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W Mack

Publications and source records attributed to W Mack.

At least 19 recordsLinked to original sources
PubMed2001

Risk factors associated with moderate and serious injuries attributable to the 1994 Northridge Earthquake, Los Angeles, California.

PURPOSE: The purpose of this study was to use emergency department data to estimate levels of morbidity and risk factors due to earthquake-related mechanisms of injury subsequent to an urban night-time earthquake. METHODS: Data were abstracted from 4190 medical records for the month of January, 1994. Injuries attributable to the earthquake were identified through emergency department and medical records. These injuries were: (a) categorized by mechanism of injury; (b) assigned an injury severity score; and (c) linked to structural and geologic data. Proportional polytomous and dichotomous logistic regression were used to estimate risk of more severe injury associated with demographic characteristics, injury characteristics, structural characteristics, and geologic factors. RESULTS: More severe earthquake-related injuries (serious versus moderate and moderate versus minor) were statistically significantly associated with patient age (> or = 60 years old), upper extremities, falling, multi-family structures, pre-1960 housing, and the 50th percentile of Peak Ground Acceleration, after adjusting for all other available demographic, injury, structural, and geologic characteristics. CONCLUSIONS: The current recommendation of 'duck, cover, and hold' might not be optimal during a nighttime earthquake, particularly if individuals are in the padded environment of the bed. Actions such as reaching for or catching objects, bracing, or holding onto perceived stable objects may increase risk for more serious injury. Alternate responses include assuming a tucked position (as in airline crashes) or staying in bed for non-ambulating people. Structural damage and structure size were not associated with more serious injuries, but structure use and age were, leading the authors to suspect that unmeasured socioeconomic factors might impact risk factors. The importance of including population demographic characteristics in hazard modeling is emphasized.

Adolescent↗
PubMed2000

Clinical criteria for the diagnosis of vascular dementia: a multicenter study of comparability and interrater reliability.

BACKGROUND: Several clinical criteria have been developed to standardize the diagnosis of vascular dementia (VaD). Significant differences in patient classification have been reported, depending on the criteria used. Few studies have examined interrater reliability. OBJECTIVE: To assess the concordance in classification and interrater reliability for the following 4 clinical definitions of VaD: the Hachinski Ischemic Score (HIS), the Alzheimer Disease Diagnostic and Treatment Centers (ADDTC), National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN), and Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). METHODS: Structured diagnostic checklists were developed for 4 criteria for VaD, 2 criteria for Alzheimer disease (AD), and 4 criteria for dementia. Twenty-five case vignettes, representing a spectrum of cognitive impairment and subtypes of dementia, were prepared in a standardized clinical format. Concordance in case classification using different criteria and interrater reliability among 7 ADDTCs given a specific set of criteria was assessed using the kappa statistic. RESULTS: The frequency of a diagnosis of VaD was highest using the modified HIS or DSM-IV criteria, intermediate using the original HIS and ADDTC criteria, and lowest using the NINDS-AIREN criteria. Scores for interrater reliability ranged from kappa = 0.30 (ADDTC) to kappa = 0.61 (original HIS). CONCLUSIONS: Clinical criteria for VaD are not interchangeable. Depending on the criteria selected, the reported prevalence of VaD will vary significantly. The traditional HIS has higher interrater reliability than the newer criteria for VaD. Prospective longitudinal studies with clinical-pathological correlation are needed to compare validity.

Aged↗
PubMed2000

A pooled analysis of thyroid cancer studies. V. Anthropometric factors.

OBJECTIVE: To assess the relation between anthropometric factors and thyroid cancer risk in a pooled analysis of individual data from 12 case-control studies conducted in the US, Japan, China and Europe. METHODS: 2056 female and 417 male cases, 3358 female and 965 male controls were considered. Odds ratios (OR) were derived from logistic regression, conditioning on age, A-bomb exposure (Japan) and study, and adjusting for radiotherapy. RESULTS: Compared to the lowest tertile of height, the pooled OR was 1.2 for females for the highest one, and 1.5 for males, and trends in risk were significant. With reference to weight at diagnosis, the OR for females was 1.2 for the highest tertile, and the trend in risk was significant, whereas no association was observed in males. Body mass index (BMI) at diagnosis was directly related to thyroid cancer risk in females (OR = 1.2 for the highest tertile), but not in males. No consistent pattern of risk emerged with BMI during the late teens. Most of the associations were observed both for papillary and follicular cancers, and in all age groups. However, significant heterogeneity was observed across studies. CONCLUSIONS: Height and weight at diagnosis are moderately related to thyroid cancer risk.

Adult↗
PubMed1998

Ideomotor apraxia in early Alzheimer's disease: time and accuracy measures.

Twenty-six Alzheimer's disease (AD) and 42 healthy control (NC) subjects were evaluated with neuropsychological and apraxia batteries. ADs produced a greater range of error types, but did not differ from NCs in their most frequent error types. Hand sequencing ability contributed significantly to AD praxis with no predictors for NCs. Although groups did not differ in gesture time, the AD group had significantly longer response latencies for periods prior to gesture execution and the effect was prominent for transitive tasks and nondominant hand use. Results illustrate the sensitivity of timing measures in identifying abnormal praxis in early stages of AD.

Alzheimer Disease↗
PubMed1994

Temporal modifiers of the radon-smoking interaction.

Data on lung cancer mortality in a cohort of 3,347 Colorado Plateau uranium miners was reanalyzed to investigate the role of time-related modifiers of the radon-smoking interaction. A nested case-control sample of the cohort was drawn, matching each of the 258 lung cancer deaths with 15 controls drawn at random from the subjects who were born in the same year and still alive at the time the case died. As reported earlier, the dose response was sublinear for both total radon and total smoking, and their joint effect was approximately multiplicative. We fitted linear multiplicative models to these data, transforming the radon and smoking variables to improve their fit, and then added variables testing various temporal modifying effects and interactions. The strongest modifiers of the main effects of each variable taken separately were latency and duration of exposure. The strongest modifier of the interaction effect was the timing of radon and smoking exposures: Exposure to radon followed by smoking produced a significantly more-than-multiplicative effect, whereas the reverse sequence produced a significantly less-than-multiplicative effect. These findings suggest that smoking may act as a promoter of radon-initiated cells.

Air Pollutants, Radioactive↗
PubMed1991

Astrocytoma risk related to job exposure to electric and magnetic fields.

To investigate the association between occupational exposure to low-frequency electric and magnetic (EM) fields and risk of brain tumors, a study was performed in Los Angeles County on 272 male adults with primary intracranial gliomas or meningiomas and 272 neighborhood controls. Complete occupational histories were collected. Risk associated with employment for more than 10 years in jobs that are presumed to entail exposure to EM fields was computed for various histological groupings. A nonsignificantly elevated risk of 1.7 was found for gliomas (all types pooled: 95% confidence interval 0.7-4.4), and a nonsignificantly reduced risk of 0.3 (95% confidence interval 0.03-3.2) was found for meningiomas. For astrocytomas, which form a subtype of the gliomas, a significantly elevated risk of 10.3 (95% confidence interval 1.3-80.8) was found; a significant upward trend (P = .01) of tumor incidence with increasing length of employment was observed. Most astrocytoma patients who worked in occupations involving exposure to EM fields were electricians or electrical engineers.

Adult↗
PubMed1991

Correlation of perceptual performance and activities of daily living in stroke patients.

Twenty-five male stroke patients were assessed with the use of a battery of perceptual tests (Gross Visual Skills [Baum, 1981]. Adult Visual-Perceptual Assessment [Baylor University Medical Center, Occupational Therapy Department, 1980], Manikin and Feature Profile subtests of the Arthur Point Scale of Performance Tests [Arthur, 1943; Buros, 1974, 1978], Judgment of Line Orientation [Benton, Varney, & DeS. Hamsber, 1978], Bender Visual Motor Gestalt Test [Bender, 1946], Haptic Visual Discrimination Test [McCarron & Dial, 1976, 1979a, 1979b], Block Design and Object Assembly subtests of the Wechsler Adult Intelligence Scale-Revised [Wechsler, 1981], and Test of Three-Dimensional Constructional Praxis [Benton, 1973a; Benton & Fogel, 1962]). Also administered was the Klein-Bell ADL Scale (Klein & Bell, 1982) to measure performance of activities of daily living. The research questions were as follows: (a) To what extent did this sample of stroke patients differ from the nomative samples on perceptual performance? (b) To what extent did any tests of perceptual performance correlate with performance of activities of daily living? and (c) What, if any, instruments were more useful in discriminating the perceptual performance of stroke patients from that of normative samples? The results indicated that stroke patients showed significant deficits in perceptual performance, some of which correlated with activities of daily living performance. Patients with right hemispheric lesions performed similarly to those with left hemispheric lesions except on the Haptic Visual Discrimination Test.

Activities of Daily Living↗
PubMed1991

Gliomas and meningiomas in men in Los Angeles County: investigation of exposures to N-nitroso compounds.

We conducted a case-control study of primary tumours of the brain and cranial meninges in Los Angeles County to investigate the hypothesis that these tumours are related to occupational exposures. We also collected limited data on diet and personal habits that are likely to involve exposure to N-nitroso compounds (NOC), NOC precursors and modulators of NOC metabolism. Interviews were conducted with 272 men with a brain tumour diagnosed in 1980-84 and with 272 individually matched neighbourhood controls. The study was of sufficient size to allow for separate analyses of the 202 pairs of glioma patients and of the 70 patients of meningioma. Six glioma cases and one control had worked in the rubber industry, in which excesses of brain tumour have been shown in previous studies and where there are high levels of volatile NOC at various work sites. Ten meningioma patients and five controls had used cooling, cutting or lubricating oils, and most had used these daily (eight cases; four controls). Cases and controls were not different, however, with respect to other occupations known to involve exposures to NOC. Cases and controls also did not differ in their consumption of alcoholic beverages or cigarettes or in their passive exposure to cigarette smoke. The most striking dietary finding was a significant protective effect among glioma pairs of use of vitamin supplements, which increased with increasing frequency of use (p for trend = 0.04; odds ratio for use at least twice a day = 0.4 (95% confidence interval = 0.24-0.77)).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Bivariate survival models for analysis of genetic and environmental effects in twins.

Classic methods in genetics for the analysis of binary attributes, based on an assumption of a "threshold" on a normally distributed latent variable called "liability," estimate the strength of genetic and environmental effects from differences in correlations between relatives of differing genetic relatedness. Two problems that are not easily addressed by these methods are the need to take the age of onset into account (particularly in chronic diseases in which incidence rates vary considerably with age and the lengths of time at risk can vary between individuals) and the desirability of incorporating measured covariates (genetic or environmental). The standard methods of cohort analysis used in epidemiology allow for both of these features, but until recently have been restricted to independent individuals. Recent developments in survival analysis have extended the widely used "proportional hazards" model of Cox by the addition of latent variable, epsilon, reflecting the shared susceptibility of related subjects because of their shared genes or shared environment. We show how this approach can be combined with more traditional models of gene-environment interaction to allow the main effects of measured genetic markers and environmental variables to be estimated, as well as the residual variance of genetic and environment and their interactions. The approaches are applied to a cohort of female twin births in Sweden from 1886 to 1958, linked with the Swedish cancer registry from 1961 to 1982.

Adult↗
PubMed1990

Naming consistency in Alzheimer's disease.

Although lexical semantic deficits are postulated to play a prominent role in the anomia of Alzheimer's disease, it is unclear whether the primary disturbance is one of lexical access or one of lexical semantic loss. Response consistency on a naming task is one means of evaluating the underlying source of naming impairment. Access dysfunction usually implies variable word-finding difficulty, while a theory of lexical loss predicts that many word names would be consistently unavailable. Nineteen Alzheimer's disease patients were administered a visual confrontation naming task (the Boston Naming Test) on two occasions 6 months apart. Eighty percent of errors occurred consistently at both times; only 20% of errors occurred on only one occasion. Response consistency occurred significantly more often than expected under the assumption of no response consistency. Findings support the hypothesis that anomia in Alzheimer's disease is in part due to a loss of lexical semantic information.

Aged↗
PubMed1990

Survival models for familial aggregation of cancer.

It has recently been shown that the relative risks of the order of 2 to 4 that are frequently found for cancer among relatives of affected cases are unlikely to be explainable by shared environmental risk factors. Classical methods of epidemiological analysis are not well suited to such analysis because they assume that the outcomes of each individual are independent. Classical methods of genetic analysis, on the other hand, are limited in their handling of environmental factors and variable ages of onset. The recent development of random effects models for survival analysis, however, appears to bridge this gap. Specifically, a proportional hazards model is postulated for the effects of measured covariates and of one or more components of frailty that are unmeasured but assumed to have some common distribution and known covariance structure within each family. From these assumptions, the posterior expectation of the hazard for each individual can be derived, given the covariate value and the observed and expected disease history of the family. These are then treated as known in a standard partial likelihood analysis; this is essentially a form of expectation-maximization algorithm. However, this does not provide a valid estimate of the covariance matrix because it fails to take account of the variability in the estimates of the frailties; an alternative approach using the imputation-posterior algorithm is suggested. This paper describes extensions of this approach to multivariate frailty distributions, modifications for application to pedigree and case-control studies, some simulation results, and applications to studies of breast cancer in twins and of lung cancer in relation to family smoking habits.

Adenocarcinoma↗
PubMed1990

Relations between Design Copying and other tests of sensory integrative dysfunction: a pilot study.

The purpose of this pilot study was to investigate possible relations between performance on the atypical approach parameters of the Design Copying (DC) subtest of the Sensory Integration and Praxis Tests (SIPT) (Ayres, 1989) and scores on the Southern California Sensory Integration Tests (SCSIT) (Ayres, 1980). An existing data set was used that consisted of SCSIT and SIPT-DC scores from 32 children identified by their performance on the SCSIT as having sensory integrative dysfunction. Three questions were addressed: (a) Are there relations between scores on the atypical approach parameters of the SIPT-DC and SCSIT scores? (b) To what extent do the SCSIT scores collectively predict the presence or absence of the SIPT-DC atypical approach parameters? and (c) Are there relations among scores on the SIPT-DC atypical approach parameters? The results suggest that the scores on individual SIPT-DC atypical approach parameters may be related to the scores on the SCSIT subtests. In particular, significant relationships were found between some of the SIPT-DC parameters and the SCSIT subtests that assess visual, tactile, and motor components.

Child↗
PubMed1989

Risk factors for gliomas and meningiomas in males in Los Angeles County.

Detailed job histories and information about other suspected risk factors were obtained during interviews with 272 men aged 25-69 with a primary brain tumor first diagnosed during 1980-1984 and with 272 individually matched neighbor controls. Separate analyses were conducted for the 202 glioma pairs and the 70 meningioma pairs. Meningioma, but not glioma, was related to having a serious head injury 20 or more years before diagnosis [odds ratio (OR) = 2.3; 95% confidence interval (CI) = 1.1-5.4], and a clear dose-response effect was observed relating meningioma risk to number of serious head injuries (P for trend = 0.01; OR for greater than or equal to 3 injuries = 6.2; CI = 1.2-31.7). Frequency of full-mouth dental X-ray examinations after age 25 related to both glioma (P for trend = 0.04) and meningioma risk (P for trend = 0.06). Glioma, but not meningioma risk, related to duration of prior employment in jobs likely to involve high exposure to electric and magnetic fields (P for trend = 0.05). This risk was greatest for astrocytoma (OR for employment in such jobs for greater than 5 years = 4.3; CI = 1.2-15.6). More glioma cases had worked in the rubber industry (discordant pairs 6/1) and more worked in hot processes using plastics (9/1). More meningioma cases had jobs that involved exposure to metal dusts and fumes (discordant pairs 13/5), and six of these cases and two controls worked as machinists. Finally, there was a protective effect among glioma pairs relating to frequency of use of vitamin C and other vitamin supplements (P for trend = 0.004); the OR for use at least twice a day was 0.4 (CI = 0.2-0.8).

Alcohol Drinking↗
PubMed1989

Spatial disorientation in Alzheimer's disease.

Spatial disorientation was investigated in 28 ambulatory patients meeting the National Institute of Neurological Disorders and Stroke-Alzheimer's Disease and Related Disorders Association Work Group criteria for "probable" Alzheimer's disease. Based on caregivers' reports, 39% of subjects engaged in at least three of four behavioral measures of spatial disorientation three or more times a week; these patients did not significantly differ from other Alzheimer's disease subjects with regard to age, sex, education, or symptom duration. Using stepwise regression analysis, we found that neuropsychologic measures of memory and visuoconstructive functions, but not disease severity, attention, or language impairment, emerged as significant predictors of spatial disorientation. In the setting of impaired memory, the tendency of some patients with Alzheimer's disease to wander or to get lost may implicate particularly severe dysfunction of right hemisphere neocortical areas concerned with visuospatial processes.

Alzheimer Disease↗
PubMed1989

Sex differences in property crime in a Danish adoption cohort.

Sex differences in genetic and environmental influences on criminal behavior against property were studied in a birth cohort of 6129 male and 7065 female Danish adoptees and their biological and adoptive parents. Both genetic and environmental factors were found to contribute to variation in liability to property criminality, the relative proportions of variance explained being similar in males and females. Important shared- and nonshared-family environmental factors were present. In separate analyses of average liability toward property criminality, however, convicted females appeared to be more genetically predisposed than convicted males, a conclusion based on the finding that female property offenders were more likely than male offenders to have convicted biological (but adopted-away) offspring. On the other hand, property-offending males and females did not appear to differ in their average shared-family environmental liabilities, since conviction rates did not differ for adoptees of convicted adoptive mothers and fathers. Also, social class in the adoptive parents of convicted sons and daughters were comparable, further indicating that average shared-family environmental liabilities do not differ between the sexes.

Adoption↗
PubMed1989

Boston Naming Test in Alzheimer's disease.

The 60-item Boston Naming Test (BNT) was administered to 55 subjects: 15 mildly-to-moderately demented patients meeting NINCDS-ADRDA criteria for "probable" Alzheimer's disease (AD), 15 age-equivalent normal control (NC) subjects, and--for purposes of validation--25 additional subjects with other forms of dementia (OD). A cutting score of 51 correctly classified 80% of AD patients and 86% of NC subjects. To facilitate rapid screening of confrontation-naming performance in these populations, three 30-item shortened versions of the BNT were constructed. Even and Odd Versions were equivalent for AD, NC, and OD subjects; high correlations between these two and the 60-item BNT permit easy extrapolation to a total BNT score. A new Empirical Version, derived from performance of our AD and NC reference groups, maintained most of the intergroup discrimination of the full BNT.

Aged↗