Ben Ewald

How many steps/day are enough? For older adults and special populations

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.

Meta-analysis of B type natriuretic peptide and N-terminal pro B natriuretic peptide in the diagnosis of clinical heart failure and population screening for left ventricular systolic dysfunction

Background:  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.

Cohort Profile: The Hunter Community Study

In almost every country, the proportion of people aged 460 years is growing faster than any other age group and is expected to reach 2 billion worldwide by 2050. Internationally and nationally, considerable efforts are being made to promote active ageing. However, Australia lacks the kind of comprehensive longitudinal research underway in Europe and North America. Although Australia does have a number of longitudinal studies designed to address various issues of health and ageing among older adults, only a few of these studies include a broad and comprehensive range of physical and biological measures. The Hunter Community Study (HCS) is a collaborative study between the University of Newcastle’s School of Medicine and Public Health and the Hunter New England Area Health Service. It is a multi disciplinary initiative that was established to fill some existing gaps in ageing research in Australia and is unique in that it has collected detailed information across all six key policy themes as identified in the Framework for an Australian Ageing Research Agenda. What does the study cover?

Pedometer counts superior to physical activity scale for identifying health markers in older adults

Objective 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. Design 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. Results 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. Conclusions 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.

Estimating the contribution of individual risk factors to disease in a person with more than one risk factor.

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.

Physical activity of older Australians measured by pedometry

Aim:  To established population norms for pedometer determined step counts in older Australians.

Microbiology of Surgical Site Infections and Associated Antimicrobial Use Among Vietnamese Orthopedic and Neurosurgical Patients

OBJECTIVES To determine the pathogens associated with surgical site infections (SSIs) and describe patterns of antimicrobial use and resistance in orthopedic and neurosurgical patients in a large university hospital in Vietnam. DESIGN Prospective cohort study. SETTING Cho Ray Hospital, Ho Chi Minh City, Vietnam. PATIENTS All patients who had operations during a 5-week study period. RESULTS Of 702 surgical patients, 80 (11.4%) developed an SSI. The incidence of SSI among orthopedic patients was 15.2% (48 of 315), and among neurosurgical patients it was 8.3% (32 of 387). Postoperative bacterial cultures of samples from the surgical sites were performed for 55 (68.8%) of the 80 patients with SSI; 68 wound swab specimens and 10 cerebrospinal fluid samples were cultured. Of these 78 cultures, 60 (76.9%) were positive for a pathogen, and 15 (25%) of those 60 cultures yielded multiple pathogens. The 3 most frequently isolated pathogens were Pseudomonas aeruginosa (29.5% of isolates), Staphylococcus aureus (11.5% of isolates), and Escherichia coli (10.3% of isolates). Ninety percent of S. aureus isolates were methicillin resistant, 91% of P. aeruginosa isolates were ceftazidime resistant, and 38% of E. coli isolates were cefotaxime resistant. All but 1 of the 702 patients received antimicrobial therapy after surgery, and the median duration of antimicrobial therapy was 11 days. Commonly used antimicrobials included aminopenicillins and second- and third-generation cephalosporins. Two or more agents were given to 634 (90%) of the patients, and most combination drug regimens (86%) included an aminoglycoside. CONCLUSIONS Our data indicate that the incidence of SSI is high in our study population, that the main pathogens causing SSI are gram-negative bacteria and are often resistant to commonly used antimicrobials, that the use of broad-spectrum antimicrobials after surgery is widespread, and that implementation of interventions aimed at promoting appropriate and evidence-based use of antimicrobials are needed in Vietnam.

How many steps are enough? Dose-response curves for pedometer steps and multiple health markers in a community-based sample of older Australians.

BACKGROUND Although an overall public health target of 10,000 steps per day has been advocated, the dose-response relationship for each health benefit of physical activity may differ. METHODS A representative community sample of 2458 Australian residents aged 55-85 wore a pedometer for a week in 2005-2007 and completed a health assessment. Age-standardized steps per day were compared with multiple markers of health using locally weighted regression to produce smoothed dose-response curves and then to select the steps per 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 per 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 SF-36 scores, the benefit of physical activity 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.

Australian Bat Lyssavirus: examination of post-exposure treatment in NSW

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.

Association between participation in outpatient cardiac rehabilitation and self-reported receipt of lifestyle advice from a healthcare provider: results of a population based cross-sectional survey

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.