Calcaneal ultrasound reference ranges for Australian men and women : the Geelong Osteoporosis Study

Summary Heel ultrasound is a more portable modality for assessing fracture risk than dual-energy X-ray absorptiometry and does not use ionising radiation. Fracture risk assessment requires appropriate reference data to enable comparisons. This study reports the first heel ultrasound reference ranges for the Australian population.

Introduction This study aimed to develop calcaneal (heel) ultrasound reference ranges for the Australian adult population using a population-based random sample.

Methods Men and women aged ≥20 years were randomly selected from the Barwon Statistical Division in 2001–2006 and 1993–1997, respectively, using the electoral roll. Broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (SI) were measured at the heel using a Lunar Achilles Ultrasonometer. Gender-specific means and standard deviations for BUA, SOS and SI were calculated for the entire sample (men 20–93 years, n = 1,104; women 20–92 years, n = 914) and for participants aged 20–29 years (men, n = 157; women, n = 151). Associations between ultrasound measures and age were examined using linear regression.

Results For men, mean ± standard deviation BUA, SOS and SI were 118.7 ± 15.8 dB/MHz, 1,577.0 ± 43.7 m/s and 100.5 ± 20.7, respectively; values for women were consistently lower (111.0 ± 16.4 dB/MHz, P < 0.001; 1,571.0 ± 39.0 m/s, P = 0.001; and 93.7 ± 20.3, P < 0.001, respectively). BUA was higher in young men compared with young women (124.5 ± 14.4 vs 121.0 ± 15.1 dB/MHz), but SOS (1,590.1 ± 43.1 vs 1,592.5 ± 35.0 m/s) and SI (108.0 ± 19.9 vs 106.3 ± 17.7) were not. The relationships between age and each ultrasound measure were linear and negative across the age range in men; associations were also negative in women but non-linear.

Conclusion These data provide reference standards to facilitate the assessment of fracture risk in an Australian population using heel ultrasound.

Alcohol consumption and body composition in a population-based sample of elderly Australian men

Background: Alcohol is calorie dense, and impacts activity, appetite and lipid processing. The aim of this study was to therefore investigate the association between alcohol consumption and components of body composition including bone, fat and lean tissue.

Methods: Participants were recruited from a randomly selected, population-based sample of 534 men aged 65 years and older enrolled in the Geelong Osteoporosis Study. Alcohol intake was ascertained using a food frequency questionnaire and the sample categorised as nondrinkers or alcohol users who consumed B2, 3–4 or C5 standard drinks on a usual drinking day. Bone mineral density (BMD), lean body mass and body fat mass were measured using dual energy X-ray absorptiometry; overall adiposity (%body fat), central adiposity (%truncal fat) and body mass index (BMI) were calculated. Bone quality was determined by quantitative heel ultrasound (QUS).

Results: There were 90 current non-drinkers (16.9 %), 266 (49.8 %) consumed 1–2 drinks/day, 104 (19.5 %) 3–4 drinks/day and 74 (13.8 %) C5 drinks/day. Those consuming C5 drinks/day had greater BMI (?4.8 %), fat mass index (?20.1 %), waist circumference (?5.0 %), %body fat (?15.2 %) and proportion of trunk fat (?5.3 %) and lower lean mass (-5.0 %) than non-drinkers after adjustment for demographic and lifestyle factors. Furthermore, they were more likely to be obese than non-drinkers according to criteria based on BMI (OR = 2.83, 95 %CI 1.10–7.29) or waist circumference (OR = 3.36, 95 %CI 1.32–8.54). There was an inverse relationship between alcohol consumption and QUS parameters and BMD at the mid forearm site; no differences were detected for BMD at other skeletal sites.

Conclusion: Higher alcohol intake was associated with greater total and central adiposity and reduced bone quality.

Undercarboxylated osteocalcin, muscle strength and indices of bone health in older women

We investigated the association between undercarboxylated osteocalcin (ucOC) and lower-limb muscle strength in women over the age of 70years. The study also aims to confirm the association between bone turnover markers and heel ultrasound measures. A post-hoc analysis using data collected as part of a randomized placebo-controlled trial of vitamin D supplementation. An immunoassay was used to quantify total OC (tOC), with hydroxyapatite pre-treatment for ucOC. We determined associations of absolute and relative (ucOC/tOC; ucOC%) measures of ucOC with lower-limb muscle strength, heel ultrasound measures of speed of sound (SOS) and broadband ultrasound attenuation (BUA), bone turnover markers (BTMs; P1NP and CTx) and the acute phase protein alpha-1-antichymotrypsin (α-ACT). ucOC%, but not absolute ucOC concentration, was positively associated with hip flexor, hip abductor and quadriceps muscle strength (all p<0.05). ucOC% was negatively associated with α-ACT (β-coefficient=-0.24, p=0.02). tOC was positively associated with both P1NP and CTx (p<0.001). For each per unit increase in tOC (μg/L) there was a corresponding lower BUA, SOS and SI (β-coefficient = -0.28; -0.23 and -0.23, respectively; all p<0.04). In conclusion, ucOC% is positively associated with muscle strength and negatively associated with α-ACT. These data support a role for ucOC in musculoskeletal interactions in humans. Whilst tOC is associated with bone health, ucOC% and ucOC may also be linked to falls and fracture risk by influencing muscle function.

Cholinesterase Research Outreach Project (CROP): measuring cholinesterase activity and pesticide use in an agricultural community

BACKGROUND: Australian farmers and their workers are exposed to a wide variety of pesticides. Organophosphate (OP) insecticides are a widely used class of pesticide used for animal husbandry practices (Naphthalophos for sheep dipping, jetting and drench), crop production for pest control (Dimethoate) and in public health (Maldison for head lice). Acute poisonings with this class of insecticide are reported among agricultural workers and children around the globe, due to the inhibition of acetylcholinesterase (AChE). Less is known about chronic exposures. Regular monitoring of erythrocyte AChE will enable farmers to identify potential exposure to organophosphate insecticides and take action to reduce exposures and improve their health and safety practices. This study aims to assess and improve the integration of AChE monitoring into routine point of care health clinics, and provide farming and non-farming people with a link between their AChE activity and their household chemical and agrichemical use. METHODS/DESIGN: The research will target individuals who work on mixed farming enterprises and routinely using OPs (n = 50) and non-farmers (n = 30). Baseline data are collected regarding demographic, health conditions and behaviours, Kessler 10 (K10) scores, chemical use and personal protection. Baseline anthropometric measures include height, weight, hip and waist circumference, body fat analysis and, biochemical analysis of fasted total serum cholesterol, triglycerides, low-density cholesterol (LDL), high-density cholesterol (HDL) and blood glucose. Analysis of erythrocyte cholinesterase (EAChE) activity is also conducted using a finger prick test. Testing of EAChE is then repeated in all participants every 3 weeks for a maximum of three times over a period 10 weeks. Participants are provided with full feedback and counselling about their EAChE activity after each reading and a detailed summary provided to all participants at the completion of the study. Data will be analysed using repeated measures within a general linear model. DISCUSSION: This work will provide an evidence base and recommendations for the integration of EAChE monitoring into Australian rural health clinics, leading to research which will further quantify pesticide exposure both on the farm and in the home, highlighting the importance of sustaining and providing a safe work and home environment for farming communities. TRIAL REGISTRATION: ACTRN12613001256763.

Which infants with eczema are at risk of food allergy? Results from a population-based cohort

BACKGROUND: The relationship between early onset eczema and food allergy among infants has never been examined in a population-based sample using the gold standard for diagnosis, oral food challenge. OBJECTIVE: We characterised the risk of challenge-proven food allergy among infants with eczema in the general population. METHODS: One-year-old infants (n = 4453 meeting criteria for this analysis) were assessed for history of eczema, received a nurse-administered eczema examination and underwent skin prick testing to peanut, egg and sesame. Those with a detectable wheal to one of the test foods underwent an oral food challenge irrespective of wheal size. The risk of food allergy, stratified by eczema severity and age of onset, was estimated using multivariate logistic regression with population sampling weights. RESULTS: One in five infants with eczema were allergic to peanut, egg white or sesame, compared to one in twenty-five infants without eczema (OR 6.2, 95% CI 4.9, 7.9, P < 0.001). The prevalence of peanut allergy was low in the absence of eczema (0.7% 95% CI 0.4, 1.1). Infants with eczema were 11.0 times more likely to develop peanut allergy (95% CI 6.6, 18.6) and 5.8 times more likely to develop egg allergy (95% CI 4.6, 7.4) by 12 months than infants without eczema. 50.8% of infants (95% CI 42.8, 58.9) with early eczema onset (<3 months) who required doctor-prescribed topical corticosteroid treatment developed challenge-proven food allergy. CONCLUSION AND CLINICAL RELEVANCE: Eczema, across the clinical severity spectrum in infancy, is a strong risk factor for IgE-mediated food allergy. Infants with eczema were six times more likely to have egg allergy and 11 times more likely to have peanut allergy by 12 months than infants without eczema. Our data suggest that a heightened awareness of food allergy risk among healthcare practitioners treating infants with eczema, especially if early onset and severe, is warranted.

Resistive vibration exercise reduces lower limb muscle atrophy during 56-day bed-rest

OBJECTIVES: The current study aimed to examine the effectiveness of a resistive vibration exercise countermeasure during prolonged bed-rest in preventing lower-limb muscle atrophy. METHODS: 20 male subjects underwent 56-days of bed-rest and were assigned to either an inactive control, or a countermeasure group which performed high-load resistive exercises (including squats, heel raises and toe raises) with whole-body vibration. Magnetic resonance imaging of the lower-limbs was performed at two-weekly intervals. Volume of individual muscles was calculated. RESULTS: Countermeasure exercise reduced atrophy in the triceps surae and the vastii muscles (F>3.0, p<.025). Atrophy of the peroneals, tibialis posterior and toe flexors was less in the countermeasure-subjects, though statistical evidence for this was weak (F

Switch point finding using polynomial regression for fuzzy type reduction algorithms

Karnik-Mendel (KM) algorithm is the most widely used type reduction (TR) method in literature for the design of interval type-2 fuzzy logic systems (IT2FLS). Its iterative nature for finding left and right switch points is its Achilles heel. Despite a decade of research, none of the alternative TR methods offer uncertainty measures equivalent to KM algorithm. This paper takes a data-driven approach to tackle the computational burden of this algorithm while keeping its key features. We propose a regression method to approximate left and right switch points found by KM algorithm. Approximator only uses the firing intervals, rnles centroids, and FLS strnctural features as inputs. Once training is done, it can precisely approximate the left and right switch points through basic vector multiplications. Comprehensive simulation results demonstrate that the approximation accuracy for a wide variety of FLSs is 100%. Flexibility, ease of implementation, and speed are other features of the proposed method.

Cohort Profile: The Barwon Infant Study

The modern environment is associated with an increasing burden of non-communicable diseases (NCDs). Mounting evidence implicates environmental exposures, experienced early in life (including in utero), in the aetiology of many NCDs, though the cellular/molecular mechanism(s) underlying this elevated risk across the life course remain unclear. Epigenetic variation has emerged as a candidate mediator of such effects. The Barwon Infant Study (BIS) is a population-derived birth cohort study (n ¼ 1074 infants) with ante-natal recruitment, conducted in the south-east of Australia (Victoria). BIS has been designed to facilitate a detailed mechanistic investigation of development within an epidemiological framework. The broad objectives are to investigate the role of specific environmental factors, gut microbiota and epigenetic variation in early-life development, and subsequent immune, allergic, cardiovascular, respiratory and neurodevelopmental outcomes. Participants have been reviewed at birth and at 1, 6, 9 and 12 months, with 2-and 4-year reviews under way. Biological samples and measures include: maternal blood, faeces and urine during pregnancy; infant urine, faeces and blood at regular intervals during the first 4 years; lung function at 1 month and 4 years; cardiovascular assessment at 1 month and 4 years; skin-prick allergy testing and food challenge at 1 year; and neurodevelopmental assessment at 9 months, 2 and 4 years. Data access enquiries can be made at [www.barwoninfantstudy.org.au] or via [peter.vuillermin@deakin.edu.au].

The PREPARE pilot RCT of home-based progressive resistance exercises for venous leg ulcers

OBJECTIVE: To establish the feasibility of conducting a home-based progressive resistance exercise programme to improve calf muscle pump function in community-based patients with venous leg ulcers. METHOD: Participants were randomised to receive a 12-week progressive resistance exercise programme using heel raises in addition to compression. The control was usual care in addition to compression. Randomisation was stratified by ulcer duration and ulcer size. Air plethysmography was used to determine changes in calf muscle pump function from baseline. Changes in ulcer parameters were measured using the SilhouetteMobile device. RESULTS: Forty participants were randomised. There were significantly greater improvements in ejection fraction of the calf muscle in the exercise group compared with the control (usual care) group (mean difference 18.5%, 95% CI 0.03 to 36.6%, p<0.05). Other parameters improved in the exercise group but the mean differences were not significant. Adherence with prescribed exercises was 81% and there was no significant difference in the numbers reporting adverse events. There were also no significant differences in ulcer healing parameters (change in area, percentage change in area, number healed at 12 weeks, time to healing). CONCLUSION: A community-based randomised trial of progressive resistance exercise is feasible. The prescribed exercises appeared to increase ejection fraction, but the effect of exercise on ulcer healing requires further investigation.

VITALITY trial: protocol for a randomised controlled trial to establish the role of postnatal vitamin D supplementation in infant immune health

Introduction Postnatal vitamin D supplementation may be associated with a reduction in IgE-mediated food allergy, lower respiratory tract infections and improved bone health. Countries in the Northern hemisphere recommend universal infant vitamin D supplementation to optimise early vitamin D levels, despite the absence of large trials proving safety or efficacy for any disease outcome. With the aim of determining the clinical and cost-effectiveness of daily vitamin D supplementation in breastfed infants from age 6–8 weeks to 12 months of age, we have started a double-blind, randomised, placebo-controlled trial of daily 400 IU vitamin D supplementation during the first year of life, VITALITY. Methods nd analysis Infants (n=3012) who are fully breastfed and not receiving vitamin D supplementation will be recruited at the time of their first immunisation, from council-led immunisation clinics throughout metropolitan Melbourne, Australia. The primary outcome is challenge-proven food allergy at 12 months of age. Secondary outcomes are food sensitisation (positive skin prick test), number of lower respiratory infections (through hospital linkage), moderately-severe and persistent eczema (by history and examination) and vitamin D deficiency (serum vitamin D <50 nmol/L) at age 12 months. The trial is underway and the first 130 participants have been recruited.

User centric design, data analysis and performance of snowboard bindings

This study focuses on soft boot snowboard bindings by looking at how users interact with their binding and proposes a possible solution to overcome such issues. Snowboarding is a multibillion-dollar sport that has only reached mainstream in the last 30 years its levels of progression in technology have evolved in that time. However, snowboard bindings for the most part still consist of the same basic architecture in the last 20 years. This study was aimed at taking a user centric point of view and using additive manufacturing technologies to be able to generate a new snowboard binding that is completely adaptable to the user. The initial part of the study was a survey of 280 snowboarders focussing on preferences, style and habits. This survey was generated from over 15 nations with the vast majority of boarders on the snow for five to fifty days a year. Significant emphasis was placed on the relationship between boarder binding set-up and occurrence of pain and/or injury. From the detailed survey it was found that boarder's experienced pain in the front foot/toe area as a result from the toe strap being too tight. However boarders wanted tighter bindings to increase responsiveness. Survey data was compared to ankle and foot biomechanics to build a relationship to assess the problem of pain versus responsiveness. The design stage of the study was to develop a binding that overcame the over-tightening of the binding but still maintain equivalent or better responsiveness compared to traditional bindings. The resulting design integrated the snowboard boot much more into the design, by using the sole as a "semi-rigid" platform and locking it in laterally between the heel cup and the new toe strap arrangement. The new design developed using additive manufacturing techniques was tested via qualitative and quantitative measures in the snow and in the lab. It was found that using the new arrangement in a system resulted in no loss of performance or responsiveness to the user. Due to the design and manufacturing approach users have the ability to customise the design to their specific needs.

Mechanical ageing performance of minimalist and traditional footwear foams

The aim of this study was to obtain a fundamental understanding of how running shoe midsole foam thickness contributes to footwear degradation using the heel and forefoot regions of traditional (TS) and minimalist (MS) running shoes. We hypothesized that ethylene vinyl acetate (EVA) foam midsole material properties and footwear degradation performance under a biofidelic mechanical ageing protocol would differ as a function of shoe type and thickness. Attenuated totalreflectance Fourier transform infrared spectra indicated that the foam chemical compositions were similar and confirmed that all midsoles were composed of EVA copolymer. Differences in density and cell size were detected between shoes and thicknesses. MS foam was uniformly high density (rMS D 240 kg/m3), while TS foam consisted of two co-molded layers with forefoot density (rTS-FF D 250 kg/m3) greater than heel (rTS-H D 160 kg/m3). Relative density and cell size values were generally proportional and inversely proportional to density, respectively. Degradation from mechanical ageing was greatest in the first 2 km of ageing, with the full ageing (21 km) resulting in an average 54% loss of energy absorption. Regardless of shoe type or foam microstructure, thicker and softer heel foams absorbed 83% more energy but degraded ata 49% faster rate. The fact that the heel degraded more rapidly than forefoot caused the drop to decrease at an equivalent rate for both shoe types. Overall, thickness was a greater predictor of average performance than microstructure variables for the present footwear conditions. However, the apparent drawback of thicker foam was exemplified by heel samples, which underwent a 1.4 mm greater loss of thickness and lost 550 mJ more energy absorption than forefoot samples.