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Biomedical subjects

M Susser

Publications and source records attributed to M Susser.

187 records · Page 11Linked to original sources
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Variation in use of corticosteroids among infants < or = 1,500 grams across hospitals in three states.

We identified factors associated with no antenatal corticosteroid treatment among 1,369 women who delivered infants < or = 1,500 g and < 34 weeks gestation, 1991-1993. At four hospitals, infants weighing 500-1,500 g were enrolled. Information regarding corticosteroid use, maternal characteristics, and perinatal events were obtained. Factors associated with no corticosteroid treatment were examined in unadjusted and adjusted logistic regression models. Overall, 693 (50.6%) women did not receive corticosteroids. Two hospitals had higher rates of no corticosteroid usage (89% and 75%) as compared with the other two (32% and 50%). Black, Hispanic, and poor women were more likely to receive care at the hospitals where the rates of corticosteroid utilization were lower. Factors in the multivariate model included: < 1 or 1 day of hospitalization, vs. delivery on > or = 2 days of hospitalization (21.4: 14.5, 97.2; 4.7: 3.2, 6.9); gestational age < 26 weeks (2.7: 1.8, 4.1) or > 28 weeks (1.8: 1.3, 2.6) vs. 26-28 weeks; < 12 hours of labor vs. > 12 hours (1.7: 1.2, 2.4); delivering at hospital 2, 3, 4 vs. hospital 1 (1.6: 1.1, 2.5; 24.3: 13.6, 43.4; 10.2: 6.8, 15.3). We conclude that variations in hospital practice limit widespread use of this important antenatal treatment.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Third variable analysis: application to causal sequences among nutrient intake, maternal weight, birthweight, placental weight, and gestation.

We applied a set of procedures, aimed at enhancing the strength of inferences about the direction of causal paths among variables measured at the same time, to foetal and maternal indices recorded at birth and collected for study of the Dutch famine of 1944/5. The analysis of three-variable sets yielded strong inferences about the relations among caloric intake, maternal weight, birthweight, placental weight, and length of gestation. These procedures constitute not only a useful preliminary to the construction of multivariate path models, but produce useful results in their own right.

Birth Weight↗
PubMedDate not supplied

Validity of family history data on seizure disorders.

Accurate family histories of seizure disorders are important for both clinical practice and genetic research. This study evaluated validity of seizure histories of parents and siblings, obtained by interviewing 1,957 adults with epilepsy (probands). Probands were asked two questions to screen for occurrence of seizures in each relative; the first asked about epilepsy specifically, the second asked about "other seizures." For each relative who screened positive for seizures, a detailed clinical description was obtained. The final diagnosis was based on a review of all assembled information. Whenever possible, the proband's mother was interviewed independently about the family history, as were eligible relatives reported to have had seizures. Sensitivity, or the proportion of affected relatives who screened positive for seizures, was higher for epilepsy than for other seizures (87% vs. 32% assuming the mother's report to be correct, and 93% vs. 18% assuming self-report to be correct). For epilepsy, estimates of risk in siblings based on the final diagnoses were similar to previously reported findings in Rochester, Minnesota. For both isolated unprovoked seizures and acute symptomatic seizures, however, risk estimates were lower than in Rochester. These findings suggest that adults with epilepsy can report reasonably accurately about epilepsy in their parents and siblings, but isolated unprovoked seizures and acute symptomatic seizures are underreported.

Epilepsy↗
PubMedDate not supplied

Stressful life events and seizure frequency in patients with epilepsy.

We tested whether unpleasant life events increased seizure occurrence in persons with epilepsy. Forty-six subjects maintained daily diaries for 10-36 weeks in which they recorded seizures and life events. Mean age of subjects was 39 years; 78% were female; 83% had complex partial seizures (CPS). On the average, subjects reported 3.3 seizures a week. Analyses first were conducted within each subject and then in the sample overall. For each person, we tested whether seizure frequency increased within 24 h of the occurrence of unpleasant events, using Poisson regression analyses that adjusted for daily antiepileptic medication, sleep duration and quality, alcohol intake, menstrual status, and pleasant events. Rarity of events precluded analyses in 9 subjects. Events increased seizure frequency in 5 subjects (14%) (p < 0.05). Events decreased seizure frequency in 2 subjects (p < 0.05). When individual risk ratios were aggregated across subjects, unpleasant events were significantly associated with seizure increase only in men (RR = 1.67, 95% Confidence interval 1.09, 2.54). However, this finding must be interpreted with caution because of the limited number of men in the sample. In other aggregate analyses, events and seizures were not associated in subjects grouped by seizure type, age of seizure onset, current age, ethnicity, educational level, or marital status. Identification of factors that distinguish patients with and without event-triggered seizures requires further study.

Adolescent↗
PubMedDate not supplied

Separating heredity and environment.

The problems of separating highly confounded heredity and environmental factors are reviewed from an epidemiological point of view. Once the fact rather than the appearance of familial aggregation is established, one can search for and analyze strong indicators of either genetic or environmental effects, and ultimately attempt their separation by strong design. Indicators of genetic effects are classified according to the presence or absence of family recurrence. In the presence of family recurrence, three analytic approaches are available: segregation analysis, linkage, and heritability estimates. In the absence of family recurrence, biological markers and endogamous groups can be used. Indicators of environmental effects are also classified according to the presence or absence of family recurrence of a disorder. In the presence of family recurrence, three environmental indicators are considered: non-Mendelian clustering, such as time of onset versus age in family clusters, and sex clusters; cohabitational effects; and maternal transmission. In the absence of family recurrence, environmental indicators include secular trends, migration, time and place clusters, family size, and birth order. Designs that aim to separate heredity and environment include twin studies, fixed clusters that include a variety of degrees of relatedness (particularly the family set-design), and comparisons of separately reared relatives. The strengths and weaknesses of twin studies and family set designs are reviewed. Separately reared relatives provide the most cogent tests of genetic and environmental hypotheses. Among these, separated twin pairs, half-sibs, and relatives separated through institutional placement or adoption are considered. Adoption strategies are illustrated by the Danish adoption studies of schizophrenia, criminality, and alcoholism, and these studies are reanalyzed from the perspective of epidemiological case-control and cohort studies. Finally, the potential uses of multiple family settings as they occur in the general population are briefly considered.

Diseases in Twins↗
PubMedDate not supplied

Steps toward discovering causes: divergence and convergence of epidemiology and clinical medicine.

Ways in which frames of reference about causation differ across disciplines are exemplified. The necessity for a multivariate concept of causation is emphasized. On the epidemiological side, divergences of clinical approaches from requirements for meeting preconditions for cause are each illustrated by several examples. Association is discussed in terms of comparability of groups, independent observation of associated variables, sampling and measurement. Securing time order among variables is a matter of sequential positioning by design, and the difficulties that inhere in the clinical situation are again illustrated by example. On the clinical side, strengths in generating hypotheses, in discovery of associations without conventional comparison and in potential precision in measuring outcomes are outlined. On the epidemiological side, the discipline adds to clinical medicine unique dimensions analogous with the basic biomedical sciences. These are essential to capturing environmental causes and the antecedent experience of sick individuals. Convergence between the two perspectives is bound to yield, and has yielded, much profit.

Causality↗