Search

Analyzing longitudinal dyadic data is a challenging task due to the complicated correlations from repeated measurements and within-dyad interdependence, as well as potentially informative (or non-ignorable) missing data. We propose a dyadic shared-parameter model to analyze longitudinal dyadic data with ordinal outcomes and informative intermittent missing data and dropouts. We model the longitudinal measurement process using a proportional odds model, which accommodates the within-dyad interdependence using the concept of the actor-partner interdependence effects, as well as dyad-specific random effects. We model informative dropouts and intermittent missing data using a transition model, which shares the same set of random effects as the longitudinal measurement model. We evaluate the performance of the proposed method through extensive simulation studies. As our approach relies on some untestable assumptions on the missing data mechanism, we perform sensitivity analyses to evaluate how the analysis results change when the missing data mechanism is misspecified. We demonstrate our method using a longitudinal dyadic study of metastatic breast cancer.

Richard E. Scammon's article, "The First Seriatim Study of Human Growth," provided one of the best-known visuals in the field of human biology. Scammon resurrected longitudinal height data of one child from Buffon's Histoire Naturelle, converted them to metric, and plotted these measurements as a function of age. The result was the first graph of one individual's growth curve from birth to 18 years of age. This image was subsequently reproduced in numerous texts on human growth and biology. Published in 1927, Scammon's article provides a snapshot of the state of growth research at the time and gives a (literal) picture of the future of human biology. The graph of the growth of one child symbolizes the importance of process and variation in biological anthropology., (© 2018 Wiley Periodicals, Inc.)

Objective: Missing data in longitudinal studies may constitute a source of bias. We suggest three simple missing data indicators for the initial phase of getting an overview of the missingness pattern in a dataset with a high number of follow-ups. Possible use of the indicators is exemplified in two datasets allowing wave nonresponse; a Norwegian dataset of 420 subjects examined at 21 occasions during 6.5 years and a Dutch dataset of 350 subjects with ten repeated measurements over a period of 35 years., Results: The indicators Last response (the timing of last response), Retention (the number of responded follow-ups), and Dispersion (the evenness of the distribution of responses) are introduced. The proposed indicators reveal different aspects of the missing data pattern, and may give the researcher a better insight into the pattern of missingness in a study with several follow-ups, as a starting point for analyzing possible bias. Although the indicators are positively correlated to each other, potential predictors of missingness can have a different relationship with different indicators leading to a better understanding of the missing data mechanism in longitudinal studies. These indictors may be useful descriptive tools when starting to look into a longitudinal dataset with many follow-ups.

Background: Knowing about predictors of attrition in a panel is important to initiate early measures against loss of participants. We investigated attrition in both early and late phase of an online panel with special focus on preferences regarding mode of participation., Methods: We used data from the HaBIDS panel that was designed to investigate knowledge, attitudes, and practice regarding infections in the German general population. HaBIDS was divided into two phases: an initial phase when some participants could choose their preferred mode of participation (paper-and-pencil or online) and an extended phase when participants were asked to become members of an online panel that was not limited regarding its duration (i.e. participants initially preferring paper questionnaires switched to online participation). Using competing risks regression, we investigated two types of attrition (formal withdrawal and discontinuation without withdrawal) among online participants, separately for both phases. As potential predictors of attrition, we considered sociodemographic characteristics, physical and mental health as well as auxiliary information describing the survey process, and, in the extended phase, initial mode preference., Results: In the initial phase, higher age and less frequent Internet usage predicted withdrawal, while younger age, higher stress levels, delay in returning the consent form, and need for receiving reminder emails predicted discontinuation. In the extended phase, only need for receiving reminder emails predicted discontinuation. Numbers of withdrawal in the extended phase were too small for analysis. Initial mode preference did not predict attrition in the extended phase. Besides age, there was no evidence of differential attrition by sociodemographic factors in any phase., Conclusions: Predictors of attrition were similar in both phases of the panel, but they differed by type of attrition (withdrawal vs. discontinuation). Sociodemographic characteristics only played a minor role for both types of attrition. Need for receiving a reminder was the strongest predictor of discontinuation in any phase, but no predictor of withdrawal. We found predictors of attrition, which can be identified already in the early phase of a panel so that countermeasures (e.g. special incentives) can be taken.

Objectives: To compare methods for analysis of longitudinal studies with missing data due to participant dropout and follow-up truncated by death., Study Design and Setting: We analyzed physical functioning in an Australian longitudinal study of elderly women where the missing data mechanism could either be missing at random (MAR) or missing not at random (MNAR). We assumed either an immortal cohort where deceased participants are implicitly included after death or a mortal cohort where the target of inference is surviving participants at each survey wave. To illustrate the methods a covariate was included. Simulation was used to assess the effect of the assumptions., Results: Ignoring attrition or restricting analysis to participants with complete follow up led to biased estimates. Linear mixed model was appropriate for an immortal cohort under MAR but not MNAR. Linear increment model and joint modeling of longitudinal outcome and time to death were the most robust to MNAR. For a mortal cohort, inverse probability weighting and multiple imputation could be used, but care is needed in specifying dropout and imputation models, respectively., Conclusion: Appropriate analysis methodology to deal with attrition in longitudinal studies depends on the target of inference and the missing data mechanism., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Genetic association studies with longitudinal markers of chronic diseases (e.g., blood pressure, body mass index) provide a valuable opportunity to explore how genetic variants affect traits over time by utilizing the full trajectory of longitudinal outcomes. Since these traits are likely influenced by the joint effect of multiple variants in a gene, a joint analysis of these variants considering linkage disequilibrium (LD) may help to explain additional phenotypic variation. In this article, we propose a longitudinal genetic random field model (LGRF), to test the association between a phenotype measured repeatedly during the course of an observational study and a set of genetic variants. Generalized score type tests are developed, which we show are robust to misspecification of within-subject correlation, a feature that is desirable for longitudinal analysis. In addition, a joint test incorporating gene-time interaction is further proposed. Computational advancement is made for scalable implementation of the proposed methods in large-scale genome-wide association studies (GWAS). The proposed methods are evaluated through extensive simulation studies and illustrated using data from the Multi-Ethnic Study of Atherosclerosis (MESA). Our simulation results indicate substantial gain in power using LGRF when compared with two commonly used existing alternatives: (i) single marker tests using longitudinal outcome and (ii) existing gene-based tests using the average value of repeated measurements as the outcome., (© 2015, The International Biometric Society.)

In the context of observational longitudinal studies, we explored the values of the number of participants and the number of repeated measurements that maximize the power to detect the hypothesized effect, given the total cost of the study. We considered two different models, one that assumes a transient effect of exposure and one that assumes a cumulative effect. Results were derived for a continuous response variable, whose covariance structure was assumed to be damped exponential, and a binary time-varying exposure. Under certain assumptions, we derived simple formulas for the approximate solution to the problem in the particular case in which the response covariance structure is assumed to be compound symmetry. Results showed the importance of the exposure intraclass correlation in determining the optimal combination of the number of participants and the number of repeated measurements, and therefore the optimized power. Thus, incorrectly assuming a time-invariant exposure leads to inefficient designs. We also analyzed the sensitivity of results to dropout, mis-specification of the response correlation structure, allowing a time-varying exposure prevalence and potential confounding impact. We illustrated some of these results in a real study. In addition, we provide software to perform all the calculations required to explore the combination of the number of participants and the number of repeated measurements., (Copyright © 2013 John Wiley & Sons, Ltd.)

AIM: This study aims to identify the key risk factors that lead to subtypes of physical frailty assessed by walking speed and grip strength among community-dwelling Japanese individuals, stratified by the presence of musculoskeletal diseases (MSDs) and age group. METHODS: We included 302 participants aged 70 or 80 years who did not exhibit subtypes of physical frailty at baseline through the Septuagenarians, Octogenarians, Nonagenarians, Investigation with Centenarians (SONIC) study. Our study was a longitudinal study. The outcome was the incidence of subtypes of physical frailty after 3 years. Subtypes of physical frailty were defined as a weak grip strength or slow walking speed, or both, based on the Japanese version of the Cardiovascular Health Study Index. The risk factors for subtypes of physical frailty incidence were examined by age group and MSD, using multivariate logistic regressions. RESULTS: Of the 302 participants, 110 (36.4%) had MSD. Those with MSD were significantly more likely to have subtypes of physical frailty after 3 years compared with those without MSD. Among all participants, older age was a risk factor of subtypes of physical frailty (P

INTRODUCTION: The spectrum of bladder health and the factors that promote bladder health and prevent lower urinary tract symptoms (LUTS) among women are not well understood. This manuscript describes the rationale, aims, study design, sampling strategy, and data collection for the RISE FOR HEALTH (RISE) study, a novel study of bladder health in women conducted by the Prevention of Lower Urinary Tract Symptom (PLUS) Research Consortium. METHODS AND RESULTS: RISE is a population-based, multicenter, prospective longitudinal cohort study of community-dwelling, English- and Spanish-speaking adult women based in the United States. Its goal is to inform the distribution of bladder health and the individual factors (biologic, behavioral, and psychosocial) and multilevel factors (interpersonal, institutional, community, and societal) that promote bladder health and/or prevent LUTS in women across the life course. Key study development activities included the: (1) development of a conceptual framework and philosophy to guide subsequent activities, (2) creation of a study design and sampling strategy, prioritizing diversity, equity, and inclusion, and (3) selection and development of data collection components. Community members and cross-cultural experts shaped and ensured the appropriateness of all study procedures and materials. RISE participants will be selected by simple random sampling of individuals identified by a marketing database who reside in the 50 counties surrounding nine PLUS clinical research centers. Participants will complete self-administered surveys at baseline (mailed paper or electronic) to capture bladder health and LUTS, knowledge about bladder health, and factors hypothesized to promote bladder health and prevent LUTS. A subset of participants will complete an in-person assessment to augment data with objective measures including urogenital microbiome specimens. Initial longitudinal follow-up is planned at 1 year. DISCUSSION: Findings from RISE will begin to build the necessary evidence base to support much-needed, new bladder health promotion and LUTS prevention interventions in women.

BACKGROUND: Evidence suggests that depression may be a risk factor for dementia in older adults, but the link between depressive symptoms and brain health earlier in life is less understood. Our aim was to investigate the association between long-term depressive symptoms in young to mid-adulthood and a measure of brain age derived from structural MRI. METHODS: From the Coronary Artery Risk Development in Young Adults study, we identified 649 participants (age 23-36 at baseline) with brain MRI and cognitive testing. Long-term depressive symptoms were measured with the Center for Epidemiological Studies Depression scale (CESD) six times across 25 years and analyzed as time-weighted averages (TWA). Brain age was derived using previously validated high dimensional neuroimaging pattern analysis, quantifying individual differences in age-related atrophy. Elevated depressive symptoms were defined as CES-D ≥16. Linear regression was used to test the association between TWA depressive symptoms, brain aging, and cognition. RESULTS: Each standard deviation (5-points) increment in TWA depression symptoms over 25 years was associated with one-year greater brain age (β: 1.14, 95 % confidence interval [CI]: 0.57 to 1.71). Participants with elevated TWA depressive symptoms had on average a 3-year greater brain age (β: 2.75, 95 % CI: 0.43 to 5.08). Moreover, elevated depressive symptoms were associated with higher odds of poor cognitive function in midlife (OR: 3.30, 95 % CI: 1.37 to 7.97). LIMITATIONS: Brain age was assessed at one time, limiting our ability to evaluate the temporality of depressive symptoms and brain aging. CONCLUSIONS: Elevated depressive symptoms in early adulthood may have implications for brain health as early as in midlife.

ObjectivesWhile adults with bipolar disorder (BD) often report symptoms starting in childhood, continuity of mania and/or hypomania (mania/hypomania) from childhood to adulthood has been questioned. Using longitudinal data from the Course and Outcome of Bipolar Youth (COBY) study, we assessed threshold mania/hypomania in young adults who manifested BD as youth.MethodsCOBY is a naturalistic, longitudinal study of 446 youth with BD (84% recruited from outpatient clinics), 7-17 years old at intake, and over 11 years of follow-up. Focusing on youth with BD-I/II (n = 297), we examined adult mania/hypomania risk (>18 years old; mean 7.9 years of follow-up) according to child (

Methods designed to measure severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) humoral response include virus neutralization tests to determine antibody neutralization activity. For ease of use and universal applicability, surrogate virus neutralization tests (sVNTs) based on antibody-mediated blockage of molecular interactions have been proposed. A surrogate virus neutralization test was established on a label-free immunoassay platform (LF-sVNT). The LF-sVNT analyzes the binding ability of SARS-CoV-2 spike protein receptor-binding domain (RBD) to angiotensin-converting enzyme 2 (ACE2) after neutralizing RBD with antibodies in serum. The LF-sVNT neutralizing antibody titers (50% inhibitory concentration [IC50]) were determined from serum samples (n = 246) from coronavirus disease 2019 (COVID-19) patients (n = 113), as well as the IgG concentrations and the IgG avidity indices. Although there was variability in the kinetics of the IgG concentrations and neutralizing antibody titers between individuals, there was an initial rise, plateau, and then in some cases a gradual decline at later time points after 40 days after symptom onset. The IgG avidity indices, in the same cases, plateaued after an initial rise and did not show a decline. The LF-sVNT can be a valuable tool in research and clinical laboratories for the assessment of the presence of neutralizing antibodies to COVID-19. This study is the first to provide longitudinal neutralizing antibody titers beyond 200 days post-symptom onset. Despite the decline of IgG concentration and neutralizing antibody titer, IgG avidity index increases, reaches a plateau, and then remains constant up to 8 months postinfection. The decline of antibody neutralization activity can be attributed to the reduction in antibody quantity rather than the deterioration of antibody quality, as measured by antibody avidity.

PurposeTo compare longitudinal hepatic proton density fat fraction (PDFF) changes estimated by magnitude- vs. complex-based chemical-shift-encoded MRI during a weight loss surgery (WLS) program in severely obese adults with biopsy-proven nonalcoholic fatty liver disease (NAFLD).MethodsThis was a secondary analysis of a prospective dual-center longitudinal study of 54 adults (44 women; mean age 52 years; range 27-70 years) with obesity, biopsy-proven NAFLD, and baseline PDFF ≥ 5%, enrolled in a WLS program. PDFF was estimated by confounder-corrected chemical-shift-encoded MRI using magnitude (MRI-M)- and complex (MRI-C)-based techniques at baseline (visit 1), after a 2- to 4-week very low-calorie diet (visit 2), and at 1, 3, and 6 months (visits 3 to 5) after surgery. At each visit, PDFF values estimated by MRI-M and MRI-C were compared by a paired t test. Rates of PDFF change estimated by MRI-M and MRI-C for visits 1 to 3, and for visits 3 to 5 were assessed by Bland-Altman analysis and intraclass correlation coefficients (ICCs).ResultsMRI-M PDFF estimates were lower by 0.5-0.7% compared with those of MRI-C at all visits (p

ObjectiveTo compare the longitudinal course of family functioning in offspring of parents with bipolar disorder (BD), offspring of parents with non-BD psychopathology, and offspring of healthy control (HC) parents.MethodOffspring of parents with BD (256 parents and 481 offspring), parents without BD (82 parents and 162 offspring), and HC parents (88 parents and 175 offspring) 7 to 18 years of age at intake, from the Bipolar Offspring Study (BIOS), were followed for an average of 4.3 years. Family functioning was evaluated using the child- and parent-reported Family Adaptability and Cohesion Scale-II and the Conflict Behavior Questionnaire. The data were analyzed using multivariate multilevel regression, generalized linear estimating equation models, and path analysis.ResultsFamilies of parents with BD and parents with non-BD psychopathology showed lower cohesion and adaptability and higher conflict compared with HC families. There were no significant differences in cohesion and adaptability between families of parents with psychopathology. The effect of parental psychopathology on family functioning was mediated by parental psychosocial functioning and, to a lesser extent, offspring disorders. In all 3 groups, parent-reported family conflict was significantly higher than child-reported conflict. Across groups, family cohesion decreased over follow-up, whereas conflict increased.ConclusionAny parental psychopathology predicted family impairment. These results were influenced by the offspring's age and were mediated by parental psychosocial functioning and, to a lesser degree, by offspring psychopathology. These findings emphasize the need to routinely assess family functioning in addition to psychopathology and provide appropriate interventions to parents and offspring.

Most research on exceptional longevity has investigated biomedical factors associated with survival, but recent work suggests nonbiological factors are also important. Thus, we tested whether higher optimism was associated with longer life span and greater likelihood of exceptional longevity. Data are from 2 cohorts, women from the Nurses Health Study (NHS) and men from the Veterans Affairs Normative Aging Study (NAS), with follow-up of 10 y (2004 to 2014) and 30 y (1986 to 2016), respectively. Optimism was assessed using the Life Orientation Test-Revised in NHS and the Revised Optimism-Pessimism Scale from the Minnesota Multiphasic Personality Inventory-2 in NAS. Exceptional longevity was defined as survival to age 85 or older. Primary analyses used accelerated failure time models to assess differences in life span associated with optimism; models adjusted for demographic confounders and health conditions, and subsequently considered the role of health behaviors. Further analyses used logistic regression to evaluate the likelihood of exceptional longevity. In both sexes, we found a dose-dependent association of higher optimism levels at baseline with increased longevity (P trend < 0.01). For example, adjusting for demographics and health conditions, women in the highest versus lowest optimism quartile had 14.9% (95% confidence interval, 11.9 to 18.0) longer life span. Findings were similar in men. Participants with highest versus lowest optimism levels had 1.5 (women) and 1.7 (men) greater odds of surviving to age 85; these relationships were maintained after adjusting for health behaviors. Given work indicating optimism is modifiable, these findings suggest optimism may provide a valuable target to test for strategies to promote longevity.

Background:It is unknown whether subjective daytime sleepiness or objective napping could precede the risk of Parkinson's disease (PD) in the long term. Methods:We studied 2920 men (mean age 76 years) without a history of PD and followed them for 11 years. Excessive daytime sleepiness (EDS) was defined as having an Epworth Sleepiness Scale score >10. Objective naps were defined as ≥5 consecutive minutes of inactivity as measured by actigraphy, and napping duration was the accumulated time of naps outside the main sleep period. We used logistic regression to compare PD risk across four groups: no EDS& napping

BackgroundChildren with conduct problems that persist into adulthood are at increased risk for future behavioral, health, and social problems. However, the longer term public service usage among these children has not been fully documented. To aid public health and intervention planning, adult service usage across criminal justice, health care, and social welfare domains is compared among all individuals from a representative cohort who followed different conduct problem trajectories from childhood into adulthood.MethodsParticipants are from the Dunedin Multidisciplinary Health and Development Study, a prospective, representative cohort of consecutive births (N = 1,037) from April 1972 to March 1973 in Dunedin, New Zealand. Regression analyses were used to compare levels of public service usage up to age 38, gathered via administrative and electronic medical records, between participants who displayed distinct subtypes of childhood conduct problems (low, childhood-limited, adolescent-onset, and life-course persistent).ResultsChildren exhibiting life-course persistent conduct problems used significantly more services as adults than those with low levels of childhood conduct problems. Although this group comprised only 9.0% of the population, they accounted for 53.3% of all convictions, 15.7% of emergency department visits, 20.5% of prescription fills, 13.1% of injury claims, and 24.7% of welfare benefit months. Half of this group (50.0%) also accrued high service use across all three domains of criminal justice, health, and social welfare services, as compared to only 11.3% of those with low conduct problems (OR = 7.27, 95% CI = 4.42-12.0).ConclusionsConduct problems in childhood signal high future costs in terms of service utilization across multiple sectors. Future evaluations of interventions aimed at conduct problems should also track potential reductions in health burden and service usage that stretch into midlife.

Background:Previous research has shown a link between low positive affect and mortality, but questions remain about how positive affect is related to mortality and how this differs by gender and age. Purpose:To investigate the relationships between positive affect, negative affect, and mortality in a general population sample, and to examine whether these relationships were related to age, sex, or cause-specific mortality. Methods:We used data from 5,554 Norwegian participants aged 47-49 and 71-74 years who completed the Positive and Negative Affect Schedule (PANAS) and also provided data on demographics, health behaviors, and physical health as part of the Hordaland Health Study. The primary outcome was mortality after an average follow-up period of 16.5 years. Results:Participants in the lowest positive affect tertile had a near twofold increased mortality risk, compared to those in the highest positive affect tertile. This association was driven primarily by the PANAS "active" item and persisted, even after controlling for activity-related confounds and other positive affect items. No significant associations were found between negative affect and mortality. The relationship between positive affect and mortality was not significantly attenuated by age or sex. Although low positive affect was associated with an increased risk of mortality, it was not related to a specific cause of death. Conclusions:Low positive affect was significantly associated with mortality risk. The relationship was driven by the PANAS active item and not associated with cause-specific mortality. Findings suggest future research should examine the association between feeling inactive, sedentary behavior, and subsequent mortality.

PurposeMonitoring distress assessment in cancer patients during the treatment phase is a component of good quality care practice. Yet, there is a dearth of prospective studies examining distress. In an attempt to begin filling this gap and inform clinical practice, we conducted a prospective, longitudinal study examining changes in distress (anxiety, depression, and problems in living) by age and gender and the roles of age and gender in predicting distress.MethodsNewly diagnosed Brazilian cancer patients (N = 548) were assessed at three time points during chemotherapy. Age and gender were identified on the first day of chemotherapy (T1); anxiety, depression, and problems in living were self-reported at T1, the planned midway point (T2), and the last day of chemotherapy (T3).ResultsAt T1, 37 and 17% of patients reported clinically significant levels of anxiety and depression, respectively. At T3, the prevalence was reduced to 4.6% for anxiety and 5.1% for depression (p 70 years (p

ContextPatients with breast cancer receiving chemotherapy (CTX) experience multiple concurrent symptoms, but little is known about how symptoms change during and after treatment. Knowledge of the identity and trajectory of symptom clusters (SCs) would enhance measurement and management.ObjectivesWe aimed to identify SCs and their change over time from baseline to completion of breast cancer CTX.MethodsSCs were identified and assessed for change in 219 women from Nebraska at four times: baseline, during cycles #3 and #4 of CTX, and one month after finishing CTX. Ten symptoms were measured: two using the Hospital Anxiety and Depression Scale and eight using the Symptom Experience Scale. Exploratory factor analysis was conducted at each time point, then changes in SCs were evaluated at different times.ResultsTwo SCs were identified before and after initiating CTX: gastrointestinal and treatment-related. The number and type of symptoms in each cluster differed over time. Clusters were dynamic during CTX with changes in the number and type of symptoms. Only one treatment-related SC, which consisted of fatigue, pain, and sleep disturbance, was identified after CTX completion.ConclusionSCs during CTX appear to be dynamic, changing over time from before until after CTX completion. Repeated assessments of SCs reveal symptoms that are present and when patients are most burdened and in need of additional support.

ObjectiveTo provide the first longitudinal characterization of mood and psychosocial functioning in youth with comorbid bipolar (BD) and autism spectrum (ASD) disorders.MethodThe Course and Outcome of Bipolar Youth study followed 368 youth (aged 7-17 years) with DSM-IV bipolar I (BP-I), BP-II, or Not Otherwise Specified (NOS) for, on average, 9 years using the Longitudinal Interval Follow-up Evaluation. This subgroup analysis compared youth with and without ASD on clinical presentation, percentage of time with mood symptomatology, and psychosocial functioning.ResultsThirty youth (∼8%) met DSM-IV criteria for Asperger's disorder or pervasive developmental disorder-NOS (referred to here as ASD). Lifetime worst episode severity was similar in both groups, but youth with both BD and ASD (BD+ASD) had elevated rates of comorbid attention-deficit/hyperactivity and obsessive-compulsive disorders, were younger at intake, and had an earlier onset of mood symptoms. Over time, in both groups, the proportion of predominantly euthymic youth increased, and episode recurrence decreased. Compared to youth with BD, the clinical presentation of youth with BD+ASD more frequently involved distractibility, racing thoughts, depressed mood, social withdrawal, and low reactivity of negative mood states. ASD-related symptomatic differences were generally strongest early and decreased over time. Youth with BD+ASD had significantly greater impairment in friendships throughout follow-up.ConclusionYouth with BD+ASD exhibit typical BD mood symptoms but with earlier onset, mixed symptom presentation, and additive functional impairments. Significant amelioration of clinical symptoms occurred over time, suggesting that early recognition and treatment of mood disorders in youth with ASD may improve clinical outcomes.

Purpose of the studyTrajectories of physical activity (PA) and sedentary time (ST) after military separation are likely important determinants of women's health outcomes later in life, because low PA and high ST are known contributors to premature mortality risk. Our objective was to compare longitudinal trajectories of recreational PA and ST between Veteran and non-Veteran postmenopausal women from the Women's Health Initiative (WHI).Design and methodsWomen Veteran (n = 3,719) and non-Veteran (n = 141,800) WHI participants were included. Self-reported participation in recreational PA, converted to metabolic equivalent (MET)-hours/week, was prospectively assessed over 8 years. Self-reported ST, defined as hours/day sitting or lying down, was collected at baseline and at Years 3 and 6. Generalized estimating equations were used to compare trajectories of PA and ST between Veterans and non-Veterans, adjusted for demographics and lifestyle behaviors.ResultsVeterans had higher baseline PA than non-Veterans (13.2 vs 12.5 MET-hours/week, p = .03). PA declined for both groups, with a steeper decline among Veterans (change/visit year -0.19 vs -0.02 MET-hours/week; interaction p < .001). At baseline, Veterans and non-Veterans had similar levels of ST (107.2 vs 105.9 hours/week, p = 0.42). Over time, ST remained stable among Veterans but declined slightly among non-Veterans (change/visit year -0.19 vs -0.49 hours/week; interaction p = .01).ImplicationsThe less favorable longitudinal trajectories of PA and ST we observed for women Veterans may contribute to worse health among these individuals later in life. Understanding barriers to enhancing PA and reducing ST in women Veterans could lead to more effective approaches to intervening on these health behaviors.

Purpose of the studyWomen's military roles, exposures, and associated health outcomes have changed over time. However, mortality risk-within military generations or compared with non-Veteran women-has not been assessed. Using data from the Women's Health Initiative (WHI), we examined all-cause and cause-specific mortality by Veteran status and military generation among older women.Design and methodsWHI participants (3,719 Veterans; 141,802 non-Veterans), followed for a mean of 15.2 years, were categorized into pre-Vietnam or Vietnam/after generations based on their birth cohort. We used cox proportional hazards models to examine the association between Veteran status and mortality by generation.ResultsAfter adjusting for sociodemographic characteristics and WHI study arm, all-cause mortality hazard rate ratios (HRs) for Veterans relative to non-Veterans were 1.16 (95% CI: 1.09-1.23) for pre-Vietnam and 1.16 (95% CI: 0.99-1.36) for Vietnam/after generations. With additional adjustment for health behaviors and risk factors, this excess mortality rate persisted for pre-Vietnam but attenuated for Vietnam/after generations. After further adjustment for medical morbidities, across both generations, Veterans and non-Veterans had similar all-cause mortality rates. Relative to non-Veterans, adjusting for sociodemographics and WHI study arm, pre-Vietnam generation Veterans had higher cancer, cardiovascular, and trauma-related morality rates; Vietnam/after generation Veterans had the highest trauma-related mortality rates (HR = 2.93, 1.64-5.23).ImplicationsVeterans' higher all-cause mortality rates were limited to the pre-Vietnam generation, consistent with diminution of the healthy soldier effect over the life course. Mechanisms underlying Vietnam/after generation Veteran trauma-related mortality should be elucidated. Efforts to modify salient health risk behaviors specific to each military generation are needed.

Perceived racial discrimination (PRD) has been associated with altered diurnal cortisol rhythms in past cross-sectional research. We investigate whether developmental histories of PRD, assessed prospectively, are associated with adult diurnal cortisol profiles. One-hundred and twelve (N=50 Black, N=62 White) adults from the Maryland Adolescent Development in Context Study provided saliva samples in adulthood (at approximately age 32 years) at waking, 30min after waking, and at bedtime for 7 days. Diurnal cortisol measures were calculated, including waking cortisol levels, diurnal cortisol slopes, the cortisol awakening response (CAR), and average daily cortisol (AUC). These cortisol outcomes were predicted from measures of PRD obtained over a 20-year period beginning when individuals were in 7th grade (approximately age 12). Greater average PRD measured across the 20-year period predicted flatter adult diurnal cortisol slopes for both Black and White adults, and a lower CAR. Greater average PRD also predicted lower waking cortisol for Black, but not White adults. PRD experiences in adolescence accounted for many of these effects. When adolescent and young adult PRD are entered together predicting cortisol outcomes, PRD experiences in adolescence (but not young adulthood) significantly predicted flatter diurnal cortisol slopes for both Black and White adults. Adolescent, but not young adult PRD, also significantly predicted lower waking and lower average cortisol for Black adults. Young adult PRD was, however, a stronger predictor of the CAR, predicting a marginally lower CAR for Whites, and a significantly larger CAR for Blacks. Effects were robust to controlling for covariates including health behaviors, depression, income and parent education levels. PRD experiences interacted with parent education and income to predict aspects of the diurnal cortisol rhythm. Although these results suggest PRD influences on cortisol for both Blacks and Whites, the key findings suggest that the effects are more pervasive for Blacks, affecting multiple aspects of the cortisol diurnal rhythm. In addition, adolescence is a more sensitive developmental period than adulthood for the impacts of PRD on adult stress biology.

In many randomized controlled trials, treatment groups are of equal size, but this is not necessarily the best choice. This paper provides a methodology to calculate optimal treatment allocations for longitudinal trials when we wish to compare multiple treatment groups with a placebo group, and the comparisons may have unequal importance. The focus is on trials with a survival endpoint measured in discrete time. We assume the underlying survival process is Weibull and show that values for the parameters in the Weibull distribution have an impact on the optimal treatment allocation scheme in an interesting way. Additionally, we incorporate different cost considerations at the subject and measurement levels and determine the optimal number of time periods. We also show that when many events occur at the beginning of the trial, fewer time periods are more efficient. As an application, we revisit a risperidone maintenance treatment trial in schizophrenia and use our proposed methodology to redesign it and compare merits of our optimal design.

BackgroundDespite epidemic childhood obesity levels, we know little about how BMI changes from preadolescence to adolescence and what factors influence changes.MethodsWe studied 3961 randomly selected public school students and 1 parent per student in 3 US metropolitan areas in fifth and again in tenth grades. In each grade, we measured child and parent height/weight and calculated BMI category. We examined whether baseline sociodemographic characteristics, child health-related factors, and parental obesity were significantly associated with exit from and entry into obesity from fifth to tenth grade.ResultsFifth- and tenth-graders were 1%/2% underweight, 53%/60% normal weight, 19%/18% overweight, and 26%/20% obese, respectively. Among obese tenth-graders, 83% had been obese as fifth-graders and 13% had been overweight. Sixty-five percent of obese fifth-graders remained obese as tenth-graders, and 23% transitioned to overweight. Multivariately, obese fifth-graders who perceived themselves to be much heavier than ideal (P = .01) and those who had lower household education (P = .006) were less likely to exit obesity; by contrast, overweight fifth-graders were more likely to become obese if they had an obese parent (P < .001) or watched more television (P = .02).ConclusionsObese fifth-graders face challenges in reducing obesity, especially when they lack advantages associated with higher socioeconomic status or when they have a negative body image. Clinicians and others should educate parents on the importance of preventing obesity very early in development. Children who are not yet obese by fifth grade but who have an obese parent or who watch considerable television might benefit from monitoring, as might children who have negative body images.

A major challenge in characterizing features of the daily cortisol curve is variability in features over time. Few studies have examined the stability of daily features of the cortisol curve over long periods or the predictors of long term changes. Repeated salivary cortisol measures on 580 adults from the MESA Stress study were used to examine the stability of various features of the daily cortisol curve (wakeup value, the cortisol awakening response (CAR), the early and late decline slope and the area under the curve (AUC)), over short periods (several days) and long periods (approximately 6-years) and to investigate the association of demographic factors with the changes. Intraclass correlation coefficients (ICCs) were used to estimate the short and long term stability. Piecewise linear mixed models were used to assess factors associated with changes in features over time. For most features, short term stability (ICCs: 0.17-0.74) was higher than long term stability (ICCs: 0.05-0.42), and long term stability was highest when several days were averaged for each time point. The decline over the day showed the highest long term stability: when several days for each wave were averaged the stability of the daily decline slope across 6 years was similar (or higher) than the stability across short periods. AUC had high stability over short periods (ICCs: 0.65-0.74) but much lower stability across long periods (ICC: 0.05). All features of daily cortisol curve investigated changed significantly over the approximately 6 year follow-up period. The wakeup cortisol became higher; the CAR became smaller; both the early and late decline became flatter; and the AUC became larger. Hispanics experienced significantly larger increases in the wakeup value; and African-Americans and Hispanics showed less flattening over time of the early decline slope than Non-Hispanic Whites. Our findings have implications for characterization of features in studies linking cortisol to health outcomes. The presence of variability over time suggests opportunities for future investigation of the predictors of changes over time as well as the links between these changes and health outcomes.

BackgroundApproximately one-third of those with pediatric-onset multiple sclerosis (MS) experience cognitive impairment. Less is known concerning their change in cognitive functioning over time.ObjectiveChanges in cognitive function over time were measured in the largest pediatric cohort to date through the US Network of Pediatric MS Centers.MethodsA total of 67 individuals with pediatric MS (n=62) or clinically isolated syndrome (CIS, n=5), ranging from 8-17 years of age (mean age ± standard deviation (SD)=14.37 ± 2.02) completed initial and follow-up neuropsychological testing after an average of 1.64 ± 0.63 years apart. The nine tests administered measure general intellect, attention and working memory, verbal memory, visuomotor integration, language, and executive functioning.ResultsRate of impairment (having one-third or more scores in the impaired range) was 37% at baseline and 33% at follow-up. Tests commonly impaired were measures of visuomotor integration, speeded processing, and attention. Most tested did not decline over two years. There was no clear pattern of change on any specific measure.ConclusionFindings suggest that, over short timeframes, stable or even improved performances on measures of cognitive ability can occur. Pediatric MS may instead prevent expected age-related cognitive gains.

ObjectiveAlthough early brain overgrowth is frequently reported in autism spectrum disorder (ASD), the relationship between ASD and head circumference (HC) is less clear, with inconsistent findings from longitudinal studies that include community controls. Our aim was to examine whether head growth in the first 3 years differed between children with ASD from a high-risk (HR) sample of infant siblings of children with ASD (by definition, multiplex), HR siblings not diagnosed with ASD, and low-risk (LR) controls.MethodParticipants included 442 HR and 253 LR infants from 12 sites of the international Baby Siblings Research Consortium. Longitudinal HC data were obtained prospectively, supplemented by growth records. Random effects nonlinear growth models were used to compare HC in HR infants and LR infants. Additional comparisons were conducted with the HR group stratified by diagnostic status at age 3: ASD (n = 77), developmental delay (DD; n = 32), and typical development (TD; n = 333). Nonlinear growth models were also developed for height to assess general overgrowth associated with ASD.ResultsThere was no overall difference in head circumference growth over the first 3 years between HR and LR infants, although secondary analyses suggested possible increased total growth in HR infants, reflected by the model asymptote. Analyses stratifying the HR group by 3-year outcomes did not detect differences in head growth or height between HR infants who developed ASD and those who did not, nor between infants with ASD and LR controls.ConclusionHead growth was uninformative as an ASD risk marker within this HR cohort.

PurposeAmong cancer patients, family interaction has been associated with depression. According to the stress generation theory, depression among cancer patients triggers stressful interpersonal events that contribute to poor family interactions and additional depression. This conflict may occur with a spouse/partner or other family member, including extended family. This study evaluated the longitudinal association between depression and marital and family conflict among low-income, predominantly Hispanic cancer patients.MethodsData were collected during a randomized controlled clinical trial of depression treatment among 472 low-income cancer patients with baseline depression scores of 10 or more on the Patient Health Questionnaire-9 and whose depression symptoms and negative family interactions were assessed at baseline and at 6, 12, 18, and 24 months. Considering that not all participants were in an intimate relationship, only 237 participants were included in the analysis of marital conflict. Mixed linear modeling with and without decomposition of between- and within-person variability was conducted to examine the longitudinal association between family interaction and depression.ResultsOverall, family conflict was significantly associated with changes in depression over time, and marital conflict was significantly associated with mean depression levels over 2 years. In addition, within-subject change in both marital and family conflict was significantly associated with within-patient deviation from average depression levels.ConclusionsFindings provide evidence of an association between depression and negative family interaction among depressed cancer patients. Cancer patients with clinically significant depressive symptoms may benefit from clinical assessment and psychotherapy relevant to family interaction.

ObjectiveTo examine the longitudinal effects of comorbid anxiety disorders in youth with bipolar spectrum disorder (BP).MethodAs part of the Course and Outcome of Bipolar Youth study, 413 youth, who were 7 through 17 years or age and who met criteria for DSM-IV BP-I (n = 244), BP-II (n = 28), and operationally defined bipolar disorder not otherwise specified (BP-NOS) (n = 141) were included. Subjects were followed on average 5 years using the Longitudinal Interval Follow-up Evaluation. Effects of anxiety on the time to mood recovery and recurrence and percentage of time with syndromal and subsyndromal mood symptomatology during the follow-up period were analyzed.ResultsAt intake and during the follow-up, 62% of youth with BP met criteria for at least 1 anxiety disorder. About 50% of the BP youth with anxiety had ≥2 anxiety disorders. Compared to BP youth without anxiety, those with anxiety had significantly more depressive recurrences and significantly longer median time to recovery. The effects of anxiety on recovery disappeared when the severity of depression at intake was taken into account. After adjusting for confounding factors, BP youth with anxiety, particularly those with ≥2 anxiety disorders, spent significantly less follow-up time asymptomatic and more time with syndromal mixed/cycling and subsyndromal depressive symptomatology compared to those without anxiety.ConclusionsAnxiety disorders are common and adversely affect the course of BP in youth, as characterized by more mood recurrences, longer time to recovery, less time euthymic, and more time in mixed/cycling and depressive episodes. Prompt recognition and the development of treatments for BP youth with anxiety are warranted.

The hippocampus is an anatomically and functionally heterogeneous structure, but longitudinal studies of its regional development are scarce and it is not known whether protracted maturation of the hippocampus in adolescence is related to memory development. First, we investigated hippocampal subfield development using 170 longitudinally acquired brain magnetic resonance imaging scans from 85 participants aged 8-21 years. Hippocampal subfield volumes were estimated by the use of automated segmentation of 7 subfields, including the cornu ammonis (CA) sectors and the dentate gyrus (DG), while longitudinal subfield volumetric change was quantified using a nonlinear registration procedure. Second, associations between subfield volumes and change and verbal learning/memory across multiple retention intervals (5 min, 30 min and 1 week) were tested. It was hypothesized that short and intermediate memory would be more closely related to CA2-3/CA4-DG and extended, remote memory to CA1. Change rates were significantly different across hippocampal subfields, but nearly all subfields showed significant volume decreases over time throughout adolescence. Several subfield volumes were larger in the right hemisphere and in males, while for change rates there were no hemisphere or sex differences. Partly in support of the hypotheses, greater volume of CA1 and CA2-3 was related to recall and retention after an extended delay, while longitudinal reduction of CA2-3 and CA4-DG was related to learning. This suggests continued regional development of the hippocampus across adolescence and that volume and volume change in specific subfields differentially predict verbal learning and memory over different retention intervals, but future high-resolution studies are called for.

Education, occupation, premorbid intelligence, and brain size are surrogate markers for cognitive reserve. Whether these markers have biological influence on Alzheimer disease (AD) pathology is not known. We thus aimed to investigate the effect of cognitive reserve proxies on longitudinal change of AD biomarkers. A total of 819 participants with normal cognition, mild cognitive impairment, and mild AD were enrolled in the Alzheimer's Disease Neuroimaging Initiative and followed up with repeated measures of cerebrospinal fluid, positron emission tomography, and magnetic resonance imaging biomarkers. Generalized estimating equations were used to assess whether biomarker rates of change were modified by reserve proxies. Cerebrospinal fluid Aβ42 decline was slower in normal cognition participants with higher cognitive reserve indexed by education, occupation, and American National Adult Reading Test (ANART). The decline of [F] fluorodeoxyglucose positron emission tomography uptake was slower in AD participants with better performance on the ANART. Education, occupation, and ANART did not modify the rates of magnetic resonance imaging hippocampal atrophy in any group. These findings remained unchanged after accounting for APOE 4, longitudinal missing data, and baseline cognitive performance. Higher levels of reserve markers may slow the rate of amyloid deposition before cognitive impairment and preserve glucose metabolism at the dementia stage over the course of AD pathologic progression.

The present study takes a motivational perspective that views youths' educational and career engagement as influential and potentially competing for the same motivational resources in the transition to adulthood. We investigated whether motivational engagement with educational and career goals in the year after high-school graduation was differentially associated with educational, career-related and subjective well-being outcomes 2 and 4 years after school graduation. Our longitudinal study of a multi-ethnic sample of Los Angeles high-school graduates followed participants 2 years (N = 561; 61.5 % female) and 4 years (N = 364; 59.8 % female) after high school graduation. The findings indicate that motivational engagement with educational goals after high school graduation predicted educational attainments and psychological well-being at follow-up 2 and 4 years after graduation, and occupational progress at 4 years after graduation. Work hours assessed shortly after high school graduation were associated with poorer educational outcomes both at 2 and 4 years after high school. Occupational goal engagement was not associated with better outcomes, but predicted less educational attainment 4 years after graduating. Thus, educational goal engagement predicted favorable outcomes, whereas career-related goal engagement for the most part was neutral with some select associations with negative educational outcomes. A strong motivational commitment to educational goals, but not to career goals, is an important component of a successful transition to adulthood.

Background/aimsThe clinical syndromes of frontotemporal lobar degeneration include behavioral variant frontotemporal dementia (bvFTD) and semantic (SV-PPA) and nonfluent variants (NF-PPA) of primary progressive aphasia. Using magnetic resonance imaging (MRI), tensor-based morphometry (TBM) was used to determine distinct patterns of atrophy between these three clinical groups.MethodsTwenty-seven participants diagnosed with bvFTD, 16 with SV-PPA, and 19 with NF-PPA received baseline and follow-up MRI scans approximately 1 year apart. TBM was used to create three-dimensional Jacobian maps of local brain atrophy rates for individual subjects.ResultsRegional analyses were performed on the three-dimensional maps and direct comparisons between groups (corrected for multiple comparisons using permutation tests) revealed significantly greater frontal lobe and frontal white matter atrophy in the bvFTD relative to the SV-PPA group (p < 0.005). The SV-PPA subjects exhibited significantly greater atrophy than the bvFTD in the fusiform gyrus (p = 0.007). The NF-PPA group showed significantly more atrophy in the parietal lobes relative to both bvFTD and SV-PPA groups (p < 0.05). Percent volume change in ventromedial prefrontal cortex was significantly associated with baseline behavioral symptomatology.ConclusionThe bvFTD, SV-PPA, and NF-PPA groups displayed distinct patterns of progressive atrophy over a 1-year period that correspond well to the behavioral disturbances characteristic of the clinical syndromes. More specifically, the bvFTD group showed significant white matter contraction and presence of behavioral symptoms at baseline predicted significant volume loss of the ventromedial prefrontal cortex.

BackgroundThe importance of a continuing care approach for substance use disorders (SUDs) is increasingly being recognized. Our prior research found that a Continuing Care model for SUDs that incorporates 3 components (regular primary care, and specialty SUD and psychiatric treatment as needed) is beneficial to long-term remission. The study builds on this work to examine the cost implications of this model.ObjectivesTo examine associations between receiving Continuing Care and subsequent health care costs over 9 years among adults entering outpatient SUD treatment in a private nonprofit, integrated managed care health plan. We also compare the results to a similar analysis of a demographically matched control group without SUDs.Study designLongitudinal observational study.MeasuresMeasures collected over 9 years include demographic characteristics, self-reported alcohol and drug use and Addiction Severity Index, and health care utilization and cost data from health plan databases.ResultsWithin the treatment sample, SUD patients receiving all components of Continuing Care had lower costs than those receiving fewer components. Compared with the demographically matched non-SUD controls, those not receiving Continuing Care had significantly higher inpatient costs (excess cost = $65.79/member-month; P < 0.01) over 9 years, whereas no difference was found between those receiving Continuing Care and controls.ConclusionsAlthough a causal link cannot be established between receiving Continuing Care and reduced long-term costs in this observational study, the findings reinforce the importance of access to health care and development of interventions that optimize patients receiving those services and that may reduce costs to health systems.

Despite broad consensus that most juvenile crimes are committed with peers, many questions regarding developmental and individual differences in criminal style (i.e., co-offending vs. solo offending) remain unanswered. Using prospective 3-year longitudinal data from 937 14- to 17-year-old serious male offenders, the present study investigates whether youths tend to offend alone, in groups, or a combination of the two; whether these patterns change with age; and whether youths who engage in a particular style share distinguishing characteristics. Trajectory analyses examining criminal styles over age revealed that, while most youth evinced both types of offending, two distinct groups emerged: an increasingly solo offender trajectory (83%); and a mixed style offender trajectory (17%). Alternate analyses revealed (5.5%) exclusively solo offenders (i.e., only committed solo offenses over 3 years). There were no significant differences between groups in individuals' reported number of friends, quality of friendships, or extraversion. However, the increasingly solo and exclusively solo offenders reported more psychosocial maturity, lower rates of anxiety, fewer psychopathic traits, less gang involvement and less self reported offending than mixed style offenders. Findings suggest that increasingly and exclusively solo offenders are not loners, as they are sometimes portrayed, and that exclusively solo offending during adolescence, while rare and previously misunderstood, may not be a risk factor in and of itself.

ObjectiveTo investigate the association between use of calcium channel blockers (CCB), dihydropyridine (DHP) or nondihydropyridine (nonDHP) type CCB and risk of developing Alzheimer's Disease (AD) or mortality. There is evidence suggesting that calcium plays a key role in changes in the brain leading to AD. Previous reports suggest a possible role for CCB in the treatment of AD. However, there are some indications that CCB increase mortality in patients with cardiac disease.MethodsSubjects were 1092 participants in the Baltimore Longitudinal Study of Aging (BLSA) older than 60 years of age. Data on CCB use was collected prospectively for up to 19 years. Cox proportional hazards regression was used to estimate relative risks (RR) and confidence intervals (CI) of AD and mortality associated with use of CCB or use of only DHP or nonDHP-CCB. Analyses were adjusted for gender, education, smoking, blood pressure and history of heart problems.ResultsUse of DHP-CCB was not associated with a significantly reduced risk of AD compared to non-users, although the estimate of the RR was low with DHP-CCB (RR = 0.30, 95% CI = 0.07-1.25, P = 0.10). Use of nonDHP-CCB was not associated with reduced risk of AD and the estimate of the RR risk was close to one (RR = 0.82, 95% CI = 0.37-1.83, P = 0.63). In addition, there was no increase in mortality among users of DHP-CCB (RR = 0.64, 95% CI = 0.32-1.29, P = 0.21) or nonDHP-CCB (RR = 1.10, 95% CI = 0.65-1.87, P = 0.72).ConclusionUsers of DHP-CCB and nonDHP-CCB in this study did not have a significantly reduced risk of AD.