Biomedical subjects

N Owen

Publications and source records attributed to N Owen.

At least 55 records · Page 3Linked to original sources

PubMed2000

The relationship between body mass index and waist circumference: implications for estimates of the population prevalence of overweight.

OBJECTIVE: Body mass index (BMI) based on self-reported height and weight is a systematically biased, but acceptable measure of adiposity and is commonly used in population surveys. Recent studies indicate that abdominal obesity is more strongly associated with obesity-related health problems than is adiposity measured by BMI. The purpose of this study was to determine the relationships of both measured and self-reported BMI with measured waist circumference in a randomly selected sample of Australian adults. DESIGN: Cross-sectional survey with self-reported and laboratory-based measures of adiposity. SUBJECTS: 1140 randomly-selected Australian adults aged 18-78 y resident in the city of Adelaide, South Australia. MEASUREMENTS: Data on self-reported and measured height and weight as well as measured waist circumference were drawn from the Pilot Survey of the Fitness of Australians database. The proportion of men and women with acceptable BMI (BMI</=25 kg/m2) and with excess abdominal adiposity (>/=94 cm for men and >/=80 cm for women) was determined. Differences in the prevalence of overweight based on BMI alone or BMI and waist circumference were also determined. RESULTS: Compared with the prevalence based on self-reported BMI alone, the prevalence of overweight among men based on self-reported BMI and waist circumference combined was 2.4%, 5.3%, 19.1% and 7.5% greater for men aged 18-39 y, 40-59 y, 60-78 y and for all men, respectively. Among women, compared with the prevalence based on self-reported BMI alone, the prevalence of overweight based on the combined measures was 9.9%, 24.0%, 33.3% and 20.6% greater for women aged 18-39 y, 40-59 y, 60-78 y and for all women, respectively. CONCLUSIONS: If waist circumference is used as the criterion, then the prevalence of overweight among Australian adults, and probably other Caucasian populations, may be significantly greater than indicated by surveys relying on self-reported height and weight. The development of valid self-reported measures of waist circumference for use in population surveys may allow more accurate epidemiological monitoring of overweight and obesity.

Abdomen↗

PubMed2000

Promoting physical activity: the new imperative for public health.

The aim of this essay is to provide an overview of initiatives designed to increase physical activity among different populations and in different settings, and to set the context for the major challenges that lie ahead. The decline in habitual physical activity with modernization, and the causal link between physical activity and health are briefly reviewed. The need to understand physical activity as a health behavior and examples of behavior change theories that have been applied to the promotion of physical activity are discussed. Diverse projects and campaigns in three countries, i.e. South Africa, Australia and the US, are highlighted. Common themes found in these physical activity initiatives include the development of a theory-driven research base, inclusion of behavioral and social scientists on multidisciplinary teams, and advocacy for environmental changes that promote physical activity. Within the next decade, research projects and national campaigns such as those described herein will yield important new findings on how to increase physical activity levels among targeted sectors of the population. The research agenda for the future includes development of both basic and applied research on physical activity, and the integration of theory across social, behavioral and biomedical disciplines.

Adult↗

PubMed2000

Too fat to exercise? Obesity as a barrier to physical activity.

OBJECTIVE: To describe perceptions of being 'too fat' as a barrier to physical activity by gender and body mass index, and to examine the associations between feeling fat and other weight-related barriers to physical activity. METHODS: Analyses of cross-sectional self-report data from a representative population survey of 2,298 Australian adults. RESULTS: Overall, 4.4% of respondents reported being too fat as a barrier to physical activity; this being more common among women (6.2%), and among the obese (22.6%). Associations were found between being too fat as a barrier, and being too shy or embarrassed to exercise; being too lazy or not motivated; having an injury or disability (males only); and being not the sporty type (females only). There was no association between feeling too fat and poor health. CONCLUSIONS: Feeling too fat to exercise is a common barrier among the overweight, particularly for women. Results suggest gender differences in weight-related barriers to physical activity. IMPLICATIONS: A better understanding of the nature of weight-related physical activity barriers can help inform public health strategies designed to increase physical activity among those who are obese.

Adult↗

PubMed2000

Environmental determinants of physical activity and sedentary behavior.

Environmental changes are expected to lead to decreased time in sedentary behavior and to increased levels of physical activity in populations. Past research has emphasized psychosocial determinants of physical activity. Progress in the field will require more focus on understanding sedentary behaviors and the role of environmental determinants.

Adult↗

PubMed1999

Insufficiently active Australian college students: perceived personal, social, and environmental influences.

BACKGROUND: A sustainable pattern of participation in physical activity is important in the maintenance of health and prevention of disease. College students are in transition from an active youth to a more sedentary adult behavior pattern. METHODS: We assessed self-reported physical activity and other characteristics in a sample of 2,729 male and female students (median age was 20 years) recruited from representative courses and year levels at four Australian College campuses. They were categorized as sufficiently or insufficiently active, using estimates of energy expenditure (kcal/week) derived from self-reported physical activity. Personal factors (self-efficacy, job status, enjoyment), social factors (social support from family/friends), and environmental factors (awareness of facilities, gym membership) were also assessed. RESULTS: Forty-seven percent of females and 32% of males were insufficiently active. For females, the significant independent predictors of being insufficiently active were lower social support from family and friends, lower enjoyment of activity, and not working. For males, predictors were lower social support from family and friends, lower enjoyment of activity, and being older. CONCLUSIONS: Factors associated with physical activity participation (particularly social support from family and friends) can inform physical activity strategies directed at young adults in the college setting.

Adolescent↗

PubMed1999

Stage distributions for five health behaviors in the United States and Australia.

BACKGROUND: A key variable for the design of individual and public health interventions is the Stage of Change. The five stages of readiness to change are Precontemplation, Contemplation, Preparation, Action, and Maintenance. The distribution of individuals across the stages of change can provide a valuable tool for designing health interventions. METHODS: The pattern of distribution across the stages of change for five behavioral risk factors is presented from five independent surveys, two from the United States and three from Australia. The five risk factors are smoking, low fat diet, regular exercise, reducing stress, and losing weight. Identical single-item questionnaire items for staging health behaviors were used in all surveys. RESULTS: The stage distributions for the five risk factors were similar across the five independent samples. In general, the pattern of stage distributions was stable across health risk factors, gender, country, and sample. CONCLUSIONS: Single-item survey measures of stage of change that are readily applicable to population studies appear to provide important information about the population characteristics of readiness to change behavioral risk factors. The stability of these distributions suggests that interventions matched by stage may have broad applicability.

Adolescent↗

PubMed1999

Physical activity of adult Australians: epidemiological evidence and potential strategies for health gain.

Physical activity is now considered a major modifiable factor for preventing and reducing the mortality from cardiovascular disease, diabetes and some cancers, as well as improving musculoskeletal and mental health. Increasing epidemiological evidence confirms the health benefits of moderate regular physical activity. A dose response relationship remains, with greater benefits derived from increased intensity and duration of physical activity. Clinicians and exercise scientists should consider physical inactivity as important a risk factor as hypertension or elevated serum cholesterol levels. The broader public health objectives are to measure and monitor physical activity levels among all Australians, and to develop interventions to increase regular participation for the whole population. Population Campaigns and behaviour change programs are needed to increase the prevalence of participation in physical activity.

Arthritis↗

PubMed1999

Analysis of mutations in the tudor domain of the survival motor neuron protein SMN.

Autosomal recessive childhood onset spinal muscular atrophy (SMA) is a leading cause of infant mortality caused by mutations in the survival motor neuron (SMN) gene. The SMN protein is involved in RNA processing and is localised in structures called GEMs in the nucleus. Nothing is yet understood about why mutations in SMN gene result in the selective motor neuron loss observed in patients. The SMN protein domains conserved across several species may indicate functionally significant regions. Exon 3 of SMN contains homology to a tudor domain, where a Type I SMA patient has been reported to harbour a missense mutation. We have generated missense mutants in this region of SMN and have tested their ability to form GEMs when transfected into HeLa cells. Our results show such mutant SMN proteins still localise to GEMs. Furthermore, exon 7 deleted SMN protein appears to exert a dominant negative effect on localisation of endogenous SMN protein. However, exon 3 mutant protein and exon 5 deleted protein exert no such effect.

Amino Acid Sequence↗

PubMed1999

Outcome of symptoms of dizziness in a general practice community sample.

BACKGROUND: Dizziness is commonly experienced in the community, but little is known about the long-term progression of the condition. OBJECTIVE: We aimed to assess over 18 months the outcome of symptoms of dizziness in a sample of patients identified from London general practices. METHOD: We followed up at 18 months a cohort of patients who reported symptoms of dizziness with or without anxiety, panic reactions or avoidance of situations that provoked the symptoms. The subjects completed a structured questionnaire both at baseline and at 18 months. RESULTS: At 18 months, 24% (95% CI = 23.5-34.8%) were more handicapped and 20% (95% CI = 15.2-25.2%) had recurrent dizziness, while 20% (95% CI = 14.9-24.8%) had improved. Patients with significant dizziness were more likely to consult their GP (OR = 14.4, 95% CI = 7.0-29.1) and were more likely to receive treatment (OR = 7.8, 95% CI = 3.2-22.4) or be referred to hospital (OR = 8.4, 95% CI = 3.2-22.4). The independent predictors of handicapping dizziness at 18 months were a history of fainting (OR = 2.4, 95% CI = 1.2-4.7), vertigo (OR = 2.6, 95% CI = 1.3-5.0) and avoidance of a situation that provoke dizziness (OR = 4.8, 95% CI = 2.5-9.0). CONCLUSION: Four per cent of all patients registered with a GP suffer persistent symptoms of dizziness and at least 3% are severely incapacitated by their symptoms. The presence of vertigo, fainting and avoidance in a person with dizziness is predictive of chronic handicapping dizziness. Further research is required on the progressions of symptoms of dizziness in a sample of GP attenders and those in the community.

Adolescent↗

PubMed1999

Health promotion research and the diffusion and institutionalization of interventions.

To examine the extent to which health promotion research is providing an empirical basis for the diffusion and institutionalization of effective interventions, we conducted a systematic audit of all articles in 12 public health and health promotion journals for the 1994 calendar year. We identified empirical/non-empirical and health promotion/non-health promotion articles. For each study, the health behaviours or outcomes studied, the target group, gender and setting were categorized. Each study was also categorized as belonging to one of four stages: basic research and development, innovation development, diffusion research, and research into institutionalization or policy implementation. Of all articles coded (n = 1210), 33.9% were identified as non-research, 39.5% were health promotion research and 26.6% were non-health promotion research. The vast majority of studies fell within the basic research and development stage (89.6%), with less than 1% categorized as diffusion research and only 5% as institutionalization or policy implementation research. The published studies reviewed provide a limited empirical basis for diffusion and institutionalization of health promotion programs. These findings suggest a need to more systematically monitor research input (funding) and research output (publications), and to develop a more explicit focus on the relevance of the stages of research innovation and development, the issues and/or behaviours addressed, the target population, and the research setting.

Bibliometrics↗

PubMed1999

Utility of pwc75% as an estimate of aerobic power in epidemiological and population-based studies.

PURPOSE: Studies of physical activity often assess physical work capacity (pwc) and this is usually achieved with extrapolated estimates of maximal aerobic power (VO2max). However, extrapolation beyond the measured values may be problematic, particularly for older subjects. On a population basis, interpolated measures of pwc may provide the same information and avoid the errors associated with extrapolated measures. METHODS: This study assessed extrapolated (pwc at 150 and 170 beats x min(-1) heart rate (HR) and estimated VO2max) and interpolated (pwc at 75% of maximum HR: pwc75%) measures of pwc in a population sample of 1043 men and women aged 18-78 yr. Each measure was assessed to determine whether it showed the key characteristics of measured VO2max: a decrease with age and an increase with reported physical activity. RESULTS: Both pwc150 and pwc170 did not decline with age, estimated VO2max (est.VO2max) exhibited a spurious plateau for older age groups, while pwc75% declined approximately 9% per decade of age. All four pwc measures detected a significant difference (approximately 10-15%) between inactive and active groups classified according to a questionnaire of leisure time physical activity. CONCLUSIONS: Although the pwc75% test requires direct validation, these results suggest that it may be a useful submaximal exercise measure for epidemiological studies of aerobic power.

Adult↗

PubMed1999

Physical inactivity and other health risks among Australian males in less-skilled occupations.

Male workers in less-skilled occupations have higher rates of cardiovascular disease, compared with higher-skilled workers. A representative population sample of Australian male workers was used to compare physical activity levels and selected cardiovascular disease risk factors in less-skilled versus professional and skilled workers. Workers in the less-skilled occupational categories reported significantly more vigorous work and home-based activity than did those in the professional and skilled categories. In multivariate comparisons, cigarette smoking was the only factor that discriminated between the less-skilled versus the professional and skilled employees. Although worksites can potentially provide health-promoting physical activity options for higher-risk groups, our findings suggest that smoking and possibly overweight are risk factors that are more strongly present in less-skilled occupations.

Adult↗

PubMed1999

Physical activity initiatives for male factory workers: gatekeepers' perceptions of potential motivators and barriers.

OBJECTIVE: Worksites have been argued to be a key setting for physical activity promotion, particularly for lower-paid, less-skilled workers. These occupational groups are at increased risk of cardiovascular disease. There is no strong evidence in support of the efficacy of worksite fitness and physical activity interventions. This study assessed potential motivators and barriers to worksite physical activity initiatives for less-skilled workers. METHOD: We conducted telephone interviews with 13 Victorian WorkCover insurance providers and 30 manufacturing industry worksite managers. The manufacturing industry was selected as it contains a substantial portion of workers from this high-risk occupational group. RESULTS: Most insurers incorporated physical activity elements into injury-prevention programs. Few worksite managers reported programs to encourage workers to be more active; they identified reduced premiums and lower-cost programs through insurers as possible motivators. Both groups identified workers' reluctance to participate in physical activity, lack of awareness of potential benefits and program cost as major barriers for worksite physical activity. Other barriers included potential adverse effects on productivity and increased injury risk. CONCLUSIONS: Broader occupational health and safety policies and joint initiatives between insurers and worksite managers may have the potential to provide more opportunities for workers to be more active. However, the barriers identified outweighed the perceived benefits. IMPLICATIONS: Without structural and regulatory changes or new incentives, the adoption of physical activity initiatives in Australian manufacturing-industry workplaces is unlikely.

Attitude to Health↗

PubMed1998

Relationship between postural control and motion sickness in healthy subjects.

This study examined the relationship between reported susceptibility to motion sickness, anxious personality and postural control. Postural stability was assessed in 34 healthy subjects standing with eyes open, eyes closed and viewing a disorienting virtual reality display. These measures were repeated with vibration of the calf muscles to distort the somatosensory feedback from the legs. Susceptibility to motion sickness and anxious personality were evaluated by questionnaire. Greater postural instability was correlated with susceptibility to motion sickness. Motion sickness susceptibility correlated most strongly with increased sway when the visual and somatosensory feedback was absent or distorted. Anxiety was correlated with reported susceptibility to motion sickness but not with postural stability. These findings suggest that deficient perceptual-motor responses to disorienting conditions may contribute to motion sickness susceptibility.

Adult↗

PubMed1998

Physical activity interventions using mass media, print media, and information technology.

INTRODUCTION: Media-based physical activity interventions include a variety of print, graphic, audiovisual, and broadcast media programs intended to influence behavior change. New information technology allows print to be delivered in personalized, interactive formats that may enhance efficacy. Media-based interventions have been shaped by conceptual models from health education, Social Cognitive Theory, the Transtheoretical Model, and Social Marketing frameworks. METHODS: We reviewed 28 studies of media-based interventions of which seven were mass media campaigns at the state or national level and the remaining 21 were delivered through health care, the workplace, or in the community. RESULTS: Recall of mass-media messages generally was high, but mass-media campaigns had very little impact on physical activity behavior. Interventions using print and/or telephone were effective in changing behavior in the short term. Studies in which there were more contacts and interventions tailored to the target audience were most effective. CONCLUSION: A key issue for research on media-based physical activity interventions is reaching socially disadvantaged groups for whom access, particularly to new forms of communication technology, may be limited. There is a clear need for controlled trials comparing different forms and intensities of media-based physical activity interventions. Controlled studies of personalized print, interactive computer-mediated programs, and web-based formats for program delivery also are needed. The integration of media-based methods into public and private sector service delivery has much potential for innovation.

Adolescent↗

PubMed1998

Feasibility and effectiveness of providing vestibular rehabilitation for dizzy patients in the community.

Since the majority of people with dizziness in the community are never referred for specialist testing and treatment, the purpose of this study was to investigate whether it was desirable and feasible to provide vestibular rehabilitation for this patient population. Demand for therapy was assessed by a survey of 9198 working age people randomly sampled from six general practices. One in 10 respondents reported current, handicapping dizziness, but fewer than 2% of those with dizziness severe enough to merit treatment proved suitable and willing to attend hospital for testing and rehabilitation. Nevertheless, vestibular rehabilitation was clearly beneficial for the 16 patients who completed the therapy programme, as their scores on measures of symptoms, disability, handicap and postural stability improved significantly post-therapy to near-normal levels. We conclude that there is a need for provision of vestibular rehabilitation in primary care for patients with dizziness in the community.

Adolescent↗

PubMed1998

Effects of body composition and fat distribution on ventilatory function in adults.

Clinically, gross obesity is associated with disturbances of ventilatory function, but less severe obesity is not generally thought to have a significant effect on ventilatory function. The purpose of this report was to examine cross-sectional data to determine the effects of body composition and fat distribution on ventilatory function in 1235 adults (621 men and 614 women). Forced vital capacity (FVC) was used as a measure of ventilatory function and was adjusted for age, height, smoking, and bronchial symptoms in separate models for men and women. Body fat and fat-free mass were estimated from skinfold-thickness measurements. Adjusted FVC was not significantly associated with body mass or body mass index, but was negatively associated with percentage body fat in men (P = 0.0003) and women (P = 0.043) and positively associated with fat-free mass in men (P = 0.018) and women (P = 0.0001). Handgrip strength was positively associated with adjusted FVC in both sexes (P < 0.02), suggesting that the effect of fat-free mass may be mediated by muscular strength. Adjusted FVC was negatively associated with subscapular-skinfold thickness in both sexes (P < 0.0003) and with waist circumference (P = 0.01) and waist-to-hip ratio (P = 0.03) in men. Previous reports that considered only body mass index or body mass failed to distinguish the opposing effects of fat-free mass and fat mass on FVC.

Adipose Tissue↗

PubMed1998

Weight-control practices of adults in a rural community.

Obesity is recognised as a significant public health problem, and health authorities are concerned with promoting a healthy weight for all adults. However, there is a paucity of data about community weight-control practices. We surveyed weight-control behaviour, strategies and goals in a population-based sample of 1342 adults living in rural Victoria. In addition to the 20 per cent of adults who were attempting to lose weight, 22 per cent were actively trying to maintain their present weight or to avoid weight gain. Those taking action for their weight most often did so for health-related reasons, and most of the strategies used were those recommended by health authorities. However, some adults, particularly women, adopted potentially unhealthy weight-control practices. One in four women whose weight was acceptable was trying to lose weight, and 14 per cent of women had a weight goal that was below the acceptable range. Conversely, 50 per cent of men had a weight goal higher than that currently considered acceptable. Additional research is required to assess more accurately the specific nature of community weight-control practices.

Adolescent↗