Biomedical subjects

Beth A Reboussin

Publications and source records attributed to Beth A Reboussin.

26 records · Page 2Linked to original sources

PubMed2004

Staphylococcus aureus nasal carriage in a student community: prevalence, clonal relationships, and risk factors.

OBJECTIVE: To evaluate the prevalence and risk factors of nasal Staphylococcus aureus (SA) in the community. DESIGN: Cross-sectional study. SETTING: Wake Forest University, Winston-Salem, North Carolina. PARTICIPANTS: Four hundred fifty students were screened for nasal SA carriage during the fall of 2000, 2001, and 2002. METHODS: Students were screened by nose swabs. A self-administered questionnaire collected information on demographics and medical history. Antibiotic testing and PFGE were performed on isolates. Risk factors were determined by logistic regression analysis. RESULTS: Of 450 volunteers, 131 (29%) were SA carriers. Antibiotic resistance was high for azithromycin (26%) and low for ciprofloxacin (1%), tetracycline (5%), mupirocin (1%), and methicillin (2%). PFGE patterns were not associated with carriage. Age, male gender, white race, medical student, allergen injection therapy, chronic sinusitis, rheumatoid arthritis, hospitalization for 6 months or less, and use of antibiotics were associated with carrier status by univariate analysis. Stepwise multivariate logistic regression led to a best fitting model with older age (OR, 1.04; CI95, 1.005-1.079), male gender (OR, 1.50; CI95, 0.982-2.296), and chronic sinusitis (OR, 2.71; CI95, 0.897-8.195) as risk factors. Antibiotic use (< 4 weeks) (OR, 0.41; CI95, 0.152-1.095) and allergen injection therapy (OR, 0.41; CI95, 0.133-1.238) were protective. Analyses of carriers revealed candidate factors for persistent carriage to be nasal SA colonization rate and male gender. Factors for azithromycin resistance were non-medical students and antibiotic use in the past 6 months. CONCLUSION: Older male volunteers suffering from chronic sinusitis and not taking antibiotics were at higher risk for carrying SA.

Adult↗

PubMed2004

Airborne dispersal as a novel transmission route of coagulase-negative staphylococci: interaction between coagulase-negative staphylococci and rhinovirus infection.

OBJECTIVE: To investigate whether rhinovirus infection leads to increased airborne dispersal of coagulase-negative staphylococci (CoNS). DESIGN: Prospective nonrandomized intervention trial. SETTING: Wake Forest University School of Medicine, Winston-Salem, North Carolina. PARTICIPANTS: Twelve nasal Staphylococcus aureus-CoNS carriers among 685 students screened for S. aureus nasal carriage. INTERVENTIONS: Participants were studied for airborne dispersal of CoNS in a chamber under three conditions (street clothes, sterile gown with a mask, and sterile gown without a mask). After 2 days of pre-exposure measurements, volunteers were inoculated with a rhinovirus and observed for 14 days. Daily quantitative nasal and skin cultures for CoNS and nasal cultures for rhinovirus were performed. In addition, assessment of cold symptoms was performed daily, mucous samples were collected, and serum titers before and after rhinovirus inoculation were obtained. Sneezing, coughing, and talking events were recorded during chamber sessions. RESULTS: All participants had at least one nasal wash positive for rhinovirus and 10 developed a symptomatic cold. Postexposure, there was a twofold increase in airborne CoNS (P = .0004), peaking at day 12. CoNS dispersal was reduced by wearing a gown (57% reduction, P < .0001), but not a mask (P = .7). Nasal and skin CoNS colonization increased after rhinovirus infection (P < .05). CONCLUSIONS: We believe this is the first demonstration that a viral pathogen in the upper airways can increase airborne dispersal of CoNS in nasal S. aureus carriers. Gowns, gloves, and caps had a protective effect, whereas wearing a mask did not further reduce airborne spread.

Adult↗

PubMed2004

Deviations from the population-averaged versus cluster-specific relationship for clustered binary data.

There has been much debate about the relative merits of mixed effects and population-averaged logistic models. We present a different perspective on this issue by noting that the investigation of the relationship between these models for a given dataset offers a type of sensitivity analysis that may reveal problems with assumptions of the mixed effects and/or population-averaged models for clustered binary response data in general and longitudinal binary outcomes in particular. We present several datasets in which the following violations of assumptions are associated with departures from the expected theoretical relationship between these two models: 1) negative intra-cluster correlations; 2) confounding of the response-covariate relationship by cluster effects; and 3) confounding of autoregressive relationships by the link between baseline outcomes and subject effects. Under each of these conditions, the expected theoretical attenuation of the population-averaged odds ratio relative to the cluster-specific odds ratio does not necessarily occur. In all cases, the naive fitting of a random intercept logistic model appears to lead to bias. In response, the random intercept model is modified to accommodate negative intra-cluster correlations, confounding due to clusters, or baseline correlations with random effects. Comparisons are made with GEE estimation of population-averaged models and conditional likelihood estimation of cluster-specific models. Several examples, including a cross-over trial, a multicentre nonrandomized treatment study, and a longitudinal observational study are used to illustrate these modifications.

Animals↗

PubMed2003

Postmenopausal hormone therapy and change in mammographic density.

BACKGROUND: Mammographic density is an independent risk factor for breast cancer. Postmenopausal hormone use is associated with an increase in mammographic density, but the magnitude of the density increase is unknown. METHODS: Baseline and 12-month mammograms were obtained for 571 (65%) of the 875 women, aged 45-64 years, who were enrolled in the Postmenopausal Estrogen/Progestin Interventions Trial and randomly assigned to receive placebo, daily conjugated equine estrogens at 0.625 mg/day (CEE), daily CEE and medroxyprogesterone acetate (MPA) at 10 mg/day on days 1-12 (CEE+MPA-cyclic), daily CEE and MPA at 2.5 mg/day (CEE+MPA-continuous), or daily CEE and micronized progesterone (MP) at 200 mg/day on days 1-12 (CEE+MP). We analyzed digitized mammograms to determine the percentage of the left breast that was composed of dense tissue (i.e., mammographic percent density). Linear regression analysis was used to examine the effects of treatments on the change in mammographic percent density between baseline and 12 months, before and after adjustment for possible confounders. All statistical tests were two-sided. RESULTS: The adjusted absolute mean changes in mammographic percent density over 12 months were 4.76% (95% confidence interval [CI] = 3.29% to 6.23%), 4.58% (95% CI = 3.19% to 5.97%), and 3.08% (95% CI = 1.65% to 4.51%) for women in the CEE+MPA-cyclic, CEE+MPA-continuous, and CEE-MP groups, respectively. Each of those absolute mean changes was statistically significantly different from the adjusted absolute mean change in mammographic percent density for women in the placebo group, which was -0.07% (95% CI = -1.50% to 1.38%). CONCLUSION: Greater mammographic density was associated with the use of estrogen/progestin combination therapy, regardless of how the progestin was given, but not with the use of estrogen only.

Breast↗

PubMed2003

Rates and predictors of aftercare services among formerly hospitalized adolescents: a prospective naturalistic study.

OBJECTIVE: To examine rates and predictors of aftercare use, lengths of service use, and predictors of the duration of aftercare service use among 180 adolescents monitored for up to 8.1 years after discharge from an inpatient psychiatry unit. METHOD: Drawing upon the Anderson-Newman model of service use, severity of illness, enabling, and predisposing factors assessed during the hospitalization were examined as potential predictors of service use. Information about outpatient mental health specialty services after hospitalization was assessed repeatedly and verified with treatment records. RESULTS: Seventy-three percent of adolescents received aftercare within the first month after discharge, and 92% eventually received outpatient services. Fifty-seven percent of adolescents remained in treatment 6 months after initiation of services. Psychiatric comorbidity, prior service use, and presence of a biological parent or grandparent in the home were related to initial service use. Psychiatric comorbidity and history of repeated suicide attempts were related to longer duration, and older age and minority group status were related to shorter duration of aftercare service use. CONCLUSIONS: Most adolescents receive aftercare services, but there are certain groups that are relatively less likely to access or remain in services. Interventions to decrease the barriers to care in such groups may be beneficial.

Adolescent↗

PubMed2003

Rates and predictors of rehospitalization among formerly hospitalized adolescents.

OBJECTIVE: The authors examined rates and predictors of rehospitalization among 180 adolescents followed up for up to 10.3 years after discharge from an inpatient psychiatric unit. METHODS: In this prospective, naturalistic study, demographic variables, including gender, race, and age, and psychiatric variables, including diagnoses, prehospitalization suicide attempts, and previous hospitalizations, were examined as potential predictors of rehospitalization. Information about rehospitalizations was repeatedly assessed and verified with treatment records. RESULTS: During the follow-up period, 79 adolescents (44 percent) had one or more rehospitalizations. By six months after discharge, 19 percent of the adolescents had been rehospitalized. The mean time to first rehospitalization was estimated to be 5.7 years. Univariate analyses revealed significant differences between adolescents who were rehospitalized and those who were not in terms of age, presence of an affective disorder, and presence of a comorbid psychiatric disorder. In the multivariate predictor model, age and the presence of an affective disorder were the only significant predictors of rehospitalization. CONCLUSIONS: Clinicians should examine risk of rehospitalization before discharge, especially for younger patients and those with depression. Future research must focus on methods of intervention for this high-risk group.

Adolescent↗

PubMed2002

Mixed effects logistic regression models for multiple longitudinal binary functional limitation responses with informative drop-out and confounding by baseline outcomes.

In the context of analyzing multiple functional limitation responses collected longitudinally from the Longitudinal Study of Aging (LSOA), we investigate the heterogeneity of these outcomes with respect to their associations with previous functional status and other risk factors in the presence of informative drop-out and confounding by baseline outcomes. We accommodate the longitudinal nature of the multiple outcomes with a unique extension of the nested random effects logistic model with an autoregressive structure to include drop-out and baseline outcome components with shared random effects. Estimation of fixed effects and variance components is by maximum likelihood with numerical integration. This shared parameter selection model assumes that drop-out is conditionally independent of the multiple functional limitation outcomes given the underlying random effect representing an individual's trajectory of functional status across time. Whereas it is not possible to fully assess the adequacy of this assumption, we assess the robustness of this approach by varying the assumptions underlying the proposed model such as the random effects structure, the drop-out component, and omission of baseline functional outcomes as dependent variables in the model. Heterogeneity among the associations between each functional limitation outcome and a set of risk factors for functional limitation, such as previous functional limitation and physical activity, exists for the LSOA data of interest. Less heterogeneity is observed among the estimates of time-level random effects variance components that are allowed to vary across functional outcomes and time. We also note that. under an autoregressive structure, bias results from omitting the baseline outcome component linked to the follow-up outcome component by subject-level random effects.

Aged↗

PubMedDate not supplied

Suicidality, school dropout, and reading problems among adolescents.

The purpose of this study was to examine the risk of suicidal ideation and suicide attempts and school dropout among youth with poor reading in comparison to youth with typical reading (n = 188) recruited from public schools at the age of 15. In a prospective naturalistic study, youth and parents participated in repeated research assessments to obtain information about suicide ideation and attempts, psychiatric and sociodemographic variables, and school dropout. Youth with poor reading ability were more likely to experience suicidal ideation or attempts and more likely to drop out of school than youth with typical reading, even after controlling for sociodemographic and psychiatric variables. Suicidality and school dropout were strongly associated with each other. Prevention efforts should focus on better understanding the relationship between these outcomes, as well as on the developmental paths leading up to these behaviors among youth with reading difficulties.

Adolescent↗