- Browse by Subject
Browsing by Subject "Longitudinal Studies"
Now showing 1 - 7 of 7
Results Per Page
Sort Options
Item Alzheimer disease brain atrophy subtypes are associated with cognition and rate of decline(American Academy of Neurology, 2017-11-21) Risacher, Shannon L.; Anderson, Wesley H.; Charil, Arnaud; Castelluccio, Peter F.; Shcherbinin, Sergey; Saykin, Andrew J.; Schwarz, Adam J.; Radiology and Imaging Sciences, School of MedicineOBJECTIVE: To test the hypothesis that cortical and hippocampal volumes, measured in vivo from volumetric MRI (vMRI) scans, could be used to identify variant subtypes of Alzheimer disease (AD) and to prospectively predict the rate of clinical decline. METHODS: Amyloid-positive participants with AD from the Alzheimer's Disease Neuroimaging Initiative (ADNI) 1 and ADNI2 with baseline MRI scans (n = 229) and 2-year clinical follow-up (n = 100) were included. AD subtypes (hippocampal sparing [HpSpMRI], limbic predominant [LPMRI], typical AD [tADMRI]) were defined according to an algorithm analogous to one recently proposed for tau neuropathology. Relationships between baseline hippocampal volume to cortical volume ratio (HV:CTV) and clinical variables were examined by both continuous regression and categorical models. RESULTS: When participants were divided categorically, the HpSpMRI group showed significantly more AD-like hypometabolism on 18F-fluorodeoxyglucose-PET (p < 0.05) and poorer baseline executive function (p < 0.001). Other baseline clinical measures did not differ across the 3 groups. Participants with HpSpMRI also showed faster subsequent clinical decline than participants with LPMRI on the Alzheimer's Disease Assessment Scale, 13-Item Subscale (ADAS-Cog13), Mini-Mental State Examination (MMSE), and Functional Assessment Questionnaire (all p < 0.05) and tADMRI on the MMSE and Clinical Dementia Rating Sum of Boxes (CDR-SB) (both p < 0.05). Finally, a larger HV:CTV was associated with poorer baseline executive function and a faster slope of decline in CDR-SB, MMSE, and ADAS-Cog13 score (p < 0.05). These associations were driven mostly by the amount of cortical rather than hippocampal atrophy. CONCLUSIONS: AD subtypes with phenotypes consistent with those observed with tau neuropathology can be identified in vivo with vMRI. An increased HV:CTV ratio was predictive of faster clinical decline in participants with AD who were clinically indistinguishable at baseline except for a greater dysexecutive presentation.Item Changes in insulin sensitivity over time and associated factors in HIV-infected adolescents(Lippincott, Williams & Wilkins, 2018-03-13) Geffner, Mitchell E.; Patel, Kunjal; Jacobson, Denise L.; Wu, Julia; Miller, Tracie L.; Hazra, Rohan; Gerschenson, Mariana; Sharma, Tanvi; Silio, Margarita; Jao, Jennifer; Takemoto, Jody K.; Van Dyke, Russell B.; Dimeglio, Linda A.; Pediatric HIV/AIDS Cohort Study (PHACS); Pediatrics, School of MedicineOBJECTIVE: To compare prevalence of insulin resistance between perinatally HIV-infected (PHIV+) and perinatally HIV-exposed, but uninfected adolescents (PHEU), determine incidence of and contributory factors to new and resolved cases of insulin resistance in PHIV+, and evaluate glucose metabolism. DESIGN: Cross-sectional design for comparison of prevalence among PHIV+ and PHEU. Longitudinal design for incidence and resolution of insulin resistance among PHIV+ at risk for these outcomes. METHODS: The source population was adolescents from pediatric HIV clinics in the United States and Puerto Rico participating in the Pediatric HIV/AIDS Cohort Study, an ongoing prospective cohort study designed to evaluate impact of HIV infection and its treatment on multiple domains in preadolescents and adolescents. Insulin resistance was assessed by homeostatic model assessment of insulin resistance. Those with incident insulin resistance underwent 2-h oral glucose tolerance test and HbA1c. Baseline demographic, metabolic, and HIV-specific variables were evaluated for association with incident or resolved insulin resistance. RESULTS: Unadjusted prevalence of insulin resistance in PHIV+ was 27.3 versus 34.1% in PHEU. After adjustment for Tanner stage, age, sex, and race/ethnicity, there was no significant difference between groups. Factors positively associated with developing insulin resistance included female sex, higher BMI z score, and higher waist circumference; those associated with resolving insulin resistance included male sex and lower BMI z score. CONCLUSION: Prevalence of insulin resistance in PHIV+ and PHEU was substantially higher than that reported in HIV-uninfected nonoverweight youth, but similar to that in HIV-uninfected obese youth. Factors associated with incident or resolved insulin resistance among PHIV+ were similar to those reported in HIV-negative obese youth. However, a contributory role of HIV infection and/or its treatment to the incident risk of insulin resistance cannot be excluded.Item Common Predictors for Explaining Youth Antisocial Behavior: A Perspective From Ten Longitudinal Studies(2010) Gentle-Genitty, CarolynFor centuries humans have and continue to interact to bring change and homeostasis in their lives. Their interaction centers among roles played within the human developmental stages from toddler to preadolescent, to adolescent, to young adult, and thereafter to adulthood. Often the changes that occur take attitudinal, behavioral, and/or relational forms. These are often examined in research, using cross-section, prospective, or retrospective longitudinal study designs. Longitudinal research has enabled researchers to describe the emergence of violence in terms of two (and possibly more) life-course trajectories. In the early-onset trajectory, this is before puberty, and in the late-onset trajectory occurring after puberty. These two trajectories offer insights into the likely course, severity, and duration of antisocial behavior over the life span. They also have practical implications for the timing of intervention programs and strategies. These trajectories along with the results from longitudinal studies have generated causal relationships between early antisocial behavior and increases in crime and violence. This article conducts a brief, yet critical, evaluation of ten popular longitudinal studies to explain what factors can predict youth antisocial behaviors. It briefly presents a discussion on the study of antisocial behavior in the last five decades, a review of how antisocial behavior and factors relating to it have been studied, and findings on each of the ten longitudinal studies. It then discusses the common predictors found after pooling together similar factors found in each study, followed by recommendations for future study and use.Item Demographic and Mental Health Predictors of Arrests Up to 10 Years Post-Traumatic Brain Injury: A Veterans Affairs TBI Model Systems Study(Wolters Kluwer, 2021-07) Miles, Shannon R.; Silva, Marc A.; Neumann, Dawn; Dillahunt-Aspillaga, Christina; Corrigan, John D.; Tang, Xinyu; Eapen, Blessen C.; Nakase-Richardson, Risa; Physical Medicine and Rehabilitation, School of MedicineOBJECTIVE: Examine rates and predictors of arrests in Veterans and Service Members (V/SM) who received inpatient rehabilitation for traumatic brain injury (TBI). SETTING: Veterans Administration (VA) Polytrauma Rehabilitation Centers. PARTICIPANTS: A total of 948 V/SM drawn from the VA TBI Model Systems cohort with arrest data up to 10 years post-TBI. DESIGN: Longitudinal cohort study; secondary analysis of pre-TBI characteristics predicting post-TBI arrests. MAIN MEASURES: Disclosure of arrests pre-TBI and up to10 years post-TBI. RESULTS: Thirty-six percent of the sample had been arrested prior to their TBI; 7% were arrested post-TBI. When considering all variables simultaneously in a multivariate model, pre-TBI mental health treatment (adjusted odds ratio [aOR] = 4.30; 95% confidence interval [CI]: 2.03-9.14), pre-TBI heavy alcohol use (aOR = 3.04; CI: 1.08-8.55), and number of follow-up interviews (aOR = 2.05; CI: 1.39-4.50) were significant predictors of post-TBI arrest. CONCLUSION: Arrest rates of V/SM prior to TBI were consistent with rates of arrest for people of similar ages in the United States. Post-TBI rates were lower for V/SM than published rates of post-TBI arrests in civilians with TBI. As part of rehabilitation planning for V/SM with TBI, providers should assess for preinjury mental health services and alcohol misuse to (1) identify those who may be at risk for postinjury arrests and (2) provide relevant resources and/or supports.Item Five-Year Longitudinal Assessment (2008 to 2012) of E-101 Solution Activity against Clinical Target and Antimicrobial-Resistant Pathogens(American Society for Microbiology (ASM), 2014-08) Denys, Gerald A.; Pillar, Chris M.; Sahm, Daniel F.; O'Hanley, Peter; Stephens, Jackson T. Jr; Department of Pathology & Laboratory Medicine, IU School of MedicineThis study summarizes the topical E-101 solution susceptibility testing results for 760 Gram-positive and Gram-negative target pathogens collected from 75 U.S. sites between 2008 and 2012 and 103 ESKAPE pathogens. E-101 solution maintained potent activity against all bacterial species studied for each year tested, with MICs ranging from <0.008 to 0.25 μg porcine myeloperoxidase (pMPO)/ml. These results confirm that E-101 solution retains its potent broad-spectrum activity against U.S. clinical isolates and organisms with challenging resistance phenotypes.Item Longitudinal associations among relationship factors, partner change, and sexually transmitted infection acquisition in adolescent women(Lippincott, Williams & Wilkins, 2011-03) Ott, Mary A.; Katschke, Adrian; Tu, Wanzhu; Fortenberry, J. Dennis; Pediatrics, School of MedicineOBJECTIVES: New sex partners put adolescents at increased risk for sexually transmitted infections (STIs), even when these sex partners are nonoverlapping. Although the risk of partner change is well described, little is known about its antecedents. We prospectively examined associations between relationship characteristics, partner change, and subsequent STI during intervals of "serial monogamy." METHODS: As part of a longitudinal study, 332 adolescent women were interviewed and tested for gonorrhea, chlamydia, and trichomonas every 3 months for up to just over 6 years. Interviews covered partner-specific relationship characteristics and sexual behaviors. The quarterly interval, a 3-month period bracketed by interviews and STI testing, was the unit of analysis. We examined associations among relationship factors, partner change, and subsequent STI using a series of mixed regression models, controlling for age, STI at Time 1, and condom nonuse. RESULTS: Age, lower relationship quality, and lower levels of partner closeness to friends and family predicted partner change from Time 1 to Time 2. In turn, partner change was associated with acquisition of a new STI at Time 2. Although relationship factors did not exert a direct effect on STI at Time 2, they improved partner change-STI model fit. Similar patterns were seen with each organism. CONCLUSION: Relationship factors drive partner change, which in turn contributes to STI acquisition. STI prevention research may need to focus on the relationship antecedents to partner change, in addition to the partner change itself.Item Simultaneous variable selection for joint models of longitudinal and survival outcomes(Wiley Blackwell (Blackwell Publishing), 2015-03) He, Zangdong; Tu, Wanzhu; Wang, Sijian; Fu, Haoda; Yu, Zhangsheng; Department of Biostatistics, Richard M. Fairbanks School of Public HealthJoint models of longitudinal and survival outcomes have been used with increasing frequency in clinical investigations. Correct specification of fixed and random effects is essential for practical data analysis. Simultaneous selection of variables in both longitudinal and survival components functions as a necessary safeguard against model misspecification. However, variable selection in such models has not been studied. No existing computational tools, to the best of our knowledge, have been made available to practitioners. In this article, we describe a penalized likelihood method with adaptive least absolute shrinkage and selection operator (ALASSO) penalty functions for simultaneous selection of fixed and random effects in joint models. To perform selection in variance components of random effects, we reparameterize the variance components using a Cholesky decomposition; in doing so, a penalty function of group shrinkage is introduced. To reduce the estimation bias resulted from penalization, we propose a two-stage selection procedure in which the magnitude of the bias is ameliorated in the second stage. The penalized likelihood is approximated by Gaussian quadrature and optimized by an EM algorithm. Simulation study showed excellent selection results in the first stage and small estimation biases in the second stage. To illustrate, we analyzed a longitudinally observed clinical marker and patient survival in a cohort of patients with heart failure.