Estimating household contact matrices structure from easily collectable metadata

Contact matrices are a commonly adopted data representation, used to develop compartmental models for epidemic spreading, accounting for the contact heterogeneities across age groups. Their estimation, however, is generally time and effort consuming and model-driven strategies to quantify the contacts are often needed. In this article we focus on household contact matrices, describing the contacts among the members of a family and develop a parametric model to describe them. This model combines demographic and easily quantifiable survey-based data and is tested on high resolution proximity data collected in two sites in South Africa. Given its simplicity and interpretability, we expect our method to be easily applied to other contexts as well and we identify relevant questions that need to be addressed during the data collection procedure.

The limits of human mobility traces to predict the spread of COVID-19: A transfer entropy approach

Mobile phone data have been widely used to model the spread of COVID-19; however, quantifying and comparing their predictive value across different settings is challenging. Their quality is affected by various factors and their relationship with epidemiological indicators varies over time. Here, we adopt a model-free approach based on transfer entropy to quantify the relationship between mobile phone-derived mobility metrics and COVID-19 cases and deaths in more than 200 European subnational regions. Using multiple data sources over a one-year period, we found that past knowledge of mobility does not systematically provide statistically significant information on COVID-19 spread. Our approach allows us to determine the best metric for predicting disease incidence in a particular location, at different spatial scales. Additionally, we identify geographic and demographic factors, such as users' coverage and commuting patterns, that explain the (non)observed relationship between mobility and epidemic patterns. Our work provides epidemiologists and public health officials with a general-not limited to COVID-19-framework to evaluate the usefulness of human mobility data in responding to epidemics.

Association of close-range contact patterns with SARS-CoV-2: a household transmission study

Background

Households are an important location for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, especially during periods when travel and work was restricted to essential services. We aimed to assess the association of close-range contact patterns with SARS-CoV-2 transmission.

Methods

We deployed proximity sensors for two weeks to measure face-to-face interactions between household members after SARS-CoV-2 was identified in the household, in South Africa, 2020-2021. We calculated the duration, frequency, and average duration of close-range proximity events with SARS-CoV-2 index cases. We assessed the association of contact parameters with SARS-CoV-2 transmission using mixed effects logistic regression accounting for index and household member characteristics.

Results

We included 340 individuals (88 SARS-CoV-2 index cases and 252 household members). On multivariable analysis, factors associated with SARS-CoV-2 acquisition were index cases with minimum C_t value <30 (aOR 16.8 95% CI 3.1-93.1) vs >35, and female contacts (aOR 2.5 95% CI 1.3-5.0). No contact parameters were associated with acquisition (aOR 1.0-1.1) for any of the duration, frequency, cumulative time in contact, or average duration parameters.

Conclusions

We did not find an association between close-range proximity events and SARS-CoV-2 household transmission. Our findings may be due to study limitations, that droplet-mediated transmission during close-proximity contacts plays a smaller role than airborne transmission of SARS-CoV-2 in the household, or due to high contact rates in households.

Funding

Wellcome Trust (Grant number 221003/Z/20/Z) in collaboration with the Foreign, Commonwealth, and Development Office, United Kingdom.

Evidence of pandemic fatigue associated with stricter tiered COVID-19 restrictions

Despite the availability of effective vaccines against SARS-CoV-2, non-pharmaceutical interventions remain an important part of the effort to reduce viral circulation caused by emerging variants with the capability of evading vaccine-induced immunity. With the aim of striking a balance between effective mitigation and long-term sustainability, several governments worldwide have adopted systems of tiered interventions, of increasing stringency, that are calibrated according to periodic risk assessments. A key challenge remains in quantifying temporal changes in adherence to interventions, which can decrease over time due to pandemic fatigue, under such kind of multilevel strategies. Here, we examine whether there was a reduction in adherence to tiered restrictions that were imposed in Italy from November 2020 through May 2021, and in particular we assess whether temporal trends in adherence depended on the intensity of the restrictions adopted. We analyzed daily changes in movements and in residential time, combining mobility data with the restriction tier enforced in the Italian regions. Through mixed-effects regression models, we identified a general trend of reduction in adherence and an additional effect of faster waning associated with the most stringent tier. We estimated both effects being of the same order of magnitude, suggesting that adherence decreased twice as fast during the strictest tier as in the least stringent one. Our results provide a quantitative measure of behavioral responses to tiered interventions-a metric of pandemic fatigue-that can be integrated into mathematical models to evaluate future epidemic scenarios.

Addressing the socioeconomic divide in computational modeling for infectious diseases

The COVID-19 pandemic has highlighted how structural social inequities fundamentally shape disease dynamics. Here, the authors provide a set of practical and methodological recommendations to address socioeconomic vulnerabilities in epidemic models.

Interplay between mobility, multi-seeding and lockdowns shapes COVID-19 local impact

Assessing the impact of mobility on epidemic spreading is of crucial importance for understanding the effect of policies like mass quarantines and selective re-openings. While many factors affect disease incidence at a local level, making it more or less homogeneous with respect to other areas, the importance of multi-seeding has often been overlooked. Multi-seeding occurs when several independent (non-clustered) infected individuals arrive at a susceptible population. This can lead to independent outbreaks that spark from distinct areas of the local contact (social) network. Such mechanism has the potential to boost incidence, making control efforts and contact tracing less effective. Here, through a modeling approach we show that the effect produced by the number of initial infections is non-linear on the incidence peak and peak time. When case importations are carried by mobility from an already infected area, this effect is further enhanced by the local demography and underlying mixing patterns: the impact of every seed is larger in smaller populations. Finally, both in the model simulations and the analysis, we show that a multi-seeding effect combined with mobility restrictions can explain the observed spatial heterogeneities in the first wave of COVID-19 incidence and mortality in five European countries. Our results allow us for identifying what we have called epidemic epicenter: an area that shapes incidence and mortality peaks in the entire country. The present work further clarifies the nonlinear effects that mobility can have on the evolution of an epidemic and highlight their relevance for epidemic control.

Socio-economic determinants of mobility responses during the first wave of COVID-19 in Italy: from provinces to neighbourhoods

After more than 1 year into the COVID-19 pandemic, governments worldwide still face the challenge of adopting non-pharmaceutical interventions to mitigate the risks posed by the emergence of new SARS-CoV-2 variants and the lack of a worldwide equitable vaccine allocation. Thus, it becomes crucial to identify the drivers of mobility responses to mitigation efforts during different restriction regimes, for planning interventions that are both economically and socially sustainable while effective in controlling an outbreak. Here, using anonymous and privacy-enhanced cell phone data from Italy, we investigate the determinants of spatial variations of reductions in mobility and co-location in response to the adoption and the lift of restrictions, considering both provinces and city neighbourhoods. In large urban areas, our analysis uncovers the desertification of historic city centres, which persisted after the end of the lockdown. Such centre-periphery gradient was mainly associated with differences in educational attainment. At the province level, the local structure of the labour market mainly explained the variations in mobility responses, together with other demographic factors, such as the population's age and sex composition. In the future, targeted interventions should take into account how the ability to comply with restrictions varies across geographical areas and socio-demographic groups.

Spatial and temporal variation in proximity networks of commercial dairy cattle in Great Britain

The nature of contacts between hosts can be important in facilitating or impeding the spread of pathogens within a population. Networks constructed from contacts between hosts allow examination of how individual variation might influence the spread of infections. Studying the contact networks of livestock species managed under different conditions can additionally provide insight into their influence on these contact structures. We collected high-resolution proximity and GPS location data from nine groups of domestic cattle (mean group size = 85) in seven dairy herds employing a range of grazing and housing regimes. Networks were constructed from cattle contacts (defined by proximity) aggregated by different temporal windows (2 h, 24 h, and approximately 1 week) and by location within the farm. Networks of contacts aggregated over the whole study were highly saturated but dividing contacts by space and time revealed substantial variation in cattle interactions. Cows showed statistically significant variation in the frequency of their contacts and in the number of cows with which they were in contact. When cows were in buildings, compared to being on pasture, contact durations were longer and cows contacted more other cows. A small number of cows showed evidence of consistent relationships but the majority of cattle did not. In one group where management allowed free access to all farm areas, cows showed asynchronous space use and, while at pasture, contacted fewer other cows and showed substantially greater between-individual variation in contacts than other groups. We highlight the degree to which variations in management (e.g. grazing access, milking routine) substantially alter cattle contact patterns, with potentially major implications for infection transmission and social interactions. In particular, where individual cows have free choice of their environment, the resulting contact networks may have a less-risky structure that could reduce the likelihood of direct transmission of infections.

Early social distancing policies in Europe, changes in mobility & COVID-19 case trajectories: Insights from Spring 2020

BACKGROUND

Social distancing have been widely used to mitigate community spread of SARS-CoV-2. We sought to quantify the impact of COVID-19 social distancing policies across 27 European counties in spring 2020 on population mobility and the subsequent trajectory of disease.

METHODS

We obtained data on national social distancing policies from the Oxford COVID-19 Government Response Tracker and aggregated and anonymized mobility data from Google. We used a pre-post comparison and two linear mixed-effects models to first assess the relationship between implementation of national policies and observed changes in mobility, and then to assess the relationship between changes in mobility and rates of COVID-19 infections in subsequent weeks.

RESULTS

Compared to a pre-COVID baseline, Spain saw the largest decrease in aggregate population mobility (~70%), as measured by the time spent away from residence, while Sweden saw the smallest decrease (~20%). The largest declines in mobility were associated with mandatory stay-at-home orders, followed by mandatory workplace closures, school closures, and non-mandatory workplace closures. While mandatory shelter-in-place orders were associated with 16.7% less mobility (95% CI: -23.7% to -9.7%), non-mandatory orders were only associated with an 8.4% decrease (95% CI: -14.9% to -1.8%). Large-gathering bans were associated with the smallest change in mobility compared with other policy types. Changes in mobility were in turn associated with changes in COVID-19 case growth. For example, a 10% decrease in time spent away from places of residence was associated with 11.8% (95% CI: 3.8%, 19.1%) fewer new COVID-19 cases.

DISCUSSION

This comprehensive evaluation across Europe suggests that mandatory stay-at-home orders and workplace closures had the largest impacts on population mobility and subsequent COVID-19 cases at the onset of the pandemic. With a better understanding of policies' relative performance, countries can more effectively invest in, and target, early nonpharmacological interventions.

Detecting adherence to the recommended childhood vaccination schedule from user-generated content in a US parenting forum

Vaccine hesitancy is considered as one of the leading causes for the resurgence of vaccine preventable diseases. A non-negligible minority of parents does not fully adhere to the recommended vaccination schedule, leading their children to be partially immunized and at higher risk of contracting vaccine preventable diseases. Here, we leverage more than one million comments of 201,986 users posted from March 2008 to April 2019 on the public online forum BabyCenter US to learn more about such parents. For 32% with geographic location, we find the number of mapped users for each US state resembling the census population distribution with good agreement. We employ Natural Language Processing to identify 6884 and 10,131 users expressing their intention of following the recommended and alternative vaccination schedule, respectively RSUs and ASUs. From the analysis of their activity on the forum we find that ASUs have distinctly different interests and previous experiences with vaccination than RSUs. In particular, ASUs are more likely to follow groups focused on alternative medicine, are two times more likely to have experienced adverse events following immunization, and to mention more serious adverse reactions such as seizure or developmental regression. Content analysis of comments shows that the resources most frequently shared by both groups point to governmental domains (.gov). Finally, network analysis shows that RSUs and ASUs communicate between each other (indicating the absence of echo chambers), however with the latter group being more endogamic and favoring interactions with other ASUs. While our findings are limited to the specific platform analyzed, our approach may provide additional insights for the development of campaigns targeting parents on digital platforms.

The importance and effectiveness of vaccines is generally high, but concerns toward vaccination contribute to eroding confidence in vaccination. Recently, alternative vaccination schedules are becoming popular as they allow parents to selectively delay or refuse certain vaccines depending on their specific concerns. Not being expressly anti-vaccination, these parents are challenging to identify on social media, however understanding the determinants of their hesitancy toward vaccines could help addressing parents’ concerns through targeted interventions. In this work, we create a Natural Language Processing pipeline to automatically identify parents who state their adherence to the recommended or alternative vaccination schedule on a popular parenting forum, BabyCenter US. We find that these users have distinct interests and different experiences with vaccination, although they frequently share similar sources of information (e.g., .gov websites). Differently from what is observed on most popular digital platforms like Facebook or Twitter, where users communicate mainly with like-minded users, Babycenter users communicate between each other independently of the vaccination schedule they adopt. These observations suggest that parenting fora may be a more suitable medium to develop intervention aiming to influence positively the vaccination behavior of parents.

COVID-19 outbreak response, a dataset to assess mobility changes in Italy following national lockdown

Italy has been severely affected by the COVID-19 pandemic, reporting the highest death toll in Europe as of April 2020. Following the identification of the first infections, on February 21, 2020, national authorities have put in place an increasing number of restrictions aimed at containing the outbreak and delaying the epidemic peak. On March 12, the government imposed a national lockdown. To aid the evaluation of the impact of interventions, we present daily time-series of three different aggregated mobility metrics: the origin-destination movements between Italian provinces, the radius of gyration, and the average degree of a spatial proximity network. All metrics were computed by processing a large-scale dataset of anonymously shared positions of about 170,000 de-identified smartphone users before and during the outbreak, at the sub-national scale. This dataset can help to monitor the impact of the lockdown on the epidemic trajectory and inform future public health decision making.

COVID-19 outbreak response, a dataset to assess mobility changes in Italy following national lockdown

Italy has been severely affected by the COVID-19 pandemic, reporting the highest death toll in Europe as of April 2020. Following the identification of the first infections, on February 21, 2020, national authorities have put in place an increasing number of restrictions aimed at containing the outbreak and delaying the epidemic peak. On March 12, the government imposed a national lockdown. To aid the evaluation of the impact of interventions, we present daily time-series of three different aggregated mobility metrics: the origin-destination movements between Italian provinces, the radius of gyration, and the average degree of a spatial proximity network. All metrics were computed by processing a large-scale dataset of anonymously shared positions of about 170,000 de-identified smartphone users before and during the outbreak, at the sub-national scale. This dataset can help to monitor the impact of the lockdown on the epidemic trajectory and inform future public health decision making.

HPV sampling options for cervical cancer screening: preferences of urban-dwelling Canadians in a changing paradigm

Introduction

Of women in Canada diagnosed with invasive cervical cancer, 50% have not been screened according to guidelines. Interventions involving self-collected samples for human papillomavirus (hpv) screening could be an avenue to increase uptake. To guide the development of cervical cancer screening interventions, we assessed ■ preferred sample collection options,■ sampling preferences according to previous screening behaviours, and■ preference for self-sampling among women not screened according to guidelines, as a function of their reasons for not being screened.

Methods

Data were collected in an online survey (Montreal, Quebec; 2016) and included information from female participants between the ages of 21 and 65 years who had not undergone hysterectomy and who had provided answers to survey questions about screening history, screening interval, and screening preferences (n = 526, weighted n = 574,392).

Results

In weighted analyses, 68% of all women surveyed and 82% of women not recently screened preferred screening by self-sampling. Among women born outside of Canada, the United States, or Europe, preference ranged from 47% to 60%. Nearly all women (95%-100%) who reported fear or embarrassment, dislike of undergoing a Pap test, or lack of time or geography-related availability of screening as one of their reasons for not being screened stated a preference for undergoing screening by self-sampling.

Conclusions

The results demonstrate a strong preference for self-sampling among never-screened and not-recently-screened women, and provides initial evidence for policymakers and researchers to address how best to integrate self-sampling hpv screening into both organized and opportunistic screening contexts.

Relationships between respiratory sinus arrhythmia and stress in college students

The purpose of this study was to examine the relationships between university students' respiratory sinus arrhythmia (RSA) profiles and both retrospective and momentary ratings of stress. Participants were undergraduate students enrolled in an introductory health science course (N = 64). Participants provided RSA data at rest (tonic) and following an orthostatic challenge (phasic), completed the 10-item Perceived Stress Scale (PSS), and completed 6 daily ecological momentary assessments (EMA) of stress for 1 week. Higher tonic RSA was associated with lower perceived stress assessed via PSS and average EMA responses. Those with higher tonic RSA did not differ in their experience of stress across the week, whereas those with lower tonic RSA experienced increased stress across the week, and these trajectories varied as a function of phasic responses. These findings suggest a need for greater emphasis on behavioral strategies for maintaining and enhancing autonomic nervous system health among college students.

Wearable Proximity Sensors for Monitoring a Mass Casualty Incident Exercise: Feasibility Study

BACKGROUND

Over the past several decades, naturally occurring and man-made mass casualty incidents (MCIs) have increased in frequency and number worldwide. To test the impact of such events on medical resources, simulations can provide a safe, controlled setting while replicating the chaotic environment typical of an actual disaster. A standardized method to collect and analyze data from mass casualty exercises is needed to assess preparedness and performance of the health care staff involved.

OBJECTIVE

In this study, we aimed to assess the feasibility of using wearable proximity sensors to measure proximity events during an MCI simulation. In the first instance, our objective was to demonstrate how proximity sensors can collect spatial and temporal information about the interactions between medical staff and patients during an MCI exercise in a quasi-autonomous way. In addition, we assessed how the deployment of this technology could help improve future simulations by analyzing the flow of patients in the hospital.

METHODS

Data were obtained and collected through the deployment of wearable proximity sensors during an MCI functional exercise. The scenario included 2 areas: the accident site and the Advanced Medical Post, and the exercise lasted 3 hours. A total of 238 participants were involved in the exercise and classified in categories according to their role: 14 medical doctors, 16 nurses, 134 victims, 47 Emergency Medical Services staff members, and 27 health care assistants and other hospital support staff. Each victim was assigned a score related to the severity of his/her injury. Each participant wore a proximity sensor, and in addition, 30 fixed devices were placed in the field hospital.

RESULTS

The contact networks show a heterogeneous distribution of the cumulative time spent in proximity by the participants. We obtained contact matrices based on the cumulative time spent in proximity between the victims and rescuers. Our results showed that the time spent in proximity by the health care teams with the victims is related to the severity of the patient's injury. The analysis of patients' flow showed that the presence of patients in the rooms of the hospital is consistent with the triage code and diagnosis, and no obvious bottlenecks were found.

CONCLUSIONS

Our study shows the feasibility of the use of wearable sensors for tracking close contacts among individuals during an MCI simulation. It represents, to our knowledge, the first example of unsupervised data collection-ie, without the need for the involvement of observers, which could compromise the realism of the exercise-of face-to-face contacts during an MCI exercise. Moreover, by permitting detailed data collection about the simulation, such as data related to the flow of patients in the hospital, such deployment provides highly relevant input for the improvement of MCI resource allocation and management.

Area-level income disparities in colorectal screening in Canada: evidence to inform future surveillance

Background

Participation in colorectal screening remains low even in countries with universal health coverage. Area-level determinants of low screening participation in Canada remain poorly understood.

Methods

We assessed the association between area-level income and two indicators of colorectal screening (having never been screened, having not been screened recently) by linking census-derived local area-level income data with self-reported screening data from urban-dwelling respondents to the Canadian Community Health Survey (50-75 years of age, cycles 2005 and 2007, n = 18,362) who reported no known risk factors for colorectal cancer. Generalized estimating equation Poisson models estimated the prevalence ratios and differences for having never been screened and having not been screened recently, adjusting for individual-level income, education, marital status, having a regular physician, age, and sex.

Results

About 53% of the study population had never been screened. Among individuals who had ever been screened, 35% had been screened recently. Adjusting for covariates, lower area-level income was associated with having never been screened [covariate-adjusted prevalence ratios: 1.24 for quartile 1; 95% confidence limits (cl): 1.16, 1.34; 1.25 for quartile 2; 95% cl: 1.15, 1.33; 1.15 for quartile 3; 95% cl: 1.08, 1.23]. Among individuals who had been screened in their lifetime, area-level income was not associated with having not been screened recently.

Conclusions

Lower area-level income is associated with having never been screened for colorectal cancer even after adjusting for individual socioeconomic factors. Those findings highlight the potential importance of socioeconomic contexts for colorectal screening initiation and merit attention in both future research and surveillance efforts.

Estimating the outcome of spreading processes on networks with incomplete information: A dimensionality reduction approach

Recent advances in data collection have facilitated the access to time-resolved human proximity data that can conveniently be represented as temporal networks of contacts between individuals. While the structural and dynamical information revealed by this type of data is fundamental to investigate how information or diseases propagate in a population, data often suffer from incompleteness, which possibly leads to biased estimations in data-driven models. A major challenge is thus to estimate the outcome of spreading processes occurring on temporal networks built from partial information. To cope with this problem, we devise an approach based on non-negative tensor factorization, a dimensionality reduction technique from multilinear algebra. The key idea is to learn a low-dimensional representation of the temporal network built from partial information and to use it to construct a surrogate network similar to the complete original network. To test our method, we consider several human-proximity networks, on which we perform resampling experiments to simulate a loss of data. Using our approach on the resulting partial networks, we build a surrogate version of the complete network for each. We then compare the outcome of a spreading process on the complete networks (nonaltered by a loss of data) and on the surrogate networks. We observe that the epidemic sizes obtained using the surrogate networks are in good agreement with those measured on the complete networks. Finally, we propose an extension of our framework that can leverage additional data, when available, to improve the surrogate network when the data loss is particularly large.

A theory of planned behaviour perspective on practitioners' beliefs toward the integration of the WIXX communication campaign messages and activities into daily practice

OBJECTIVES

To favour the dissemination and the implementation of the WIXX multimedia communication campaign, the aim of this study was to examine practitioners' beliefs towards the integration of the WIXX campaign activities into daily practice.

STUDY DESIGN

An exploratory qualitative study.

METHODS

Overall, 58 community-based practitioners completed an online questionnaire based on the theory of planned behaviour guidelines pertaining to perceived advantages/disadvantages and perceived barriers/facilitators toward the campaign. A content analysis was performed by two independent coders to extract modal beliefs. Results were validated by a third coder.

RESULTS

Local partners had a positive attitude toward the WIXX campaign, but significant barriers remained and needed to be addressed to ensure full implementation of this campaign (e.g. lack of time or resources, additional workload, complexity of the registration process and so forth). Beliefs were fragmented and diversified, indicating that they were highly context dependent.

CONCLUSIONS

To conclude, some remaining challenges regarding the full implementation of the WIXX communication campaign were identified, suggesting that additional efforts might be needed to ensure the full adoption of the campaign by local practitioners.

User-based representation of time-resolved multimodal public transportation networks

Multimodal transportation systems, with several coexisting services like bus, tram and metro, can be represented as time-resolved multilayer networks where the different transportation modes connecting the same set of nodes are associated with distinct network layers. Their quantitative description became possible recently due to openly accessible datasets describing the geo-localized transportation dynamics of large urban areas. Advancements call for novel analytics, which combines earlier established methods and exploits the inherent complexity of the data. Here, we provide a novel user-based representation of public transportation systems, which combines representations, accounting for the presence of multiple lines and reducing the effect of spatial embeddedness, while considering the total travel time, its variability across the schedule, and taking into account the number of transfers necessary. After the adjustment of earlier techniques to the novel representation framework, we analyse the public transportation systems of several French municipal areas and identify hidden patterns of privileged connections. Furthermore, we study their efficiency as compared to the commuting flow. The proposed representation could help to enhance resilience of local transportation systems to provide better design policies for future developments.

Activity clocks: spreading dynamics on temporal networks of human contact

Dynamical processes on time-varying complex networks are key to understanding and modeling a broad variety of processes in socio-technical systems. Here we focus on empirical temporal networks of human proximity and we aim at understanding the factors that, in simulation, shape the arrival time distribution of simple spreading processes. Abandoning the notion of wall-clock time in favour of node-specific clocks based on activity exposes robust statistical patterns in the arrival times across different social contexts. Using randomization strategies and generative models constrained by data, we show that these patterns can be understood in terms of heterogeneous inter-event time distributions coupled with heterogeneous numbers of events per edge. We also show, both empirically and by using a synthetic dataset, that significant deviations from the above behavior can be caused by the presence of edge classes with strong activity correlations.

What is the association between quality of treatment for depression and patient outcomes? A cohort study of adults consulting in primary care

BACKGROUND

The association between adequate treatment for a Major Depressive Episode (MDE) and improvements in depressive symptoms is not well established in naturalistic practice conditions. The main objective of this study was to examine the association between receiving at least one minimally adequate treatment for MDE (i.e. according to clinical guidelines) in the previous 12 months and evolution of depressive symptoms at 6- and 12-months. Associations with receiving pharmacotherapy and/or psychotherapy and the role of severity of depression were examined.

METHODS

This cohort study included 908 adults meeting criteria for previous-year MDE and consulting at one of 65 primary care clinics in Quebec, Canada. Multilevel analyses were performed.

RESULTS

Results show that (i) receiving at least one minimally adequate treatment for depression was associated with greater improvements in depression symptoms at 6 and at 12 months; (ii) adequate pharmacotherapy and adequate psychotherapy were both associated with greater improvements in depression symptoms, and (iii) the association between adequate treatment and improvement in depression symptoms varied as a function of severity of symptoms at the time of inclusion in the cohort with worse symptoms at the time of inclusion being associated with greater reductions at 6 and 12 months.

LIMITATIONS

Measures are self-reported. Participants were recruited at different stages over the course of their MDE.

CONCLUSIONS

This study shows that adequate treatment for depression is associated with improvements in depressive symptoms in naturalistic primary care practice conditions, but that those with more severe depressive symptoms are more likely to receive adequate treatment and improve across time.

Baseline determinants of global diet quality in older men and women from the NuAge cohort

Judicious food choices are of prime importance during aging.

OBJECTIVES

This study was conducted to identify individual and collective attributes determining global diet quality (DQ).

METHODOLOGY

Participants were 1,793 adults (52% women) from the NuAge study on nutrition and successful aging. Subjects aged 67 to 84 years in relatively good health were recruited from the Québec Medicare Database. Sociodemographic, affective, and cognitive data, health conditions, perceived physical health and functional status, dietary habits and dietary attributes and community resources were obtained using questionnaires. Body weight and height were measured and body mass index (BMI) was calculated. Three non-consecutive 24-hour diet recalls were collected at recruitment. DQ, assessed using the Canadian Healthy Eating Index (C-HEI, /100), was computed on the mean intakes from the diet recalls. Analyses were stratified by gender. Variables significantly related to DQ in bivariate analyses (p<.05) were entered into backward stepwise multiple regression analyses.

RESULTS

Among men, the final model showed higher education (β=0.23, p=.01), diet knowledge (β=0.96, p<.0001), number of daily meals (β=1.91, p=.02) and perceived physical health (β=0.06, p=.01) to be positive determinants of DQ, whereas alcohol consumption (β=-2.25, p=.05), wearing dentures (β=-2.31, p=.01) and eating regularly in restaurants (β=-1.65, p=.03) were negative determinants of DQ (adjusted R2 = 13.7%). Among women, higher education (β=0.29, p=.002), diet knowledge (β=0.54, p=.002), number of daily meals (β=3.61, p<.0001), and hunger (β=0.61, p<.0001) were positive determinants of global DQ; greater BMI (β=-0.16, p=.03) and chewing problems (β=-0.48, p=.03) were negative determinants of DQ (adjusted R2 = 7.8%).

DISCUSSION

These results point to several key factors influencing global DQ in older adults and also show gender-based differences. More research must be done to better understand how these factors change with aging and exert their impact on diet, particularly since variance in DQ was largely unexplained. As diet knowledge was an independent predictor for both genders, targeted, sustainable interventions are needed to ensure good diet quality as people age.

Schelling segregation in an open city: a kinetically constrained Blume-Emery-Griffiths spin-1 system

In the 70s Schelling introduced a multiagent model to describe the segregation dynamics that may occur with individuals having only weak preferences for "similar" neighbors. Recently variants of this model have been discussed, in particular, with emphasis on the links with statistical physics models. Whereas these models consider a fixed number of agents moving on a lattice, here, we present a version allowing for exchanges with an external reservoir of agents. The density of agents is controlled by a parameter which can be viewed as measuring the attractiveness of the city lattice. This model is directly related to the zero-temperature dynamics of the Blume-Emery-Griffiths spin-1 model, with kinetic constraints. With a varying vacancy density, the dynamics with agents making deterministic decisions leads to a variety of "phases" whose main features are the characteristics of the interfaces between clusters of agents of different types. The domains of existence of each type of interface are obtained analytically as well as numerically. These interfaces may completely isolate the agents leading to another type of segregation as compared to what is observed in the original Schelling model, and we discuss its possible socioeconomic correlates.

Validation of a measure of maternal perception of the child's health status

BACKGROUND

The main objective of this population-based and cross-sectional study was to determine the validity of maternal perception as an indicator of the 17-month-old child's health status.

METHODS

Data from this study came from the Quebec Longitudinal Study of Child Development (QLSCD, Round 1999) which was based on a representative sample of babies born in Québec in 1997 and 1998. The analyses were based on the 2045 children aged 17 months who participated in the survey in 1999. Maternal perception of the child's health status was examined as a function of a series of children's health indicators, namely the presence of acute health problems (last 3 months), asthma attacks since birth, presence of chronic problem and hospitalizations during the previous 12 months. Confounding influences of both maternal and child-related characteristics were controlled in the analyses.

RESULTS

Sequential logistic regressions indicated that maternal perception was strongly associated with the different health indicators even after controlling for confounding variables. However, a significant interaction between the child's gender and the presence of chronic health problems was observed. The association between maternal perception of the child's health and the presence of chronic health problems was stronger for boys than for girls.

CONCLUSIONS

The analyses confirm that the mother's perception of the health status of her 17-month-old child corresponds with the actual health status of the child as reflected by the presence or absence of selected health problems.

Adiposity, physical fitness and incident diabetes: the physical activity longitudinal study

AIMS/HYPOTHESIS

The purpose of this study was to investigate the relationships among adiposity, physical activity, physical fitness and the development of diabetes in a diverse sample of Canadians.

METHODS

The sample included 1,543 adults (709 men and 834 women) from the Canadian Physical Activity Longitudinal Study who were free of diabetes at baseline (1988). Several indicators of adiposity (BMI, waist circumference, WHR, sum of skinfold thicknesses), musculoskeletal fitness (sit-ups, push-ups, grip strength, trunk flexibility), cardiorespiratory fitness (maximal metabolic equivalents [METs]) and leisure-time physical activity levels were measured at baseline. Participants were followed until 2002-2004 for the ascertainment of new cases of diabetes.

RESULTS

The 15.5-year cumulative incidence of diabetes was 5.0% (5.2% in men, 4.9% in women). Adiposity and physical fitness, but not physical activity, were significant predictors of diabetes after adjustment for age, sex and several covariates. For each standard deviation of the indicators of adiposity, the risk of diabetes was 99-194% higher. Conversely, the risk was 70 and 61% lower for each standard deviation of maximal METs and composite musculoskeletal fitness score, respectively. Receiver operating characteristic curve analyses confirmed that neither adiposity nor physical fitness provided a superior prediction of incident diabetes.

CONCLUSIONS/INTERPRETATION

Adiposity and physical fitness were both important predictors of the development of diabetes in this cohort of Canadians.

A two-factor model of disordered eating

General psychopathology (i.e., personality disturbance, mood/affect dysregulation) has been identified as common and perhaps etiologically important in eating disorder (ED) patients. In this context, we examined a two-factor model of disordered eating which implicated the independent and interactive contribution of (a) general psychopathology (personality) and (b) eating-related psychopathology (body esteem) in explaining deviant eating patterns. A sample of 266 female college/university students (M age=22.1) and 76 women with a clinically diagnosed ED (M age=28.09) completed paper and pencil questionnaires of deviant eating patterns, body esteem, and personality pathology. First, a K-means cluster procedure revealed a compelling three-cluster solution among the nonclinical women based on deviant eating variables: <<deviant eaters>>(n=61), <<restrainers>> (n=92), and <<nondeviant eaters>> (n=103). The ED women were classified as Cluster 4; <<clinical>> (n=76). Second, to evaluate our two-factor model, multinomial logistic regression (MLR) was used with cluster membership as the outcome variable and the following variables as predictors: body esteem, personality pathology, and all two-way interactions. In addition to several significant main effects, three interaction terms were marginally significant: Body esteem appearance x Narcissism (P=.047), Body esteem weight x Narcissism (P=.044), and Body esteem attribution x Stimulus seeking(P=.051). The overall extent of correct cluster classification was 63%. These results indicate that the presence of both low body esteem and maladaptive personality, and the interactive operation of these two factors, seems to contribute to the likelihood of having an eating disorder, beyond the independent contribution of either factor alone. Results are considered in the context of etiological models in which general psychopathology presents a vulnerability factor in ED development.

Interpersonal influence and disordered eating behaviors in adolescent girls: the role of peer modeling, social reinforcement, and body-related teasing

This study investigated the association between interpersonal relationships, eating behaviors, and body esteem in a sample of adolescent girls. Participants included 876 girls who completed questionnaires regarding body esteem, eating behavior, peer pressure, and interpersonal relationships. Peer pressure was a strong predictor of eating behavior and body esteem after controlling for interpersonal variables. High externalized self-perceptions, self-reported teasing, and attributions about the importance of weight and shape for popularity and dating were important predictors of both body esteem and eating behavior. Also, girls who were nominated as popular by peers were more likely to engage in disordered eating and have lower body esteem. Results highlight the need for eating disorder prevention at the level of the peer group. Programs should focus on decreasing pressure to be thin, acceptance by peers for attributes other than appearance, and combating weight- and shape-related teasing within the school system.

The cumulative impact of being overweight on women's body esteem: a preliminary study

As much research indicates that a woman's current weight status is an important predictor of her body esteem, we examined the relationship between weight status history (retrospective self-report since the age of 5 years) and current body esteem among 266 female college students, who completed a measure of body esteem and reported whether they had been "underweight", "normal weight", or "overweight" during 3 age ranges. Analysis of variance (ANOVA) was used to examine differences in current body esteem between groups characterised by the following weight history trajectories: "always overweight", "always normal/underweight", "increase in weight over time" and "decrease in weight over time". Although the women in the groups "always overweight" and "increase in weight over time" were currently overweight [according to self-reported body mass index (BMI)], the current body esteem of the former was significantly lower (worse) than that of the latter. We introduce the idea that being overweight for a long period of time has a cumulatve negative impact on adult body esteem.

Neighbourhood level versus individual level correlates of women's body dissatisfaction: toward a multilevel understanding of the role of affluence

STUDY OBJECTIVE

This study examined the prevalence of body dissatisfaction as a function of individual level and neighbourhood level indicators of affluence.

PARTICIPANTS AND SETTING

A subset of data from a larger random digit dialling telephone survey was used to obtain individual level data on body dissatisfaction, body weight and height, and income from a group of 895 adult women (age 24-56, 61% English speaking) living in 52 neighbourhoods (census tract areas) within the provinces of Alberta, Ontario, and Quebec, Canada who were selected for their heterogeneity in social class.

DESIGN

Aggregated census tract data from 1996 were used to develop neighbourhood indicators of affluence. Using hierarchical linear modelling, body dissatisfaction (dichotomous) was examined as a function of individual body mass index, individual level affluence and neighbourhood level affluence.

MAIN RESULTS

The impact of body mass index on body dissatisfaction depended on the level of neighbourhood affluence: an average body mass index was associated with higher likelihood of reporting body dissatisfaction in a neighbourhood of above average affluence (71% probability) than in a neighbourhood of average affluence (58% probability), independent of a woman's individual affluence (whether she was low income or not).

CONCLUSION

It is concluded that a clearer understanding of the role of affluence on body dissatisfaction can be achieved by a joint examination of individual and neighbourhood level influences.

Association of serotonin and cortisol indices with childhood abuse in bulimia nervosa

BACKGROUND

Bulimia nervosa (BN) is reported to co-occur with childhood abuse and alterations in central serotonin (5-hydroxytryptamine [5-HT]) and cortisol mechanisms. However, findings also link childhood abuse to anomalous 5-HT and cortisol function, and this motivated us to explore relationships between childhood abuse and neurobiological variations in BN.

METHODS

Thirty-five bulimic and 25 nonbulimic women were assessed for childhood physical and sexual abuse, eating symptoms, and comorbid psychopathological tendencies. These women provided blood samples for measurement of platelet hydrogen-3-paroxetine binding and serial prolactin and cortisol responses following oral administration of the partial 5-HT agonist meta-chlorophenylpiperazine (m-CPP).

RESULTS

Bulimic women showed markedly lower mean +/- SD density (B(max)) of paroxetine-binding sites (631.12 +/- 341.58) than did normal eaters (1213.00 +/- 628.74) (t(54) = -4.47; P =.001). Paroxetine binding did not vary with childhood abuse. In contrast, measures of peak change on prolactin levels after m-CPP administration (Delta-peak prolactin) indicated blunted response in abused bulimic women (7.26 +/- 7.06), nonabused bulimic women (5.62 +/- 3.95), and abused women who were normal eaters (5.73 +/- 5.19) compared with nonabused women who were normal eaters (13.57 +/- 9.94) (F(3,51) = 3.04, P =.04). Furthermore, individuals reporting childhood abuse showed decreased plasma cortisol levels relative to nonabused women who were normal eaters.

CONCLUSION

Findings imply that BN and childhood abuse are both generally associated with reduced 5-HT tone but that childhood abuse may be somewhat more specifically linked to reduced cortisol levels (ie, hypothalamic-pituitary-adrenal axis) activity.

The role of perfectionism and excessive commitment to exercise in explaining dietary restraint: replication and extension

The etiological complexity of the eating disorders has incited researchers to examine how personality characteristics and other variables operate jointly in the development of deviant eating patterns.

OBJECTIVE

This study investigated the independent, interactive, and indirect prediction of dietary restraint by perfectionism and excessive commitment to exercise.

METHOD

Multiple regression analyses designed to test moderating and mediating models were conducted on a sample of female university students (n = 269).

RESULTS

Several dimensions of perfectionism, as well as excessive commitment to exercise, significantly and independently predicted dietary restraint in these women. There was no evidence for an interaction effect. Mediation analyses suggested that for selected dimensions of perfectionism, the direct relationship between perfectionism and dietary restraint is partially explained by excessive commitment to exercise.

DISCUSSION

Interventions aimed at challenging perfectionistic standards in the context of dieting need to address not only one's self-standards, but one's perceptions of standards held by others. The mediating role of excessive exercise commitment pinpoints this variable as an alternative intervention target in the prevention of excessive dieting.

Contributions of acute bouts of vigorous physical activity to explaining diurnal variations in feeling states in active, middle-aged women

This study describes diurnal variations in feeling states in 84 women as a function of involvement in physical activity. Women completed feeling state checklists before and after bouts of vigorous physical activity that lasted a minimum of 20 min and on a stratified random-sampling protocol in response to a stimulus from an electronic pager. Participants self-reported the date, the time of day, the stimulus for responding, their current feeling states, and their ongoing activity. A total of 7,295 complete mood and activity reports were recorded in response to pager calls that were further coded into experience samplings that occurred on a nonexercise day, prior to exercise on an exercise day, and following exercise on an exercise day. Multilevel modeling analyses showed that in samplings recorded following exercise on exercise days, positive engagement, revitalization, and tranquility were elevated in comparison with predicted diurnal patterns.

Contributions of acute bouts of vigorous physical activity to explaining diurnal variations in feeling states in active, middle-aged women

This study describes diurnal variations in feeling states in 84 women as a function of involvement in physical activity. Women completed feeling state checklists before and after bouts of vigorous physical activity that lasted a minimum of 20 min and on a stratified random-sampling protocol in response to a stimulus from an electronic pager. Participants self-reported the date, the time of day, the stimulus for responding, their current feeling states, and their ongoing activity. A total of 7,295 complete mood and activity reports were recorded in response to pager calls that were further coded into experience samplings that occurred on a nonexercise day, prior to exercise on an exercise day, and following exercise on an exercise day. Multilevel modeling analyses showed that in samplings recorded following exercise on exercise days, positive engagement, revitalization, and tranquility were elevated in comparison with predicted diurnal patterns.

Effects of leadership style and group dynamics on enjoyment of physical activity

PURPOSE

The primary purpose of this study was to examine the independent and combined effects of leadership style and group dynamics on the enjoyment of physical activity.

DESIGN

A completely randomized 2 x 2 factorial design was used in which the manipulation of "leadership style" (socially enriched vs. bland) was crossed with a manipulation of "group dynamics" (socially enriched vs. bland).

SETTING

The study was conducted in an aerobics studio on a university campus.

SUBJECTS

The sample included 48 male and 42 female undergraduate students who were moderately active.

INTERVENTION

Each participant was involved in a single session of step aerobics. A female graduate student provided either an enriched or bland series of interactions to manipulate leadership style, and a trained group of planted undergraduates was used to promote either an enriched or bland group environment.

MEASURES

The outcome measures of interest were enjoyment and the probability of engaging in a similar activity in the future.

RESULTS

Participants in the enriched leadership style plus enriched group dynamics condition reported higher enjoyment than did participants in the other three conditions. On average, the level of enjoyment was 22.07% higher in this condition than in the other three conditions (p < .001). The probability of future involvement was 13.93% higher for participants in the enriched group environment, irrespective of leadership style (p < .03).

CONCLUSIONS

Enjoyment during physical activity is optimized when a positive and supportive leadership style is coupled with an enriched and supportive group environment. Future research is required to extend these findings to other activities and populations.

Hypersensitivity to social interactions in bulimic syndromes: relationship to binge eating

This study used a 6- to 22-day experience-sampling procedure to test for hypersensitivity to social interactions in bulimic individuals. Ratings on daily social interactions, self-concepts, moods, and eating behaviors from 55 actively bulimic, 18 formerly bulimic, and 31 noneating-disordered women were obtained. Hierarchical linear modeling analyses showed negative social interactions to be associated with significant increases in self-criticism (SC) and deteriorations in mood in all participants. However, bulimic participants (active or in remission) showed larger increases in SC following negative social interactions than did normal eaters (and thus seemed to be hypersensitive to interpersonal experiences). Additional analyses indicated that binge episodes tended to be preceded by poorer than average social experiences, self-concepts, and moods and followed by deteriorations in self-concept, mood, and social perception. The authors discuss possible perpetuating influences of interpersonal sensitivity in bulimic syndromes.

Impulsivity, dietary control and the urge to binge in bulimic syndromes

OBJECTIVE

Naturalistic studies on sufferers of bulimic syndromes suggest that binge episodes are often precipitated by episodes of dietary restraint. However, evidence also implies that binge eating may, in certain psychopathological contexts, have less direct connection with dietary control factors. Applying an 8- to 22-day experience-sampling procedure in individuals with bulimic syndromes, we explored possible moderating effects of trait impulsivity upon the ongoing association between cognitive dietary control and binge eating.

METHOD

Fifty-one women with bulimia spectrum eating disorders provided periodic daily observations on cognitive control over eating, urges to binge, and binge episodes. Impulsivity was assessed by self-report questionnaire. Hierarchical linear modeling techniques were used to assess relationships of interest.

RESULTS

Urge to Binge was higher (on average) prior to eating binges than at comparable times on binge-free days, and thus seemed to signal the potential for binge eating. More importantly, scores on Urge to Binge and Dietary Control covaried systematically over time in most participants, but were desynchronous in highly impulsive individuals.

CONCLUSIONS

Binge eating is closely linked to dietary control in most bulimic individuals, but this may be less typical of individuals showing marked impulsivity. We discuss factors that may explain the disconnection between Dietary Control and Urge to Binge in impulsive binge eaters as well as the implications of such factors for the management of bulimic patients with marked impulsivity.

Hypersensitivity to social interactions in bulimic syndromes: relationship to binge eating

This study used a 6- to 22-day experience-sampling procedure to test for hypersensitivity to social interactions in bulimic individuals. Ratings on daily social interactions, self-concepts, moods, and eating behaviors from 55 actively bulimic, 18 formerly bulimic, and 31 noneating-disordered women were obtained. Hierarchical linear modeling analyses showed negative social interactions to be associated with significant increases in self-criticism (SC) and deteriorations in mood in all participants. However, bulimic participants (active or in remission) showed larger increases in SC following negative social interactions than did normal eaters (and thus seemed to be hypersensitive to interpersonal experiences). Additional analyses indicated that binge episodes tended to be preceded by poorer than average social experiences, self-concepts, and moods and followed by deteriorations in self-concept, mood, and social perception. The authors discuss possible perpetuating influences of interpersonal sensitivity in bulimic syndromes.

A risk-adjusted measure of hospitalization rates for evaluating community mental health program performance

The authors describe the use of risk-adjusted hospitalization rates to measure community mental health treatment outcomes. The risk adjustment involves comparing rates of hospitalization subsequent to treatment with rates of hospitalization prior to treatment. The research uses a probabilistic methodology that reliably estimates caseload overlap by comparing the distribution of the dates of birth observed in data sets to the distribution of dates of birth in the general population. Findings indicate that risk-adjusted hospitalization rates are substantially different than unadjusted rates. Half of the community programs in one state consistently achieved positive outcomes in four consecutive years; other programs had mixed results or no change.

Family process in health research: extending a family typology to a new cultural context

To describe family context in health research, the authors tested a typology of families developed in California with a sample of families in Quebec, Canada. Family scales from the California study were submitted to focus groups, translated, and standardized on a sample of 209 parents. A panel of experts then revised the scales to make them relevant to Quebec families and to health promotion. Data from the new and revised scales were collected on 509 Quebec couples (1,018 spouses) and were clustered separately by gender, using K means. The procedure classified all respondents into family types that paralleled the original typology. Discriminant analyses indicated that family profile variables significantly distinguished family types. Comparisons with family, stress, and health variables further differentiated among the types and expanded their meaning. The study demonstrates a method for redefining and extending family data in health research with different cultural groups.