Ben Ewald

University of Newcastle, Newcastle, New South Wales, Australia

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Publications (21)51.89 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Although an overall public health target of 10,000 steps/day has been advocated, the dose response relationship for each health benefit of physical activity (PA) may differ. METHODS: A representative, community sample of 2458 people aged 55-85 in Australia wore a pedometer for a week in 2005-2007 and completed a health assessment. Age standardised steps/day were compared to multiple markers of health using locally weighted regression to produce smoothed dose response curves, then to select the steps/day matching 60% or 80% of the range in each health marker. RESULTS: There is a linear relationship between activity level and markers of inflammation throughout the range of steps/day; this is also true for BMI in women and high density lipoprotein in men. For other markers, including waist:hip ratio, fasting glucose, depression, and SF36 scores, the benefit of PA is mostly in the lower half of the distribution. CONCLUSIONS: Older adults have no plateau in the curve for some health outcomes, even beyond 12 000 steps per day. For other markers however there is a threshold effect, indicating that most of the benefit is achieved by 8000 steps per day, supporting this as a suitable public health target for older adults.
    Journal of Physical Activity and Health 03/2013; · 1.95 Impact Factor
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    ABSTRACT: Older adults and special populations (living with disability and/or chronic illness that may limit mobility and/or physical endurance) can benefit from practicing a more physically active lifestyle, typically by increasing ambulatory activity. Step counting devices (accelerometers and pedometers) offer an opportunity to monitor daily ambulatory activity; however, an appropriate translation of public health guidelines in terms of steps/day is unknown. Therefore this review was conducted to translate public health recommendations in terms of steps/day. Normative data indicates that 1) healthy older adults average 2,000-9,000 steps/day, and 2) special populations average 1,200-8,800 steps/day. Pedometer-based interventions in older adults and special populations elicit a weighted increase of approximately 775 steps/day (or an effect size of 0.26) and 2,215 steps/day (or an effect size of 0.67), respectively. There is no evidence to inform a moderate intensity cadence (i.e., steps/minute) in older adults at this time. However, using the adult cadence of 100 steps/minute to demark the lower end of an absolutely-defined moderate intensity (i.e., 3 METs), and multiplying this by 30 minutes produces a reasonable heuristic (i.e., guiding) value of 3,000 steps. However, this cadence may be unattainable in some frail/diseased populations. Regardless, to truly translate public health guidelines, these steps should be taken over and above activities performed in the course of daily living, be of at least moderate intensity accumulated in minimally 10 minute bouts, and add up to at least 150 minutes over the week. Considering a daily background of 5,000 steps/day (which may actually be too high for some older adults and/or special populations), a computed translation approximates 8,000 steps on days that include a target of achieving 30 minutes of moderate-to-vigorous physical activity (MVPA), and approximately 7,100 steps/day if averaged over a week. Measured directly and including these background activities, the evidence suggests that 30 minutes of daily MVPA accumulated in addition to habitual daily activities in healthy older adults is equivalent to taking approximately 7,000-10,000 steps/day. Those living with disability and/or chronic illness (that limits mobility and or/physical endurance) display lower levels of background daily activity, and this will affect whole-day estimates of recommended physical activity.
    International Journal of Behavioral Nutrition and Physical Activity 07/2011; 8:80. · 3.58 Impact Factor
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    ABSTRACT: To determine the suitability of using the self-controlled case series design to assess improvements in health outcomes using the effectiveness of beta blockers for heart failure in reducing hospitalisations as the example. The Australian Government Department of Veterans' Affairs administrative claims database was used to undertake a self-controlled case-series in elderly patients aged 65 years or over to compare the risk of a heart failure hospitalisation during periods of being exposed and unexposed to a beta blocker. Two studies, the first using a one year period and the second using a four year period were undertaken to determine if the estimates varied due to changes in severity of heart failure over time. In the one year period, 3,450 patients and in the four year period, 12, 682 patients had at least one hospitalisation for heart failure. The one year period showed a non-significant decrease in hospitalisations for heart failure 4-8 months after starting beta-blockers, (RR, 0.76; 95% CI (0.57-1.02)) and a significant decrease in the 8-12 months post-initiation of a beta blocker for heart failure (RR, 0.62; 95% CI (0.39, 0.99)). For the four year study there was an increased risk of hospitalisation less than eight months post-initiation and significant but smaller decrease in the 8-12 month window (RR, 0.90; 95% CI (0.82, 0.98)). The results of the one year observation period are similar to those observed in randomised clinical trials indicating that the self-controlled case-series method can be successfully applied to assess health outcomes. However, the result appears sensitive to the study periods used and further research to understand the appropriate applications of this method in pharmacoepidemiology is still required. The results also illustrate the benefits of extending beta blocker utilisation to the older age group of heart failure patients in which their use is common but the evidence is sparse.
    BMC Medical Research Methodology 01/2011; 11:106. · 2.21 Impact Factor
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    International Journal of Epidemiology 12/2010; 39(6):1452-63. · 6.98 Impact Factor
  • Journal of Science and Medicine in Sport - J SCI MED SPORT. 01/2010; 12.
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    ABSTRACT: We test the hypothesis that the odds of self-reported receipt of lifestyle advice from a health care provider will be lower among outpatient cardiac rehabilitation (OCR) nonattendees and nonreferred patients compared to OCR attendees. Logistic regression was used to analyse cross-sectional data provided by 65% (4971/7678) of patients aged 20 to 84 years discharged from public hospitals with a diagnosis indicating eligibility for OCR between 2002 and 2007. Among respondents, 71% (3518) and 55% (2724) recalled advice regarding physical activity and diet, respectively, while 88% (592/674) of smokers recalled quit advice. OCR attendance was low: 36% (1764) of respondents reported attending OCR, 11% (552) did not attend following referral, and 45% (2217) did not recall being invited. The odds of recalling advice regarding physical activity and diet were significantly lower among OCR nonattendees compared to attendees (OR 0.34, 95% CI 0.21, 0.56 and OR 0.33, 95% CI 0.25, 0.44, resp.) and among nonreferred respondents compared to OCR attendees (OR 0.10, 95% CI 0.07, 0.15 and OR 0.17, 95% CI 0.14, 0.22, resp.). Patients hospitalised for coronary heart disease should be referred to OCR or a suitable alternative to improve recall of lifestyle advice that will reduce the risk of further coronary events.
    Rehabilitation research and practice. 01/2010; 2010:541741.
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    ABSTRACT: To established population norms for pedometer determined step counts in older Australians. A representative sample of 684 participants over the age of 55 years wore a pedometer for a week in Newcastle, Australia. Response rate was 32%. Median daily step count was 8605 in those aged 55-59 years declining to 3778 in those over 80 years old. The proportion who reached 8000 steps per day was 62% in those 55-59 years and 12% in those over 80 years. Daily step counts were highest on Thursdays and Fridays and least on Sundays. Weekend days had on average 620 less steps than weekdays. After adjusting for age, there was a negative association of step count with body mass index >30, and with a history of arthritis but no significant association with other demographic variables. Pedometry is feasible in an elderly sample, and research involving pedometers must take days of the week into account.
    Australasian Journal on Ageing 09/2009; 28(3):127-33. · 0.94 Impact Factor
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    ABSTRACT: To explore use of bone densitometry in Australia and to identify any sex and geographic differences, as a marker of osteoporosis diagnosis and care. Analysis of claims data from Medicare Australia in patients aged over 45 years during the period 2001-2005. Age-standardised rates of bone densitometry use, by sex and by metropolitan, rural or remote classification. Bone densitometry use increased by 26% over the 5 years. Rates were lower for rural and remote populations, with people in capital cities about three times as likely to undergo the investigation as those in remote areas. The sex ratio for the rate of bone densitometry use (women to men) decreased from more than 6 : 1 in 2001 to 4 : 1 in 2005. Although the sex ratio for osteoporotic fracture is close to 2 : 1 (women to men), the sex ratio for testing is much higher, suggesting underuse of bone densitometry in men. Sex and rural inequities in use of the investigation need to be addressed as part of a national approach to reducing minimal trauma fracture.
    The Medical journal of Australia 03/2009; 190(3):126-8. · 2.85 Impact Factor
  • Bone 01/2009; 44. · 4.46 Impact Factor
  • B Ewald, M McEvoy, J Attia
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    ABSTRACT: Measuring physical activity is a key part of studying its health effects. Questionnaires and pedometers each have weaknesses but are the cheapest and easiest to use measurement methods for large-scale studies. We examined their capacity to detect expected associations between physical activity and a range of surrogate health measures. Cross-sectional analysis of 669 community-dwelling participants (mean age 63.3 (7.7) years) who completed the Physical Activity Scale for the Elderly (PASE) questionnaire and who, within 2 weeks, wore a pedometer for 7 days. PASE score and step count were only poorly correlated (r = 0.37 in women, r = 0.30 in men). Of 12 expected associations examined between activity and surrogate markers of health, 10 were detected as statistically significant by step counts but only 3 by PASE scores. Significant associations in the expected direction were found between step counts and high-density lipoprotein, body mass index, waist circumference, waist-to-hip ratio, blood glucose level, white cell count and fibrinogen. There was no association with either systolic or diastolic blood pressure. The association between PASE score and these markers was detected as significant only for body mass index and waist circumference in women and waist-to-hip ratio in both sexes. Associations were stronger for steps multiplied by stride length than for raw step count. Pedometer-derived step counts are a more valid measurement of overall physical activity in this sample than PASE score. Researchers should use objective measures of physical activity whenever possible.
    British journal of sports medicine 08/2008; 44(10):756-61. · 3.67 Impact Factor
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    ABSTRACT: We set out to review the validity of tests for B type natriuretic peptide (BNP) and N-terminal pro BNP (NTproBNP) in the diagnosis of clinical heart failure (HF) in primary care and hospital settings and to examine the effect of age. We also examined the accuracy of the test in population screening for left ventricular systolic dysfunction. Medline and Embase were searched systematically till June 2005. Forty-seven studies were identified for systematic review and 27 were included in meta-analyses. Test performance was summarized as the diagnostic odds ratio (DOR). As a secondary data analysis, this paper does not require ethical approval. In groups of symptomatic patients with average age less than 80 years, the summary DOR of 27 for BNP equates to a sensitivity of 85% and specificity of 84% in the detection of clinical HF. Summary of head-to-head studies shows BNP is a better indicator than NTproBNP. The performance of both tests decreased with the age of patients, the DOR declining by a factor of 2.0 for BNP and 2.5 for NTproBNP for each decade of increasing age. BNP correlated better to clinical status than to echocardiographic parameters, and test performance was similar in acute inpatient and general practice settings. Tests for BNP are helpful in the diagnosis of clinical HF or in screening for left ventricular systolic dysfunction and are superior to NTproBNP. In the clinical setting, test performance declined with increasing patient age.
    Internal Medicine Journal 03/2008; 38(2):101-13. · 1.82 Impact Factor
  • Internal Medicine Journal 02/2008; 38(2). · 1.82 Impact Factor
  • Ben Ewald, Daniel Ewald
    BMC Family Practice 01/2008; · 1.61 Impact Factor
  • Ben Ewald, David Durrheim
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    ABSTRACT: Ten years after the recognition of Australian Bat Lyssavirus, it is timely to review the occurrence of the virus in native microbat and flying fox species in Australia, and the effectiveness of post-exposure treatment in humans. Differences between post-exposure treatment protocols adopted by state and territory health departments were examined. In Queensland and the United States of America, post-exposure treatment is withheld in people who are bitten by bats that subsequently test negative for ABLV and rabies, respectively. The good outcomes from these protocols support the revised NSW policy, which delays post-exposure treatment for up to 48 hours for minor exposures while awaiting bat test results. Post-exposure treatment can be withheld or ceased if the bat test result is negative.
    New South Wales Public Health Bulletin 01/2008; 19(5-6):104-7.
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    ABSTRACT: NSW has a putative malaria vector in Anopheles annulipes, and increased numbers of immigrants from malaria endemic countries who may be infective to mosquitoes but asymptomatic. We examine the factors known to influence malaria transmission and conclude that local transmission is possible but unlikely. The public health implications are that there should be systematic screening of immigrants from malaria endemic countries on arrival, and that the public health capacity to identify and respond to a malaria outbreak should be maintained.
    New South Wales Public Health Bulletin 01/2008; 19(7-8):127-31.
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    Ben Ewald
    Journal of Clinical Epidemiology 07/2007; 60(7):756-756. · 5.48 Impact Factor
  • Ben Ewald
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    ABSTRACT: To examine the extent of bias introduced to diagnostic test validity research by the use of post hoc data driven analysis to generate an optimal diagnostic cut point for each data set. Analysis of simulated data sets of test results for diseased and nondiseased subjects, comparing data driven to prespecified cut points for various sample sizes and disease prevalence levels. In studies of 100 subjects with 50% prevalence a positive bias of five percentage points of sensitivity or specificity was found in 6 of 20 simulations. For studies of 250 subjects with 10% prevalence a positive bias of 5% was observed in 4 of 20 simulations. The use of data-driven cut points exaggerates test performance in many simulated data sets, and this bias probably affects many published diagnostic validity studies. Prespecified cut points, when available, would improve the validity of diagnostic test research in studies with less than 50 cases of disease.
    Journal of Clinical Epidemiology 09/2006; 59(8):798-801. · 5.48 Impact Factor
  • Ben Ewald, John Attia
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    ABSTRACT: Current guidelines suggest general practitioners should screen their diabetic patients for microalbuminuria. There is a range of possible tests. We looked for studies that compared a timed urine sample (the gold standard) with a random spot sample. Systematic review and meta analysis of studies comparing albumin to creatinine ratio (ACR) on a random specimen to albumin excretion rate from an overnight or 24 hour timed sample. Studies were identified using Medline and EMBASE to June 2003. Studies were pooled using diagnostic odds ratios and were checked for heterogeneity. Ten studies covering 1470 patients were included. Use of the ACR in screening 100 diabetic patients would miss only two out of the 20 patients who would be expected to have microalbuminuria, while there would be 13 false positives. A timed specimen would be required to clarify the diagnosis for 31 patients. The marginal benefit of using a timed urine collection over a spot ACR to detect microalbuminuria in the screening of diabetic patients is small, and not worth the cost and inconvenience of collecting a timed sample.
    Australian family physician 08/2004; 33(7):565-7, 571. · 0.71 Impact Factor
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    ABSTRACT: To assess the accuracy and variability of clinicians' estimates of pre-test probability for three common clinical scenarios. Postal questionnaire survey conducted between April and October 2001 eliciting pre-test probability estimates from scenarios for risk of ischaemic heart disease (IHD), deep vein thrombosis (DVT), and stroke. Physicians and general practitioners randomly drawn from College membership lists for New South Wales and north-west England. Agreement with the "correct" estimate (being within 10, 20, 30, or > 30 percentage points of the "correct" estimate derived from validated clinical-decision rules); variability in estimates (median and interquartile ranges of estimates); and association of demographic, practice, or educational factors with accuracy (using linear regression analysis). 819 doctors participated: 310 GPs and 288 physicians in Australia, and 106 GPs and 115 physicians in the UK. Accuracy varied from about 55% of respondents being within 20% of the "correct" risk estimate for the IHD and stroke scenarios to 6.7% for the DVT scenario. Although median estimates varied between the UK and Australian participants, both were similar in accuracy and showed a similarly wide spread of estimates. No demographic, practice, or educational variables substantially predicted accuracy. Experienced clinicians, in response to the same clinical scenarios, gave a wide range of estimates for pre-test probability. The development and dissemination of clinical decision rules is needed to support decision making by practising clinicians.
    The Medical journal of Australia 06/2004; 180(9):449-54. · 2.85 Impact Factor
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    ABSTRACT: Various measures have been proposed to express the excess risk of an outcome attributable to one particular risk factor, such as attributable risk and risk fraction. However, there is sometimes a need, both in epidemiological studies and in awarding compensation in legal cases, to simultaneously consider the contribution of several risk factors to a disease outcome, when a biological model is not available. We propose a method that allocates the proportional contribution of several risk factors to a disease outcome, based on the weighted contribution of the risk fraction for each risk factor. We demonstrate the use of this method using figures for renal cell carcinoma, and discuss the caveats in using this method for epidemiologic studies, and in awarding compensation in legal cases.
    Journal of Clinical Epidemiology 07/2002; 55(6):588-92. · 5.48 Impact Factor

Publication Stats

224 Citations
51.89 Total Impact Points

Institutions

  • 2004–2013
    • University of Newcastle
      • • Centre for Clinical Epidemiology and Biostatistics
      • • School of Medicine and Public Health
      Newcastle, New South Wales, Australia
  • 2008
    • Newcastle University
      Newcastle-on-Tyne, England, United Kingdom