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Biomedical subjects

David H Wilson

Publications and source records attributed to David H Wilson.

At least 19 recordsLinked to original sources
PubMed2006

Central obesity is associated with nonatopic but not atopic asthma in a representative population sample.

BACKGROUND: Epidemiologic studies have consistently demonstrated the association between high body mass index (BMI) and asthma, yet the relationship between asthma and the alternative central obesity phenotypes, waist circumference (WC) and waist-to-hip ratio (WHR), has not been assessed in a representative population sample. OBJECTIVE: To determine the strength of the association of WC and WHR with current asthma and whether the association is modified by atopic status in a representative population sample. METHODS: The North West Adelaide Health Study, a biomedical population study of n = 4060, assessed current asthma, respiratory symptoms, and participant demographics by self-completed questionnaire. Clinic assessment included measures of WC and WHR, spirometry, and skin prick tests to a panel of allergens. RESULTS: Logistic regression analysis showed a significant, marginal increased adjusted risk of asthma associated with obese levels of WC and WHR and BMI > or =35.0 kg/m2 in female subjects only. When the association was considered stratified according to atopic status, the relationship between obese levels of WC and WHR with asthma held only for the nonatopic population in both males (WC: odds ratio [OR] 5.7, 95% confidence interval [CI] 1.1-28.8; WHR: OR 6.2, 95% CI, 1.1-32.9) and females (WC: OR 2.3, 95% CI, 1.2-4.4; WHR: OR 3.0, 95% CI, 1.5-5.9). BMI > or =35.0 kg/m2 showed an inconsistent pattern in the association with asthma. CONCLUSION: Central obesity was significantly associated with an increased risk of nonatopic asthma only. The causal pathway is unknown, but this study suggests the involvement of different pathophysiological mechanisms requiring further investigation. CLINICAL IMPLICATIONS: Asthma should be considered in older, nonatopic, centrally obese, symptomatic individuals.

Adolescent↗
PubMed2006

The North West Adelaide Health Study: detailed methods and baseline segmentation of a cohort for selected chronic diseases.

The North West Adelaide Health Study is a population-based biomedical cohort study investigating the prevalence of a number of chronic conditions and health-related risk factors along a continuum. This methodology may assist with evidence-based decisions for health policy makers and planners, and inform health professionals who are involved in chronic disease prevention and management, by providing a better description of people at risk of developing or already diagnosed with selected chronic conditions for more accurate targeting groups for health gain and improved health outcomes. Longitudinal data will provide information on progression of chronic conditions and allow description of those who move forward and back along the continuum over time. Detailed methods are provided regarding the random recruitment and examination of a representative sample of participants (n = 4060), including the rationale for various processes and valuable lessons learnt. Self-reported and biomedical data were obtained on risk factors (smoking, alcohol consumption, physical activity, family history, body mass index, blood pressure, cholesterol) and chronic conditions (asthma, chronic obstructive pulmonary disease, diabetes) to classify participants according to their status along a continuum. Segmenting this population sample along a continuum showed that 71.5% had at least one risk factor for developing asthma, chronic obstructive pulmonary disease or diabetes. Almost one-fifth (18.8%) had been previously diagnosed with at least one of these chronic conditions, and an additional 3.9% had at least one of these conditions but had not been diagnosed. This paper provides a novel opportunity to examine how a cohort study was born. It presents detailed methodology behind the selection, recruitment and examination of a cohort and how participants with selected chronic conditions can be segmented along a continuum that may assist with health promotion and health services planning.

Journal Article↗
PubMed2006

Trends in asthma prevalence and population changes in South Australia, 1990-2003.

OBJECTIVES: To examine changes in asthma prevalence in the context of other population changes between 1990 and 2003, for specific age and sex groups. DESIGN: Cross-sectional survey based on household interviews, repeated annually. SETTING AND PARTICIPANTS: Representative samples of the South Australian population between 1990 and 2003 (around 3000 people per year). MAIN OUTCOME MEASURES: Current prevalence of doctor-diagnosed asthma and other health and demographic variables potentially associated with asthma, and asthma management. RESULTS: Response rate was over 71%. Between 1990 and 2003, asthma prevalence increased significantly, doubling in females (from 7.3% in 1990 to 14.6% in 2003), with a smaller increase in males (from 7.8% to 9.4%). Asthma also increased in all age groups, but the largest relative increases occurred in people aged 55 years and older. Logistic regression analyses showed that obesity was a major predictive variable for every age group studied. The prevalence of asthma morbidity (waking at night and days lost from usual activities because of asthma) among those with asthma showed no significant changes between 1990 and 2003. Asthma action plans (introduced on a population basis in 1992) peaked in their distribution at 42% in 1994, and then declined to half that percentage in 2003. The increase in asthma prevalence occurred at the same time as increases in population prevalence of obesity (10.3% to 18.7%) and diabetes (3.1% to 6.9%), and decline in recent vigorous exercise (42.4% to 32.7%). CONCLUSIONS: The increase in asthma prevalence over a decade was large, but concentrated among specific sex and age groups. The increase accompanied population increases in obesity and diabetes and a decline in vigorous exercise.

Adolescent↗
PubMed2006

Do people with risky behaviours participate in biomedical cohort studies?

BACKGROUND: Analysis was undertaken on data from randomly selected participants of a bio-medical cohort study to assess representativeness. The research hypotheses was that there was no difference in participation and non-participations in terms of health-related indicators (smoking, alcohol use, body mass index, physical activity, blood pressure and cholesterol readings and overall health status) and selected socio-demographics (age, sex, area of residence, education level, marital status and work status). METHODS: Randomly selected adults were recruited into a bio-medical representative cohort study based in the north western suburbs of the capital of South Australia--Adealide. Comparison data was obtained from cross-sectional surveys of randomly selected adults in the same age range and in the same region. The cohort participants were 4060 randomly selected adults (18+ years). RESULTS: There were no major differences between study participants and the comparison population in terms of current smoking status, body mass index, physical activity, overall health status and proportions with current high blood pressure and cholesterol readings. Significantly more people who reported a medium to very high alcohol risk participated in the study. There were some demographic differences with study participants more likely to be in the middle level of household income and education level. CONCLUSION: People with risky behaviours participated in this health study in the same proportions as people without these risk factors.

Adult↗
PubMed2006

How valid are self-reported height and weight? A comparison between CATI self-report and clinic measurements using a large cohort study.

OBJECTIVE: To examine the relationship between self-reported and clinical measurements for height and weight in adults aged 18 years and over and to determine the bias associated with using household telephone surveys. METHOD: A representative population sample of adults aged 18 years and over living in the north-west region of Adelaide (n = 1,537) were recruited to the biomedical cohort study in 2002/03. A computer-assisted telephone interviewing (CATI) system was used to collect self-reported height and weight. Clinical measures were obtained when the cohort study participants attended a clinic for biomedical tests. RESULT: Adults over-estimated their height (by 1.4 cm) and under-estimated their weight (by 1.7 kg). Using the self-report figures the prevalence of overweight/ obese was 56.0% but this prevalence estimate increased to 65.3% when clinical measurements were used. The discrepancy in self-reported height and weight is partly explained by 1) a rounding effect (rounding height and weight to the nearest 0 or 5) and 2) older persons (65+ years) considerably over-estimating their height. CONCLUSION: Self-report is important in monitoring overweight and obesity; however, it must be recognised that prevalence estimates obtained are likely to understate the problem. IMPLICATIONS: The public health focus on obesity is warranted, but self-report estimates, commonly used to highlight the obesity epidemic, are likely to be underestimations. Self-report would be a more reliable measure if people did not round their measurements and if older persons more accurately knew their height.

Adolescent↗
PubMed2006

Coexistent chronic conditions and asthma quality of life: a population-based study.

OBJECTIVE: Reports of the prevalence and impact of comorbid conditions among people with asthma have been limited to certain population groups or convenience samples. Our aim was to examine the prevalence of major comorbidity in asthma and associations with quality of life and functional status in the general population. STUDY DESIGN/SETTING: The WANTS Health and Well-being Survey is a cross-sectional representative population household telephone interview survey in three Australian states. PARTICIPANTS: Representative sample of noninstitutionalized adults in three Australian states. MEASUREMENT AND RESULTS: From the available sample of 10,080 patients, 7,619 interviews were completed (participation rate, 74.8%), with 834 people reporting current doctor-diagnosed asthma (11.2%). People with asthma were more likely to report one of the selected comorbid conditions: diabetes, arthritis, heart disease, stroke, cancer, osteoporosis (adjusted odds ratio, 1.9; 95% confidence interval, 1.5 to 2.2). Among people with asthma, there were statistically and clinically significant decreases in usual activity levels and in Short Form-12 physical component summary scores when another chronic condition was also present. For those with any of the chronic conditions, the additional presence of asthma was associated with significant further impairment in quality of life in those aged > 35 years but not in younger adults. CONCLUSION: The significant reduction in quality of life associated with comorbidity in asthma has implications for disease management and organization of care, as well as for the design and external validity of single-disease clinical trials.

Activities of Daily Living↗
PubMed2005

Undiagnosed asthma in older people: an underestimated problem.

WHAT WE NEED TO KNOW: Are older people with respiratory symptoms aware this could be asthma? Which explanations for undiagnosed asthma apply most commonly in older Australians with asthma? Can we improve awareness of asthma in older people with undiagnosed asthma? Is the possibility of asthma in older people firmly established on the general practitioners' radar screen? What reasons most often determine whether GPs perform spirometry in their practice? WHAT WE NEED TO DO: Conduct a representative population study to assess whether older Australians recognise respiratory symptoms as being asthma and are reporting these symptoms. Conduct and evaluate a pilot asthma health promotion program for older people. Conduct a controlled therapeutic trial of people with undiagnosed asthma to assess treatment benefits and produce treatment recommendations. Identify whether the prominence of asthma in older people can be brought to the attention of GPs. Analyse more carefully the issues associated with innovation of office spirometry.

Age Distribution↗
PubMed2005

An algorithmic approach to diagnosing asthma in older patients in general practice.

WHAT WE NEED TO KNOW: How effective would an algorithm be in helping general practitioners diagnose asthma? What proportion of older people with undiagnosed asthma fail to recognise symptoms? What proportion of the population believe asthma does not occur in the older population? What systems or supports do GPs need to diagnose asthma more effectively? WHAT WE NEED TO DO: Work on developing a gold standard for asthma diagnosis. Develop prototype algorithms for general practice discussion. Conduct a general practice study to assess the effectiveness of an algorithm. In conjunction with GPs, develop a pilot program to increase awareness of the current asthma problem. Conduct focus-group research to identify why some people do not believe they can develop asthma for the first time in adult life. Conduct focus-group research to identify why some adults do not attribute asthma symptoms to asthma. Conduct focus groups with GPs to identify what support is needed to diagnose asthma more effectively. Consult with all stakeholders before an intervention is used. Evaluate any interventions used.

Aged↗
PubMed2005

Spirometric criteria for asthma: adding further evidence to the debate.

BACKGROUND: Objective assessments of pulmonary function are considered essential for the diagnosis of asthma. The degree of reversibility of FEV(1) considered supportive of asthma varies between international asthma guidelines. OBJECTIVE: We sought to compare the relative performance of international guideline reversibility criteria for identifying impairment in persons with a significant bronchodilator response (SBR) without an asthma diagnosis. METHODS: The North West Adelaide Health (Cohort) Study, a population biomedical study of 4060 subjects, conducted spirometry according to American Thoracic Society criteria. SBR was defined as postbronchodilator FEV(1) responses of at least 12% or 15% of baseline values, 9% of predicted values, or 400 mL. A self-completed questionnaire assessed current asthma (CA), respiratory symptoms, and participant demographics. RESULTS: The prevalence of CA was 9.4% (n = 380), whereas 1.3% (>/=400 mL) to 4.5% (>/=9% of predicted value) of participants demonstrated an SBR in the absence of CA. With the exception of the 9% predicted criterion, prebronchodilator mean FEV(1) (percent predicted) in those demonstrating an SBR but no CA was significantly worse than that in the CA group. Significantly more respiratory symptoms were experienced by the SBR groups than the group without asthma. Logistic regression analyses identified different characteristics of those classified by the following criteria: 12% and 15%, age of 40 years or greater and household income of less than $40,000; 9% predicted, household income of less than $40,000; 400 mL, male sex (odds ratio, 4.5; 95% CI, 2.1-9.3). CONCLUSIONS: Different criteria identify different persons, but SBR by any criteria was associated with significant respiratory impairment, some of which might be attributable to asthma. Postbronchodilator change as a percentage of predicted value was the least biased of the criteria.

Adult↗
PubMed2005

Participatory decision making, asthma action plans, and use of asthma medication: a population survey.

Use of controller asthma medication and possession of asthma action plans remains suboptimal. Our aim was to investigate the association of the propensity of physicians to involve patients in their care (participatory decision-making style) and their asthma management in a representative population sample of 3015 adults. Current doctor-diagnosed asthma was reported by 393 (13.0%). People who rated their doctors as more participatory were significantly more likely to report more regular use of controller medications and possession of a written asthma action plan, but not less asthma morbidity. Possession of a written action plan was associated with more participatory interactions (OR 2.3; 95% CI 1.1-4.7, for upper tertile scores compared to lowest tertile); more severe symptoms (OR 4.8; 95% CI 1.7-13.0), being female (OR 2.2; 95% CI 1.2-4.3), those with higher education, and residence outside the metropolitan area (OR 2.1; 95% CI 1.1-4.0). Increasing patient participation in their own care is associated with better asthma management, independent of asthma symptoms. Longitudinal studies are needed to examine if increasing participation in decisions can also improve asthma outcomes.

Adolescent↗
PubMed2004

The health-related quality of life of male and female heavy smokers.

OBJECTIVES: Heavy smokers are a segment of the smoking population who are at increased risk of smoking-related morbidity and least likely to achieve cessation. This study identifies the impact of heavy smoking on quality of life by gender and describes the subpopulation for improved targeting. METHODS: South Australian representative population data (n = 3010) was used to compare the health-related quality of life status of male and female heavy smokers as assessed by the SF-36. RESULTS: Of the smoking population 18% were classified as heavy smokers. There was a clear dose response relationship between amount smoked and deteriorating quality of life for all female smokers. Female heavy smokers were found to be significantly more impaired on all health-related quality of life dimensions, when compared to male heavy smokers. CONCLUSIONS: The association of smoking with impaired quality of life is more marked in females than in males. There is a need to identify female smokers as a distinct target group in smoking cessation initiatives and programs.

Activities of Daily Living↗
PubMed2004

Diabetes, depression, and quality of life: a population study.

OBJECTIVE: The aim of the study was to assess the prevalence of diabetes and depression and their associations with quality of life using a representative population sample. RESEARCH DESIGN AND METHODS: The study consisted of a representative population sample of individuals aged > or = 15 years living in South Australia comprising 3,010 personal interviews conducted by trained health interviewers. The prevalence of depression in those suffering doctor-diagnosed diabetes and comparative effects of diabetic status and depression on quality-of-life dimensions were measured. RESULTS: The prevalence of depression in the diabetic population was 24% compared with 17% in the nondiabetic population. Those with diabetes and depression experienced an impact with a large effect size on every dimension of the Short Form Health-Related Quality-of-Life Questionnaire (SF-36) as compared with those who suffered diabetes and who were not depressed. A supplementary analysis comparing both depressed diabetic and depressed nondiabetic groups showed there were statistically significant differences in the quality-of-life effects between the two depressed populations in the physical and mental component summaries of the SF-36. CONCLUSIONS: Depression for those with diabetes is an important comorbidity that requires careful management because of its severe impact on quality of life.

Adolescent↗
PubMed2003

Prevalence of asthma and asthma action plans in South Australia: population surveys from 1990 to 2001.

OBJECTIVES: To assess trends in the prevalence of self-reported doctor-diagnosed asthma, associated asthma related morbidity, and the uptake of written asthma action plans in South Australia, 1990-2001. DESIGN, SETTING AND PARTICIPANTS: Surveys by telephone interview of the South Australian population between 1990 and 2001, and interview of participants in their own homes by trained health interviewers. MAIN OUTCOME MEASURES: Asthma prevalence, percentage of patients with written action plans, and asthma associated morbidity. RESULTS: The reported prevalence of doctor-diagnosed asthma has increased from 8% (95% CI, 6.4%-9.6%) in 1990 to 12.8% (95% CI, 11.4%-14.2%) in 2001. Morbidity, as measured by wakening at night (daily or weekly) and days lost from normal activities because of asthma, has remained constant over the decade. The percentage of patients with written asthma action plans increased to a peak of 42.3% (95% CI, 40.3%-44.3%) in 1995, but then declined to 22.2% (95% CI, 20.7%-23.7%) in 2001. CONCLUSIONS: The prevalence of asthma has increased while morbidity has remained constant, indicating that the burden of asthma has increased. The associated decline in the percentage of patients with asthma action plans in recent years is cause for concern.

Asthma↗
PubMed2003

Asthma symptoms associated with depression and lower quality of life: a population survey.

OBJECTIVE: To identify any association between asthma and depression and quality of life. DESIGN AND SETTING: A face-to-face Health Omnibus Survey of a random and representative sample of the South Australian population in August 1998. PARTICIPANTS: 3010 randomly selected participants aged 15 years and over. MAIN OUTCOME MEASURES: Prevalence of doctor-diagnosed asthma, and scores for depression (measured by PRIME-MD instrument) and quality of life (measured by SF-36) in affected participants. RESULTS: The prevalence of asthma was 9.9%. The prevalence of major depression was significantly higher for those who experienced dyspnoea, wakening at night with asthma, and morning symptoms of asthma. Quality-of-life scores were also lower for the same groups. CONCLUSIONS: Depression is a serious but potentially remediable comorbidity with asthma that may affect appropriate diagnosis and outcome.

Adult↗
PubMed2002

The escalating cost and prevalence of alternative medicine.

BACKGROUND: The purpose of this study was to measure trends in the prevalence and cost of alternative medicines and alternative practitioner use in an Australian population and to obtain a profile of users and their beliefs. METHODS: In 2000, we repeated a 1993 representative population survey of persons ages 15 years or older living in South Australia, which provided 3,027 personal interviews. We assessed the rates of use, types of alternative medicine and therapists, costs, and beliefs of users and nonusers. Comparisons in usage patterns with the 1993 survey were also made. FINDINGS: In 2000, the overall use of at least one nonmedically prescribed alternative medicine (excluding calcium, iron, and prescribed vitamins) was 52.1% (CI +/- 1.8). Users were more likely to be female, be better educated, have a higher income, and be employed. Since 1993, females were using significantly more herbal medicines, ginseng, Chinese medicines, and aromatherapy oils. Many were self-prescribed. Among users, 57.2% (CI +/- 1.2) did not tell their doctor. In 2000, 23.3% of respondents had visited at least one alternative practitioner with increasing use of acupuncturists, reflexologists, aromatherapists, and herbal therapists. Most thought alternative medicines were safe but thought they were, or should be, subject to the same standards as prescribed medicines. Among respondents, 92.9% wished product information to be of standard and content similar to those supplied with pharmaceuticals. INTERPRETATION: Extrapolation of the costs to the Australian population gives an expenditure on alternative therapies in 2000 of $AUD2.3 billion and for the U.S. population an annual expenditure of $US34 billion. In Australia this represents a 120 and 62% increase in the cost of alternative medicines and therapists, respectively, since 1993. In 2000 expenditure on alternative therapies was nearly four times the public contribution to all pharmaceuticals. The public appears to have ambivalent standards for alternative therapies but wishes to be empowered with accurate information to facilitate self-prescription. The public health ramifications of an expanding alternative medicine industry are great.

Adult↗