A warmer climate impairs the growth performance of Central Europe's major timber species in lowland regions.

Recent hot droughts have caused tree vitality decline and increased mortality in many forest regions on earth. Most of Central Europe's important timber species have suffered from the extreme 2018/2019 hot drought, confronting foresters with difficult questions about the choice of more drought- and heat-resistant tree species. We compared the growth dynamics of European beech, sessile oak, Scots pine and Douglas fir in a warmer and a cooler lowland region of Germany to explore the adaptive potential of the four species to climate warming (24 forest stands). The basal area increment (BAI) of the two conifers has declined since about 1990-2010 in both regions, and that of beech in the warmer region, while oak showed positive BAI trends. A 2 °C difference in mean temperatures and a higher frequency of hot days (temperature maximum >30 °C) resulted in greater sensitivity to a negative climatic water balance in beech and oak, and elevated sensitivity to summer heat in Douglas fir and pine. This suggests to include hot days in climate-growth analyses. Negative pointer years were closely related to dry years. Nevertheless, all species showed growth recovery within one to three years. We conclude that all four species are sensitive to a deteriorating climatic water balance and hot temperatures, and have so far not been able to successfully acclimate to the warmer climate, with especially Douglas and beech, but also Scots pine, being vulnerable to a warming and drying climate.

A person-centered approach to characterizing longitudinal ambulatory impairment in Parkinson's disease.

Loss of ambulation is common and highly variable in Parkinson's disease (PD), and poorly understood from the perspectives of those with PD. Gaining insights to the anticipated perceived trajectories and their drivers, will facilitate patient-centered care. Latent class growth analysis, a person-centered mixture modelling approach, was applied to 16,863 people with PD stratified by early (N = 8612; < 3 years), mid (N = 6181; 3-10 years) and later (N = 2070; > 10 years) disease to discern clusters with similar longitudinal patterns of self-reported walking difficulty, measured by EuroQoL 5D-5L that is validated for use in PD. There were four clusters in early and mid-disease strata, with a fifth identified in later disease. Trajectories ranged from none to moderate walking difficulty, with small clusters with severe problems. The percentage of subjects with moderate (early = 17.5%, mid = 26.4%, later = 32.5%) and severe (early = 3.8%, mid = 7.4%, later = 15.4%) walking difficulty at baseline increased across disease duration groups. The trajectories tended to be stable with variability in moderate and severe groups. Across strata, clusters with moderate to severe problems were associated with more severe impairment, depression, anxiety, arthritis, higher BMI, lower income, and lower education, but no consistent race or gender differences. The findings reveal distinct longitudinal patterns in perceived difficulties in walking in PD.

Morphophysiological Characterisation of Guayule (Parthenium argentatum A. Gray) in Response to Increasing NaCl Concentrations: Phytomanagement and Phytodesalinisation in Arid and Semiarid Areas.

Water and soil salinity continuously rises due to climate change and irrigation with reused waters. Guayule (Parthenium argentatum A. Gray) is a desert perennial shrub native to northern Mexico and the southwestern United States; it is known worldwide for rubber production and is suitable for cultivation in arid and semiarid regions, such as the Mediterranean. In the present study, we investigated the effects of high and increasing concentrations of sodium chloride (NaCl) on the growth and the morphophysiological and biochemical characteristics of guayule to evaluate its tolerance to salt stress and suitability in phytomanagement and, eventually, the phytodesalinisation of salt-affected areas. Guayule originates from desert areas, but has not been found in salt-affected soils; thus, here, we tested the potential tolerance to salinity of this species, identifying the toxicity threshold and its possible sodium (Na) accumulation capacity. In a hydroponic floating root system, guayule seedlings were subjected to salinity-tolerance tests using increasing NaCl concentrations (from 2.5 to 40 g L-1 and from 43 to 684 mM). The first impairments in leaf morphophysiological traits appeared after adding 15 g L-1 (257 mM) NaCl, but the plants survived up to the hypersaline conditions of 35-40 g L-1 NaCl (about 600 mM). The distribution of major cell cations modulated the high Na content in the leaves, stems and roots; Na bioconcentration and translocation factors were close to one and greater than one, respectively. This is the first study on the morphophysiological and (bio)chemical response of guayule to different high and increasing levels of NaCl, showing the parameters and indices useful for identifying its salt tolerance threshold, adaptative mechanisms and reclamation potential in high-saline environments.

Solitary foundation or colony fission in ants: an intraspecific study shows that worker presence and number increase colony foundation success.

Dispersal and establishment strategies are highly variable. Each strategy is associated with specific costs and benefits, and understanding which factors favour or disfavour a strategy is a key issue in ecology and evolution. Ants exhibit several strategies of establishment, i.e. of colony foundation. Some species rely on winged queens that found new colonies alone when others found with accompanying workers (colony fission). The benefits conferred by these workers have been little studied and quantified, because comparing the costs and benefits of solitary foundation vs. colony fission is difficult when comparing different species. We investigated this using the ant Myrmecina graminicola, one of the few species that use both strategies. Young mated queens were allowed to found new colonies in the laboratory, with either zero (solitarily), two or four workers (colony fission). The presence of workers increased both survival and growth of the foundations over the first year, with more workers yielding higher growth. Few workers (as little as two workers) were sufficient to provide benefits, suggesting that in M. graminicola the strategy of colony fission may not dramatically decrease the number of new colonies produced compared to solitary foundation. Because queens performing solitary foundation or colony fission differ in dispersal (by flight vs. on foot), our results support the hypothesis that these two strategies of foundation coexist along a competition-colonization trade-off, where solitary foundation offers a colonization advantage, while colony fission has a competitive advantage.

Salt Tolerance of Sea Flax (Linum maritimum L.), a Rare Species with Conservation Interest in Eastern Spain.

Seldom found in saltmarshes, Linum maritimum is a halophyte of great conservation interest in the eastern Iberian Peninsula. Although the species has been reported in different plant communities, there is no information on its range of salinity tolerance or mechanisms of response to environmental stress factors. In this study, L. maritimum plants were subjected to increasing salt concentrations in controlled conditions in a greenhouse. After six months of watering with salt solutions, only plants from the control, 50 mM and 100 mM NaCl treatment groups survived, but seeds were produced only in the first two. Significant differences were found between the plants from the various treatment groups in terms of their growth parameters, such as plant height, fresh weight, and the quantity of flowers and fruits. The main mechanism of salt tolerance is probably related to the species' ability to activate K+ uptake and transport to shoots to partly counteract the accumulation of toxic Na+ ions. A biochemical analysis showed significant increases in glycine betaine, flavonoids and total phenolic compounds, highlighting the importance of osmotic regulation and antioxidant compounds in the salt tolerance of Linum maritimum. These findings have implications for the conservation of the species, especially under changing climatic conditions that may lead to increased soil salinity in its Mediterranean distribution area.

Longitudinal trajectories of substance use disorder treatment use: A latent class growth analysis using a national cohort in Chile.

BACKGROUND AND AIMS: Longitudinal studies have revealed that substance use treatment use is often recurrent among patients; the longitudinal patterns and characteristics of those treatment trajectories have received less attention, particularly in the global south. This study aimed to disentangle heterogeneity in treatment use among adult patients in Chile by identifying distinct treatment trajectory groups and factors associated with them. DESIGN: National-level registry-based retrospective cohort. SETTING AND PARTICIPANTS: Adults admitted to publicly funded substance use disorder treatment programs in Chile from November 2009 to November 2010 and followed for 9 years (n = 6266). MEASUREMENTS: Monthly treatment use; type of treatment; ownership of the treatment center; discharge status; primary substance used; sociodemographic. FINDINGS: A seven-class treatment trajectory solution was chosen using latent class growth analysis. We identified three trajectory groups that did not recur and had different treatment lengths: Early discontinuation (32%), Less than a year in treatment (19.7%) and Year-long episode, without recurrence (12.3%). We also identified a mixed trajectory group that had a long first treatment or two treatment episodes with a brief time between treatments: Long first treatment, or immediate recurrence (6.3%), and three recurrent treatment trajectory groups: Recurrent and decreasing (14.2%), Early discontinuation with recurrence (9.9%) and Recurrent after long between treatments period (5.7%). Inpatient or outpatient high intensity (vs. outpatient low intensity) at first entry increased the odds of being in the longer one-episode groups compared with the Early discontinuation group. Women had increased odds of belonging to all the recurrent groups. Using cocaine paste (vs. alcohol) as a primary substance decreased the odds of belonging to long one-episode groups. CONCLUSIONS: In Chile, people in publicly funded treatment for substance use disorder show seven distinct care trajectories: three groups with different treatment lengths and no recurring episodes, a mixed group with a long first treatment or two treatment episodes with a short between-treatment-episodes period and three recurrent treatment groups.

What makes children aged 10 to 13 engage in problematic smartphone use? A longitudinal study of changing patterns considering individual, parental, and school factors.

Background and aims: The current research aimed to discover classification concerning problematic smartphone use in children. Furthermore, to investigate their longitudinal trajectories, as well as to discover the connection concerning problematic smartphone usage by individual, parental, and school factors. Methods: A total of 2,399 South Korean children who were in the 4th grade (female 1,206 (50.3%), age 10-13 years) at baseline. Latent class growth analysis was utilized to discover typologies in problematic smartphone use and their longitudinal trajectories. Multinomial logistic regression analysis was used to find various associations among problematic smartphone use and individual, parental, as well as school factors. Results: The results identified three distinct trajectories of problematic smartphone use: (1) a high-level group (7.7%), (2) a mid-increasing group (62.5%), and (3) a low-increasing group (29.8%). The increasing group showed the highest level of problematic smartphone use. Gender, self-esteem, social withdrawal, exercise, parental inconsistency, monthly income, and teacher support were significant predictors. Discussion and Conclusions: The findings suggest that there are distinct developmental trajectories concerning problematic smartphone usage of childhood. The results show that the early discovery of children in danger of problematic smartphone use and targeted interventions aimed at reducing parental inconsistency and social withdrawal, improving self-esteem, exercise, and teacher support may be effective strategies for preventing problematic smartphone usage during childhood.

Three-dimensional fruit growth analysis clarifies developmental mechanisms underlying complex shape diversity in persimmon fruit.

The determination of fruit size and shape are of considerable interest in horticulture and developmental biology. Fruit typically exhibits three-dimensional structures characterized by geometric features that are dependent on the genotype. Although minor developmental variations have been recognized, few studies have fully visualized and measured these variations throughout fruit growth. Here, a high-resolution 3D scanner was used to investigate the fruit development of 51 persimmon (Diospyros kaki) cultivars with various complex shapes. We obtained 2380 3D models that fully represented fruit appearance, and enabled precise and automated measurements of shape features throughout fruit development, including horizontal and vertical grooves, length-to-width ratio, and roundness. The 3D fruit model analysis identified key stages that determined the shape attributes at maturity. Typically, genetic diversity was found in vertical groove development, and these grooves could be filled by tissue expansion in the carpel fusion zone during fruit development. In addition, transcriptome analysis of fruit tissues from groove and non-groove tissues revealed gene co-expression networks that were highly associated with groove depth variation. The presence of YABBY homologs was most closely associated with groove depth and indicated the possibility that this pathway is a key molecular contributor to vertical groove depth variation. Overall, our results revealed deterministic patterns of complex shape traits in persimmon fruit and showed that different growth patterns among tissues are the main factor contributing to the shape of both vertical and horizontal grooves.

A multi-population approach supports common patterns in marine growth and maturation decision in Atlantic salmon (Salmo salar L.) from southern Europe.

This study provides a regional picture of long-term changes in Atlantic salmon growth at the southern edge of their distribution, using a multi-population approach spanning 49 years and five populations. We provide empirical evidence of salmon life history being influenced by a combination of common signals in the marine environment and population-specific signals. We identified an abrupt decline in growth from 1976 and a more recent decline after 2005. As these declines have also been recorded in northern European populations, our study significantly expands a pattern of declining marine growth to include southern European populations, thereby revealing a large-scale synchrony in marine growth patterns for almost five decades. Growth increments during their sea sojourn were characterized by distinct temporal dynamics. At a coarse temporal resolution, growth during the first winter at sea seemed to gradually improve over the study period. However, the analysis of finer seasonal growth patterns revealed ecological bottlenecks of salmon life histories at sea in time and space. Our study reinforces existing evidence of an impact of early marine growth on maturation decision, with small-sized individuals at the end of the first summer at sea being more likely to delay maturation. However, each population was characterized by a specific probabilistic maturation reaction norm, and a local component of growth at sea in which some populations have better growth in some years might further amplify differences in maturation rate. Differences between populations were smaller than those between sexes, suggesting that the sex-specific growth threshold for maturation is a well-conserved evolutionary phenomenon in salmon. Finally, our results illustrate that although most of the gain in length occurs during the first summer at sea, the temporal variability in body length at return is buffered against the decrease in post-smolt growth conditions. The intricate combination of growth over successive seasons, and its interplay with the maturation decision, could be regulating body length by maintaining diversity in early growth trajectories, life histories, and the composition of salmon populations.

Memory Trajectories and Disability Among Older Couples: The Mediating Role of Depressive Symptoms.

OBJECTIVES: Using a dyadic approach, this study examined the mediating effect of depressive symptoms on the longitudinal relationships between husbands' and wives' memory trajectories and their prospective disability status. METHODS: Longitudinal data from the Health and Retirement Study 2004-2018 were used. Older (aged 50+) heterosexual couples who had no limitations in the activity of daily living at the baseline (2004) were included (N = 1,310). Latent class growth analysis grouped wives and husbands into distinct memory trajectories in 2004-2014. A structural equation model examined the actor and partner effects of memory trajectories on depressive symptoms in 2016 and disability status in 2018. The mediating effect of depressive symptoms was tested. RESULTS: A total of 4 distinct memory trajectories were found: persistently high, high and slow decline, moderate and slow decline, and low and rapid decline. Only the wife's low and rapid decline memory trajectory predicted her own more depressive symptoms (ß = 0.588, 95% CI: 0.209, 0.967) and her husband's more depressive symptoms (ß = 0.326, 95% CI: 0.004, 0.648). Meanwhile, depressive symptoms had strong and significant actor effects on disability (ß = 0.046, 95% CI: = 0.036, 0.057 for wives; ß = 0.060, 95% CI: = 0.046, 0.074 for husbands). DISCUSSION: The wife's low and rapid decline trajectory was associated with her own and her husband's more depressive symptoms, which in turn increased the disability risk for both partners. Timely identification and treatment of memory decline among wives have the potential to mitigate couples' depressive symptoms and, ultimately, disability risks.

Role of DEAD-box RNA helicases in low-temperature adapted growth of Antarctic Pseudomonas syringae Lz4W.

IMPORTANCE: RNA metabolism is important as RNA acts as a link between genomic information and functional biomolecules, thereby playing a critical role in cellular response to environment. We investigated the role of DEAD-box RNA helicases in low-temperature adapted growth of P. syringae, as this group of enzymes play an essential role in modulation of RNA secondary structures. This is the first report on the assessment of all major DEAD-box RNA helicases in any Antarctic bacterium. Of the five RNA helicases, three (srmB, csdA, and dbpA) are important for the growth of the Antarctic P. syringae at low temperature. However, the requisite role of dbpA and the indispensable requirement of csdA for low-temperature adapted growth are a novel finding of this study. Growth analysis of combinatorial deletion strains was performed to understand the functional interaction among helicase genes. Similarly, genetic complementation of RNA helicase mutants was conducted for identification of gene redundancy in P. syringae.

Trajectories of depressive symptoms in young and middle-aged men who have sex with men with new HIV-diagnosis: a 1-year prospective cohort study in Beijing, China.

Introduction: Due to the sexual orientation and HIV diagnosis, young and middle-aged men who have sex with men (MSM) with new HIV-diagnosis may experience more depressive syndromes and face greater psychological stress. The study explored trajectories of depressive symptoms of young and middle-aged MSM within 1 year after new HIV-diagnosis and analyze the related factors. Methods: From January 2021 to March 2021, 372 young and middle-aged MSM who were newly diagnosed as HIV-infection were recruited in two hospitals in Beijing. Self-rating Depression Scale was used to measure the participants' depressive symptom in 1st month, 3rd month, 6th month, 9th month and 12th month after HIV diagnosis. The latent class growth model was used to identify trajectories of the participants' depressive symptoms. Multinomial logistic regression was used to analyse factors related with the trajectories. Results: Three hundred and twenty-eight young and middle-aged MSM with new HIV-diagnosis completed the research. Depressive symptom in 328 young and middle-aged MSM was divided into three latent categories: non-depression group (56.4%), chronic-mild depression group (28.1%), and persistent moderate-severe depression group (15.5%). The participants assessed as non-depression (non-depression group) or mild depression (chronic-mild depression group) at the baseline were in a non-depression state or had a downward trend within one-year, and the participants assessed as moderate and severe depression (persistent moderate-severe depression group) at the time of diagnosis were in a depression state continuously within 1-year. Multinomial logistic regression analysis showed that, compared with the non-depression group, monthly income of 5,000 ~ 10,000 RMB (equal to 690 ~ 1,380 USD) was the risk factor for the chronic-mild depression group, and self-rating status being fair/good and self-disclosure of HIV infection were protective factors for the persistent moderate-severe depression group while HIV-related symptoms was the risk factor. Conclusion: Depressive symptoms in young and middle-aged MSM is divided into three latent categories. Extra care must be given to young and middle-aged MSM assessed as moderate or severe depression at the time of HIV-diagnosis, especially to those who had poor self-rating health status, did not tell others about their HIV-infection and experienced HIV-related symptoms.

Trajectories and determinants of acute stress disorder during the COVID-19 centralized quarantine: A latent class growth analysis.

COVID-19 centralized quarantine may cause acute stress disorder (ASD). However, it is unknown how individuals present heterogeneous ASD trajectories during the COVID-19 centralized quarantine and what factors contribute to these patterns. This study aimed to identify the ASD trajectories and their determinants during the centralized quarantine period, and the mediating effects of resilience on these associations. A longitudinal survey with three waves was conducted in a randomly selected quarantine hotel in Shenzhen, China from October to November 2020. A total of 273 participants completed online measures assessing ASD symptoms, Eysenck's personality constructs of extraversion (E), neuroticism (N), psychoticism (P), and resilience on Day 1, and reported ASD symptoms on Days 7 and 14 during their 14-day centralized quarantine periods. Latent class growth analysis identified three trajectories: constantly high symptoms (CHS, 4.76%), decreasing symptoms (DS, 11.72%), and constantly low symptoms (CLS, 83.52%). The CHS and DS subgroups both reported lower E and higher N scores, but not P, compared with the CLS subgroup. Resilience mediated the effects of three personality constructs on ASD trajectories, except for the association between N and DS membership. Our study highlights the heterogeneity in stress responses to the COVID-19 centralized quarantine. The high-risk subgroup with persistent ASD symptoms was characterized by lower E and higher N. The resilience process accounted for the effects of personality in shaping distinct ASD trajectories. Our findings have implications to detect the populations vulnerable to ASD and provide insights for developing timely resilience enhancement intervention programs.

Physical activity and transitioning to retirement: evidence from the China health and retirement longitudinal study.

BACKGROUND: The impact of retirement on physical activity among older individuals remains ambiguous. This study aims to investigate the influence of retirement on physical activity and delineate the trajectories of physical activity changes during the retirement transition among elderly Chinese residents. Additionally, we endeavor to examine the factors that contribute to each trajectory. METHODS: This longitudinal cohort study used data from four surveys of the China Health and Retirement Longitudinal Study and included a sample of 428 individuals who underwent formal retirement and provided information on physical activity. We employed generalized estimating equation to explore the impact of the retirement transition on physical activity among Chinese older adults. Latent class growth analysis was used to identify distinct trajectories of physical activity, and binary logistic regression was performed to identify pre-retirement factors influencing changes in physical activity. RESULTS: Our findings indicate that retirement can lead to a decline in physical activity among older Chinese residents (OR = 0.85, 95%CI 0.75 ~ 0.97). We identified three distinct trajectories of physical activity during the retirement transition: Trajectory 1 - "sustained low level of physical activity" (7.94%); Trajectory 2 - "middle level of physical activity with gradual decline" (69.16%); Trajectory 3 - "sustained high level of physical activity with significant fluctuations" (22.90%). Furthermore, we discovered that individuals in the "middle level of physical activity and gradual decline" trajectory were more likely to have an annual income exceeding 40,000 yuan (OR = 9.69, 95%CI 1.12 ~ 83.63), reside in urban areas (OR = 2.27, 95%CI 1.14 ~ 4.52), and have a fondness for playing Mahjong (OR = 2.42, 95%CI 1.18 ~ 5.00) compared to those in the "sustained high level of physical activity with significant fluctuations" trajectory. Additionally, having an annual income exceeding 40,000 yuan (OR = 19.67, 95%CI 1.30 ~ 298.61) predicted membership in the "sustained low level of physical activity" trajectory when compared to the "sustained high level of physical activity with significant fluctuations" trajectory. CONCLUSION: Retirement represents a substantial milestone in the life course and is associated with notable alterations in physical activity patterns. Among older Chinese residents, the trajectories of physical activity during the retirement transition exhibit diverse paths and are influenced by pre-retirement factors, including annual income, residential location, and hobbies. The findings of this study have important implications for the formulation of policies aimed at promoting healthy aging among individuals approaching retirement age.

Trajectories of cognitive reactivity and its predictive value on postpartum depression in Chinese women: a latent class growth modeling analysis.

Many women are experiencing postpartum depression (PPD) after giving birth. How to recognize and intervene in high-risk PPD women early and effectively remains unknown. Our objective is to describe the latent trajectory groups of cognitive reactivity (CR) in perinatal women, and their relationship to demographic and disease-related factors, as well as investigate the associations with PPD. Data from 321 perinatal women who were evaluated in urban tertiary hospitals in China at three-time points: 32-35 weeks of pregnancy, 1 week postpartum, and 6 weeks postpartum. Latent class growth modeling was used to identify the trajectory patterns of CR and logistic regression was used to explore the association between demographic and disease-related factors, CR trajectories, and depression. Three trajectory groups were identified: the continuing deterioration group (17.2%), the postpartum deterioration group (22.1%), and the consistent resilient group (60.7%). Participants with a bachelor's degree or higher and with gestational diabetes diagnosis were more likely to be in the continuing deterioration group. Those who were from only-child families were more likely to be in the postpartum deterioration group. Women in the continuing deterioration group and postpartum deterioration group were more likely to experience PPD. Targeted interventions should be developed based on trajectory group of CR.

Trends in output of hypertension management and associated factors in primary care facilities: a latent trajectory analysis in China from 2009 to 2017.

BACKGROUND: The prevalence of hypertension is high (25.2% in 2012) and there were a large number of patients with hypertension (more than 200 million) in China. Township health centres in rural areas and community health centres in urban areas are responsible for hypertension management. This study aims to identify trends in hypertension management output and related facility-level, geographical and economic factors in primary care facilities and to assess the effect of the national project of basic public health services in China from 2009 to 2017. METHODS: A cross-sectional survey (2018) was combined with retrospective data collection (2009-2017) from 685 primary care facilities in six provinces in China. The hypertension management output was indicated by the number of patients with hypertension under management per 10,000 population. Latent class growth analysis and group-based trajectory models were applied to classify trajectories and determine associations with facility-level, geographic and economic characteristics. RESULTS: The trend in the output increased rapidly from 2009 to 2012 with an average growth rate of 54.58% and slowed down from 2012 to 2017 (growth rate of 5.94%). Five trajectories of the output were identified and labelled according to baseline status and increase rates: low-gradually increasing (16.9%), middle-slightly increasing (16.2%), low-sharply increasing (7.9%), middle-sharply increasing (34.2%) and persistently high (24.9%). The time-stable characteristics, including region (eastern, central or western), district (urban or rural), landform, were associated with hypertension management output of the facilities. Number of public health physicians was a significant time-dependent characteristic influencing management output. CONCLUSIONS: Five latent trajectories of hypertension management output were identified. The output was still at a low level compared with the prevalence of hypertension. Hypertension screening in young people need to be emphasized. Facilities are recommended to establish good relationships with residents for better hypertension management outcomes especially in urban areas.

Marginal structural models with latent class growth analysis of treatment trajectories: Statins for primary prevention among older adults.

Latent class growth analysis is increasingly proposed as a solution to summarize the observed longitudinal treatment into a few distinct groups. When latent class growth analysis is combined with standard approaches like Cox proportional hazards models, confounding bias is not properly addressed because of time-varying covariates that have a double role of confounders and mediators. We propose to use latent class growth analysis to classify individuals into a few latent classes based on their medication adherence pattern, then choose a working marginal structural model that relates the outcome to these groups. The parameter of interest is defined as a projection of the true marginal structural model onto the chosen working model. Simulation studies are used to illustrate our approach and compare it with unadjusted, baseline covariates adjusted, time-varying covariates adjusted, and inverse probability of trajectory groups weighted adjusted models. Our proposed approach yielded estimators with little or no bias and appropriate coverage of confidence intervals in these simulations. We applied our latent class growth analysis and marginal structural model approach to a database comprising information on 52,790 individuals from the province of Quebec, Canada, aged more than 65 and who were statin initiators to estimate the effect of statin-usage trajectories on a first cardiovascular event.

Analysis of heterogeneous growth changes in longitudinal height of children.

BACKGROUND: There have been methodologies developed for a wide range of longitudinal data types; nevertheless, the conventional growth study is restricted if individuals in the sample have heterogeneous growth trajectories across time. Using growth mixture modeling approaches, we aimed to investigate group-level heterogeneities in the growth trajectories of children aged 1 to 15 years. METHOD: This longitudinal study examined group-level growth heterogeneities in a sample of 3401 males and 3200 females. Data were analyzed using growth mixture modeling approaches. RESULTS: We examined different trajectories of growth change in children across four low- and middle-income countries using a data-driven growth mixture modeling technique. The study identified two-group trajectories: the most male samples group (n = 4260, 69.7%) and the most female samples group (n = 2341, 81.6%). The findings show that the two groups had different growth trajectories. Gender and country differences were shown to be related to growth factors; however, the association varied depending on the trajectory group. In both latent groups, females tended to have lower growth factors (initial height and rate of growth) than their male counterparts. Compared with children from Ethiopia, children from Peru and Vietnam tended to exhibit faster growth in height over time: In contrast, children from India showed a lower rate of change in both latent groups than that of children from Ethiopia. CONCLUSIONS: The height of children in four low- and middle-income countries showed heterogeneous changes over time with two different groups of growth trajectories.

Long-term trajectories of ambulatory impairment in multiple sclerosis.

BACKGROUND: Ambulatory impairment is a common and complex manifestation of multiple sclerosis (MS), and longitudinal patterns are not well understood. OBJECTIVE: To characterize longitudinal walking speed trajectories in a general MS patient population and in those with early disease (⩽ 5 years from onset), identify subgroups with similar patterns, and examine associations with individual attributes. METHODS: Using a retrospective cohort study design, latent class growth analysis was applied to longitudinal timed 25-foot walk (T25-FW) data from 7683 MS patients, to determine T25-FW trajectories. Associations were evaluated between trajectory assignment and individual attributes. Analyses were repeated for 2591 patients with early disease. RESULTS: In the general patient population, six trajectories were discerned, ranging from very minimal to very high impairment at baseline, with variability in impairment accrual. The clusters with moderate to very high walking impairment were associated with being female, older and Black American, longer symptom duration, progressive course, and depressive symptoms. In the early disease subset, eight trajectories were discerned that included two subgroups that rapidly accrued impairment. CONCLUSION: We identified novel subgroups of MS patients will distinct long-term T25-FW trajectories. These results underscore that socially disadvantaged and economically marginalized MS patients are the most vulnerable for severe ambulatory impairment.

Child abuse and individual traits related to developmental trajectories of bullying victimization: An integrated, multitheoretical approach.

INTRODUCTION: Adolescents who experience prior victimization such as child abuse within the home and experience low self-esteem/depression are at higher risk of repetitive bullying victimization when compared to those without such experiences. Recent scholarship has explored growth trajectories of bullying during adolescent development; however, relatively little is known about distinct trajectory patterns of bullying victimization across adolescent development. The current study identifies unobserved subgroups thus capturing the heterogeneity in developmental pathways in bullying victimization. METHOD: The current study uniquely utilized a multitheoretical approach to help explain the phenomenon of bullying victimization among a national sample of 2,190 youth in South Korea from 2010 to 2016. Theories tested include the integrated approach of target congruence, lifestyle and routine activities theories (LRAT), and the state dependence and population heterogeneity perspectives. To conduct this analysis, we performed a three-step latent class growth analysis. RESULTS: The study revealed three distinct trajectory groups. Korean adolescents who had higher levels of low self-esteem demonstrated greater odds of belonging to both the early-onset and decreasing and increasing and late peak groups. Those who had low-self-esteem and were depressed demonstrated greater odds of belonging to the early-onset and decreasing group. Prior experience of child abuse for the early-onset and decreasing group was fully mediated by the measures of target congruence and lifestyles. CONCLUSION: The current study contributes to research on developmental victimization by demonstrating the utility of integrating target congruence variables with lifestyle-routine activity concepts in explaining heterogeneity.