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Biomedical subjects

H Morgenstern

Publications and source records attributed to H Morgenstern.

At least 109 records · Page 6Linked to original sources
PubMed1989

Ecological bias, confounding, and effect modification.

Ecological bias is sometimes attributed to confounding by the group variable (ie the variable used to define the ecological groups), or to risk factors associated with the group variable. We show that the group variable need not be a confounder (in the strict epidemiological sense) for ecological bias to occur: effect modification can lead to profound ecological bias, whether or not the group variable or the effect modifier are independent risk factors. Furthermore, an extraneous risk factor need not be associated with the study variable at the individual level in order to produce ecological bias. Thus the conditions for the production of ecological bias by a covariate are much broader than the conditions for the production of individual-level confounding by a covariate. We also show that standardization or ecological control of variables responsible for ecological bias are generally insufficient to remove such bias.

Data Interpretation, Statistical↗
PubMed1989

Blood alcohol tests, prevalence of involvement, and outcomes following brain injury.

We collected data on all residents of San Diego County, California who were hospitalized for or died from a brain injury in 1981. The objectives were to assess the frequency of blood alcohol concentration (BAC) testing and the associations of BAC prevalence with the external cause of the brain injury and case outcome. We found that high BAC levels were most frequent among brain-injured subjects between the ages of 25 and 44 and among those subjects involved in motor vehicle crashes and assaults. Contrary to expectations, injury severity and hospital mortality were inversely related to BAC level, controlling for other predictors. We believe that these inverse associations might be due to differential rates of BAC testing by severity. Among brain-injured survivors with more severe injuries, however, we found that BAC level was positively associated with the prevalence of physician-diagnosed neurological impairment at discharge and with the length of hospitalization.

Accidents↗
PubMed1988

Determinants of pediatric injuries.

Injuries are an important health issue for children. Previous research, however, has presented confusing and conflicting results on the determinants of childhood injuries, particularly psychosocial predictors, largely due to methodologic problems. The purpose of this analysis, based on a prospective follow-up study of 532 children, was to identify factors related to injuries encountered in a prepaid group practice during a 12-month period. Using logistic regression, we found four factors independently associated with the risk of at least one treated injury: high activity level, high rate of pediatric utilization for non-injury-related visits during the follow-up period, occurrence of a treated injury during the year preceding the follow-up period, and negative attitude toward medical care providers by the child's mother. In addition, four factors were found to be independent predictors of injuries judged severe enough to always warrant medical care: occurrence of a treated injury in the preceding year, high rate of pediatric utilization for non-injury-related visits during the follow-up period, working more than 15 hours a week outside the home by the child's mother, and more life events reported by the mother for the year preceding the follow-up period. Since family stressors are related specifically to the risk of more severe injuries, which are unlikely to escape medical attention, we conclude that these factors probably are related to the occurrence of common injuries of early childhood and not exclusively to utilization behavior. We therefore suggest that children from families with these characteristics be targeted for injury prevention strategies.

Attitude↗
PubMed1988

Up-regulatory effect of triphasic oral contraceptive on platelet 3H-imipramine binding sites.

Triphasic oral contraceptive (Logynon) induced a significant increase (36%) in the maximal binding capacity of platelet membranes for [3H]imipramine. The increase was achieved in the second Logynon cycle as compared to pretreatment and first Logynon cycle binding values. The pill contains a combination of ethinyl estradiol and levonorgestrel, and it is as yet unclear which of the two hormones is responsible for the up-regulatory effect. The increase in the density of platelet imipramine binding sites may reflect a similar alteration in brain. The increase in imipramine binding did not correlate with alteration in mood as assessed by Beck Depression Inventory scores.

Adult↗
PubMed1988

Platelet monoamine oxidase activity and tardive dyskinesia.

A few studies of chronic psychiatric inpatients have reported an inverse association between platelet monoamine oxidase (MAO) activity level and tardive dyskinesia (TD). In contrast to these earlier findings, we found no significant or consistent association between platelet MAO activity level and TD occurrence when we controlled for other TD predictors in a case-control study of 80 outpatients maintained on neuroleptic medications. We did find, however, that black subjects had significantly lower levels of MAO activity than did whites in an analysis controlling for age, sex, and neuroleptic dose.

Adult↗
PubMed1988

Heterogeneity of tardive dyskinesia. A multivariate analysis.

To determine whether tardive dyskinesia (TD) is a single abnormal movement syndrome or multiple syndromes involving different anatomical areas, we examined 228 out-patients diagnosed with TD at the Connecticut Mental Health Center in New Haven. Application of factor analysis to the seven anatomical severity scores of the Abnormal Involuntary Movement Scale yielded three statistically independent factors involving abnormal movements primarily of the jaw-tongue, face-lips, and extremities-trunk. Using logistic regression to predict the severity of these factors, we found that the severity of the orofacial scores was positively associated with age, schizoaffective or affective disorder, and living alone, while severity of non-orofacial movement was positively associated with current neuroleptic dose, non-use of psychiatric medication, and living alone. Our findings suggest that orofacial and non-orofacial dyskinetic movements may involve distinct clinical syndromes of TD, each having a different set of prognostic and, possibly, aetiological determinants.

Adult↗
PubMed1988

Predictors of occurrence, severity, and course of tardive dyskinesia in an outpatient population.

This paper summarizes the results of three different studies of tardive dyskinesia conducted within a single-source, outpatient population at the Connecticut Mental Health Center in New Haven. Emerging themes from this work suggest that prevalence, severity and course of tardive dyskinesia are influenced--probably in different ways--by treatment, psychiatric illness, and other personal characteristics.

Dyskinesia, Drug-Induced↗
PubMed1988

Factors affecting pediatric preventive care utilization in a prepaid group practice.

Previous research on the utilization of pediatric preventive care has shown that certain sociodemographic factors, such as age, birth order, family size and race, as well as health attitudes and beliefs are related to the use of well-child services. To examine the simultaneous effects of sociodemographic, psychosocial and behavioral factors, we conducted a 16-month prospective investigation of 532 children belonging to a university-affiliated prepaired group practice. The children were under 5 years of age upon enrollment and came predominantly from white, middle-class families with well-educated parents. Our bivariable results showed that 13 factors were related to preventive care utilization (p less than 0.05) and, in effect, confirmed findings from previous investigations. However, using model-fitting procedures, we found that only two variables, child's age and birth order, significantly predicted the rate of preventive care visits; a high utilization rate was observed for younger children and for first-born children. Since the observed age-specific rates of preventive care utilization were nearly identical to the schedule recommended by the pediatricians in this practice, we believe that most of the variability in well-child care in our population was due to provider-induced demand. Furthermore, none of the other demographic or psychosocial factors that significantly predicted acute care utilization in this population had any effect on preventive care once age and birth order were accounted for.

Birth Order↗
PubMed1988

[Haemophilus cellulitis--a contribution to the differential diagnosis of cheek swelling in childhood].

The Haemophilus influenzae cellulitis in infancy is a disease with special features in relation to early clinical recognition and treatment. We describe three such cases seen in our hospital with Haemophilus influenzae as etiological agent. One patient died in consequence of a purulent meningitis recognized not in time and developing under antibiotic therapy not suitable for H. i. cellulitis. After review of the most important data from the literature suggestions were made for adequate diagnostic and therapeutic procedures in patients with H. i. cellulitis.

Anti-Bacterial Agents↗
PubMed1987

Predictors of tardive dyskinesia: results of a cross-sectional study in an outpatient population.

A cross-sectional study was conducted to identify predictors of tardive dyskinesia (TD) in a group of 180 psychiatric outpatients maintained on neuroleptic medications. The estimated prevalence of this involuntary movement disorder was 33% in the total study population. Using multiple logistic regression, we found that TD was independently related to five factors: being 55 yr of age and older; being male; using depot (injectable) neuroleptics; having 6 or more years of neuroleptic exposure; and having less than 6 months of psychiatric hospitalization. In addition, the effect of depot medication was much greater in white males than it was in other race-sex groups. We observed no other interaction effects between pairs of predictor variables, nor did we find significant independent effects of race, denture use, DSM III diagnosis, current neuroleptic dose and potency, percent time on neuroleptics, and recent use of antiparkinsonian drugs or lithium. This study is serving as a pilot investigation for a large prospective incidence study that has already begun among patients at risk of developing TD in the same source population.

Adult↗
PubMed1987

Serum dopamine beta hydroxylase activity and tardive dyskinesia.

A case-control study was done to test the effect of serum dopamine-beta-hydroxylase (DBH) activity on tardive dyskinesia (TD) among 85 schizophrenic outpatients treated with neuroleptics. In contrast to the results of several previous studies, we found no significant association between serum DBH activity and the occurrence or severity of TD, controlling for other TD predictors.

Adult↗
PubMed1987

The impact of neuroleptic medication on tardive dyskinesia: a meta-analysis of published studies.

To quantify the impact of chronic exposure to neuroleptic medication on the occurrence of tardive dyskinesia (TD), we conducted a meta-analysis of data collected from 21 studies published between 1966 and 1985. The observed prevalence of dyskinesia was greater among exposed subjects in all 21 studies; we estimate that, on the average, the occurrence rate was 2.9 times greater in exposed persons than would be expected if they had been unexposed. We estimate that 65 per cent of exposed cases and 51 per cent of all cases in these investigations were caused by long-term neuroleptic exposure. Among adult United States residents in 1980, we estimate that there were approximately 193,000 neuroleptic-induced TD cases of which about 60 per cent occurred in outpatients. We also observed substantial heterogeneity of effect (rate ratio) across studies, however, partially explained, by changes and differences in the rate of dyskinesia, by differences in the frequency of certain effect modifiers, and by differences in diagnostic methods. Methodologic limitations of the studies and their possible effects on our results are discussed.

Adolescent↗
PubMed1986

The rare-disease assumption revisited. A critique of "estimators of relative risk for case-control studies".

The extension of case-control methods to the study of common outcomes has led to the development of several design and analysis techniques which do not employ the rare-disease assumption. Unfortunately, the principles underlying valid application of these techniques are more subtle than those first considered by Cornfield in the rare-disease setting, and appear to be easily misunderstood. We especially wish to caution that: The unrestricted inclusion of prevalent cases in the control group (as described by Hogue et al. for estimation of the risk ratio) will not make the odds ratio an unbiased estimate of the risk ratio (or anything else). In their response to our article, following, Hogue et al. describe restrictions on prevalence and duration necessary for the odds ratio from a case-exposure design to unbiasedly estimate the risk ratio in a stable population; these conditions were not mentioned in their original article, and in their new paper Hogue et al. do not provide mathematical proof that the conditions are sufficient to guarantee unbiasedness. Exclusion ("decontamination") of incident cases from the control group (as recommended by Hogue et al. for testing and test-based interval estimation) will result in improperly narrow risk-ratio confidence intervals whether or not the population is stable, and, in unstable populations, will generally lead to an invalid test. Methods that replace the rare-disease assumption with the stable-population assumption (such as case-exposure designs applied to open populations) will not yield unbiased results when the source population is a fixed cohort. (Of course, this will not be an issue for methods that are not based on either assumption, such as the case-base design applied to fixed cohorts, and the matched density design.) As each case-control design has certain practical implications for selection and interviewing, in choosing a design one should carefully consider practical issues (such as vulnerability to recall bias and ease of control selection) in addition to the statistical issues discussed here. In general, however, one should be wary of methods of studying incidence that involve the use of prevalent cases (such as the approach of Hogue et al.): prevalence is influenced by factors related to treatment, recovery, and fatality, and thus any etiologic study employing prevalent cases may be biased by such factors.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1986

A case-control study of factors affecting the development of renal cell cancer.

A hospital-based case-control study was conducted between 1977 and 1983 of 189 men and 78 women with renal cell carcinoma at 18 hospital centers in six US cities and an equal number of controls matched on the basis of hospital, sex, race, age (+/- 5 years), and time of admission (+/- 12 months). Quetelet index (weight/height2) was found to be associated with renal cell cancer in both men and women. Crude odds ratios (ORs) for individuals in the upper tertile of the Quetelet index distribution (28 or more) were calculated to be 2.7 (95% confidence interval (CI) = 1.5-5.9) among men and 2.4 (95% CI = 1.2-6.8) among women compared to the lowest tertile. This relationship was found to be independent of the effects of cigarette smoking, chewing tobacco use, and decaffeinated coffee consumption. The use of chewing tobacco among men was positively associated with disease (OR = 4.0; 95% CI = 1.2-12.9). This was due primarily to a significant interaction between chewing tobacco use and cumulative cigarette smoking. The fitted odds ratio for persons who chewed tobacco and had 30 pack-years of cigarette smoke exposure, compared to never users of either tobacco product, was 26.0 (95% CI = 4.4-153.0) after adjusting for Quetelet index and decaffeinated coffee use. The odds ratio for decaffeinated coffee consumption among men and women combined was 1.9 (95% CI = 1.0-3.8) after controlling for other risk factors. A consistent dose-response was not found, however, by number of cups of decaffeinated coffee consumed per day. Those drinking 1-2 cups had an odds ratio of 2.0 while those drinking 3 cups or more per day had an odds ratio of 1.3, thus casting doubt on a causal interpretation of the finding. Alcohol drinkers had a lower, although not significantly different, rate of renal cell cancer than did never drinkers when the data were examined separately by sex. However, combining the data for both sexes yielded a crude odds ratio of 0.6 (95% CI = 0.4-1.0) for this association. There was no independent effect of tobacco smoking on the odds ratio for renal cell cancer. No significant differences between cases and controls were found for either the amount or duration of artificial sweetener use or the lifetime consumption of saccharin. Beverages such as caffeinated coffee, soft drinks, and tea, in addition to physical activity and occupation, were unrelated to the occurrence of disease.

Adult↗