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Biomedical subjects

J A Hanley

Publications and source records attributed to J A Hanley.

At least 19 recordsLinked to original sources
PubMed1992

The psychological and physical health of family members caring for an elderly person with dementia.

Most elderly persons with dementia are cared for at home, usually by the spouse or an adult child. The objective of the present study was to determine whether there is an excess of psychological and physical health problems among family caregivers (CGs) of elderly persons with dementia. Data were obtained by interview from close family members of dementia patients (CGs), and from a comparison group made up of close family members of patients undergoing cataract surgery (non-caregivers, NCGs). CGs had significantly higher levels of depression and physical symptoms than NCGs. The association between caregiving and the health variables was stronger among subjects who were the patient's spouse than among those who were the patient's child. Furthermore, greater behavioral disturbance in the demented patient was associated with higher levels of morbidity in the CG. The results suggest that CGs might benefit from careful monitoring of their health status, and from greater access to specialized support services.

Aged↗
PubMed1992

Mantel-Haenszel techniques and logistic regression: always examine one's data first and don't overlook the simpler techniques.

The authors point out that, in addition to logistic regression, there are other, simpler techniques available for making an adjusted estimate of association between an outcome and a risk factor. Also, the consequence of mismodelling with regression, i.e. of missing the real relationship between an outcome and a risk factor, is illustrated with an example. The need to 'examine one's data' prior to performing multivariable techniques is emphasised.

Epidemiologic Methods↗
PubMed1991

Sampling events in space and time: a case study of burn injuries.

We describe the sampling plan used to estimate the number of burn injuries seen at emergency departments of hospitals in New England. We present the rationale for each of the options considered and the implications of each. The chosen plan included all 256 hospitals, but used a different systematic one-day-in-ten sample for each of ten subgroupings of the hospitals. The findings suggest that over 47,000 injuries or almost 400 per 100,000 population were seen at New England Emergency Departments in a 1-year period. This incidence is 60 per cent higher than pre-project estimates would have suggested. From the variability of the data in the sample, we calculate that our estimate is probably no more than 3 per cent under or over the 'correct' rate that would have been obtained by a full non-sampling approach, costing almost 10 times as much. Additional support for our strong belief in the accuracy of the sample-based estimate is provided by the fact that if we had used the same sampling approach to estimate the number of hospitalized burn injuries, our estimate would have been in error by only 124 or 4 per cent from the total 3276 obtained by 100 per cent sampling of hospitalization records.

Burns↗
PubMed1991

Twin pregnancy: the impact of the Higgins Nutrition Intervention Program on maternal and neonatal outcomes.

Perinatal outcomes were compared between 354 twins treated with the Higgins Nutrition Intervention Program and 686 untreated twins. After differing distributions of key confounding variables were adjusted for, the twins in the intervention group weighed an average of 80 g more (P less than 0.06) than the nonintervention twins; their low-birth-weight rate was 25% lower (P less than 0.05) and their very-low-birth-weight rate was almost 50% lower (P less than 0.05). Although the rate of preterm delivery was 30% lower in the intervention group (P less than 0.05), the rates of intrauterine growth retardation were similar in the two groups. Fetal mortality was slightly higher (14 vs 12 per 1000, NS), but early neonatal mortality was fivefold lower (3 vs 19 per 1000, P less than 0.06) in the intervention group. Maternal morbidity was significantly lower (P less than 0.05) in the intervention group. There was a trend towards lower infant morbidity in the intervention group. These results suggest that nutritional intervention can significantly improve twin-pregnancy outcome.

Birth Weight↗
PubMed1990

Rural physician survey.

In August 1989, the Physician Manpower Training Commission conducted a survey in an effort to learn what factors influence the recruitment and retention of physicians in rural Oklahoma communities. The results of the survey are summarized in this article.

Humans↗
PubMed1989

Signal detection in digital chest-phantom images acquired with an image intensifier.

Signal detection performance was evaluated on the basis of ROC analysis using both digital and conventional images of a humanoid chest phantom. Simulated focal (coin) lesions were the target pathology. Digital images were acquired using a 57-cm image intensifier, digitized to 1024 x 1024 x 10 bits, and compared, in both video and laser-printed film formats, with conventional 14 x 17-inch chest films. Signal detection using digital video and laser printed images, of the same image polarity as conventional images, was found not to differ significantly from that achieved using conventional images, despite the smaller size of the digital images.

Humans↗
PubMed1989

Predicting mortality based on body composition analysis.

The role of the Nae/Ke ratio (the ratio of exchangeable sodium to exchangeable potassium) was examined as a nutritional marker in surgical patients in relation to anthropometrical and biochemical indexes by its ability to identify patients at risk for mortality after hospitalization. In 73 patients with sepsis and malnutrition (Training Group, Madrid) the following were determined: percentage of recent weight loss, triceps skin fold, midarm muscle circumference, serum albumin, serum transferrin, delayed hypersensitivity skin test response, total lymphocytes, and Nae/Ke ratio by multiple isotope dilution. The predictive power of Nae/Ke ratio was so strong (F = 105.1; p less than 0.00001) that it displaced anthropometric, biochemical, and immunologic variables from the linear equation derived from stepwise discriminant analysis using hospital mortality as the dependent variable. A theoretical curve of expected deaths was developed, based on an equation obtained by logistic regression analysis: Pr/death/ = 1/(1 + e[11.8-5.2 Nae/Ke]). Pre- and post-test probabilities on that curve allowed us to determine two cut-off values, Nae/Ke ratios of 1.5 and 2.5, which were markers for nonrisk and mortality, respectively. The model was tested in a heterogeneous data base of surgical patients (n = 417) in another hospital (Validation Group, Montreal). For patients exhibiting an abnormal Nae/Ke ratio (greater than 1.2) and a greater than 10% of probability of death, 54 deaths were expected and 53 observed (X2 = 1.8 NS). Two tests confirmed the basic agreement between the model and its performance, a G statistic of -0.704 and the area beneath the "receiver-operating-characteristic" (ROC) curve (Az = 0.904 + 0.0516 for the Madrid group vs. Az = 0.915 + 0.0349 for the Montreal group, NS). It was concluded from this analysis that, compared with the usual anthropometric measurements, the Nae/Ke ratio, if available, is the best method for identifying malnourished patients at risk of dying.

Adolescent↗
PubMed1989

Receiver operating characteristic (ROC) methodology: the state of the art.

Receiver operating characteristic (ROC) methodology has been increasingly used in medical applications in the last 10 years. The text by Swets and Pickett has popularized the technique and the journal Medical Decision Making (1981--) provides a forum for further methodologic issues. In this article, I will (1) describe the nature of the data generated by ROC studies; (2) evaluate the choices of summary indices of performance (accuracy); (3) outline the data-analytic techniques used, and how to incorporate data from multiple observers and multiple "readings"; (4) review proposed alternatives to the commonly used binormal ROC model; and (5) discuss issues, such as verification bias, and challenges, such as multicenter comparative imaging studies and the difficulty of obtaining "truth data", which need to be addressed when adapting ROC methods to medical contexts.

ROC Curve↗
PubMed1988

Environmental exposure to tobacco smoke and lung function in young adults.

The relationship between lung function and environmental exposure to tobacco smoke (passive smoking) was studied in 293 nonsmoking young men and women, 15 to 35 yr of age. A self-administered mailed questionnaire was used to assess the lifetime environmental exposure to cigarette smoke at home and at work for each subject. Lung function information used here had been gathered in the course of a previous study of the determinants of lung function in early adulthood. In men, maximal midexpiratory flow rate (FEF25-75) decreased in relation to an index of cumulative lifetime environmental exposure to tobacco smoke at home, after taking into account the effects of cumulative exposure at work as well as age, height, body size, respiratory pressures, and cooking fuels used at home. The components of this exposure index most closely related to the reduction in FEF25-75 were maternal smoking habits and exposure to second-hand smoke during childhood. In women, the diffusing capacity of the lung (DLCO) decreased in relation to cumulative exposure to tobacco smoke at work, after accounting for the effects of cumulative lifetime exposure at home and the other factors mentioned above. These findings contribute to the gathering evidence that environmental exposure to tobacco smoke is harmful to respiratory health, and suggest that the effects are not insignificant. For instance, the FEF25-75 of a young man 20 yr of age who had never smoked and always lived at home would be 800 ml less if both his parents smoked than if they did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Computer modelling of measurement error in longitudinal lung function data.

The effect of measurement error on the accuracy of results in two epidemiological study designs involving longitudinal lung function data was assessed using computer modelling. Five realistic data sets (cohorts) were created, each of 400 subjects, half of whom were exposed to an agent whose effects approximated in magnitude that of cigarette smoking. In each cohort, FEV1 decline was modelled after 6, 4 and 2 years of observation with and without error in the measurement of level of FEV1. For each length of observation the effect of exposure on decline was estimated using a follow-up design comparing the FEV1 decline between exposure groups, and a case-control design comparing risk of exposure in subjects in the top 20th percentile of FEV1 decline (cases) to exposure in those in the bottom 20th percentile (controls). For both study designs an exposure effect at p less than or equal to 0.01 could only be consistently detected after 6 years of observation.

Computer Simulation↗
PubMed1987

Prediction of airway reactivity from responses to a standardized respiratory symptom questionnaire.

A standardized respiratory symptom questionnaire was administered to 200 male insulators who then underwent inhalational bronchial challenge to measure their airway reactivity. The results were analyzed to determine the value of questionnaire information in predicting airway reactivity measured objectively. Questionnaire information was grouped according to topic, scored according to severity, and then combined to create several airway reactivity indices by stepwise multivariate analysis. The final index selected for testing contained information on a history of "asthma," "wheeze," "episodes of cough with sputum," and "pneumonia." It had a sensitivity ranging from 5% to 67% and positive predictive value from 67% to 28% depending on the cutoff point chosen as indicative of increased airway reactivity. These results indicate that questionnaire information is not adequate for discriminating between those with and those without increased airway reactivity in population screening.

Adult↗
PubMed1986

The Montreal Type A Intervention Project: major findings.

This article reports a comparison of three short-term treatments (aerobic exercise, cognitive-behavioral stress management, and weight training) in modifying behavioral and cardiovascular reactivity to laboratory psychosocial stressors in healthy Type A men. One hundred seven men completed the treatments and evaluations, 33 in the aerobic exercise group, and 37 each in the cognitive-behavioral stress management and weight-training groups. The stress management group showed significantly greater changes in behavioral reactivity (reductions of 13% to 23% below initial values) than the two physical exercise groups, which did not differ significantly from each other. For physiological reactivity, changes attributable to intervention were trivial for all three treatment groups. The positive finding of reduced behavioral reactivity as a result of the stress management intervention is of potential clinical significance and warrants further exploration. The lack of meaningful reductions in physiological reactivity also requires further exploration in that it raises questions concerning the ability of behavioral treatments in general to modify physiological reactivity, the ability of existing measures to assess accurately changes that are produced and, most fundamental of all, the relevance of physiological reactivity as an outcome measure for treatment efforts with Type As.

Adaptation, Psychological↗
PubMed1986

The decreased incidence of aseptic necrosis in renal transplant recipients--a case control study.

Before 1971 the incidence of aseptic necrosis in renal transplant recipients was 29%, and after 1971 it was 5%. To investigate the reasons for this decreased incidence and to elucidate the causes of aseptic necrosis we studied all 26 transplant patients with aseptic necrosis and 42 controls matched for year of transplantation, age, and sex. Development of aseptic necrosis was not related to duration of dialysis before transplant, severity of uremia at the time the patient started dialysis, adequacy of dialysis before transplantation, transplant dysfunction at the time aseptic necrosis was diagnosed, hyperparathyroidism before or after transplantation, lack of Vitamin D supplementation after transplantation, or fatty infiltration of liver. Total steroid dose 1 month after transplantation was actually lower in aseptic necrosis compared with the control group (2.47 +/- 0.3 g vs. 3.6 +/- 0.3 g SEM g) and was similar after 4 months (6.72 +/- 0.55 g vs. 7.14 +/- 0.6 g), as were total numbers of i.v. doses of methylprednisolone or hydrocortisone. However, blood urea nitrogen (BUN) during the dialysis period was significantly higher in the aseptic necrosis group. Of the aseptic necrosis group, 27% had a previous transplant compared with 5% of controls. Half the aseptic necrosis group (5/10) had parenchymal iron on liver biopsy one year after transplant compared with 15% (2/13) of those without aseptic necrosis. Patients transplanted before 1971 (with and without aseptic necrosis) received significantly more i.v. hydrocortisone and less i.v. methylprednisolone, had higher BUN levels at the time of starting dialysis, and had lower serum calcium and higher serum phosphate at transplantation compared with patients transplanted in or after 1971. The incidence of aseptic necrosis following transplantation has decreased during the past 13 years for reasons that are unclear. Risk factors for aseptic necrosis may include previous transplantation, severe iron overload that may lead to marrow fibrosis and osteopenia, and increased protein catabolism/turnover during dialysis.

Adult↗
PubMed1986

Cardiovascular involvement in osteogenesis imperfecta.

While aortic root dilatation and valvular dysfunction have been well-documented in osteogenesis imperfecta (OI), the nature and extent of cardiovascular involvement in OI have not been clearly delineated. A clinical and echocardiographic survey involving 109 individuals with various nonlethal OI syndromes from 66 separate families was undertaken. Clinically discernible valvular dysfunction was encountered in only four of the 109 individuals (aortic regurgitation in two, aortic stenosis in one, and mitral valve prolapse in one), none of whom were related. Aortic root dilatation was recognized echocardiographically in eight (12.1%) of 66 individuals comprising a subset of the sample in which each family was represented by a single individual. The extent of the aortic root dilatation was mild (the largest dimension measuring 4.3 cm) and was unrelated to the age of the individual. Dilatation was seen in each of the different OI syndromes but was strikingly segregated within certain families (p less than .001). In the same subset of 66 individuals, mitral valve prolapse was encountered in two or 6.9% of the 29 individuals aged 15 years or greater in whom adequate studies were obtained. This observed frequency was not different from that seen in a normal adult population. Aortic root dilatation appears to represent a distinct phenotypic trait in patients with OI that is nonprogressive and occurs in about 12% of affected individuals. Whether mitral valve prolapse should be considered as a part of the cardiovascular phenotype in OI, or alternately segregates as an independent autosomal dominant trait has yet to be determined.

Adolescent↗
PubMed1986

Evaluating primary prevention programmes against cancer.

Based on current knowledge, roughly one third of all cancers worldwide are preventable, and primary prevention is increasingly seen as an important cancer control strategy. Interventions to reduce the exposure to known causes can be effected through legislation or education, or by means of vaccination or chemoprevention. Since primary prevention actions can be costly and will compete for resources needed for other disease control activities, and since there is no guarantee that they will be successful, they should not be introduced haphazardly but on the basis of scientific evaluations. This paper presents the main principles to be followed in designing such evaluations; the illustrations often, of necessity, come from other diseases (particularly cardiovascular disease), where there is considerably more experience. Because the interventions involve changes in lifestyle and behaviour, and because a long time is necessary to observe the ultimate endpoints, controlled intervention studies against cancer present many scientific and logistical difficulties. Some interventions, such as vaccination and chemoprevention (to test suspected protective agents) may be evaluated by traditional clinical trial methodology, using intermediate as well as final (cancer incidence and/or mortality) endpoints. Active, target-directed and preferably controlled health service research studies will definitely be needed to assess community or population interventions based on legislation or education.

Evaluation Studies as Topic↗
PubMed1985

A Bayesian approach for predicting judged hearing disability.

A method of determining the cutoff point for an administrative decision to award compensation is proposed. To construct the predictive system a Bayesian approach and discriminant analysis were employed. Judged hearing disability was used as the criterion with audiometric scores as the determining variables. The common law doctrine of the balance of probability was used as the criterion, namely the 50th centile, on which to propose a cutoff point. The highest precision in predicting judged hearing disability was obtained with an average audiometric score at 1,000, 2,000, 3,000, 4,000 Hz in the worse ear. Assuming that judged hearing disability is a valid predictor of handicap, the cutoff point based on the balance of probability (50th centile) was obtained at 25 dB. The study also confirmed results from previous studies: hearing sensitivity in frequencies higher than 2,000 Hz is required to predict hearing disability and handicap, judged hearing disability is better correlated with hearing sensitivity in the worst ear, and the audiometric cutoff point for a medical legal definition of impairment should be lower than what certain technical groups have proposed in the past.

Audiometry↗