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Biomedical subjects

J B Carlin

Publications and source records attributed to J B Carlin.

At least 73 records · Page 4Linked to original sources
PubMed1997

Walking to school and traffic exposure in Australian children.

Daily patterns of pedestrian activity in young children have important health implications, primarily because of the risk of road traffic injury, but also because they may reflect the commencement of exercise habits with long-term consequences. A cross-sectional survey in two Australian cities, Melbourne and Perth, aimed to collect, by parent self-administered questionnaire, population-based data on modes of travel, numbers of street crossings (both accompanied and unaccompanied by an adult), and sociodemographic factors for six- and nine-year-old children. Results indicate that 35 per cent (95 per cent confidence interval (CI) 31 to 39 per cent) and 31 per cent (CI 28 to 34 per cent) walk to school in Melbourne and Perth respectively, while over 60 per cent are driven to school by car, with very small proportions riding bicycles or taking public transport. A higher level of walking was associated with lower levels of several indicators of socioeconomic status. Logistic regression analysis showed that the strongest predictor of walking activity was school type (government versus independent), and after adjusting for this, lesser car ownership, non-English-speaking background and lower occupational category were associated with walking to school, while a different set of predictors--age, sex and maternal education--was associated with the unaccompanied crossing of streets. There was little difference in overall walking levels between boys and girls, but boys were significantly more likely to cross streets unaccompanied (adjusted odds ratio 1.41, CI 1.14 to 1.72), providing a partial explanation of documented sex differences in injury rates.

Accidents, Traffic↗
PubMed1997

Adolescent dieting: healthy weight control or borderline eating disorder?

Dieting in adolescent girls is ubiquitous but its health significance is uncertain. On the one hand it might be seen as promoting healthy weight control and on the other it might be considered as a risk factor for eating disorders. Dieting levels were systematically assessed in a representative group of 2525 Australian teenagers and classified using item response theory. In this group, 38% of girls and 12% of boys were categorised as intermediate dieters; 7% of girls and 1% of boys fell into a group of extreme dieters. Body mass carried a strong positive association with intermediate dieting. Most female dieters, nevertheless, fell within a normal weight range. Psychiatric morbidity was the clearest factor associated with extreme dieting and 62% of extreme dieters reported high levels of depression and anxiety. Extreme dieting might reasonably be viewed as lying on a spectrum with clinical eating disorders. Most dieting is unjustified on the grounds of appropriate weight control and appears to reflect a widespread striving of teenage girls towards body shapes at the lower end of age-adjusted norms.

Adolescent↗
PubMed1997

Lower airway inflammation in infants and young children with cystic fibrosis.

Airway inflammation is an important component of cystic fibrosis (CF) lung disease. To determine whether this begins early in the illness, before the onset of infection, we examined bronchoalveolar lavage (BAL) fluid from 46 newly diagnosed infants with CF under the age of 6 mo identified by a neonatal screening program. These infants were divided into three groups: 10 had not experienced respiratory symptoms or received antibiotics and pathogens were absent in their BAL fluid; 18 had clear evidence of lower respiratory viral or bacterial (> or = 10(5) CFU/ml) infection; and the remaining 18 had either respiratory symptoms, taken antibiotics, or had < 10(5) CFU/ml of respiratory pathogens. Their BAL cytology, interleukin-8, and elastolytic activity were compared with those from 13 control subjects. In a longitudinal study to assess if inflammation develops or persists in the absence of infection, the results of 56 paired annual BAL specimens from 44 CF infants were grouped according to whether they showed absence, development, clearance, or persistence of infection. In newly diagnosed infants with CF, those without infection had BAL profiles comparable with control subjects while those with a lower respiratory infection had evidence of airway inflammation. In older children, the development and persistence of infection was accompanied by increased inflammatory markers, whereas these were decreased in the absence, or with the clearance, of infection. We conclude that airway inflammation follows respiratory infection and, in young children, improves when pathogens are eradicated from the airways.

Anti-Bacterial Agents↗
PubMed1996

Streptococcal pharyngitis in a paediatric emergency department.

OBJECTIVE: To determine the prevalence and clinical features of beta-haemolytic streptococcal infection in children with acute pharyngitis and thereby to define those requiring antibiotic therapy. DESIGN: Prospective 2:1 case--control study. SETTING: Emergency Medicine Department of the Royal Children's Hospital, Melbourne, between May 1994 and May 1995. PARTICIPANTS: Cases (n = 271) were the first 10 self-referred children in each week with pharyngitis and no antibiotic use in the previous week. Controls (n = 135) were age-matched children without infection. MAIN OUTCOME MEASURES: Presence of groups A, C or G beta-haemolytic streptococci in oropharyngeal cultures; demographic and clinical characteristics. RESULTS: Group A beta-haemolytic streptococci (GABHS) were isolated from significantly more case than control children (cases, 57/271 [21%]; controls, 9/135 [7%]; odds ratio [OR], 3.7; P < 0.001). Groups C and G beta-haemolytic streptococci were isolated from 10 (4%) and 5 (2%) case children, respectively, but not from controls. Age > or = 4 years, tender cervical lymph nodes, pharyngotonsillitis, absent coryza and scarlatiniform rash were significantly associated with GABHS (P < 0.02). GABHS was uncommon in children aged < 4 years (4%), but was present in 12 of 14 children > or = 4 years with a rash (86%). However, most cases lacked a rash, and for children > or = 4 years likelihood of GABHS varied from 10%-65%, depending on other clinical features. CONCLUSIONS: In children aged < 4 years, GABHS is an unlikely cause of acute pharyngitis and symptomatic treatment alone should be considered. In children > or = 4 years, the likelihood of GABHS being the cause of acute pharyngitis increases with presence of scarlatiniform rash, pharyngotonsillitis and tender cervical nodes.

Acute Disease↗
PubMed1996

Lifetime cost of human immunodeficiency virus-related health care.

Estimates of the lifetime cost of illnesses are needed for temporal and international comparisons and for assessment of the efficiency of prevention strategies. The goal of the present study was to estimate the average present value, at both the time of diagnosis and the time of seroconversion, of the lifetime cost of health care for HIV infection. Australian data on the monthly cost of HIV-related health care for homosexual men were linked with published data on disease progression using survival analysis methods. Future costs were discounted at 5% per annum. For a patient diagnosed when his CD4+ count fell below 500 x 10(6)/L, the average present value in 1992-1993 of lifetime cost was approximately $93,000, of which 49% was for drugs and 32% was for hospital bed-days. For a man infected in 1992-1993 and diagnosed when his CD4+ count falls below 500 x 10(6)/L, the average present value of lifetime cost at the time of seroconversion is approximately $70,000. These estimates are lower than the lifetime cost of $119,000 reported recently in the United States. However, when the U.S. figure was adjusted to make discounting of future costs consistent between the two studies, lifetime costs were approximately 17% lower in the United States. The lower American costs appear to be due to lower rates of hospitalization and drug prescribing, possibly because of reduced access to health services, but underestimation of costs due to study methodology might also explain the difference.

Australia↗
PubMed1996

Bronchoalveolar lavage or oropharyngeal cultures to identify lower respiratory pathogens in infants with cystic fibrosis.

As collections of lower respiratory tract specimens from young children with cystic fibrosis (CF) are difficult, we determined whether oropharyngeal cultures predicted lower airway pathogens. During 1992-1994, 75 of 90 (83%) infants with CF diagnosed by neonatal screening had 150 simultaneous bronchoalveolar lavage (BAL) and oropharyngeal specimens collected for quantitative bacterial culture at a mean age of 17 months (range, 1-52). Ten children undergoing bronchoscopy for stridor served as controls. Total and differential cell counts and interleukin-8 concentrations were measured in BAL fluid. A subset of bacterial pathogens were typed by pulsed field gel electrophoresis. A non-linear relationship with inflammatory markers supported a diagnosis of lower airway infection when > or = 10(5) colony-forming units/ml were detected. This criterion was met in 47 (31%) BAL cultures from 37 (49%) children. Staphylococcus aureus (19%), Pseudomonas aeruginosa (11%), and Hemophilus influenzae (8%) were the major lower airway pathogens. In oropharyngeal cultures, S. aureus (47%), Escherichia coli (23%), H. influenzae (15%), and P. aeruginosa (13%) predominated. The sensitivity, specificity, and positive and negative predictive values of oropharyngeal cultures for pathogens causing lower respiratory infections were 82%, 83%, 41%, and 97%, respectively. When there was agreement between paired oropharyngeal and BAL cultures, genetic fingerprinting showed some strains of the same organism were unrelated. We conclude that oropharyngeal cultures do not reliably predict the presence of bacterial pathogens in the lower airways of young CF children.

Bacteriological Techniques↗
PubMed1996

A comparison of patient interview data with pharmacy and medical records for patients with acquired immunodeficiency syndrome or human immunodeficiency virus infection.

To assess the reliability of information reported by patients with AIDS or HIV infection, 123 homosexual men were recruited in Victoria, Australia, in 1992-1993 and interviewed to collect data retrospectively and prospectively on HIV-related illness and treatment. These data were compared with information in medical and pharmacy records. There was no evidence of bias in the patient report of date of diagnosis of HIV infection or date or result of most recent CD4 count, although there was considerable imprecision. Past and current prescription of AZT were recalled accurately by patients compared with medical records (kappa = 0.89 and 0.86, respectively), but previous HIV-related illnesses and enrollment in clinical studies or trials were generally recalled poorly (kappa < 0.4 in some cases). Data collected prospectively on prescription of drugs and use of health care services were reasonably accurately reported by patients. This analysis supports the need for routine assessment of the validity of patient-reported exposure and outcome data in epidemiological studies in order to minimize the possible biases that can result from inaccurate information.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Validation of questionnaire and bronchial hyperresponsiveness against respiratory physician assessment in the diagnosis of asthma.

BACKGROUND: The Tasmanian Asthma survey (TAS) and the International Study of Asthma and Allergies in Childhood (ISAAC) have used questionnaires to measure the prevalence of asthma in adults and children. We have investigated the validity of these questionnaires by comparing response to questionnaire with a physician assessment of asthma status in the past 12 months. METHODS: Ninety-three adults were given the TAS questionnaire to complete and 361 children were given the ISAAC questionnaire. Ninety-one adults and 168 children completed bronchial challenge with hypertonic saline. A consultation with a respiratory physician blinded to the results of the questionnaire and bronchial challenge was given to all subjects. RESULTS: In both adults and children, questionnaires showed high agreement with respiratory physician diagnosis with respect to asthma symptoms in the past 12 months. For the TAS questionnaire the positive and negative predictive values (95% confidence limits) for physician diagnosis for adults were 0.89 (0.68-0.98) and 0.94 (0. 86-0.98) respectively. The instrument was also sensitive 0.80 (0. 58-0.93) and highly specific 0.97 (0.90-0.99). For the ISAAC questionnaire the positive and negative predictive vales for physician diagnosis of asthma in children were 0.61 (0.50-0.71) and 0.94 (0.88-0.98) respectively. Sensitivity and specificity were 0.85 (0.73-0.93) and 0.81 (0.76-0.86) respectively. Compared to the physician diagnosis, the sensitivity of bronchial hyperresponsiveness (BHR) for asthma was low for adults 0.39 (0.21-0. 61) and children 0.54 (0.48-0.67) as were the positive predictive values: 0.55 (0.31-0.79) for adults and 0.64 (0.449-0.77) for children. A definition of asthma requiring both a positive questionnaire response and BHR was highly specific but not sensitive for adults 0.37 (0.20-0.59) or children 0.47 (0.35-0.60). CONCLUSIONS: Both the TAS and ISAAC questionnaires are valid instruments for the determination of asthma symptoms in the past 12 months.

Adolescent↗
PubMed1996

Health care and its costs for children with perinatally acquired HIV infection.

OBJECTIVE: To describe survival patterns, use of health services and related costs for Australian children with perinatally acquired human immunodeficiency virus (HIV) infection. METHODOLOGY: A retrospective cross-sectional survey was made of 20 children with HIV infection (91% of those diagnosed) and 13 children with maternal antibodies who subsequently seroreverted, treated at 10 medical centres. Details of disease progression and use of health services were obtained from hospital medical records. Monthly costs for three phases of infection were estimated by linking service usage rates with estimates of the unit cost of each service. The average lifetime cost was estimated by combining monthly costs and phase duration estimates from the literature. RESULTS: Patterns of disease progression were similar to those reported internationally, with a median survival of 8 years. Use of health services increased with severity of illness. Mean monthly costs were $120 per month (1992 Australian dollars) for children with maternal antibodies who subsequently seroreverted, $320 per month for children with HIV infection but no acquired immunodeficiency syndrome (AIDS)-defining illness, and $1830 per month for children with AIDS. The present value of total lifetime cost for a child with HIV infection was $48174, 46% of which was for treatment of AIDS. DISCUSSION: The mean lifetime cost for a perinatally infected child was just over half that for a man with HIV in Australia. Health service usage and costs were lower for Australian than American children with HIV.

Australia↗
PubMed1996

Is smoking associated with depression and anxiety in teenagers?

OBJECTIVES: An association of smoking with depression and anxiety has been documented in adult smokers. This study examines this association in a representative group of teenage smokers. METHODS: A two-stage cluster sample of secondary school students in Victoria, Australia, were surveyed by using a computerized questionnaire, which included a 7-day retrospective diary for tobacco use and a structured psychiatric interview. RESULTS: Subjects reporting high levels of depression and anxiety were twice as likely to be smokers after the potential confounders of year level, sex, alcohol use, and parental smoking were controlled for. Regular smokers were almost twice as likely as occasional smokers to report high levels of depression and anxiety. In a stratified analysis, an association between regular smoking and psychiatric morbidity was found in girls of all ages but for boys only in the youngest group. CONCLUSIONS: The cross-sectional association is consistent with the use of smoking by teenage girls as self-medication for depression and anxiety. Therefore, future health promotional campaigns might consider strategies that attend to perceived psychological benefits of smoking.

Adult↗
PubMed1995

A case-control study of child bicycle injuries: relationship of risk to exposure.

In order to assess the relationship of the risk of injury requiring hospital attendance in children riding bicycles to sociodemographic factors and to measures of exposure, a population-based case-control study is being undertaken in a large area of suburban Melbourne, Australia. Particular attention is given to the measurement of individual exposure in several dimensions. Analysis of interim data from 109 cases and 118 controls shows that 51% of injuries occurred while the child was playing rather than making a trip on the bicycle and only 22% involved another vehicle. Boys used bicycles more commonly than girls but there was minimal evidence of an increased risk of injury in boys, adjusting for exposure. There was no evidence for an age trend in injury risk, but children from families in the lowest income category were at significantly increased risk. Exposure measures showed complex patterns of association with injury risk. Estimated time spent riding was more closely associated with risk than distance travelled, with an odds ratio of 2.2 (95% confidence interval 1.1-4.2) for children riding for more than 3 hours per week compared to children riding less than 1 hour. Riding more than 5 km on the sidewalk was also associated with increased risk (odds ratio 3.1, 95% CI 1.1-8.5). The elevated risk associated with sidewalk riding may be due to difficulties in negotiating uneven surfaces. The case-control study provides an ideal design for this type of investigation but valid and reliable measurement of exposure is difficult.

Accidents, Traffic↗
PubMed1995

The usage and costs of health services for HIV infection in Australia.

OBJECTIVE: To describe patterns of health-service usage and the resulting costs in 1992-1993 for Australian men. DESIGN: A prospective survey, stratified by phase of illness. SETTING: Hospital and community-based care. PATIENTS: A total of 128 homosexual men: 20 in phase 1 (CD4+ count > or = 500 x 10(6)/l), 31 in phase 2 (CD4+ count < 500 and > or = 200 x 10(6)/l), 30 in phase 3 (CD4+ count < 200 x 10(6)/l), and 47 in phase 4 (AIDS). MAIN OUTCOME MEASURES: Mean monthly service usage rates and costs. RESULTS: Health-service utilization increased and became more hospital-based as illness worsened; the main exception was use of antiretroviral drugs, which peaked in phases 2 and 3. Hospital admission was rare before diagnosis of AIDS. Hospital bed-days per patient per month averaged 3.3 for AIDS patients until the final 3 months of life increasing to 15.8 in the 3 months before death. Mean monthly costs (in 1992-1993 Australian dollars) were $331 [95% confidence interval (CI), 218-455] in phase 1, $667 (95% CI, 540-836) in phase 2, $1372 (95% CI, 1044-1776) in phase 3, and $4615 (95% CI, 3456-5985) for AIDS patients until the last 3 months of life and $13,308 (95% CI, 10,538-16,516) in the 3 months before death. Drugs comprised 57% of total costs in phase 1, but only 30% of costs for patients with AIDS, whereas hospital bed-days comprised 10% of phase 1 costs and 60% of AIDS costs. CONCLUSIONS: Health-care utilization and resulting costs increased with severity of illness, and were particularly high for AIDS patients in the 3 months before death. Service-utilization patterns and components of costs varied between each phase.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Increase in the self-reported prevalence of asthma and hay fever in adults over the last generation: a matched parent-offspring study.

The study compared current measures on a population-based cohort of adults with past measures on their parents to determine whether the prevalence of self-reported asthma and hay fever in adults increased between 1968 and the early 1990s. In 1968, 8585 cohort members (99 per cent of eligible Tasmanian 7-year-old school children born in 1961), 16,273 (95 per cent) of their parents (mean age 35 years) and 20,937 siblings completed a questionnaire about asthma and hay fever. In 1991-1993, 1494 members (75 per cent) of a stratified random sample of the cohort (aged 29 to 32 years), 75 per cent resident in Tasmania, were surveyed again. In 1968, the proportion of parents who reported having ever had asthma or attacks of wheezing like asthma was 10.9 per cent, independent of age and sex. In 1991-1993, the estimated adult prevalence of having ever suffered from attacks of asthma or wheezy breathing was 23.2 per cent. The proportion reporting at least one asthma attack within the previous 10 years, 5 years, 2 years, 12 months and 6 months was 17.6 per cent, 16.1 per cent, 14.5 per cent, 13.3 per cent and 10.3 per cent, respectively. For hay fever, the adult prevalence was 19.2 per cent in 1968, and 41.3 per cent in 1991-1993. The self-reported lifetime prevalence of asthma and hay fever among adults in the 1961 birth cohort of Tasmanians was twice as high in 1991-1993 as in their parents 25 years earlier.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Patterns of common drug use in teenagers.

To ascertain current levels of drug use among teenagers and to examine interrelationships in use, a two-stage cluster sample of Victorian secondary school students in years 7 (aged 12 to 13 years), 9 (14 to 15 years) and 11 (16 to 17 years) were surveyed using a questionnaire on computer. Tobacco use and alcohol consumption were evaluated by self-reported frequency of use and seven-day retrospective diaries. Marijuana and coffee consumption were assessed by self-reported frequency of recent use. The questionnaire was completed by 2525, a participation rate of 83 per cent. Tobacco use rose with year, with 24 per cent of young women and 16 per cent of young men in year 11 being regular smokers. Trends across year level for heavier alcohol consumption were also observed, with just under 10 per cent of year 11 students reporting a weekly consumption higher than the current recommended guidelines for adults. Strong interrelationships in drug use were found, with a pattern of association between smoking and drinking consistent with a mutual elevation of risk. Frequent use of tobacco and alcohol had a high risk for associated marijuana use. Coffee consumption carried a significant independent association with regular smoking. Teenage substance use is common and most occurs at low level and frequency. However, for a substantial and increasing minority across the teenage years, high levels of tobacco and alcohol consumption potentially compromise health. Frequent alcohol or tobacco use rather than heavy intermittent consumption is most likely to be associated with concurrent substance use potentially damaging to health.

Adolescent↗
PubMed1995

Head injuries in helmeted child bicyclists.

OBJECTIVE: To determine the characteristics and the severity of head and facial injuries to helmeted child bicyclists, and whether the helmet contributed to the injury, and to study factors related to bicycle accidents. DESIGN: Retrospective review of two case series. Children sustaining head injury while not wearing helmets were studied as a form of reference group. SETTING: Large paediatric teaching hospital. SUBJECTS: 34 helmeted child bicyclists and 155 non-helmeted bicyclists, aged 5-14 years. MAIN OUTCOME MEASURES: Number of injuries, type of injuries, injury severity score, deaths, and accident circumstances. RESULTS: 79% of the head injuries of the helmeted child group were mild and two thirds of these had facial injuries. Children in the helmet group were in a greater proportion of bike-car collisions than the no helmet group and at least 15% of the helmets were lost on impact. There were no injuries secondary to the helmet. CONCLUSIONS: Most of the head injuries sustained by the helmeted children were of mild severity and there was no evidence to suggest that the helmet contributed to injury. Nevertheless, consideration should be given to designing a facial protector for the bicycle helmet and to improvement of the fastening device.

Accidents, Traffic↗
PubMed1995

A method for estimating baseline health care costs.

STUDY OBJECTIVES: Studies estimating the cost of specific illnesses do not generally take into account the fact that health care costs would have been incurred in the absence of the disease of interest. The goal of this study was to develop a method of estimating age specific baseline health care costs. These costs were calculated for Australian men, and their magnitude was compared with the costs of caring for men with HIV infection. DESIGN: Information about health service usage was obtained from the 1989-90 national health survey and linked with data on the costs of services to obtain average monthly costs for individual and total health services. SETTING: The Australian community. PARTICIPANTS: Average total health service costs per man per month were $103 (Australian). Hospital admissions comprised approximately 40% of these costs and casualty/outpatient visits, consultations with a doctor, and prescribed medication comprised 10%, 13%, and 12%, respectively. Costs increased with age, from around $60 per month for men aged 20-39 years to $213 per month for men aged 60 and over. CONCLUSION: Baseline costs comprised around 18% of health care costs for men with asymptomatic HIV infection, but less than 1% of costs for men with AIDS. These estimates provide an essential baseline for determining the costs attributable to specific diseases.

Adult↗