Traffic-Calming Measures and Road Traffic Collisions and Injuries: A Spatiotemporal Analysis

Traffic-calming measures (TCMs) are physical modifications of the road network aimed at making the roads safer. Although researchers have reported reductions in numbers of road crashes and injuries tied to the presence of TCMs, such studies have been criticized for their pre-/post- designs. In this study, we aimed to complement our knowledge of TCMs' effectiveness by assessing their impact using a longitudinal design. The implementation of 8 TCMs, including curb extensions and speed humps, was evaluated at the intersection and census tract levels in Montreal, Quebec, Canada, from 2012 to 2019. The primary outcome was fatal or serious collisions among all road users. Inference was performed using a Bayesian implementation of conditional Poisson regression in which random effects were used to account for the spatiotemporal variation in collisions. TCMs were generally implemented on local roads, although most collisions occurred on arterial roads. Overall, there was weak evidence that TCMs were associated with study outcomes. However, subgroup analyses of intersections on local roads suggested a reduction in collision rates due to TCMs (median incidence rate ratio, 0.31; 95% credible interval: 0.12, 0.86). To improve road safety, effective counterparts of TCMs on arterial roads must be identified and implemented.

The complex story of educational identity in adolescence: Longitudinal relations with academic achievement and perfectionism

OBJECTIVE

Education has a strong impact on adolescent development. This study investigated the complex longitudinal associations between educational identity processes, academic achievement, and perfectionism.

METHOD

The study used a 4-wave design (N = 744 adolescents, M_age = 15.2 years, 55% girls).

RESULTS

Results showed that self-oriented perfectionism mediated the longitudinal relation between academic achievement and educational commitment, whereas educational commitment mediated the longitudinal relation between self-oriented perfectionism and academic achievement. Also, a unidirectional positive direct link from educational in-depth exploration to socially prescribed perfectionism was found, while self-oriented perfectionism mediated the positive relationship between academic achievement and exploration. Finally, higher academic achievement led to decreases in educational reconsideration of commitment, whereas socially prescribed perfectionism predicted increases in educational reconsideration of commitment and decreases in academic achievement.

CONCLUSIONS

These findings bring forward the intricate and possibly sabotaging links between educational identity processes, academic achievement, and perfectionism.

Severe COVID-19 and non-COVID-19 severe sepsis converge transcriptionally after a week in the intensive care unit, indicating common disease mechanisms

Introduction

Severe COVID-19 and non-COVID-19 pulmonary sepsis share pathophysiological, immunological, and clinical features. To what extent they share mechanistically-based gene expression trajectories throughout hospitalization was unknown. Our objective was to compare gene expression trajectories between severe COVID-19 patients and contemporaneous non-COVID-19 severe sepsis patients in the intensive care unit (ICU).

Methods

In this prospective single-center observational cohort study, whole blood was drawn from 20 COVID-19 patients and 22 non-COVID-19 adult sepsis patients at two timepoints: ICU admission and approximately a week later. RNA-Seq was performed on whole blood to identify differentially expressed genes and significantly enriched pathways.

Results

At ICU admission, despite COVID-19 patients being almost clinically indistinguishable from non-COVID-19 sepsis patients, COVID-19 patients had 1,215 differentially expressed genes compared to non-COVID-19 sepsis patients. After one week in the ICU, the number of differentially expressed genes dropped to just 9 genes. This drop coincided with decreased expression of antiviral genes and relatively increased expression of heme metabolism genes over time in COVID-19 patients, eventually reaching expression levels seen in non-COVID-19 sepsis patients. Both groups also had similar underlying immune dysfunction, with upregulation of immune processes such as "Interleukin-1 signaling" and "Interleukin-6/JAK/STAT3 signaling" throughout disease compared to healthy controls.

Discussion

Early on, COVID-19 patients had elevated antiviral responses and suppressed heme metabolism processes compared to non-COVID-19 severe sepsis patients, although both had similar underlying immune dysfunction. However, after one week in the ICU, these diseases became indistinguishable on a gene expression level. These findings highlight the importance of early antiviral treatment for COVID-19, the potential for heme-related therapeutics, and consideration of immunomodulatory therapies for both diseases to treat shared immune dysfunction.

Conceptualizing and Examining Change in Communication Research

Communication research often focuses on processes of communication, such as how messages impact individuals over time or how interpersonal relationships develop and change. Despite their importance, these change processes are often implicit in much theoretical and empirical work in communication. Intensive longitudinal data are becoming increasingly feasible to collect and, when coupled with appropriate analytic frameworks, enable researchers to better explore and articulate the types of change underlying communication processes. To facilitate the study of change processes, we (a) describe advances in data collection and analytic methods that allow researchers to articulate complex change processes of phenomena in communication research, (b) provide an overview of change processes and how they may be captured with intensive longitudinal methods, and (c) discuss considerations of capturing change when designing and implementing studies. We are excited about the future of studying processes of change in communication research, and we look forward to the iterations between empirical tests and theory revision that will occur as researchers delve into studying change within communication processes.

Work ability score as predictor of rehabilitation, disability pensions and death? A German cohort study among employees with back pain

BACKGROUND

Sickness absence, disability pensions, and use of healthcare due to disabling back pain are a high economic burden in Germany. Assessment are needed to identify employees who are likely to need intensive support.

OBJECTIVE

The cohort study examined whether rehabilitation, disability pensions and death can be predicted by a simple self-reported rating of work ability in employees with back pain in Germany.

METHODS

Employees aged 45 to 59 years who reported back pain in the last 3 months completed the Work Ability Score in 2017 (0-10 points). Individual scores were categorized into poor (0-5 points), moderate (6-7) and at least good (8-10) work ability. Outcomes were extracted from administrative records covering the period until the end of 2018. Proportional hazard models were fitted to determine the prognostic benefit of the Work Ability Score.

RESULTS

Data for 6,917 participants were included (57.8% women). The median follow-up time was 20 months. Of the participants, 52.1% had a good or excellent, 27.7% a moderate, and 20.2% a poor Work Ability Score. During follow-up, 548 persons were granted rehabilitation measures, 57 persons disability pensions, and 23 died. Fully adjusted analyses showed an increased risk of a rehabilitation measure (hazard ratio = 2.65; 95% CI 2.11; 3.34) and a disability pension (HR = 4.12; 95% CI 2.02; 8.39) in employees with poor work ability. A premature death was not associated with poor work ability.

CONCLUSIONS

The Work Ability Score is a potential tool to identify individuals, reporting back pain, with an increased risk of health-related early retirement and work disability.

Associations between childhood autistic traits and adolescent eating disorder behaviours are partially mediated by fussy eating

Objective

Previous literature shows an increased risk for eating disorders in autistic individuals. This study tested whether fussy eating contributes to the association between childhood autistic traits and adolescent eating disorder behaviours.

Method

Using data from the Avon Longitudinal Study of Parents and Children, we estimated the intercept and slope of parent‐rated autistic traits and fussy eating between 7 and 14 years (N = 8982) and their association with self‐reported eating disorder behaviours at age 14 years, including the indirect path from autistic traits to eating disorder behaviours via fussy eating. Analyses were adjusted for child sex, maternal age at delivery, maternal body mass index and maternal education.

Results

Analyses found a small indirect pathway from autistic traits intercept to eating disorder behaviours via fussy eating slope (b = 0.017, 95% CI = 0.002–0.032, p = 0.026), with higher levels of autistic traits at age 7 years being associated with a shallower decline in fussy eating, which in turn was associated with greater eating disorder behaviours.

Conclusion

Findings point towards fussy eating as a potential link between childhood autistic traits and later disordered eating. Addressing fussy eating patterns before they become entrenched may decrease risk for eating disorders later in development.

There is evidence that high levels of autistic traits are associated with an increased likelihood of experiencing an eating disorder.

The current study sought to test whether the link between autism and eating disorders could in part be explained by variation in fussy eating.

In a large prospective cohort study, we found a significant indirect effect of fussy eating, such that higher childhood autistic traits were associated with a shallower decline in fussy eating between childhood and adolescence, which in turn was associated with higher levels of eating disorder behaviours in adolescence.

Determinants of social health trajectories during the COVID-19 pandemic in older adults: the Rotterdam Study

OBJECTIVES

The coronavirus disease-2019 (COVID-19) pandemic and accompanying lockdown restrictions impacted social life significantly. We studied associations of sociodemographic factors, mental and social health markers, and brain structure with social health trajectories during the COVID-19 pandemic.

DESIGN

Prospective longitudinal population-based cohort study.

SETTING

Community-dwelling inhabitants of Rotterdam, the Netherlands.

PARTICIPANTS

Repeated questionnaires including questions on social health were sent to Rotterdam Study participants from April 2020 onwards. Social health data at study baseline were available for 5017 participants (mean age: 68.7 ± 11.3; 56.9% women).

MEASUREMENTS

Determinants were assessed in routine Rotterdam Study follow-up (1990-2020), including global brain volumes in a subset of participants (N = 1720). We applied linear mixed models and generalized estimating equations to quantify associations between determinants and trajectories of loneliness, perceived social isolation and social connectedness over three time points from April 22nd to July 31st 2020.

RESULTS

Loneliness prevalence was 27.9% in April 2020 versus 12.6% prepandemic. Social isolation (baseline mean 4.7 ± 2.4) and loneliness scores (baseline mean 4.9 ± 1.5) decreased over time, whereas social connectedness trajectories remained stable. Depressive symptoms, female sex, prepandemic loneliness, living alone, and not owning a pet were independently associated with lower social connectedness and higher social isolation and loneliness at COVID-19 baseline, but recovery of social health was similar for all determinants. Larger intracranial volume was associated with higher social connectedness.

CONCLUSIONS

Despite baseline differences for specific determinants, older adults showed similar recovery of loneliness and social isolation alongside stable social connectedness over time during the pandemic. Social health is multidimensional, especially during a global health crisis.

Uptake of Hearing Aids and Hearing Assistive Technology in a Working Population: Longitudinal Analyses of The Netherlands Longitudinal Study on Hearing

OBJECTIVE

To identify predictors of the 5-year uptake of hearing aids (HAs) and hearing assistive technology (HAT) in a sample of Dutch employees eligible for HAs and/or HAT. The potential predictors included demographic factors (age, sex, marital status, and living situation), education, hearing factors (ability to recognize speech in noise and self-reported hearing disability), distress, self-efficacy, and work-related factors (job demand, job control, and need for recovery).

DESIGN

Five-year follow-up data of the Netherlands Longitudinal Study on Hearing (NL-SH) collected until January 2019 were included. An online digit-triplet in noise test, the National Hearing Test (NHT), was used to assess speech-recognition-in-noise ability. In addition, online questionnaires on demographic, socioeconomic, self-reported hearing disability, health, and work-related characteristics were administered. Adults who worked over 12 hours per week, who had not yet taken up HAs or HAT, but who would be eligible for HAs/HAT based on their NHT score (insufficient or poor hearing ability), were included in the study. The 5-year uptake of HAs/HAT was defined as a dichotomous variable of self-reported HA/HAT use reported 5 years later. Generalized Estimating Equations analyses were performed to analyze the associations between potential predicting factors and the 5-year uptake of HAs/HAT, taking into account the repeated measurements of the predicting factors and the 5-year uptake of HAs/HAT.

RESULTS

Data of 218 participants were included. The cumulative incidence of the 5-year uptake of HAs/HAT was 15 to 33%, of which 52 employees took up HAs and 11 employees took up HAT. Married participants had increased odds for 5-year uptake of HAs/HAT compared with unmarried participants (odds ratio [OR] = 2.13, 95% confidence interval [CI] = 1.05 to 4.35). Higher self-reported hearing disability (per one unit, scale range 0 to 74) was associated with increased odds for 5-year uptake of HAs/HAT (OR = 1.05, 95% CI = 1.03 to 1.07). Job demand showed a significant interaction with sex (p = 0.002), and therefore, stratified analyses were performed. In male participants, participants with higher job demand scores (per one unit, scale range 12 to 48) had increased odds for 5-year uptake of HAs/HAT (OR = 1.18, 95% CI = 1.05 to 1.35). No difference was seen in females.

CONCLUSION

This study confirms that factors predicting the uptake of HAs/HAT in the general or older populations, including marital status and self-reported hearing disability, also extend to the working population. The identification of job demand as a predictor of the uptake of HAs/HAT (in males only) was a novel finding. It demonstrates the importance of considering work-related factors in aural rehabilitation.

Effect size measures for longitudinal growth analyses: Extending a framework of multilevel model R-squareds to accommodate heteroscedasticity, autocorrelation, nonlinearity, and alternative centering strategies

Developmental researchers commonly utilize multilevel models (MLMs) to describe and predict individual differences in change over time. In such growth model applications, researchers have been widely encouraged to supplement reporting of statistical significance with measures of effect size, such as R-squareds (R² ) that convey variance explained by terms in the model. An integrative framework for computing R-squareds in MLMs with random intercepts and/or slopes was recently introduced by Rights and Sterba and it subsumed pre-existing MLM R-squareds as special cases. However, this work focused on cross-sectional applications, and hence did not address how the computation and interpretation of MLM R-squareds are affected by modeling considerations typically arising in longitudinal settings: (a) alternative centering choices for time (e.g., centering-at-a-constant vs. person-mean-centering), (b) nonlinear effects of predictors such as time, (c) heteroscedastic level-1 errors and/or (d) autocorrelated level-1 errors. This paper addresses these gaps by extending the Rights and Sterba R-squared framework to longitudinal contexts. We: (a) provide a full framework of total and level-specific R-squared measures for MLMs that utilize any type of centering, and contrast these with Rights and Sterba's measures assuming cluster-mean-centering, (b) explain and derive which measures are applicable for MLMs with nonlinear terms, and extend the R-squared computation to accommodate (c) heteroscedastic and/or (d) autocorrelated errors. Additionally, we show how to use differences in R-squared (ΔR² ) measures between growth models (adding, for instance, time-varying covariates as level-1 predictors or time-invariant covariates as level-2 predictors) to obtain effects sizes for individual terms. We provide R software (r2MLMlong) and a running pedagogical example analyzing growth in adolescent self-efficacy to illustrate these methodological developments. With these developments, researchers will have greater ability to consider effect size when analyzing and predicting change using MLMs.

Declining Trajectories of Co-occurring Psychopathology Symptoms in Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder: A 10-Year Longitudinal Study

Objective: Our objective was to examine developmental trajectories of co-occurring psychopathology symptoms from childhood to young adulthood in individuals with Attention-Deficit/Hyperactivity Disorder (ADHD), individuals with Autism Spectrum Disorder (ASD), and typically developing (TD) individuals. Method: We assessed co-occurring psychopathology symptoms in 61 individuals with ADHD, 26 with ASD, and 40 TD individuals at baseline (T1; M_age = 11.72, 64% boys), 2-year follow up (T2; M_age = 13.77), and 10-year follow up (T3; M_age = 21.35). We analyzed trajectories of internalizing behaviors, externalizing behaviors, and total problems with linear mixed models. Results: From T1 to T3, the ADHD group displayed a small decline in internalizing behaviors (d = -0.49) and large declines in externalizing behaviors (d = -0.78) and total problems (d = -0.71). The ASD group displayed large declines in internalizing behaviors (d = -0.79), externalizing behaviors (d = -0.80), and total problems (d = -0.89). From T1 to T2, the decline in externalizing behaviors and total problems were significantly smaller in the ADHD group compared with the ASD group. The ADHD and the ASD group displayed more co-occurring symptoms compared with the TD group at T3. Conclusion: Individuals with ADHD and ASD, respectively, displayed declines in co-occurring symptoms from childhood to young adulthood. Individuals with ASD displayed an earlier decline compared with individuals with ADHD. Compared with TD individuals, individuals with ADHD and ASD, respectively, continued to display elevated levels of co-occurring symptoms in young adulthood.

Standardized Testing, Use of Assessment Data, and Low Reading Performance of Immigrant and Non-immigrant Students in OECD Countries

This paper investigates the effects of standardized testing and publication of achievement data on low reading performance for immigrant and non-immigrant students in 30 OECD countries. The paper aims to test hypotheses derived from a principal-agent framework. According to this theoretical perspective, standardized assessments alone should not be associated with reading performance. Instead, the model proposes that the provision of the results to the principle (parents and education authorities) is associated with higher student performance, as this reduces the information asymmetry between principal (parents and educational authorities) and agent (teachers and schools). The results of our analyses of PISA 2009 and 2015 reading data from 422.172 students show that first, the use of standardized achievement tests alone was not associated with the risk of low performance. Second, making the results of standardized tests available to the public was associated with a decreased risk of low reading performance among all students, and, third, particularly among first generation immigrant students. These results were robust across various modeling approaches. In accordance with the predictions from the principal-agent framework, our findings suggest that the mere implementation of standardized assessments has no effects on low performance. Testing along with the public provision of the testing results, which decreases the information asymmetry between schools and teachers on the one hand and parents and education authorities on the other, was associated with a decreased risk of low performance, with the effect being stronger for immigrant students.

Factors predicting poor glycemic control in the first two years of childhood onset type 1 diabetes in a cohort from East London, UK: Analyses using mixed effects fractional polynomial models

BACKGROUND/OBJECTIVE

Poor early glycemic control in childhood onset type 1 diabetes (T1D) is associated with future risk of acute and chronic complications. Our aim was to identify the predictors of higher glycated hemoglobin (HbA1c) within 24 months of T1D diagnosis in children and adolescents.

METHODS

Mixed effects models with fractional polynomials were used to analyze longitudinal data of patients <19 years of age, followed from T1D diagnosis for up to 2 years, at three diabetes clinics in East London, United Kingdom.

RESULTS

A total of 2209 HbA1c observations were available for 356 patients (52.5% female; 64.4% non-white), followed from within 3 months of diagnosis during years 2005 to 2015, with a mean ± SD of 6.2 ± 2.5 HbA1c observations/participant. The mean age and HbA1c at diagnosis were 8.9 ± 4.3 years and 10.7% ±4.3% (or expressed as mmol/mol HbA1c mean ± SD 92.9 ± 23.10 mmol/mol) respectively. Over the 2 years following T1D diagnosis, HbA1c levels were mostly above the National Institute for Health, Care and Excellence (NICE), UK recommendations of 7.5% (<58 mmol/mol). Significant (P < .05) predictors of poorer glycemic control were: Age at diagnosis (12-18 years), higher HbA1c at baseline (>9.5%, ie, >80 mmol/mol), clinic site, non-white ethnicity, and period (pre-year 2011) of diagnosis. Additionally in univariable analyses, frequency of clinic visits, HbA1c at diagnosis, and type of insulin treatment regimen showed association with poor glycemic control (P < .05).

CONCLUSIONS

Major risk factors of poorer glycemic control during 3-24 months following childhood onset T1D are: diagnosis prior to 2011, higher HbA1c levels at baseline, age at diagnosis, non-white ethnicity, and clinic site.

Short and sporadic injecting cessation episodes as predictors of incident hepatitis C virus infection: findings from a cohort study of people who inject drugs in Montréal, Canada

BACKGROUND AND AIMS

For most people who inject drugs (PWID), drug injecting follows a dynamic process characterized by transitions in and out of injecting. The objective of this investigation was to examine injecting cessation episodes of 1-3-month duration as predictors of hepatitis C virus (HCV) acquisition.

DESIGN

Cohort study.

SETTING

Montréal, Canada.

PARTICIPANTS

A total of 372 HCV-uninfected (HCV RNA-negative, HCV antibody-positive or -negative) PWID (mean age = 39.3 years, 82% male, 45% HCV antibody-positive) enrolled between March 2011 and June 2016.

MEASUREMENTS

At 3-month intervals, participants completed an interviewer-administered questionnaire and were tested for HCV particles (HCV RNA). At each visit, participants indicated whether they injected in each of the past 3 months (defined as three consecutive 30-day periods). Injecting cessation patterns were evaluated on a categorical scale: persistent injecting (no injecting cessation in the past 3 months), sporadic injecting cessation (injecting cessation in 1 of 3 or 2 of 3 months) and short injecting cessation (injecting cessation in 3 of 3 months). Their association with HCV infection risk was examined using Cox regression analyses with time-dependent covariates, including age, gender, incarceration, opioid agonist treatment and other addiction treatments.

FINDINGS

At baseline, 61, 26 and 13% of participants reported persistent injecting, sporadic injecting cessation and short injecting cessation, respectively. HCV incidence was 7.5 per 100 person-years [95% confidence interval (CI) = 5.9-9.5; 916 person-years of follow-up]. In adjusted Cox models, sporadic injecting cessation and short injecting cessation were associated with lower risks of incident HCV infection compared to persistent injecting (adjusted hazard ratios = 0.56, 95% CI = 0.30-1.04 and 0.24, 95% CI = 0.09-0.61), respectively.

CONCLUSION

Short and sporadic injecting cessation episodes were common among a cohort of people who inject drugs in Montréal, Canada. Injecting cessation episodes appear to be protective against hepatitis C virus acquisition, particularly when maintained for at least 3 months.

Predictive models for short-term and long-term improvement in women under physiotherapy for chronic disabling neck pain: a longitudinal cohort study

OBJECTIVES

To develop predictive models for short-term and long-term clinically important improvement in women with non-specific chronic disabling neck pain during the clinical course of physiotherapy.

DESIGN

Longitudinal cohort study based on data from a randomised controlled trial evaluating short-term and long-term effects on sensorimotor function over 11 weeks of physiotherapy.

PARTICIPANTS AND SETTINGS

Eighty-nine women aged 31-65 years with non-specific chronic disabling neck pain from Gävle, Sweden.

MEASURES

The outcome, clinically important improvement, was measured with the Patient Global Impression of Change Scale (PGICS) and the Neck Disability Index (NDI), assessed by self-administered questionnaires at 3, 9 and 15 months from the start of the interventions (baseline). Twelve baseline prognostic factors were considered in the analyses. The predictive models were built using random-effects logistic regression. The predictive ability of the models was measured by the area under the receiver operating characteristic curve (AUC). Internal validity was assessed with cross-validation using the bootstrap resampling technique.

RESULTS

Factors included in the final PGICS model were neck disability and age, and in the NDI model, neck disability, depression and catastrophising. In both models, the odds for short-term and long-term improvement increased with higher baseline neck disability, while the odds decreased with increasing age (PGICS model), and with increasing level of depression (NDI model). In the NDI model, higher baseline levels of catastrophising indicated increased odds for short-term improvement and decreased odds for long-term improvement. Both models showed acceptable predictive validity with an AUC of 0.64 (95% CI 0.55 to 0.73) and 0.67 (95% CI 0.59 to 0.75), respectively.

CONCLUSION

Age, neck disability and psychological factors seem to be important predictors of improvement, and may inform clinical decisions about physiotherapy in women with chronic neck pain. Before using the developed predictive models in clinical practice, however, they should be validated in other populations and tested in clinical settings.

Longitudinal Analyses of Pediatrician Burnout

OBJECTIVE

Utilize the unique capabilities of a longitudinal design to 1) examine whether burnout is increasing over time among 2 cohorts of pediatricians, and 2) identify factors associated with decreased burnout.

METHODS

Data from a national longitudinal study, the American Academy of Pediatrics Pediatrician Life and Career Experience Study, were used to examine self-reported burnout over a 5-year period (2012 to 2016) among 2002 to 2004 and 2009 to 2011 residency graduates (N = 1804). Study participation rates ranged from 94% in 2012 to 85% in 2016. Mixed-effects logistic regression for longitudinal analysis was used to examine burnout over time.

RESULTS

In any given year, between 20% and 35% of study pediatricians reported that they were currently experiencing burnout. Significant increases in burnout over time were found for all participants combined and for each subgroup examined. Several factors were associated with reduced burnout. The largest associations with reduced burnout were found for increased flexibility in work schedule (adjusted odds ratio [aOR], 0.28; 95% confidence interval [CI], 0.22-0.35), decreased work busyness (aOR, 0.28; 95% CI, 0.22-0.36), or a job change (aOR, 0.48; 95% CI, 0.36-0.65).

CONCLUSIONS

Following 5 years of participation in a longitudinal study, more than 1 in 3 early- to mid-career pediatricians reported experiencing burnout. This represents a 75% relative increase in burnout from the start of the study. Specific characteristics of pediatricians' jobs, such as flexible work schedules and busyness of work settings, were most strongly associated with reduced burnout.

The respiratory effects of toner exposure according to long-term occupational toner handling history: A longitudinal analysis, 2004-2013

OBJECTIVES

This report shows the relationship between toner exposure and respiratory effects for individuals with a longterm occupational toner-handling history, from 2004 to 2013.

MATERIAL AND METHODS

Authors studied 752 Japanese male workers in toner handling workshops. A total of 673 men who participated in an annual monitoring survey were analyzed in this study. The following monitoring was performed in the same season each year: personal exposure measurements, biological markers, respiratory function tests, a chest X-ray, chronic respiratory symptoms and incidences of respiratory diseases. To evaluate the toner exposure effect, the exposure categories suitable for each evaluation index were established.

RESULTS

For those with an occupational toner-handling history, the mean occupational toner-handling period was 14.36 years (standard deviation = 6.62); one participant had 35 years of exposure, which was the longest and one participant had 1 year of exposure which was the shortest. There were no statistically significant differences in the rate of change of respiratory function tests. An ANOVA conducted on blood and urine test results showed that statistically significantly differences were observed for a few items but all the values were very low and within the standard range.

CONCLUSIONS

Authors conducted a 10-year ongoing study, but no obvious negative influences on health were attributed to toner exposure. In a work environment where adequate administrative controls are in place, personal toner exposure levels may be expected to be low, with no adverse effects on human health. Int J Occup Med Environ Health 2018;31(6):809-822.

Changes in anti-citrullinated protein antibody isotype levels in relation to disease activity and response to treatment in early rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease where serum analysis of anti-citrullinated peptide/protein antibodies (ACPA) is an important diagnostic/prognostic tool. Levels and changes of ACPA in RA patients have been studied previously in relation to disease course and therapy response, but less is known regarding ACPA isotype changes in early RA. Hence, recent-onset RA patients (n = 231) were subjected to a 3-year clinical and radiological follow-up. Serum samples were serially collected and ACPA isotypes were analysed using the second-generation cyclic citrullinated peptide (CCP) as capture antigen. Changes in ACPA isotype levels and status were related to disease course and pharmacotherapy. At inclusion, 74% of the patients tested positive for ACPA IgG; 55% for immunoglobulin (Ig)A, 37% for secretory IgA (SIgA) and 35% for IgM. The proportion of positive patients decreased significantly at follow-up regarding ACPA SIgA, IgM and IgA. During the initial 3 months, reduction of the 28-joint disease activity score (DAS28) correlated with reduced levels of ACPA IgG (Rho = 0·242, P = 0·003), IgA (Rho = 0·260, P = 0·008), IgM (Rho = 0·457, P < 0·001) and SIgA (Rho = 0·402, P < 0·001). Levels of ACPA SIgA (P = 0·008) and IgM (P = 0·021) decreased significantly among patients with good response to treatment, which was not seen regarding ACPA IgA or IgG. Changes in ACPA isotype levels were not associated with radiographic damage. In conclusion, ACPA SIgA and IgM declined rapidly upon anti-rheumatic therapy and correlated with decreased disease activity in recent-onset RA. This may indicate that down-regulation of mucosal immunity to citrullinated proteins/peptides and recruitment of new B cells are key features of therapy responses in early RA.

Reading Habits Among Older Adults in Relation to Level and 15-Year Changes in Verbal Fluency and Episodic Recall

The main objective of this study was to investigate reading habits in older adults in relation to level and 15-year changes in verbal fluency and episodic recall. We examined a sample of 1157 participants (≥55 years at baseline) up to 15 years after the baseline assessment using latent growth curve modeling of cognitive measures with baseline reading frequency (books, weekly magazines) as a predictor of cognitive level (intercept) and rate of change (slope). Subgroup analyses were performed to investigate the role of an early adult g factor in the association between reading habits and cognitive ability in midlife. Frequent reading of books, but not of magazines, was associated with higher levels of verbal fluency and recall but unrelated to rate of longitudinal decline. Subgroup analyses indicated that the g factor in early adulthood predicted reading and cognitive level in midlife and this factor removed the current association between reading habits and level of cognitive ability (both cognitive factors). The results indicate an enduring relationship between book reading and level of cognitive ability across the adult life span and provide little support of the hypothesis that frequent reading protects against late-life cognitive decline. The extent to which book reading promotes cognitive functioning in childhood/youth remains to be demonstrated. Intervention studies may be useful in this regard.

Time Spent Commuting to Work and Mental Health: Evidence From 13 Waves of an Australian Cohort Study

Time-related stressors, such as long working hours, are recognized as being detrimental to health. We considered whether time spent commuting to work was a risk factor for poor mental health. Data from the Household, Income Labour Dynamics in Australia Survey were used to conduct fixed-effects longitudinal regression analyses. The outcome variable was the Mental Health Inventory, and the main exposure represented hours per week traveling to and from a place of paid employment. Effect modifiers included sex, low job control, high demands, and low job security. Compared with when a person commuted for ≤2 hours per week, there was a small decline (coefficient = -0.33, 95% CI: -0.62, -0.04; P = 0.025) in the Mental Health Inventory score when they commuted for over 6 hours per week. Compared with persons with high job control, persons working in jobs with low job control experienced significantly greater declines in the Mental Health Inventory score when commuting 4 to 6 hours per week and when commuting over 6 hours per week. We found no influence from the other hypothesized effect modifiers. These results suggest the importance of considering commuting time as an additional work-related time stressor.

Revisiting the Link between Job Satisfaction and Life Satisfaction: The Role of Basic Psychological Needs

The link between job satisfaction and life satisfaction has been extensively explored in the relevant literature. However, the great majority of past research has been carried out using cross-sectional analyses, and almost exclusively in the Western world. Moreover, the underlying psychological mechanisms explaining the link are not yet completely understood. Thus, we report the first research to date which uses both cross-sectional and longitudinal data among workers in Chile—a fast-developing Latin American economy—and which aims to tackle previous limitations. Three studies consistently support a positive link between the constructs. Study 1 (N = 636) found that higher job satisfaction predicted higher life satisfaction both contemporaneously and longitudinally, and vice versa, above and beyond several key control variables. Study 2 (N = 725) and Study 3 (N = 703) replicated Study 1 results, but tested for the first time the role of satisfaction of basic psychological needs (as stated by self-determination theory) in the job–life satisfaction link. This is the most novel contribution of our paper. Key implications not only for individual quality of life, but also for companies' human resource practices emerge from our findings.

Implementing a Data Management Platform for Longitudinal Health Research

Health IT adoption research is rooted in Rogers' Diffusion of Innovation theory, which is based on longitudinal analyses. However, many studies in this field use cross-sectional designs. The aim of this study therefore was to design and implement a system to (i) consolidate survey data sets originating from different years (ii) integrate additional secondary data and (iii) query and statistically analyse these longitudinal data. Our system design comprises a 5-tier-architecture that embraces tiers for data capture, data representation, logics, presentation and integration. In order to historicize data properly and to separate data storage from data analytics a data vault schema was implemented. This approach allows the flexible integration of heterogeneous data sets and the selection of comparable items. Data analysis is prepared by compiling data in data marts and performed by R and related tools. IT Report Healthcare data from 2011, 2013 and 2017 could be loaded, analysed and combined with secondary longitudinal data.

Statistics for Sleep and Biological Rhythms Research

This article is part of a Journal of Biological Rhythms series exploring analysis and statistical topics relevant to researchers in biological rhythms and sleep research. The goal is to provide an overview of the most common issues that arise in the analysis and interpretation of data in these fields. In this article, we address issues related to the collection of multiple data points from the same organism or system at different times, since such longitudinal data collection is fundamental to the assessment of biological rhythms. Rhythmic longitudinal data require additional specific statistical considerations, ranging from curve fitting to threshold definitions to accounting for correlation structure. We discuss statistical analyses of longitudinal data including issues of correlational structure and stationarity, markers of biological rhythms, demasking of biological rhythms, and determining phase, waveform, and amplitude of biological rhythms.

Mothers' and Fathers' Sensitivity and Children's Cognitive Development in Low-Income, Rural Families

This study examines associations between maternal and paternal sensitive parenting and child cognitive development across the first 3 years of life using longitudinal data from 630 families with co-residing biological mothers and fathers. Sensitive parenting was measured by observational coding of parent-child interactions and child cognitive development was assessed with the Bayley Scales of Infant Development and the Wechsler Preschool and Primary Scales of Intelligence. There were multiple direct and indirect associations between parenting and cognitive development across mothers and fathers, suggesting primary effects, carry-forward effects, spillover effects across parents, and transactional effects across parents and children. Associations between parenting and cognitive development were statistically consistent across mothers and fathers, and the cumulative effects of early parenting on later cognitive development were comparable to the effects of later parenting on later cognitive development. As interpreted through a family systems framework, findings suggest additive and interdependent effects across parents and children.

Workers' compensation claims for musculoskeletal disorders and injuries of the upper extremity and knee among union carpenters in Washington State, 1989-2008

BACKGROUND

Numerous aspects of construction place workers at risk of musculoskeletal disorders and injuries (MSDIs). Work organization and the nature of MSDIs create surveillance challenges.

METHODS

By linking union records with workers' compensation claims, we examined 20-year patterns of MSDIs involving the upper extremity (UE) and the knee among a large carpenter cohort.

RESULTS

MSDIs were common and accounted for a disproportionate share of paid lost work time (PLT) claims; UE MSDIs were three times more common than those of the knee. Rates declined markedly over time and were most pronounced for MSDIs of the knee with PLT. Patterns of risk varied by extremity, as well as by age, gender, union tenure, and predominant work. Carpenters in drywall installation accounted for the greatest public health burden.

CONCLUSIONS

A combination of factors likely account for the patterns observed over time and across worker characteristics. Drywall installers are an intervention priority.

Hot flushes and night sweats are associated with coronary heart disease risk in midlife: a longitudinal study

OBJECTIVE

The purpose of this study was to investigate associations between vasomotor menopausal symptoms (VMS), i.e. hot flushes and night sweats, and the incidence of coronary heart disease (CHD).

DESIGN

A prospective cohort study.

SETTING AND POPULATION

11 725 women, aged 45-50 years at baseline in 1996, were followed up at 3-year intervals for 14 years.

METHODS

Self-reported VMS and incident CHD were measured at each survey.

MAIN OUTCOME MEASURE

We determined the association between VMS and CHD at the subsequent survey, using generalised estimating equation analysis, adjusting for time-varying covariates.

RESULTS

At baseline, 14% reported rarely, 17% reported sometimes, and 7% reported often having night sweats. During follow-up, 187 CHD events occurred. In the age-adjusted analysis, women who reported their frequency of experiencing hot flushes and night sweats as 'often' had a greater than two-fold increased odds of CHD (OR hot flushes 2.18, 95% CI 1.49-3.18; OR night sweats 2.38, 95% CI 1.62-3.50) compared with women with no symptoms (P trend < 0.001 for frequency of symptoms). Adjustment for menopausal status, lifestyle factors, body mass index, diabetes, and hypertension attenuated the associations (OR hot flushes 1.70, 95% CI 1.16-2.51, P trend = 0.01; OR night sweats 1.84, 95% CI 1.24-2.73), P trend = 0.004).

CONCLUSIONS

Women who report having hot flushes or night sweats 'often' have an increased risk of developing CHD over a period of 14 years, even after taking the effects of age, menopause status, lifestyle, and other chronic disease risk factors into account.

Hippocampal atrophy and subsequent depressive symptoms in older men and women: results from a 10-year prospective cohort

Several studies have reported smaller hippocampal volume in patients with depression. However, the temporality of the association is undetermined. One hypothesis is that hippocampal atrophy might be a susceptibility factor for depression. In the present study, we assessed whether hippocampal atrophy was associated with subsequent depressive symptoms in a cohort of older French adults (n = 1,309) who were 65-80 years of age and enrolled into the study in 1999-2001 in Dijon, France. Subjects were followed for more than 10 years. Participants underwent 2 cerebral magnetic resonance imaging scans, one at baseline and one at the 4-year follow-up. We used linear mixed models to estimate the associations of hippocampal atrophy with 1) the average depressive symptom scores over follow-up (using the Center for Epidemiologic Studies-Depression scale) measured biennially over the subsequent 6 years and 2) changes in symptom scores over follow-up. In women, a 2-standard-deviation increase in annual hippocampal atrophy was associated with a 1.67-point (95% confidence interval: 0.59, 2.77) increase in the average depressive symptom score over follow-up and with a 1.97-point (95% confidence interval: 0.68, 3.24) increase in scores over the 2 subsequent years but not with later changes in symptoms. No association was detected in men. Accounting for potential selective attrition (using inverse probability weights) did not alter results. Hippocampal atrophy was associated with more subsequent depressive symptoms and with shorter-term worsening of symptoms in women.

Trends in dietary carbohydrate consumption from 1991 to 2008 in the Framingham Heart Study Offspring Cohort

The intake of carbohydrates has been evaluated cross-sectionally, but not longitudinally in an ageing American adult population. The aim of the present study was to examine trends in the intake of dietary carbohydrates and their major food sources among the Framingham Heart Study Offspring (FOS) cohort, which had been uniquely tracked for 17 years in the study. The FOS cohort was recruited in 1971-1975. Follow-up examinations were conducted, on average, every 4 years. Dietary data collection began in 1991 (examination 5) using a validated semi-quantitative FFQ. The study included 2894 adults aged ≥ 25 years with complete dietary data in at least three examinations from 1991 to 2008. Descriptive statistics were generated using SAS version 9.3, and a repeated-measures model was used to examine trends in the intake of carbohydrates and their food sources in the whole sample, and by sex and BMI category. Over 17 years of follow-up, the percentage of energy from total carbohydrates (51·0-46·8 %; P for trend < 0·001) and total sugars (18·2-16·6 %; P for trend < 0·001) decreased. There was a decrease in the percentage of energy from fructose (5·4-4·7 %; P for trend < 0·001) and sucrose (9·8-8·8 %; P for trend < 0·001). Dietary fibre intake increased (18·0-19·2 g/d; P for trend < 0·001). The number of weekly servings of yeast bread, soft drinks/soda, cakes/cookies/quick breads/doughnuts, potatoes, milk, pasta, rice and cooked grains, fruit juice/drinks, potato chips/maize chips/popcorn, and lunch foods (e.g. pizzas and burgers) decreased significantly (P for trend < 0·001), while the intake of ready-to-eat cereals, legumes, fruits, dairy products, candy and ice cream/sherbet/frozen yogurt increased significantly (P for trend<0·04). Similar trends were observed when the analyses were stratified by sex and BMI. The present results suggest favourable trends in dietary carbohydrate consumption, but dietary guidelines for fruits, vegetables and fibre were not met in this cohort.

The Academic Backbone: longitudinal continuities in educational achievement from secondary school and medical school to MRCP(UK) and the specialist register in UK medical students and doctors

BACKGROUND

Selection of medical students in the UK is still largely based on prior academic achievement, although doubts have been expressed as to whether performance in earlier life is predictive of outcomes later in medical school or post-graduate education. This study analyses data from five longitudinal studies of UK medical students and doctors from the early 1970s until the early 2000s. Two of the studies used the AH5, a group test of general intelligence (that is, intellectual aptitude). Sex and ethnic differences were also analyzed in light of the changing demographics of medical students over the past decades.

METHODS

Data from five cohort studies were available: the Westminster Study (began clinical studies from 1975 to 1982), the 1980, 1985, and 1990 cohort studies (entered medical school in 1981, 1986, and 1991), and the University College London Medical School (UCLMS) Cohort Study (entered clinical studies in 2005 and 2006). Different studies had different outcome measures, but most had performance on basic medical sciences and clinical examinations at medical school, performance in Membership of the Royal Colleges of Physicians (MRCP(UK)) examinations, and being on the General Medical Council Specialist Register.

RESULTS

Correlation matrices and path analyses are presented. There were robust correlations across different years at medical school, and medical school performance also predicted MRCP(UK) performance and being on the GMC Specialist Register. A-levels correlated somewhat less with undergraduate and post-graduate performance, but there was restriction of range in entrants. General Certificate of Secondary Education (GCSE)/O-level results also predicted undergraduate and post-graduate outcomes, but less so than did A-level results, but there may be incremental validity for clinical and post-graduate performance. The AH5 had some significant correlations with outcome, but they were inconsistent. Sex and ethnicity also had predictive effects on measures of educational attainment, undergraduate, and post-graduate performance. Women performed better in assessments but were less likely to be on the Specialist Register. Non-white participants generally underperformed in undergraduate and post-graduate assessments, but were equally likely to be on the Specialist Register. There was a suggestion of smaller ethnicity effects in earlier studies.

CONCLUSIONS

The existence of the Academic Backbone concept is strongly supported, with attainment at secondary school predicting performance in undergraduate and post-graduate medical assessments, and the effects spanning many years. The Academic Backbone is conceptualized in terms of the development of more sophisticated underlying structures of knowledge ('cognitive capital' and 'medical capital'). The Academic Backbone provides strong support for using measures of educational attainment, particularly A-levels, in student selection.

Work-related injuries among union drywall carpenters in Washington State, 1989-2008

BACKGROUND

Drywall installers are at high-risk of work-related injury. Comprehensive descriptive epidemiology of injuries among drywall installers, particularly over time, is lacking.

METHODS

We identified worker-hours and reported and accepted workers' compensation (WC) claims for a 20-year (1989-2008) cohort of 24,830 Washington State union carpenters. Stratified by predominant type of work (drywall installation, other carpentry), work-related injury rates were examined over calendar time and by worker characteristics. Expert interviews provided contextual details.

RESULTS

Drywall installers' injury rates, higher than those of other carpenters, declined substantially over this period by 73.6%. Common injury mechanisms were struck by/against, overexertion and falls. Drywall material was considered a contributing factor in 19.7% of injuries. One-third of these drywall material-related injuries resulted in paid lost time, compared to 19.4% of injuries from other sources. Rates of injury were particularly high among workers with 2 to <4 years in the union. Notable declines over time in rates of overexertion injury in which drywall material was a contributing factor were still observed after controlling for secular temporal trends. Experts highlighted changes over the past 20 years that improved both work safety and, in some cases, production.

CONCLUSIONS

Declines in drywall installers' injury rates over time likely reflect, in part, enhanced workplace safety, including efforts to reduce overexertion hazards associated with handling drywall. Continued injury prevention efforts are needed, particularly for less tenured workers. Given the potential for under-reporting to WC, additional sources of health outcomes data may provide a more complete picture of workers' health.

Self-reported tooth loss and cognitive function: Data from the Hispanic Established Populations for Epidemiologic Studies of the Elderly (Hispanic EPESE)

OBJECTIVE

To explore the association between tooth loss and cognitive functioning among persons 65 years and older.

METHODS

Data from the Hispanic Established Populations for Epidemiologic Studies of the Elderly (Wave 1: 1993-1994, n= 3,032; Wave 2: 1995-1996, n= 2,424; and Wave 3: 1998-1999, n= 1,967). The dependent variables were the scores from the total Mini-Mental State Examination (MMSE: score 0-30) and its global domains (memory: score 0-6; and no-memory: score 0-24). Independent variables included the number of teeth (0-12 vs. 13-32), socio-demographic characteristics, last dental office visit, medical conditions, depressive symptoms, and functional limitations which were tested for associations with the dependent variables.

RESULTS

In bivariate analyses, participants with fewer teeth (0-12) tended to have significantly lower mean scores for memory, no-memory, and total MMSE when compared to those with more teeth (13-32), both at baseline and at follow-up. In fully adjusted longitudinal-mixed models, participants with fewer teeth had a greater decline in total MMSE through five years of follow-up with a decrease of 0.12 fewer points each year (SE ± 0.05, p <0.01), when compared to those with more teeth.

CONCLUSION

Having fewer teeth was associated with greater cognitive decline over time.

Preconception health trajectories and birth weight in a national prospective cohort

PURPOSE

This study was designed to assess the relationship between birth weight and prospectively measured trajectories of preconception health across adolescence and young adulthood in a diverse national cohort of young adult women.

METHODS

Data came from Waves I (1994-1995), III (2001-2002), and IV (2007-2008) of the National Longitudinal Study of Adolescent Health. Eligibility was restricted to all the singleton live births (n = 3,436) to female participants occurring between the Wave III (ages 18-26 years) and Wave IV (ages 24-32 years) interviews. Preconception cigarette smoking, overweight/obesity, adequate physical activity, heavy alcohol consumption, and fair/poor self-rated health were measured in adolescence (Wave I) and early adulthood (Wave III) and combined into four-category variables to capture the timing and sequencing of exposure. The outcome measure, birth weight, was classified as low (<2,500 g), normal (2,500-4,000 g), and macrosomic (>4,000 g).

RESULTS

Multinomial logistic regression results indicated that adult-onset overweight significantly increased the odds of having a macrosomic birth (odds ratio = 1.56; 95% confidence interval = 1.02-2.38).

CONCLUSIONS

This study provides new evidence about the influence of maternal body mass index trajectories on offspring birth weight. Adult-onset overweight/obesity during the transition to adulthood was common in the sample and increased the odds of subsequently delivering a macrosomic infant by 56%. This finding suggests that healthy weight promotion before this transition would confer intergenerational benefits, and supports recommendations for preconception care to address overweight/obesity.

Estimating the Reliability of Single-Item Life Satisfaction Measures: Results from Four National Panel Studies

Life satisfaction is often assessed using single-item measures. However, estimating the reliability of these measures can be difficult because internal consistency coefficients cannot be calculated. Existing approaches use longitudinal data to isolate occasion-specific variance from variance that is either completely stable or variance that changes systematically over time. In these approaches, reliable occasion-specific variance is typically treated as measurement error, which would negatively bias reliability estimates. In the current studies, panel data and multivariate latent state-trait models are used to isolate reliable occasion-specific variance from random error and to estimate reliability for scores from single-item life satisfaction measures. Across four nationally representative panel studies with a combined sample size of over 68,000, reliability estimates increased by an average of 16% when the multivariate model was used instead of the more standard univariate longitudinal model.

The relationship of perceived neighborhood social climate to walking in Hispanic older adults: a longitudinal, cross-lagged panel analysis

OBJECTIVE

This study examines possible bidirectional relationships between neighborhood climate (i.e., perceived neighborhood social environment) and walking behavior across a 12-month period in older Hispanics.

METHOD

A population-based sample of 217 community-dwelling older Hispanics in Miami, Florida, completed measures of perceived neighborhood climate and neighborhood walking, at two assessment time points (12 months apart).

RESULTS

Structural equation modeling analyses revealed that neighborhood climate predicted subsequent walking 12 months later, such that more positive perceptions of neighborhood climate predicted more walking. Follow-up analyses revealed that older adults who resided in the top half of neighborhoods based on perceived neighborhood climate scores at initial assessment were 2.57 times as likely to have walked at least one block in the last week at follow-up, relative to older adults residing in neighborhoods whose climate was in the lower half.

DISCUSSION

Perceptions of a more positive neighborhood social environment may promote walking in urban, older Hispanics.

Positive-engagement behaviors in observed family interactions: a social relations perspective

The present study investigates the nature of positive engagement (an interpersonal style characterized by attentiveness, warmth, cooperation, and clear communication) in family interactions involving at least one adolescent. Approximately 400 families (mothers, fathers, and two siblings) were videotaped during brief conflict-resolution discussions that occurred on a yearly basis for 3 years. Coders rated the degree to which each family member was positively engaged with every other family member during the interactions. The social relations model was used to partition variation in positive-engagement behavior into family-level, individual-level, and dyad-level effects. Results demonstrated the importance of family norms and individual factors in determining the expression of positive-engagement behaviors in dyadic family relationships. Moreover, longitudinal analyses indicated that these effects are stable over a 3-year period. Finally, results highlighted the relative distinctiveness of the marital and sibling relationships, as well as the existence of reciprocity within these dyads.

The relationship between depressive symptoms and walking among Hispanic older adults: a longitudinal, cross-lagged panel analysis

OBJECTIVES

This study examines the relationship between depressive symptoms and walking behavior across 30 months in a prospective study of 217 community-dwelling, Hispanic older adults in Miami, Florida (ages 70-100 years).

METHOD

Analyses examine the direction of the relationship between depressive symptoms and physical activity (i.e., walking) over time, as well as test for a potential bi-directional or reciprocal relationship between these two variables.

RESULTS

Structural equation modeling (SEM) with a cross-lagged panel design revealed that walking was unrelated to subsequent depressive symptoms. However, depressive symptoms were related to subsequent walking behavior at every time-point, such that higher levels of depressive symptoms were predictive of less walking in the future. Older adults who had clinically-relevant depressive symptoms at the initial assessment had 1.34 times the risk of not walking 30 months later, compared to older adults without clinically-relevant depressive symptoms.

CONCLUSION

Results support the need for primary care providers to evaluate and address depressive symptoms among older adults, as a means of reducing sedentary behavior and potentially improving health. Further research on the prevention and management of depressive symptoms and sedentary behavior is needed, given the morbidity related to both of these health risks, particularly for minority and low-socio-economic status (SES) older adults.

Linkages over time between adolescents' relationships with parents and friends

This 5-wave longitudinal study examines linkages over time between adolescents' perceptions of relationships with parents and friends with respect to support, negative interaction, and power. A total of 575 early adolescents (54.1% boys) and 337 middle adolescents (43.3% boys) participated. Path analyses mainly showed bidirectional associations between adolescents' perceptions of parent-adolescent relationships and friendships with a predominantly stronger influence from parent-adolescent relationships to friendships than vice versa in early to middle adolescence and an equal mutual influence in middle to late adolescence. The findings support the theoretical ideas that perceptions of relationships with parents generalize to perceptions of relationships with friends and that relationship skills and principles of adolescent friendships generalize to relationships with parents. Furthermore, the results indicate that the influence of parents decreases, whereas the influence of friends increases, and that both social worlds become equally important and overlapping towards late adolescence.

Estimation of vaccine efficacy in a repeated measures study under heterogeneity of exposure or susceptibility to infection

Vaccine efficacy (VE) is commonly estimated through proportional hazards modelling of the time to first infection or disease, even when the event of interest can recur. These methods can result in biased estimates when VE is heterogeneous across levels of exposure and susceptibility in subjects. These two factors are important sources of unmeasured heterogeneity, since they vary within and across areas, and often cannot be individually quantified. We propose an estimator of VE per exposure that accounts for heterogeneous susceptibility and exposure for a repeated measures study with binary recurrent outcomes. The estimator requires only information about the probability distribution of environmental exposures. Through simulation studies, we compare the properties of this estimator with proportional hazards estimation under the heterogeneity of exposure. The methods are applied to a reanalysis of a malaria vaccine trial in Brazil.