Group-based trajectory modeling in clinical research

Identifying Patterns of FEES-Derived Swallowing Trajectories Using Group-Based Trajectory Model

The present study delineates and visualizes swallowing trajectories along seven swallow trials in dysphagic patients using group-based trajectory modeling (GBTM). This model facilitates the recognition of swallowing functional categories, estimates their frequency of occurrence, and enhances the understanding of swallowing dynamics. Two hundred and five dysphagic patients underwent a standardized FEES examination protocol. Five ordinal variables were blindly assessed for each swallow by two observers independently. GBTM analysis was conducted to find and characterize trajectories of FEES responses. For most FEES outcome variables, trajectories were qualitatively distinct in degree and kind (level of impairment and how this changed over the seven swallow trials). Two FEES outcome variables—delayed initiation of the pharyngeal reflex and postswallow pyriform sinus pooling—showed the highest prevalence of severe swallowing impairment. Highly impaired categories were more stable throughout the different swallow trials. Intermediate trajectories, by contrast, were erratic, responding more sensitively to shifts in bolus consistency. GBTM can identify distinct developmental trajectories of measured FEES variables in patients with oropharyngeal dysphagia. In clinical practice, classification into distinct groups would help to identify the subgroup of dysphagic patients who may need specific medical attention.

Investigating Progression in Substance Use Initiation Using a Discrete-Time Multiple Event Process Survival Mixture (MEPSUM) Approach

The order and timing of substance initiation has significant implications for later problematic patterns of use. Despite the need to study initiation from a multivariate framework, survival analytic methods typically cannot accommodate more than two substances in one model. The Discrete-Time Multiple Event Process Survival Mixture (MEPSUM; Dean, Bauer, & Shanahan, 2014) model represents an advance by incorporating more than two outcomes and enabling establishment of latent classes within a multivariate hazard distribution. Employing a MEPSUM approach, we evaluated patterns of tobacco, alcohol, and cannabis initiation in the National Longitudinal Study of Adolescent to Adult Health (N=18,923). We found four classes that differed in their ages and ordering of peak initiation risk. Demographics, externalizing psychopathology, and personality significantly predicted class membership. Sex differences in the association between delinquency and initiation patterns also emerged. Findings support the utility of the MEPSUM approach in elucidating developmental pathways underlying clinically relevant phenomena.

Longitudinal investigation of anxiety sensitivity growth trajectories and relations with anxiety and depression symptoms in adolescence

Anxiety sensitivity (AS), the belief that anxious arousal is harmful, is a malleable risk factor that has been implicated in anxiety and depression symptoms in adolescents. Although there is some evidence that adolescents possess distinct developmental trajectories, few studies have explored this topic. This study examined the developmental trajectory of AS in 248 adolescents (M age = 11.0 years, SD = 0.82; 56% male) across 6 years, beginning when children were age 11. This study also examined the influence of AS trajectories on anxiety and depression at age 16. Finally, this study examined the utility of AS classes in identifying anxiety and depression growth. Three AS classes were found, described by normative-stable, high-stable, and high-unstable trajectories. Adolescents in the high-stable and the high-unstable AS classes had higher levels of anxiety and depression at age 16 than did adolescents in the normative-stable AS class. In addition, the anxiety and depression trajectories fit by AS class mirrored the AS class trajectories. These findings suggest three AS trajectories can be identified in adolescents. These trajectories are discussed in relation to a developmental perspective of AS.

Developmental trajectories of physical activity and television viewing during adolescence among girls: National Growth and Health Cohort Study

Background

Analytic methodology for investigating physical activity patterns over time has been limited. The aim of this study was to demonstrate the group-based trajectory analysis process for identifying developmental physical activity (PA) and television (TV) viewing trajectories and the risk factor of PA trajectories, and for examining a relationship between PA and TV viewing trajectories among adolescent girls.

Methods

Secondary analysis was conducted using the National Growth and Health Study (NGHS) dataset. The NGHS administered the Habitual Activity Questionnaire and TV viewing questionnaire to White and Black girls at age 10, 12, 14, 16, 17, 18, and 19 years. Group-based trajectory analyses were conducted to identify distinct PA trajectories. Race was chosen to present an example of the risk factor analysis and was added as a predictor in the trajectory model. Dual-trajectory analysis was conducted to estimate probabilities of TV viewing trajectory groups conditional on the PA trajectory groups.

Results

A total of 2,155 girls (52 % Black) were included in the data analysis. We identified four PA trajectories: substantially decreasing from high PA (PA group 1, 9.4 %), maintaining moderate PA (PA group 2, 31.6 %), maintaining high PA (PA group 3, 5.8 %), and decreasing from moderate PA (PA group 4, 53.2 %). A significantly lower proportion of Black girls had high PA levels at baseline and maintained their baseline PA than White girls. Most girls who were classified as maintaining high PA (88 %) were also classified as decreasing TV viewing.

Conclusions

A group-based trajectory approach provides new insights about the patterns of maintaining moderate or high levels of PA that exist among adolescent girls. However, a lower proportion of Black girls followed the maintenance patterns than White girls. The behavioral development of PA and TV viewing may be intertwined among adolescent girls.

Developmental trajectories of adiposity from birth until early adulthood and association with cardiometabolic risk factors

OBJECTIVE

To identify developmental trajectories of adiposity from birth until early adulthood, and to investigate how they relate with cardiometabolic risk factors at 21 years of age.

METHODS

Participants' weight and height measurements were obtained using the EPITeen cohort protocol at 13, 17 and 21 years of age, and extracted from child health books as recorded during health routine evaluations since birth. Blood pressure, triglycerides, cholesterol and insulin resistance (HOMA-IR) were assessed at 21 years. Trajectories were defined using 719 participants contributing 11 459 measurements. The individual growth curves were modelled using mixed-effects fractional polynomial, and the trajectories were estimated using normal mixture modelling for model-based clustering. Differences in cardiometabolic risk factors at 21 years according to adiposity trajectories were estimated through analysis of covariance (ANCOVA), and adjusted means are presented.

RESULTS

Two trajectories-'Average body mass index (BMI) growth' (80.7%) and 'Higher BMI growth' (19.3%)-were identified. Compared with those in 'Average BMI growth', 'Higher BMI growth' participants were more frequently delivered by caesarean section, mothers were younger and had higher BMI, and parental education was lower; and at 21 years showed higher adjusted mean systolic (111.6 vs 108.3 mm Hg, P<0.001) and diastolic blood pressure (71.9 vs 68.4 mm Hg, P<0.001), and lower high-density lipoprotein cholesterol (53.3 vs 57.0 mg dl(-1), P=0.001). As there was a significant interaction between trajectories and sex, triglycerides and HOMA-IR were stratified by sex and we found significantly higher triglycerides, in males, and higher HOMA-IR in both sexes in 'Higher BMI growth' trajectory. All the differences were attenuated after adjustment for BMI at 21 years.

CONCLUSIONS

In this long-term follow-up, we were able to identify two adiposity trajectories, statistically related to the BMI and cardiometabolic profile in adulthood. Our results also suggest that the impact of the adiposity trajectory on cardiometabolic profile is mediated by current BMI.

Trajectories of Depressive Symptoms in Elderly Mexican Americans

OBJECTIVES

To identify depressive symptom trajectories and factors associated with trajectory group membership in the very old segment of the rapidly growing and long-living Mexican-American population.

DESIGN

Latent growth curve modeling was used to identify depressive symptom trajectories and multinomial logistic regression to identify factors associated with trajectory group membership.

SETTING

Data spanning three waves and 7 years (2004-05, 2007-08, 2010-11) drawn from the Hispanic Established Populations for Epidemiologic Studies of the Elderly; homes of Mexican-origin elderly adults.

PARTICIPANTS

Community-dwelling Mexican Americans aged 75 and older living in the southwestern United States (N = 1,487).

MEASUREMENTS

The 20-item version of the Center for Epidemiologic Studies Depression Scale.

RESULTS

Three trajectory groups were identified: low throughout, increasing, and high but decreasing. Activity of daily living disability was the strongest predictor of depressive symptoms, followed by social support. Foreign-born individuals were at greater risk than those who are U.S. born for high but decreasing depressive symptoms than for low depressive symptoms.

CONCLUSION

Early detection and treatment of chronic disabling conditions, especially heart disease, cancer, visual impairment, and cognitive impairment, and increasing access to social participation should be the focus of treatment and intervention strategies for depression in very old Mexican Americans.

Early Risk Factors of Overweight Developmental Trajectories during Middle Childhood

BACKGROUND

Research is needed to identify early life risk factors associated with different developmental paths leading to overweight by adolescence.

OBJECTIVES

To model heterogeneity in overweight development during middle childhood and identify factors associated with differing overweight trajectories.

METHODS

Data was drawn from the Quebec Longitudinal Study of Child Development (QLSCD; 1998-2010). Trained research assistants measured height and weight according to a standardized protocol and conducted yearly home interviews with the child's caregiver (mother in 98% of cases). Information on several putative early life risk factors for the development of overweight were obtained, including factors related to the child's perinatal, early behavioral family and social environment. Group-based trajectories of the probability of overweight (6-12 years) were identified with a semiparametric method (n=1678). Logistic regression analyses were used to identify early risk factors (5 months- 5 years) associated with each trajectory.

RESULTS

Three trajectories of overweight were identified: "early-onset overweight" (11.0 %), "late-onset overweight" (16.6%) and "never overweight" (72.5%). Multinomial analyses indicated that children in the early and late-onset group, compared to the never overweight group, had 3 common types of risk factors: parental overweight, preschool overweight history, and large size for gestational age. Maternal overprotection (OR= 1.12, CI: 1.01-1.25), short nighttime sleep duration (OR=1.66, CI: 1.07-2.57), and immigrant status (OR=2.01, CI: 1.05-3.84) were factors specific to the early-onset group. Finally, family food insufficiency (OR=1.81, CI: 1.00-3.28) was weakly associated with membership in the late-onset trajectory group.

CONCLUSIONS

The development of overweight in childhood follows two different trajectories, which have common and distinct risk factors that could be the target of early preventive interventions.

Utilizing mHealth methods to identify patterns of high risk illicit drug use

INTRODUCTION

We assessed patterns of illicit drug use using mobile health (mHealth) methods and subsequent health care indicators among drug users in Baltimore, MD.

METHODS

Participants of the EXposure Assessment in Current Time (EXACT) study were provided a mobile device for assessment of their daily drug use (heroin, cocaine or both), mood and social context for 30 days from November 2008 through May 2013. Real-time, self-reported drug use events were summed for individuals by day. Drug use risk was assessed through growth mixture modeling. Latent class regression examined the association of mHealth-defined risk groups with indicators of healthcare access and utilization.

RESULTS

109 participants were a median of 48.5 years old, 90% African American, 52% male and 59% HIV-infected. Growth mixture modeling identified three distinct classes: low intensity drug use (25%), moderate intensity drug use (65%) and high intensity drug use (10%). Compared to low intensity drug users, high intensity users were younger, injected greater than once per day, and shared needles. At the subsequent study visit, high intensity drug users were nine times less likely to be medically insured (adjusted OR: 0.10, 95%CI: 0.01-0.88) and at greater risk for failing to attend any outpatient appointments (aOR: 0.13, 95%CI: 0.02-0.85) relative to low intensity drug users.

CONCLUSIONS

Real-time assessment of drug use and novel methods of describing sub-classes of drug users uncovered individuals with higher-risk behavior who were poorly utilizing healthcare services. mHealth holds promise for identifying individuals engaging in high-risk behaviors and delivering real-time interventions to improve care outcomes.

Childhood body mass index trajectories predicting cardiovascular risk in adolescence

PURPOSE

The present study compared growth parameters of girls' and boys' body mass index (BMI) trajectories from infancy to middle childhood and evaluated these parameters as predictors of cardiovascular disease (CVD) risk in adolescence.

METHODS

Using 657 children from the NICHD Study of Early Child Care and Youth Development, quadratic growth curve analyses were conducted to establish growth parameters (intercept, slope, and quadratic term) for girls and boys from age 15 months to 10.5 years. Parameters were compared across gender and evaluated as predictors of a CVD risk index at the age of 15 years, controlling for characteristics of the adiposity rebound (AR) including age at which it occurred and children's BMI at the rebound.

RESULTS

Boys had more extreme trajectories of growth than girls with higher initial BMI at age 15 months (intercept), more rapid declines in BMI before the AR (slope), and sharper rebound growth in BMI after the rebound (quadratic term). For boys and girls, higher intercept, slope, and quadratic term values predicted higher CVD risk at the age of 15 years, controlling for characteristics of the AR.

CONCLUSIONS

Findings suggest that individuals at risk for developing CVD later in life may be identified before the AR by elevated BMI at 15 months and slow BMI declines. Because of the importance of early intervention in altering lifelong health trajectories, consistent BMI monitoring is essential in identifying high-risk children.

Long-Term BMI Trajectories and Health in Older Adults: Hierarchical Clustering of Functional Curves

OBJECTIVE

This project contributes to the emerging research that aims to identify distinct body mass index (BMI) trajectory types in the population. We identify clusters of long-term BMI curves among older adults and determine how the clusters differ with respect to initial health.

METHOD

Health and Retirement Study cohort (N = 9,893) with BMI information collected in up to 10 waves (1992-2010) is analyzed using a powerful cutting-edge approach: hierarchical clustering of BMI functions estimated via the Principal Analysis by Conditional Expectations (PACE) algorithm.

RESULTS

Three BMI trajectory clusters emerged for each gender: stable, gaining, and losing. The initial health of the gaining and stable groups in both genders was comparable; the losing cluster experienced significantly poorer health at baseline.

DISCUSSION

BMI trajectories among older adults cluster into distinct types in both genders, and the clusters vary substantially in initial health. Weight loss but not gain is associated with poor initial health in this age group.

Childhood obesity: evidence for distinct early and late environmental determinants a 12-year longitudinal cohort study (EarlyBird 62)

BACKGROUND/OBJECTIVE

The prevalence of childhood obesity continues to rise in most countries, but the exposures responsible remain unclear. The shape of the body mass index (BMI) distribution curve defines how a population responds, and can be described by its three parameters-skew (L), median (M) and variance (S). We used LMS analysis to explore differences in the BMI trajectories of contemporary UK children with those of 25 years ago, and to draw inferences on the exposures responsible.

SUBJECTS/METHODS

We applied Cole's LMS method to compare the BMI trajectories of 307 UK children (EarlyBird cohort) measured annually from 5-16 years (2000-2012) with those of the BMI data set used to construct the UK 1990 growth centiles, and used group-based trajectory modelling (GBTM) to establish whether categorical trajectories emerged.

RESULTS

Gender-specific birth weights were normally distributed and similar between both data sets. The skew and variance established by 5 years in the 1990 children remained stable during the remainder of their childhood, but the pattern was different for children 25 years on. The skew at 5 years among the EarlyBird children was greatly exaggerated, and involved selectively the offspring of obese parents, but returned to 1990 levels by puberty. As the skew diminished, so the variance in BMI rose sharply. The median BMI of the EarlyBird children differed little from that of 1990 before puberty, but diverged from it as the variance rose. GBTM uncovered four groups with distinct trajectories, which were related to parental obesity.

CONCLUSIONS

There appear to be two distinct environmental interactions with body mass among contemporary children, the one operating selectively according to parental BMI during early childhood, the second more generally in puberty.

Changes in forced vital capacity over time in systemic sclerosis: application of group-based trajectory modelling

OBJECTIVE

An accelerated rate of decline in forced vital capacity (FVC) affects >50% of patients with SSc but data on the variability and determinants of this change are scarce. We sought to identify trajectories of FVC and their associated variables in SSc patients over a 12-year period.

METHODS

Clinical and pulmonary function data were retrospectively collected. SSc patients with three or more FVC values were included. Group-based modelling was used to cluster similar FVC patterns into trajectories. Baseline variables were associated with the trajectories using multinomial logistic regression. The effect of CYC on FVC was examined with each trajectory as a time-varying covariate.

RESULTS

In 254 SSc patients we identified seven distinct FVC trajectories: very low slow decline (5.5%), very low improve (13.8%), low fast decline (9.5%), low stable (19.7%), low-normal improve (31.1%), normal improve (16.1%) and normal stable (4.3%). Younger age and the presence of pulmonary hypertension, Interstitial lung disease and shortness of breath at baseline significantly increased the odds of declining trajectories vs the reference trajectory (low-normal improve). CYC was associated with FVC improvement in the low fast decline trajectory.

CONCLUSION

The course of FVC in SSc was highly variable, with improvement and stability experienced even by those with low baseline FVC. Trajectory modelling was able to identify SSc patients who were most likely to experience FVC decline and thus could be a useful tool for patient management as well as clinical trial design.

Trajectories of maternal depression and offspring psychopathology at 6 years: 2004 Pelotas cohort study

BACKGROUND

Few studies have addressed the course and severity of maternal depression and its effects on child psychiatric disorders from a longitudinal perspective. This study aimed to identify longitudinal patterns of maternal depression and to evaluate whether distinct depression trajectories predict particular psychiatric disorders in offspring.

METHODS

Cohort of 4231 births followed-up in the city of Pelotas, Brazil. Maternal depressive symptoms were assessed with the Edinburgh Postnatal Depression Scale (EPDS) at 3, 12, 24 and 48 months and 6 years after delivery. Psychiatric disorders in 6-year-old children were evaluated through the development and well-being assessment (DAWBA) instrument. Trajectories of maternal depression were calculated using a group-based modelling approach.

RESULTS

We identified five trajectories of maternal depressive symptoms: a "low" trajectory (34.8%), a "moderate low" (40.9%), a "increasing" (9.0%), a "decreasing" (9.9%), and a "high-chronic" trajectory (5.4%). The probability of children having any psychiatric disorder, as well as both internalizing and externalizing problems, increased as we moved from the "low" to the "high-chronic" trajectory. These differences were not explained by maternal and child characteristics examined in multivariate analyses.

LIMITATIONS

Data on maternal depression at 3-months was available on only a sub-sample. In addition, we had to rely on maternal report of child's behavior alone.

CONCLUSIONS

The study revealed an additive effect on child outcome of maternal depression over time. We identified a group of mothers with chronic and severe symptoms of depression throughout the first six years of the child life and for this group child psychiatric outcome was particularly compromised.

Group-based modeling of ecological trajectories in restored wetlands

Repeated measures taken at the same restoration sites over time are used to describe restoration trajectories and identify sites that are trending toward unexpected outcomes. Analogously, social scientists use repeated measures of individuals to describe developmental trajectories of behaviors or other outcomes. Group-based trajectory modeling (GBTM) is one statistical method used in behavioral and health sciences for this purpose. I introduce the use of GBTM to identify clusters of similar restoration trajectories within a sample of sites. Data collected at 54 restored wetlands in Illinois for up to 15 years post-restoration were used to describe trajectories of six indicators: plant species richness, number of Carex (sedge) species, mean coefficient of conservatism (mean C), native plant cover, perennial plant cover, and planted species cover. For each indicator, I used GBTM to classify wetlands into three to four groups with distinct trajectories. In general, cover by native and planted species declined, while species richness and mean C increased over time or peaked then declined. Site context and management may explain trajectory group membership. Specifically, wetlands restored more recently and those restored within forested contexts were more likely to follow increasing trajectories. I show GBTM to be useful for identifying typical restoration trajectory patterns, developing hypotheses regarding factors driving those patterns and pinpointing critical times for intervention. Furthermore, GBTM might be applied more broadly in ecological research to identify common patterns of community assembly in large numbers of plots or sites.

Acute CSF interleukin-6 trajectories after TBI: associations with neuroinflammation, polytrauma, and outcome

Traumatic brain injury (TBI) results in a significant inflammatory burden that perpetuates the production of inflammatory mediators and biomarkers. Interleukin-6 (IL-6) is a pro-inflammatory cytokine known to be elevated after trauma, and a major contributor to the inflammatory response following TBI. Previous studies have investigated associations between IL-6 and outcome following TBI, but to date, studies have been inconsistent in their conclusions. We hypothesized that cohort heterogeneity, temporal inflammatory profiles, and concurrent inflammatory marker associations are critical to characterize when targeting subpopulations for anti-inflammatory therapies. Toward this objective, we used serial cerebrospinal fluid (CSF) samples to generate temporal acute IL-6 trajectory (TRAJ) profiles in a prospective cohort of adults with severe TBI (n=114). We examined the impact of injury type on IL-6 profiles, and how IL-6 profiles impact sub-acute (2weeks-3months) serum inflammatory marker load and long-term global outcome 6-12months post-injury. There were two distinct acute CSF IL-6 profiles, a high and low TRAJ group. Individuals in the high TRAJ had increased odds of unfavorable Glasgow Outcome Scale (GOS) scores at 6months (adjusted OR=3.436, 95% CI: 1.259, 9.380). Individuals in the high TRAJ also had higher mean acute CSF inflammatory load compared to individuals in the low TRAJ (p⩽0.05). The two groups did not differ with respect acute serum profiles; however, individuals in the high CSF IL-6 TRAJ also had higher mean sub-acute serum IL-1β and IL-6 levels compared with the low TRAJ group (p⩽0.05). Lastly, injury type (isolated TBI vs. TBI+polytrauma) was associated with IL-6 TRAJ group (χ(2)=5.31, p=0.02). Specifically, there was 70% concordance between those with TBI+polytrauma and the low TRAJ; in contrast, isolated TBI was similarly distributed between TRAJ groups. These data provide evidence that sustained, elevated levels of CSF IL-6 are associated with an increased inflammatory load, and these increases are associated with increased odds for unfavorable global outcomes in the first year following TBI. Future studies should explore additional factors contributing to IL-6 elevations, and therapies to mitigate its detrimental effects on outcome.

Longitudinal systolic blood pressure characteristics and integrity of white matter tracts in a cohort of very old black and white adults

BACKGROUND

We sought to determine which systolic blood pressure (SBP) characteristics are associated with reduced brain integrity and whether these associations are stronger for white or gray matter. We hypothesized that exposure to higher and variable SBP will be associated with lower structural integrity of both gray and white matter.

METHODS

Neuroimaging, SBP, and cognition were obtained in 311 community-dwelling adults in 2006–2008 (average age = 83 years; 58% women; 40% black). Antihypertensive medications, SBP, and health-related factors were collected from 1997 to 1998 to time of neuroimaging. SBP values obtained from 1997 to 1998 to time of neuroimaging were used to compute mean; pulse pressure; coefficient of variation; and peak, load, and group-based trajectories.

RESULTS

Higher mean SBP was associated with lower white matter integrity in uncinate and superior lateral fasciculi bilaterally, independent of age, stroke history, antihypertensive medication use (odds ratio of having white matter hyperintensities greater than or equal to the median for 10mm Hg of SBP = 10.4, 95% confidence interval = 10.2–10.6, P = 0.0001; standardized beta for fractional anisotropy = −13.54, SE = 4.58, P = 0.003). These neuroimaging markers attenuated the association between higher SBP and lower digit symbol substitution test. Results were similar for trajectories of SBP and stronger for those with previously higher and variable SBP even if SBP was normal at neuroimaging. Results were similar for those without stroke. Associations with gray matter measures were not significant.

CONCLUSIONS

If confirmed, these data suggest a history of higher and variable SBP for very old adults may be useful to alert clinicians to potential lower integrity in selected tracts, whereas cross-sectional SBP measurements may obscure the risk of underlying white matter hyperintensities. Whether lowering and/or stabilizing SBP levels in very old adults without a remarkable cardiovascular history would have neuroprotective effects and reduce dementia risk needs further study.

Drinking trajectories among HIV-infected men who have sex with men: a cohort study of United States veterans

BACKGROUND

Although high rates of alcohol consumption and related problems have been observed among HIV-infected men who have sex with men (MSM), little is known about the long-term patterns of and factors associated with hazardous alcohol use in this population. We sought to identify alcohol use trajectories and correlates of hazardous alcohol use among HIV-infected MSM.

METHODS

Sexually active, HIV-infected MSM participating in the Veterans Aging Cohort Study were eligible for inclusion. Participants were recruited from VA infectious disease clinics in Atlanta, Baltimore, New York, Houston, Los Angeles, Pittsburgh, and Washington, DC. Data from annual self-reported assessments and group-based trajectory models were used to identify distinct alcohol use trajectories over an eight-year study period (2002-2010). We then used generalized estimate equations (GEE) to examine longitudinal correlates of hazardous alcohol use (defined as an AUDIT-C score ≥4).

RESULTS

Among 1065 participants, the mean age was 45.5 (SD=9.2) and 606 (58.2%) were African American. Baseline hazardous alcohol use was reported by 309 (29.3%). Group-based trajectory modeling revealed a distinct group (12.5% of the sample) with consistently hazardous alcohol use, characterized by a mean AUDIT-C score of >5 at every time point. In a GEE-based multivariable model, hazardous alcohol use was associated with earning <$6000 annually, having an alcohol-related diagnosis, using cannabis, and using cocaine.

CONCLUSIONS

More than 1 in 10 HIV-infected MSM US veterans reported consistent, long-term hazardous alcohol use. Financial insecurity and concurrent substance use were predictors of consistently hazardous alcohol use, and may be modifiable targets for intervention.

Predicting the post-treatment recovery of patients suffering from traumatic brain injury (TBI)

Predicting the evolution of individuals is a rather new mining task with applications in medicine. Medical researchers are interested in the progression of a disease and/or how do patients evolve or recover when they are subjected to some treatment. In this study, we investigate the problem of patients' evolution on the basis of medical tests before and after treatment after brain trauma: we want to understand to what extend a patient can become similar to a healthy participant. We face two challenges. First, we have less information on healthy participants than on the patients. Second, the values of the medical tests for patients, even after treatment started, remain well-separated from those of healthy people; this is typical for neurodegenerative diseases, but also for further brain impairments. Our approach encompasses methods for modelling patient evolution and for predicting the health improvement of different patients' subpopulations, i.e. prediction of label if they recovered or not. We test our approach on a cohort of patients treated after brain trauma and a corresponding cohort of controls.

Characterizing long-term patterns of weight change in China using latent class trajectory modeling

BACKGROUND

Over the past three decades, obesity-related diseases have increased tremendously in China, and are now the leading causes of morbidity and mortality. Patterns of weight change can be used to predict risk of obesity-related diseases, increase understanding of etiology of disease risk, identify groups at particularly high risk, and shape prevention strategies.

METHODS

Latent class trajectory modeling was used to compute weight change trajectories for adults aged 18 to 66 using the China Health and Nutrition Survey (CHNS) data (n = 12,611). Weight change trajectories were computed separately for males and females by age group at baseline due to differential age-related patterns of weight gain in China with urbanization. Generalized linear mixed effects models examined the association between weight change trajectories and baseline characteristics including urbanicity, BMI category, age, and year of study entry.

RESULTS

Trajectory classes were identified for each of six age-sex subgroups corresponding to various degrees of weight loss, maintenance and weight gain. Baseline BMI status was a significant predictor of trajectory membership for all age-sex subgroups. Baseline overweight/obesity increased odds of following 'initial loss with maintenance' trajectories. We found no significant association between baseline urbanization and trajectory membership after controlling for other covariates.

CONCLUSION

Trajectory analysis identified patterns of weight change for age by gender groups. Lack of association between baseline urbanization status and trajectory membership suggests that living in a rural environment at baseline was not protective. Analyses identified age-specific nuances in weight change patterns, pointing to the importance of subgroup analyses in future research.

Short-term trajectories of use of a caloric-monitoring mobile phone app among patients with type 2 diabetes mellitus in a primary care setting

BACKGROUND

Self-management plays an important role in maintaining good control of diabetes mellitus, and mobile phone interventions have been shown to improve such self-management. The Health Promotion Board of Singapore has created a caloric-monitoring mobile health app, the "interactive Diet and Activity Tracker" (iDAT).

OBJECTIVE

The objective was to identify and describe short-term (8-week) trajectories of use of the iDAT app among patients with type 2 diabetes mellitus in a primary care setting in Singapore, and identify patient characteristics associated with each trajectory.

METHODS

A total of 84 patients with type 2 diabetes mellitus from a public primary care clinic in Singapore who had not previously used the iDAT app were enrolled. The app was demonstrated and patients' weekly use of the app was monitored over 8 weeks. Weekly use was defined as any record in terms of food entry or exercise workout entry in that week. Information on demographics, diet and exercise motivation, diabetes self-efficacy (Diabetes Empowerment Scale-Short Form), and clinical variables (body mass index, blood pressure, and glycosylated hemoglobin/HbA1c) were collected at baseline. iDAT app use trajectories were delineated using latent-class growth modeling (LCGM). Association of patient characteristics with the trajectories was ascertained using logistic regression analysis.

RESULTS

Three iDAT app use trajectories were observed: Minimal Users (66 out of 84 patients, 78.6%, with either no iDAT use at all or use only in the first 2 weeks), Intermittent-Waning Users (10 out of 84 patients, 11.9%, with occasional weekly use mainly in the first 4 weeks), and Consistent Users (8 out of 84 patients, 9.5%, with weekly use throughout all or most of the 8 weeks). The adjusted odds ratio of being a Consistent User, relative to a Minimal User, was significantly higher for females (OR 19.55, 95% CI 1.78-215.42) and for those with higher exercise motivation scores at baseline (OR 4.89, 95% CI 1.80-13.28). The adjusted odds ratio of being an Intermittent-Waning User relative to a Minimal User was also significantly higher for those with higher exercise motivation scores at baseline (OR 1.82, 95% CI 1.00-3.32).

CONCLUSIONS

This study provides insight into the nature and extent of usage of a caloric-monitoring app among patients with type 2 diabetes and managed in primary care. The application of LCGM provides a useful framework for evaluating future app use in other patient populations.

Heterogeneity of sex-stratified BMI trajectories in children from 8 to 14 years old

OBJECTIVE

Describe and predict sex-stratified trajectories of weight change in youths transitioning from childhood to adolescence.

METHODS

Using an accelerated longitudinal design, 461 children between 8 and 12 years old at baseline were followed over three years. Body mass index was calculated from self-reported height and weight. Latent class growth analysis was used to identify BMI trajectories and multinomial logistic regressions, to predict group membership.

RESULTS

A four-group heterogeneous trajectory model emerged for boys and girls alike. Characteristics of the trajectories differed between sexes and no obesity group was found for boys. Sociocultural factors, such as media influence, body dissatisfaction, weight victimization, awareness of thin-ideal standards and related pressures were important correlates of trajectory membership.

CONCLUSION

BMI trajectories during preadolescence are stable over time for heavier children. Body image concerns and weight stigmatization stand out as important factors in the prediction of developmental weight trajectories and could therefore be integrated in weight gain prevention programs for children of all weights as well as in weight management interventions for overweight and obese children.

Characteristics of primary care providers who adopted the hospitalist model from 2001 to 2009

BACKGROUND

The characteristics of primary care providers (PCPs) who use hospitalists are unknown.

METHODS

Retrospective study using 100% Texas Medicare claims from 2001 through 2009. Descriptive statistics characterized proportion of PCPs using hospitalists over time. Trajectory analysis and multilevel models of 1172 PCPs with ≥20 inpatients in every study year characterized how PCPs adopted the hospitalist model and PCP factors associated with this transition.

RESULTS

Hospitalist use increased between 2001 and 2009. PCPs who adopted the hospitalist model transitioned rapidly. In multilevel models, hospitalist use was associated with US training (odds ratio [OR] 1.46, 95% confidence interval [CI]: 1.23-1.73 in 2007-2009), family medicine specialty (OR: 1.46, 95% CI: 1.25-1.70 in 2007-2009), and having high outpatient volumes (OR: 1.32, 95% CI: 1.20-1.44 in 2007-2009). Over time, relative hospitalist use decreased among female PCPs (OR: 1.91, 95% CI: 1.46-2.50 in 2001-2003; OR: 1.50, 95% CI: 1.15-1.95 in 2007-2009), those in urban locations (OR: 3.34, 95% CI: 2.72-4.09 in 2001-2003; OR: 2.22, 95% CI: 1.82-2.71 in 2007-2009), and those with higher inpatient volumes (OR: 1.05, 95% CI: 0.95-1.18 in 2001-2003; OR: 0.55, 95% CI: 0.51-0.60 in 2007-2009). Longest-practicing PCPs were more likely to transition in the early 2000s, but this effect disappeared by the end of the study period (OR: 1.35, 95% CI: 1.06-1.72 in 2001-2003; OR: 0.92, 95% CI: 0.73-1.17 in 2007-2009). PCPs with practice panels dominated by patients who were white, male, or had comorbidities are more likely to use hospitalists.

CONCLUSIONS

PCP characteristics are associated with hospitalist use. The association between PCP characteristics and hospitalist use has evolved over time.

Posttraumatic stress symptom trajectories among children exposed to violence

Little research has examined the developmental course of posttraumatic stress symptoms (PTSS) in children. The current study aimed to identify developmental trajectories of PTSS in childhood and to examine predictors of symptom presentation in 1,178 children from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN) studies, a consortium of studies focusing on the causes and effects of child maltreatment. Most children had a history of documented reports with Child Protective Services (CPS) and all were identified as living in high-risk environments. Using group-based trajectory modeling, 3 unique developmental trajectories were identified: Resilient, Clinical-Improving (PTSS in the clinical range at baseline then declining over time), and Borderline-Stable (chronically subclinical PTSS). Children in the Clinical-Improving group were more likely than children in the Resilient group to have reports of physical abuse (RRR = 1.76), emotional abuse (RRR = 2.55), neglect (RRR = 1.57), and exposure to violence at home and in the community (RRR = 1.04). Children in the Borderline-Stable group were more likely than children in the Resilient group to have a CPS history of neglect (RRR = 2.44) and exposure to violence at home and in the community (RRR = 1.04). Many children living in high-risk environments exhibit resilience to PTSS, but exposure to witnessed violence and neglect appear to put children at chronic risk for poor adjustment. These children may require more intensive, integrated clinical services that attend to multiple adverse experiences.

Breastfeeding duration and weight gain trajectory in infancy

BACKGROUND AND OBJECTIVES

Short breastfeeding duration may exacerbate accelerated early growth, which is linked to higher obesity risk in later life. This study tested the hypothesis that infants at higher risk for obesity were more likely to be members of a rising weight-for-length (WFL) z score trajectory if breastfed for shorter durations.

METHODS

This prospective, observational study recruited women from an obstetric patient population in rural central New York. Medical records of children born to women in the cohort were audited for weight and length measurements (n = 595). We identified weight gain trajectories for infants' WFL z scores from 0 to 24 months by using maximum likelihood latent class models. Individual risk factors associated with weight gain trajectories (P ≤ .05) were included in an obesity risk index. Logistic regression analysis was performed to investigate whether the association between breastfeeding duration (<2 months, 2-4 months, >4 months) and weight gain trajectory varied across obesity risk groups.

RESULTS

Rising and stable weight gain trajectories emerged. The obesity risk index included maternal BMI, education, and smoking during pregnancy. High-risk infants breastfed for <2 months were more likely to belong to a rising rather than stable weight gain trajectory (odds ratio, 2.55; 95% confidence interval, 1.14-5.72; P = .02).

CONCLUSIONS

Infants at the highest risk for rising weight patterns appear to benefit the most from longer breastfeeding duration. Targeting mothers of high-risk infants for breastfeeding promotion and support may be protective against overweight and obesity during a critical window of development.

Maternal depressive symptoms during childhood and risky adolescent health behaviors

OBJECTIVE

Maternal depression is a risk factor for adolescent depression; however, the effect of childhood exposure to maternal depression on adolescent engagement in health risk behaviors (eg, substance use, delinquency) is unclear.

METHODS

We examined the relationship between maternal depressive symptoms (child's age 4-15) and engagement in health risk behaviors at age 16 to 17 by using data from 2910 mother-youth pairs in a nationally representative prospective Canadian cohort. Maternal depressive trajectories were estimated through finite mixture modeling, and multiple regression analyses examined the relationship between maternal depressive symptoms and engagement in various health risk behaviors (linear regression) and age of debut of various behaviors (Cox regression).

RESULTS

Five trajectories of maternal depressive symptoms were found: recurrent maternal symptoms, midchildhood exposure to maternal symptoms, adolescent exposure to maternal symptoms, mild maternal symptoms, and low symptoms. Adolescents exposed to maternal depressive symptoms during middle childhood were more likely to use common substances (alcohol, cigarettes, marijuana), engage in violent and nonviolent delinquent behavior, and have an earlier debut ages of cigarette, alcohol, marijuana, and hallucinogen use.

CONCLUSIONS

The results of this study suggest that exposure to maternal depressive symptoms, particularly in middle childhood, is associated with greater and earlier engagement in health risk behaviors.

Pain trajectory groups in persons with, or at high risk of, knee osteoarthritis: findings from the Knee Clinical Assessment Study and the Osteoarthritis Initiative

OBJECTIVE

The authors aimed to characterize distinct trajectories of knee pain in adults who had, or were at high risk of, knee osteoarthritis using data from two population-based cohorts.

METHOD

Latent class growth analysis was applied to measures of knee pain severity on activity obtained at 18-month intervals for up to 6 years between 2002 and 2009 from symptomatic participants aged over 50 years in the Knee Clinical Assessment Study (CAS-K) in the United Kingdom. The optimum latent class growth model from CAS-K was then tested for reproducibility in a matched sample of participants from the Osteoarthritis Initiative (OAI) in the United States.

RESULTS

A 5-class linear model produced interpretable trajectories in CAS-K with reasonable goodness of fit and which were labelled "Mild, non-progressive" (N = 201, 35%), "Progressive" (N = 162, 28%), "Moderate" (N = 124, 22%) "Improving" (N = 68, 12%), and "Severe, non-improving" (N = 15, 3%). We were able to reproduce "Mild, non-progressive", "Moderate", and "Severe, non-improving" classes in the matched sample of participants from the OAI, however, absence of a "Progressive" class and instability of the "Improving" classes in the OAI was observed.

CONCLUSIONS

Our findings strengthen the grounds for moving beyond a simple stereotype of osteoarthritis as "slowly progressive". Mild, non-progressive or improving symptom trajectories, although difficult to reproduce, can nevertheless represent a genuinely favourable prognosis for a sizeable minority.

Overweight in infancy: which pre- and perinatal factors determine overweight persistence or reduction? A birth cohort followed for 11 years

BACKGROUND

A considerable proportion of children with early-life overweight attain a normal weight. To recognize infants at risk of persistent overweight, we compared early-life factors of children with a longitudinal pattern of persistent overweight to children with a pattern of overweight in early but not in later childhood.

METHODS

In 3,550 children participating in a birth cohort that started in 1996/1997 in the Netherlands, body mass index was repeatedly assessed until age 11 and dichotomized into with/without overweight. Latent class growth modeling was used to distinguish trajectories. Our analysis was focused on the comparison of early-life factors in children in a persistent overweight pattern with those in an overweight reduction pattern using multivariable log-binomial regression analyses.

RESULTS

Children (n = 133) in the persistent overweight pattern were more likely to have overweight parents [relative risk (RR)mother: 1.85, 95% CI: 1.37-2.49: RRfather: 1.75, 95% CI: 1.21-2.55] than children in the overweight reduction pattern (n = 303). Maternal education, child's gender, ethnicity, birth weight, breast-feeding and maternal smoking during pregnancy did not differ between the trajectories.

CONCLUSION

Health care practitioners should focus on high-weight infants with overweight parents, as these children are less likely to resolve their overweight.

Trajectories of injecting behavior in the Amsterdam Cohort Study among drug users

BACKGROUND

Injecting frequency among people who inject drugs (IDU) can change along distinct trajectories, which can reflect on incidence of HIV and HCV infections. We aimed at assessing these patterns of longitudinal changes, their predictors and their association with the incidence of HIV and HCV.

METHODS

We analyzed data from the Amsterdam Cohort Study among Drug Users, selecting participants recruited from 1985 to 2005, injecting drugs before cohort entry and with records in at least three different six months intervals (N=740). We used latent class mixed models to identify distinct trajectories of injecting, multinomial regression to identify socio-demographic variables associated with those patterns and Kaplan-Meier analysis for the estimation of the corresponding cumulative HIV and HCV incidence.

RESULTS

Five distinct patterns for injecting frequency and for injecting since last visit were identified. The majority of participants (three groups, 69% of participants) had stable risk injecting behavior; the remaining displayed a decrease in injecting over time. Those with longer duration of injecting at cohort entry and those who entered the cohort in earlier years tended to have continuing high risk behavior. The HIV risk was highest among those with continuing high risk behavior and its changes over time mirrored the patterns of change in injecting in a group with decrease in injecting.

CONCLUSIONS

Individual longitudinal patterns of changes in injecting behavior are related to socio-demographic and drug use variables and are reflected in the incidence of HIV infections. Understanding these associations might provide valuable information for targeted interventions.

Handling Missing Covariates in Conditional Mixture Models Under Missing at Random Assumptions

Mixture modeling is a popular method that accounts for unobserved population heterogeneity using multiple latent classes that differ in response patterns. Psychologists use conditional mixture models to incorporate covariates into between-class and/or within-class regressions. Although psychologists often have missing covariate data, conditional mixtures are currently fit with a conditional likelihood, treating covariates as fixed and fully observed. Under this exogenous-x approach, missing covariates are handled primarily via listwise deletion. This sacrifices efficiency and does not allow missingness to depend on observed outcomes. Here we describe a modified joint likelihood approach that (a) allows inference about parameters of the exogenous-x conditional mixture even with nonnormal covariates, unlike a conventional multivariate mixture; (b) retains all cases under missing at random assumptions; (c) yields lower bias and higher efficiency than the exogenous-x approach under a variety of conditions with missing covariates; and (d) is straightforward to implement in available commercial software. The proposed approach is illustrated with an empirical analysis predicting membership in latent classes of conduct problems. Recommendations for practice are discussed.

The symphonic structure of childhood stress reactivity: patterns of sympathetic, parasympathetic, and adrenocortical responses to psychological challenge

Despite widespread recognition that the physiological systems underlying stress reactivity are well coordinated at a neurobiological level, surprisingly little empirical attention has been given to delineating precisely how the systems actually interact with one another when confronted with stress. We examined cross-system response proclivities in anticipation of and following standardized laboratory challenges in 664 4- to 14-year-olds from four independent studies. In each study, measures of stress reactivity within both the locus coeruleus-norepinephrine system (i.e., the sympathetic and parasympathetic branches of the autonomic nervous system) and the corticotrophin releasing hormone system (i.e., the hypothalamic-pituitary-adrenal axis) were collected. Latent profile analyses revealed six distinctive patterns that recurred across the samples: moderate reactivity (average cross-system activation; 52%-80% of children across samples), parasympathetic-specific reactivity (2%-36%), anticipatory arousal (4%-9%), multisystem reactivity (7%-14%), hypothalamic-pituitary-adrenal axis specific reactivity (6%-7%), and underarousal (0%-2%). Groups meaningfully differed in socioeconomic status, family adversity, and age. Results highlight the sample-level reliability of children's neuroendocrine responses to stress and suggest important cross-system regularities that are linked to development and prior experiences and may have implications for subsequent physical and mental morbidity.

Links between trajectories of self-reported violent and nonviolent offending and official offending during adolescence and adulthood

BACKGROUND

Little is known about the associations between self-reported offending and official offending whilst considering different types of offences.

AIMS

The aims of the present study are to identify developmental trajectories of self-reported violent and nonviolent offending (SRVO; SRNVO) and to examine their associations with official violent and nonviolent offences (as juveniles and adults).

METHODS

Developmental trajectories of SRVO and SRNVO from 11 to 17 years of age were estimated with data from the Montreal Longitudinal and Experimental Study, a prospective longitudinal study of 1037 boys from disadvantaged neighbourhoods.

RESULTS

Five trajectories of SRVO (i.e. Chronic, Desisting, Delayed, Moderate and Low) and three trajectories of SRNVO (Chronic, Moderate and Low) were identified. Chronic, Desisting and Delayed trajectories of SRVO were associated with violent and nonviolent official offending in adolescence and early adulthood, over and above the trajectories of SRNVO. In comparison, trajectories of SRNVO were weakly and inconsistently associated with official offending, once controlling for their overlap with trajectories of SRVO.

CONCLUSIONS

Individuals on high trajectories of violent offending during adolescence are most at risk for being exposed to the justice system both concurrently and longitudinally. Differentiating violent and nonviolent offending can help resolve part of the discordance between self-reported and official offending.

Developmental trajectories of Body Mass Index from infancy to 18 years of age: prenatal determinants and health consequences

BACKGROUND

Knowledge on the long-term development of adiposity throughout childhood/adolescence and its prenatal determinants and health sequelae is lacking. We sought to (1) identify trajectories of Body Mass Index (BMI) from 1 to 18 years of age, (2) examine associations of maternal gestational smoking and early pregnancy overweight with offspring BMI trajectories and (3) determine whether BMI trajectories predict health outcomes: asthma, lung function parameters (forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) ratio), and blood pressure, at 18 years.

METHODS

The Isle of Wight birth cohort, a population-based sample of 1456 infants born between January 1989 and February 1990, was prospectively assessed at ages 1, 2, 4, 10 and 18 years. Group-based trajectory modelling was applied to test for the presence of latent BMI trajectories. Associations were assessed using log-binomial and linear regression models.

RESULTS

Four trajectories of BMI were identified: 'normal', 'early persistent obesity', 'delayed overweight', and 'early transient overweight'. Risk factors for being in the early persistent obesity trajectory included maternal smoking during pregnancy (RR 2.16, 95% CI 1.02 to 4.68) and early pregnancy overweight (3.16, 1.52 to 6.58). When comparing the early persistent obesity to the normal trajectory, a 2.15-fold (1.33 to 3.49) increased risk of asthma, 3.2% (0.4% to 6.0%) deficit in FEV1/FVC ratio, and elevated systolic 11.3 mm Hg (7.1 to 15.4) and diastolic 12.0 mm Hg (8.9 to 15.1) blood pressure were observed at age 18 years.

CONCLUSIONS

Maternal prenatal exposures show prolonged effects on offspring's propensity towards overweight-obesity. Distinct morbid BMI trajectories are evident during the first 18 years of life that are associated with higher risk of asthma, reduced FEV1/FVC ratio, and elevated blood pressure.

Student-teacher relationship trajectories and mental health problems in young children

BACKGROUND

This longitudinal study classified groups of children experiencing different trajectories of student-teacher relationship quality over the transition from preschool into school, and determined the strength of the association between different student-teacher relationship trajectories and childhood mental health problems in the second year of primary school.

METHODS

A community sample of 460 Australian children were assessed in preschool (age 4), the first school year (age 5), and second school year (age 6). Teachers at all three assessments reported on student-teacher relationship quality with the Student Teacher Relationship Scale. When the children were at preschool and in their second school year, parents and teachers rated children's mental health problems using the Strengths and Difficulties Questionnaire.

RESULTS

Latent-class growth modelling identified two trajectories of student-teacher relationship quality: (1) a stable-high student-teacher relationship quality and (2) a moderate/declining student-teacher relationship quality trajectory. Generalised linear models found that after adjusting for family demographic characteristics, having a stable high quality student-teacher relationship trajectory was associated with fewer parent-rated and teacher-rated total mental health problems, and fewer conduct, hyperactivity, and peer problems, and greater prosocial behaviour at age 6. A stable high quality trajectory was also associated with fewer teacher-rated, but not parent-rated emotional symptoms. These effects remained after adjustment for levels of mental health problems at age 4.

CONCLUSIONS

Findings suggest that early intervention and prevention strategies that focus on building stable high quality student-teacher relationships during preschool and children's transition into formal schooling, may help reduce rates of childhood mental health problems during the early school years.

Patterns, predictors, and outcomes of falls trajectories in older adults: the MOBILIZE Boston Study with 5 years of follow-up

Background

Falls may occur as unpredictable events or in patterns indicative of potentially modifiable risks and predictive of adverse outcomes. Knowing the patterns, risks, and outcomes of falls trajectories may help clinicians plan appropriate preventive measures. We hypothesized that clinically distinct trajectories of falls progression, baseline predictors and their coincident clinical outcomes could be identified.

Methods

We studied 765 community-dwelling participants in the MOBILIZE Boston Study, who were aged 70 and older and followed prospectively for falls over 5 years. Baseline demographic and clinical data were collected by questionnaire and a comprehensive clinic examination. Falls, injuries, and hospitalizations were recorded prospectively on daily calendars. Group-Based Trajectory Modeling (GBTM) was used to identify trajectories.

Results

We identified 4 distinct trajectories: No Falls (30.1%), Cluster Falls (46.1%), Increasing Falls (5.8%) and Chronic Recurring Falls (18.0%). Predictors of Cluster Falls were faster gait speed (OR 1.69 (95CI, 1.50–2.56)) and fall in the past year (OR 3.52 (95CI, 2.16–6.34)). Predictors of Increasing Falls were Diabetes Mellitus (OR 4.3 (95CI, 1.4–13.3)) and Cognitive Impairment (OR 2.82 (95CI, 1.34–5.82)). Predictors of Chronic Recurring Falls were multi-morbidity (OR 2.24 (95CI, 1.60–3.16)) and fall in the past year (OR 3.82 (95CI, 2.34–6.23)). Symptoms of depression were predictive of all falls trajectories. In the Chronic Recurring Falls trajectory group the incidence rate of Hospital visits was 121 (95% CI 63–169) per 1,000 person-years; Injurious falls 172 (95% CI 111–237) per 1,000 person-years and Fractures 41 (95% CI 9–78) per 1,000 person-years.

Conclusions

Falls may occur in clusters over discrete intervals in time, or as chronically increasing or recurring events that have a relatively greater risk of adverse outcomes. Patients with multiple falls, multimorbidity, and depressive symptoms should be targeted for preventive measures.

Lifestyle and health factors associated with progressing and remitting trajectories of untreated lower urinary tract symptoms among elderly men

BACKGROUND

Knowledge of factors associated with the course of lower urinary tract symptoms (LUTS) before treatment is needed to inform preventive interventions. In a prospective study of elderly men untreated for LUTS, we identified factors associated with symptom progression and remission.

METHODS

In community-dwelling US men aged ≥65 years, the American Urological Association Symptom Index (AUA-SI) was repeated four times, once at baseline (2000-2002) and then every 2 years thereafter. Analyses included 1740 men with all four AUA-SI assessments, who remained free from diagnosed prostate cancer, and who reported no treatment for LUTS or BPH during follow-up that averaged 6.9 (±0.4) years. LUTS change was determined with group-based trajectory modelingof the repeated AUA-SI measures. Multivariable logistic regression was then used to determine the baseline factors associated with progressing compared with stable trajectories, and with remitting compared with progressing trajectories. Lifestyle, body mass index (BMI) (kg/m(2)), mobility, mental health (Short-Form 12), medical history and prescription medications were considered for selection. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for variables in each model.

RESULTS

We identified 10 AUA-SI trajectories: 4 stable (1277 men, 73%), three progressing (345 men, 20%), two remitting (98 men, 6%) and one mixed (20 men, 1%). Men in progressing compared with stable trajectories were more likely to have mobility limitations (OR=2.0, 95% CI: 1.0-3.8), poor mental health (OR=1.9, 95% CI: 1.1-3.4), BMI≥25.0 kg m(-2) (OR=1.7, 95% CI: 1.0-2.8), hypertension (OR=1.5, 95% CI: 1.0-2.4) and back pain (OR=1.5, 95% CI: 1.0-2.4). Men in remitting compared with progressing trajectories more often used central nervous system medications (OR=2.3, 95% CI: 1.1-4.9) and less often had a history of problem drinking (OR=0.4, 95% CI: 0.2-0.9).

CONCLUSIONS

Several non-urological lifestyle and health factors were independently associated with risk of LUTS progression in older men.

Can change in prolonged walking be inferred from a short test of gait speed among older adults who are initially well-functioning?

BACKGROUND

The ability to walk for short and prolonged periods of time is often measured with separate walking tests. It is unclear whether decline in the 2-minute walk coincides with decline in a shorter 20-m walk among older adults.

OBJECTIVE

The aim of this study was to describe patterns of change in the 20-m walk and 2-minute walk over 8 years among a large cohort of older adults. Should change be similar between tests of walking ability, separate retesting of prolonged walking may need to be reconsidered.

DESIGN

A longitudinal, observational cohort study was conducted.

METHODS

Data were from 1,893 older adults who were well-functioning (≥70 years of age). The 20-m walk and 2-minute walk were repeatedly measured over 8 years to measure change during short and prolonged periods of walking, respectively. Change was examined using a dual group-based trajectory model (dual model), and agreement between walking trajectories was quantified with a weighted kappa statistic.

RESULTS

Three trajectory groups for the 20-m walk and 2-minute walk were identified. More than 86% of the participants were in similar trajectory groups for both tests from the dual model. There was high chance-corrected agreement (kappa=.84; 95% confidence interval=.82, .86) between the 20-m walk and 2-minute walk trajectory groups.

LIMITATIONS

One-third of the original Health, Aging and Body Composition (Health ABC) study cohort was excluded from analysis due to missing clinic visits, followed by being excluded for health reasons for performing the 2-minute walk, limiting generalizability to healthy older adults.

CONCLUSIONS

Patterns of change in the 2-minute walk are similar to those in the 20-m walk. Thus, separate retesting of the 2-minute walk may need to be reconsidered to gauge change in prolonged walking.

Trajectories of positive aging: observations from the women's health initiative study

BACKGROUND

The purpose of this study was to describe the longitudinal trajectories and bidirectional relationships of the physical-social and emotional functioning (EF) dimensions of positive aging and to identify their baseline characteristics.

METHODS

Women age 65 and older who enrolled in one or more Women's Health Initiative clinical trials (WHI CTs) and who had positive aging indicators measured at baseline and years 1, 3, 6, and 9 were included in these analyses (N = 2281). Analytic strategies included latent class growth modeling to identify longitudinal trajectories and multinomial logistic regression to examine the effects of baseline predictors on these trajectories.

RESULTS

A five-trajectory model was chosen to best represent the data. For Physical-Social Functioning (PSF), trajectory groups included Low Maintainer (8.3%), Mid-Low Improver (10.4%), Medium Decliner (10.7%), Mid-High Maintainer (31.2%), and High Maintainer (39.4%); for EF, trajectories included Low Maintainer (3%), Mid-Low Improver (9%), Medium Decliner (7.7%), Mid-High Maintainer (22.8%), and High Maintainer (57.5%). Cross-classification of the groups of trajectories demonstrated that the impact of a high and stable EF on PSF might be greater than the reverse. Low depression symptoms, low pain, and high social support were the most consistent predictors of high EF trajectories.

CONCLUSION

Aging women are heterogeneous in terms of positive aging indicators for up to 9 years of follow-up. Interventions aimed at promoting sustainable EF might have diffused effects on other domains of healthy aging.

Sexual and general offending trajectories of men referred for civil commitment

Policies aimed at managing high-risk offenders, which include sex offenders, often assume they are a homogeneous population. These policies also tend to assume the pattern of offending is the same for all sex offenders, and is stable. This study challenges these assumptions by examining the life course offending trajectories of 780 convicted adult male sexual offenders. The men were referred to the Massachusetts Treatment Center for civil commitment between 1959 and 1984. The changing number of both sexual and any offenses were examined by age using Group-Based Trajectory Modeling. We identified a four-trajectory model for all offending and a four-trajectory model for sexual offending. The identified groups varied in several offending patterns including criminal onset, length of criminal careers, age of peak offending, and time of entry into the treatment center. Late adult onset of sex offending was found to be associated with child molestation, whereas early-onset trajectories were associated with rape. Implications for future research and policy are discussed.

Dietary pattern trajectories during 15 years of follow-up and HbA1c, insulin resistance and diabetes prevalence among Chinese adults

BACKGROUND

Most research on dietary patterns and health outcomes does not include longitudinal exposure data. We used an innovative technique to capture dietary pattern trajectories and their association with haemoglobin A1c (HbA1c), homeostasis model of insulin resistance (HOMA-IR) and prevalence of newly diagnosed diabetes.

METHODS

We included 4096 adults with 3-6 waves of diet data (1991-2006) and biomarkers measured in 2009 from the China Health and Nutrition Survey. Diet was assessed with three 24-h recalls and a household food inventory. We used a dietary pattern previously identified with reduced rank regression that positively predicted diabetes in 2006 (high in wheat products and soy milk and low in rice, legumes, poultry, eggs and fish). We estimated a score for this dietary pattern for each subject at each wave. Using latent class trajectory analysis, we grouped subjects with similar dietary pattern score trajectories over time into five classes.

RESULTS

Three trajectory classes were stable over time, and in two classes the diet became unhealthier over time (upward trend in dietary pattern score). Among two classes with similar scores in 2006, the one with the lower (healthier) initial score had an HbA1c 1.64% lower (-1.64 (95% CI -3.17 to -0.11)) and non-significantly a HOMA-IR 6.47% lower (-6.47 (-17.37 to 4.42)) and lower odds of diabetes (0.86 (0.44 to 1.67)).

CONCLUSIONS

Our findings suggest that dietary pattern trajectories with healthier scores longitudinally had a lower HbA1c compared with those with unhealthier scores, even when the trajectories had similar scores in the end point.

Maternal depressive symptoms: associations with adolescents' internalizing and externalizing problems and social competence

BACKGROUND

The negative effect of maternal depressive symptoms on child wellbeing has been quite extensively studied. There is, however, debate as to whether it is the timing, the recurrence or the chronicity of maternal depressive symptoms that puts the child's wellbeing at risk.

AIMS

This study explores the associations between the timing, recurrence and the patterns of maternal depressive symptoms and adolescent psychosocial functioning.

METHODS

One hundred and ninety-one mothers and 192 adolescents were followed up from the mother's pregnancy to the child's adolescence. Maternal depressive symptoms were screened with the Edinburgh Postnatal Depression Scale prenatally, postnatally, in early and middle childhood, and at adolescence. The adolescents' outcomes were screened using Child Behavior Checklists and Youth Self Reports.

RESULTS

The results indicate that the initial exposure to maternal depressive symptoms at pregnancy is associated with more externalizing problems in adolescence, 2 months postnatally with more internalizing problems, in early childhood with poorer social competence and concurrently with more externalizing problems. Combined analyses indicate that recurrent maternal depressive symptoms best explain adolescents' internalizing problems and the chronic pattern of maternal depressive symptoms externalizing problems. The chronic and intermittent patterns of maternal depressive symptoms best explained adolescents' poorer social competence.

CONCLUSIONS

Recurrent or chronic maternal depressive symptoms rather than the timing predict adolescents' psychosocial problems better. The timing, however, may explain the different kinds of problems in adolescence depending on the developmental task at the time of the exposure. The findings should be noted when treating both mothers and children in psychiatric clinics and other health services.