This paper is concerned with the analysis of multivariate categorical data from epidemiologic and clinical studies with longitudinal designs. An expository discussion of pertinent hypotheses for such ...situations is provided within the context of two relevant data sets. Appropriate large-sample tests of these hypotheses are developed through the application of weighted least squares to generate Wald statistics. These procedures are illustrated with extensive analyses of one of these data sets. In some situations, the resulting cross-classification of the response variables leads to extremely sparse frequency data, especially when the number of subjects is not large. For such repeated measurement designs in which a single variable is measured repeatedly over time, this paper considers the use of a generalized Mantel-Haenszel strategy for tests of marginal homogeneity (symmetry). These randomization model methods are illustrated for data in which the repeated measurement variable is reported on an ordinal scale. This paper also focuses on the available computing software to implement these methods within the version 5 release of the SAS system. The randomization model approach can be implemented within the FREQ procedure and a broad range of models and hypotheses can be investigated within the CATMOD procedure.
In recent years, methods have been developed for modelling repeated observations of a categorical response obtained over time on the same individual. Although situations in which the repeated ...response is binary or Poisson have been studied extensively, relatively little attention has been given to polytomous categorical response variables. In this paper, we extend the estimating equations initially developed for clustered discrete data by Liang and Zeger (1986, Biometrika 73, 13-22), and subsequently extended by Prentice (1988, Biometrics 44, 1033-1048), to polytomous response variables. Under certain assumptions, we illustrate that these estimating equations simplify to the weighted least squares (WLS) equations formalized by Koch et al. (1977, Biometrics 33, 133-158). This connection provides a formal framework for obtaining iterated weighted least squares model parameter estimates. Cumulative logit models are developed and applied to a representative longitudinal data set. Simulation results comparing WLS, an iterative form of WLS, and independence estimating equations using a robust estimate of the variance are presented.
Data from four National Health Examination Surveys conducted of the US population from 1960 to 1980 were analyzed to determine secular trends in obesity for white and for black adolescents and young ...adults of both sexes. Body mass index was categorized into four levels using cut points determined by the 50th, 75th, and 85th percentiles at the first survey in 1960-1962. The weighted proportions of persons in these body mass categories were determined, and statistical models were developed to describe secular trend and race effects. No consistent secular trends were found for white or black youths aged 12-17 years. No significant secular trends in obesity were found for white or black young males aged 18-34 years. Both for white and for black adult females, there were significant secular increases in the proportion of adult females in each of the successively heavier categories of body mass index. These increases were identical for white and for black adult females on the log-odds scale, but black adult females were already significantly heavier at the first survey. This race effect persisted throughout the entire time interval.
Objectives/Hypothesis
To investigate olfactory and gustatory function in patients with maxillofacial trauma and associated fractures.
Study Design
Retrospective cohort study.
Methods
Olfactory and ...gustatory function was assessed psychophysically in 124 patients who had sustained maxillofacial trauma with an associated fracture. Five groups were defined based on the fracture type: Le Fort, mandibular, nasal, orbital, and zygomatic. Olfaction was measured with Sniffin' Sticks (threshold, discrimination, identification TDI score) and gustation with the taste spray method. Patients self‐rated olfactory and gustatory function on a visual analog scale prior to formal testing.
Results
Ten out of 124 patients were found to be anosmic (8%), with half of them found in the Le Fort (skull base) group. The Le Fort fracture group had significantly lower olfactory function than other fracture types (TDI score = 22.4 ± 10.7; P = .01; possible range = 1–48). The mean gustatory spray test score was 3.82 ± 0.4 (possible range = 0–4) without any intergroup differences. Self‐rated olfactory function showed a correlation with the measured scores (r = 0.61, P < .001) across all groups.
Conclusions
The present data show a significant effect of maxillofacial fracture type on the development of anosmia. Maxillofacial fractures involving the skull base, such as Le Fort fractures, are more likely to cause permanent smell loss, whereas the other fracture types are rarely associated with anosmia.
Level of Evidence
4 Laryngoscope, 131:E331–E337, 2021
We used psychological contract theory as a framework to meta-analytically review subjective and objective predictors of employees' perceived job insecurity. Seventy-six samples from 68 studies were ...included in our review. Results revealed that lower levels of job insecurity are associated with having an internal locus of control, lower amounts of role ambiguity and role conflict, greater amounts of organizational communication, less organizational change, younger employees, and white-collar and permanent work. Moderator analyses further revealed that relations between job insecurity and age, gender, education, and formal contracts are moderated by unemployment rates, countries of origin, and type of job insecurity measure. We discuss theoretical and practical implications for psychological contract theory and occupational health, and offer directions for future research.
Breast cancer research is hampered by difficulties in obtaining and studying primary human breast tissue, and by the lack of in vivo preclinical models that reflect patient tumor biology accurately. ...To overcome these limitations, we propagated a cohort of human breast tumors grown in the epithelium-free mammary fat pad of severe combined immunodeficient (SCID)/Beige and nonobese diabetic (NOD)/SCID/IL-2γ-receptor null (NSG) mice under a series of transplant conditions. Both models yielded stably transplantable xenografts at comparably high rates (∼21% and ∼19%, respectively). Of the conditions tested, xenograft take rate was highest in the presence of a low-dose estradiol pellet. Overall, 32 stably transplantable xenograft lines were established, representing 25 unique patients. Most tumors yielding xenografts were "triple-negative" estrogen receptor (ER)-progesterone receptor (PR)-HER2+; n = 19. However, we established lines from 3 ER-PR-HER2+ tumors, one ER+PR-HER2-, one ER+PR+HER2-, and one "triple-positive" (ER+PR+HER2+) tumor. Serially passaged xenografts show biologic consistency with the tumor of origin, are phenotypically stable across multiple transplant generations at the histologic, transcriptomic, proteomic, and genomic levels, and show comparable treatment responses as those observed clinically. Xenografts representing 12 patients, including 2 ER+ lines, showed metastasis to the mouse lung. These models thus serve as a renewable, quality-controlled tissue resource for preclinical studies investigating treatment response and metastasis.
Since the name Thomomys clusius was first proposed in 1875, it has been applied and misapplied to a variety of different pocket gophers. Study of specimens and chromosomal material of pocket gophers ...collected from southern Wyoming permits the recognition of Thomomys clusius as a distinct species within the Thomomys talpoides complex. Thomomys clusius is a small, pale-colored animal with 2n = 46 chromosomes. It does not interbreed with T. talpoides ocius where the two are found together. The known range of T. clusius is almost entirely within that of T. t. ocius, but the two occur in different habitats. Also, T. clusius is chromosomally and morphologically distinct from the pale-colored populations of T. talpoides of central Wyoming to which Long (1965) applied this name.
Twenty-eight percent of people with mild to moderate obstructive sleep apnea experience daytime sleepiness, which interferes with daily functioning. It remains unclear whether treatment with ...continuous positive airway pressure improves daytime function in these patients.
To evaluate the efficacy of continuous positive airway pressure treatment to improve functional status in sleepy patients with mild and moderate obstructive sleep apnea.
Patients with self-reported daytime sleepiness (Epworth Sleepiness Scale score >10) and an apnea-hypopnea index with 3% desaturation and from 5 to 30 events per hour were randomized to 8 weeks of active or sham continuous positive airway pressure treatment. After the 8-week intervention, participants in the sham arm received 8 weeks of active continuous positive airway pressure treatment.
The Total score on the Functional Outcomes of Sleep Questionnaire was the primary outcome measure. The adjusted mean change in the Total score after the first 8-week intervention was 0.89 for the active group (n = 113) and -0.06 for the placebo group (n = 110) (P = 0.006). The group difference in mean change corresponded to an effect size of 0.41 (95% confidence interval, 0.14-0.67). The mean (SD) improvement in Functional Outcomes of Sleep Questionnaire Total score from the beginning to the end of the crossover phase (n = 91) was 1.73 ± 2.50 (t90 = 6.59; P < 0.00001) with an effect size of 0.69.
Continuous positive airway pressure treatment improves the functional outcome of sleepy patients with mild and moderate obstructive sleep apnea.
An important if not predominant component of porosity in many gas shales has been identified in organic matter. An organic network in shales has been described in the literature as organic matter ...(generalized term), kerogen (primary), or bitumen (secondary). Recognition of the type and origin of an organic network in shales has relevance in establishing the origin and timing of porosity and fracture development. The pervasive nature of the organic network adopting the shape of pores in Type II kerogen-rich Woodford Shale suggests it is the residue of primary oil migration. We use the term “post-oil solid bitumen” to distinguish this bitumen occurrence from “pre-oil solid bitumen” (defined as a precursor of oil). Three forms of this post-oil solid bitumen network are recognized in reflected white light at 500× magnification and confirmed in backscattered scanning electron microscope images at >2500× magnification, namely speckled (~1–2μm), wispy (~2–5μm), and connected (>5μm). The post-oil solid bitumen network demonstrates the prior occurrence of oil generation and migration within this hydrocarbon source rock, provides porosity for hydrocarbon storage sites, and forms hydrocarbon migration pathways.
•Primary oil migration leaves behind a post-oil solid bitumen network.•Three post-oil solid bitumen network forms are speckled, wispy, and connected.•Post-oil solid bitumen network demonstrates oil generation and migration.•Post-oil solid bitumen network provides porosity for hydrocarbon storage sites.•Post-oil solid bitumen network forms hydrocarbon migration pathways.
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