men and women with high lean mass have low risk of MetS regardless of PA. Low lean mass identifies men who may benefit most from increasing PA, with an optimal level associated with lowest risk. 25-OH-D and PA do not interact on MetS risk.

Evaluation of 4-Amino 2-Anilinoquinazolines against Plasmodium and Other Apicomplexan Parasites In Vitro and in a P. falciparum Humanized NOD-scid IL2Rγnull Mouse Model of Malaria.

A series of 4-amino 2-anilinoquinazolines optimized for activity against the most lethal malaria parasite of humans, Plasmodium falciparum, was evaluated for activity against other human Plasmodium parasites and related apicomplexans that infect humans and animals. Four of the most promising compounds from the 4-amino 2-anilinoquinazoline series were equally as effective against the asexual blood stages of the zoonotic P. knowlesi, suggesting that they could also be effective against the closely related P. vivax, another important human pathogen. The 2-anilinoquinazoline compounds were also potent against an array of P. falciparum parasites resistant to clinically available antimalarial compounds, although slightly less so than against the drug-sensitive 3D7 parasite line. The apicomplexan parasites Toxoplasma gondii, Babesia bovis, and Cryptosporidium parvum were less sensitive to the 2-anilinoquinazoline series with a 50% effective concentration generally in the low micromolar range, suggesting that the yet to be discovered target of these compounds is absent or highly divergent in non-Plasmodium parasites. The 2-anilinoquinazoline compounds act as rapidly as chloroquine in vitro and when tested in rodents displayed a half-life that contributed to the compound's capacity to clear P. falciparum blood stages in a humanized mouse model. At a dose of 50 mg/kg of body weight, adverse effects to the humanized mice were noted, and evaluation against a panel of experimental high-risk off targets indicated some potential off-target activity. Further optimization of the 2-anilinoquinazoline antimalarial class will concentrate on improving in vivo efficacy and addressing adverse risk.

Serum 25-hydroxyvitamin D as a predictor of mortality and cardiovascular events: A 20-year study of a community-based cohort.

OBJECTIVE: Prospective studies, mostly from Europe and North America, suggest that serum 25-hydroxyvitamin D (25(OH)D) is inversely associated with mortality and cardiovascular disease (CVD) risk. Data from other regions are limited, and threshold levels for adverse cardiovascular outcomes are uncertain. We examined serum 25(OH)D as a predictor of total mortality and cardiovascular outcomes in an Australian cohort. DESIGN: A 20-year, community-based cohort study. PATIENTS: Participants in the 1994/1995 Busselton Health Survey (n = 3946, baseline age 25-84 years). MEASUREMENTS: Baseline serum 25(OH)D and mortality and cardiovascular outcomes to 2014 obtained by record linkage. RESULTS: The mean serum 25(OH)D concentration was 60.6 ± 18.0 nmol/L. During 20-year follow-up (excluding the first 2 years), 889 participants died (including 363 from CVD) and 944 experienced a CVD event (including 242 with heart failure). In the full cohort, controlling for Framingham risk score variables, higher baseline 25(OH)D was associated with significantly reduced all-cause mortality (adjusted HR 0.83 per SD increment of 25(OH)D, 95% CI 0.77-0.90), CVD death (HR 0.85, 95% CI 0.74-0.96) and heart failure (HR 0.81, 95% CI 0.69-0.94), but not CVD events (HR 0.99, 0.92-1.07). In restricted cubic spline regression models, serum 25(OH)D below 65 and 55 nmol/L was associated with higher total mortality and higher CVD mortality/heart failure, respectively. In participants without CVD at baseline (n = 3220), results were similar, but hazard ratios were attenuated and associations with CVD mortality no longer significant. CONCLUSIONS: In an Australian community-based cohort, baseline vitamin D levels below 55-65 nmol/L are predictive of all-cause mortality, CVD death and heart failure.

Vitamin D and respiratory health in the Busselton Healthy Ageing Study.

BACKGROUND AND OBJECTIVE: The relationship between vitamin D and respiratory disease was examined by cross-sectional analysis of a large community-based sample. METHODS: Serum 25-hydroxyvitamin D (25OHD) and history of respiratory disease, symptoms (recorded by questionnaire) and spirometry were measured in 5011 adults aged 45-69 years. Adjustments were made for age, sex, season and smoking (Model A), plus body mass index (BMI) and physical activity level (Model B), plus history of chronic diseases (Model C). RESULTS: Mean (SD) age was 58 (SD 6) years with 45% males, 10% current smokers and 12% taking vitamin D supplements. The prevalence of 25OHD level <50 nmol/L was 8.0%. In all the three models, 25OHD <50 nmol/L was significantly associated with asthma (Model C: odds ratio (OR): 1.32; 95% CI: 1.00, 1.73), bronchitis (1.54; 1.17, 2.01), wheeze (1.37; 1.10, 1.71) and chest tightness (1.42; 1.10, 1.83). Participants with vitamin D level > 100 nmol/L had higher forced vital capacity (FVC) in all the three models (1.17% higher, compared with the 50-100 nmol/L group in Model C). CONCLUSION: Low levels of serum 25OHD were independently associated with asthma, bronchitis, wheeze and chest tightness after three levels of adjustment for potential confounders. Higher vitamin D levels were associated with higher levels of lung function.

Proposal for a unified classification system and nomenclature of lagoviruses.

Lagoviruses belong to the Caliciviridae family. They were first recognized as highly pathogenic viruses of the European rabbit (Oryctolagus cuniculus) and European brown hare (Lepus europaeus) that emerged in the 1970-1980s, namely, rabbit haemorrhagic disease virus (RHDV) and European brown hare syndrome virus (EBHSV), according to the host species from which they had been first detected. However, the diversity of lagoviruses has recently expanded to include new related viruses with varying pathogenicity, geographic distribution and host ranges. Together with the frequent recombination observed amongst circulating viruses, there is a clear need to establish precise guidelines for classifying and naming lagovirus strains. Therefore, here we propose a new nomenclature based on phylogenetic relationships. In this new nomenclature, a single species of lagovirus would be recognized and called Lagovirus europaeus. The species would be divided into two genogroups that correspond to RHDV- and EBHSV-related viruses, respectively. Genogroups could be subdivided into genotypes, which could themselves be subdivided into phylogenetically well-supported variants. Based on available sequences, pairwise distance cutoffs have been defined, but with the accumulation of new sequences these cutoffs may need to be revised. We propose that an international working group could coordinate the nomenclature of lagoviruses and any proposals for revision.