Psychosocial factors, health behaviors and risk of cancer incidence: Testing interaction and effect modification in an individual participant data meta-analysis.

Depression, anxiety and other psychosocial factors are hypothesized to be involved in cancer development. We examined whether psychosocial factors interact with or modify the effects of health behaviors, such as smoking and alcohol use, in relation to cancer incidence. Two-stage individual participant data meta-analyses were performed based on 22 cohorts of the PSYchosocial factors and CAncer (PSY-CA) study. We examined nine psychosocial factors (depression diagnosis, depression symptoms, anxiety diagnosis, anxiety symptoms, perceived social support, loss events, general distress, neuroticism, relationship status), seven health behaviors/behavior-related factors (smoking, alcohol use, physical activity, body mass index, sedentary behavior, sleep quality, sleep duration) and seven cancer outcomes (overall cancer, smoking-related, alcohol-related, breast, lung, prostate, colorectal). Effects of the psychosocial factor, health behavior and their product term on cancer incidence were estimated using Cox regression. We pooled cohort-specific estimates using multivariate random-effects meta-analyses. Additive and multiplicative interaction/effect modification was examined. This study involved 437,827 participants, 36,961 incident cancer diagnoses, and 4,749,481 person years of follow-up. Out of 744 combinations of psychosocial factors, health behaviors, and cancer outcomes, we found no evidence of interaction. Effect modification was found for some combinations, but there were no clear patterns for any particular factors or outcomes involved. In this first large study to systematically examine potential interaction and effect modification, we found no evidence for psychosocial factors to interact with or modify health behaviors in relation to cancer incidence. The behavioral risk profile for cancer incidence is similar in people with and without psychosocial stress.

The mediating role of health behaviors in the association between depression, anxiety and cancer incidence: an individual participant data meta-analysis.

BACKGROUND: Although behavioral mechanisms in the association among depression, anxiety, and cancer are plausible, few studies have empirically studied mediation by health behaviors. We aimed to examine the mediating role of several health behaviors in the associations among depression, anxiety, and the incidence of various cancer types (overall, breast, prostate, lung, colorectal, smoking-related, and alcohol-related cancers). METHODS: Two-stage individual participant data meta-analyses were performed based on 18 cohorts within the Psychosocial Factors and Cancer Incidence consortium that had a measure of depression or anxiety (N = 319 613, cancer incidence = 25 803). Health behaviors included smoking, physical inactivity, alcohol use, body mass index (BMI), sedentary behavior, and sleep duration and quality. In stage one, path-specific regression estimates were obtained in each cohort. In stage two, cohort-specific estimates were pooled using random-effects multivariate meta-analysis, and natural indirect effects (i.e. mediating effects) were calculated as hazard ratios (HRs). RESULTS: Smoking (HRs range 1.04-1.10) and physical inactivity (HRs range 1.01-1.02) significantly mediated the associations among depression, anxiety, and lung cancer. Smoking was also a mediator for smoking-related cancers (HRs range 1.03-1.06). There was mediation by health behaviors, especially smoking, physical inactivity, alcohol use, and a higher BMI, in the associations among depression, anxiety, and overall cancer or other types of cancer, but effects were small (HRs generally below 1.01). CONCLUSIONS: Smoking constitutes a mediating pathway linking depression and anxiety to lung cancer and smoking-related cancers. Our findings underline the importance of smoking cessation interventions for persons with depression or anxiety.

SARS-CoV-2 vaccination uptake in six ethnic groups living in Amsterdam, the Netherlands: A registry-based study within the HELIUS cohort.

OBJECTIVE: Ethnic minority groups have experienced a disproportionate burden of COVID-19, and should therefore be especially encouraged to receive SARS-CoV-2 vaccination. This study compared first-dose uptake of the primary SARS-CoV-2 vaccination series across six ethnic groups in Amsterdam, the Netherlands in 2021. METHODS: We analyzed data from participants of the population-based HELIUS cohort. We linked their data to the SARS-CoV-2 vaccination registry data of the Public Health Service of Amsterdam. We included registry data from January 6, 2021 (the start of the Dutch vaccination campaign) until September 6, 2021 (a date by which all adults in the Netherlands could have received one or two vaccine doses). SARS-CoV-2 vaccination uptake was defined as having received at least one vaccine dose of the primary vaccination series. We examined the association between ethnicity and vaccination uptake using multivariable logistic regression, while accounting for the age and sex distribution of ethnic groups in Amsterdam. RESULTS: We included 19,006 participants (median age 53 years [interquartile range 41-62], 57% female). SARS-CoV-2 vaccination uptake was highest in the South-Asian Surinamese group (60.3%, 95%CI = 58.2-62.3%), followed by the Dutch (59.6%, 95%CI = 58.0-61.1%), Ghanaian (54.1%, 95%CI = 51.7-56.5%), Turkish (47.7%, 95%CI = 45.9-49.6%), African Surinamese (43.0%, 95%CI = 41.2-44.7%), and Moroccan (35.8%, 95%CI = 34.1-37.5%) groups. After adjusting for age, sex, perceived social support, and presence of relevant comorbidities, participants of African Surinamese, Ghanaian, Turkish and Moroccan origin were significantly less likely to be vaccinated than those of Dutch origin. CONCLUSIONS: Prevention strategies should continue tailoring to specific ethnic groups to encourage vaccination uptake and reduce barriers to vaccination.

Development of an action programme tackling obesity-related behaviours in adolescents: a participatory system dynamics approach.

System dynamics approaches are increasingly addressing the complexity of public health problems such as childhood overweight and obesity. These approaches often use system mapping methods, such as the construction of causal loop diagrams, to gain an understanding of the system of interest. However, there is limited practical guidance on how such a system understanding can inform the development of an action programme that can facilitate systems changes. The Lifestyle Innovations Based on Youth Knowledge and Experience (LIKE) programme combines system dynamics and participatory action research to improve obesity-related behaviours, including diet, physical activity, sleep and sedentary behaviour, in 10-14-year-old adolescents in Amsterdam, the Netherlands. This paper illustrates how we used a previously obtained understanding of the system of obesity-related behaviours in adolescents to develop an action programme to facilitate systems changes. A team of evaluation researchers guided interdisciplinary action-groups throughout the process of identifying mechanisms, applying the Intervention Level Framework to identify leverage points and arriving at action ideas with aligning theories of change. The LIKE action programme consisted of 8 mechanisms, 9 leverage points and 14 action ideas which targeted the system's structure and function within multiple subsystems. This illustrates the feasibility of developing actions targeting higher system levels within the confines of a research project timeframe when sufficient and dedicated effort in this process is invested. Furthermore, the system dynamics action programme presented in this study contributes towards the development and implementation of public health programmes that aim to facilitate systems changes in practice.

How exposure to chronic stress contributes to the development of type 2 diabetes: A complexity science approach.

Chronic stress contributes to the onset of type 2 diabetes (T2D), yet the underlying etiological mechanisms are not fully understood. Responses to stress are influenced by earlier experiences, sex, emotions and cognition, and involve a complex network of neurotransmitters and hormones, that affect multiple biological systems. In addition, the systems activated by stress can be altered by behavioral, metabolic and environmental factors. The impact of stress on metabolic health can thus be considered an emergent process, involving different types of interactions between multiple variables, that are driven by non-linear dynamics at different spatiotemporal scales. To obtain a more comprehensive picture of the links between chronic stress and T2D, we followed a complexity science approach to build a causal loop diagram (CLD) connecting the various mediators and processes involved in stress responses relevant for T2D pathogenesis. This CLD could help develop novel computational models and formulate new hypotheses regarding disease etiology.

Depression, anxiety, and the risk of cancer: An individual participant data meta-analysis.

BACKGROUND: Depression and anxiety have long been hypothesized to be related to an increased cancer risk. Despite the great amount of research that has been conducted, findings are inconclusive. To provide a stronger basis for addressing the associations between depression, anxiety, and the incidence of various cancer types (overall, breast, lung, prostate, colorectal, alcohol-related, and smoking-related cancers), individual participant data (IPD) meta-analyses were performed within the Psychosocial Factors and Cancer Incidence (PSY-CA) consortium. METHODS: The PSY-CA consortium includes data from 18 cohorts with measures of depression or anxiety (up to N = 319,613; cancer incidences, 25,803; person-years of follow-up, 3,254,714). Both symptoms and a diagnosis of depression and anxiety were examined as predictors of future cancer risk. Two-stage IPD meta-analyses were run, first by using Cox regression models in each cohort (stage 1), and then by aggregating the results in random-effects meta-analyses (stage 2). RESULTS: No associations were found between depression or anxiety and overall, breast, prostate, colorectal, and alcohol-related cancers. Depression and anxiety (symptoms and diagnoses) were associated with the incidence of lung cancer and smoking-related cancers (hazard ratios [HRs], 1.06-1.60). However, these associations were substantially attenuated when additionally adjusting for known risk factors including smoking, alcohol use, and body mass index (HRs, 1.04-1.23). CONCLUSIONS: Depression and anxiety are not related to increased risk for most cancer outcomes, except for lung and smoking-related cancers. This study shows that key covariates are likely to explain the relationship between depression, anxiety, and lung and smoking-related cancers. PREREGISTRATION NUMBER: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=157677.

Complexity in Epidemiology and Public Health. Addressing Complex Health Problems Through a Mix of Epidemiologic Methods and Data.

Public health and the underlying disease processes are complex, often involving the interaction of biologic, social, psychologic, economic, and other processes that may be nonlinear and adaptive and have other features of complex systems. There is therefore a need to push the boundaries of public health beyond single-factor data analysis and expand the capacity of research methodology to tackle real-world complexities. This article sets out a way to operationalize complex systems thinking in public health, with a particular focus on how epidemiologic methods and data can contribute towards this end. Our proposed framework comprises three core dimensions-patterns, mechanisms, and dynamics-along which complex systems may be conceptualized. These dimensions cover seven key features of complex systems-emergence, interactions, nonlinearity, interference, feedback loops, adaptation, and evolution. We relate this framework to examples of methods and data traditionally used in epidemiology. We conclude that systematic production of knowledge on complex health issues may benefit from: formulation of research questions and programs in terms of the core dimensions we identify, as a comprehensive way to capture crucial features of complex systems; integration of traditional epidemiologic methods with systems methodology such as computational simulation modeling; interdisciplinary work; and continued investment in a wide range of data types. We believe that the proposed framework can support the systematic production of knowledge on complex health problems, with the use of epidemiology and other disciplines. This will help us understand emergent health phenomena, identify vulnerable population groups, and detect leverage points for promoting public health.

Ethnic Differences in Carotid Intima Media Thickness and Plaque Presence - The HELIUS study.

Introduction In the Netherlands, the prevalence of cardiovascular diseases (CVD) is higher among South-Asian Surinamese and lower among Moroccans compared to the Dutch. Traditional risk factors for atherosclerotic CVD do not fully explain these disparities. We aim to assess ethnic differences in plaque presence and intima media thickness (cIMT) and explore to which extent these differences are explained by traditional risk factors. Methods We used cross-sectional data from a subgroup of participants enrolled in the multi-ethnic population-based HEalthy Life In an Urban Setting (HELIUS) study who underwent carotid ultrasonography. Logistic and linear regression models were built to assess ethnic differences in plaque presence and cIMT with the Dutch population as reference. Additional models were created to adjust for socioeconomic status, body height and cardiovascular risk factors. Results Of the 3022 participants, 1183, 1051 and 790 individuals were of Dutch, South-Asian Surinamese and Moroccan descent. Mean age was 60.9 years (SD 8.0), 52.8% was female. Compared to the Dutch, we found lower odds for plaque presence in Moroccans (0.77, 95% CI 0.62; 0.95) and no significant differences between the South-Asian Surinamese and Dutch population (0.91, 95% CI 0.76; 1.10). After adjustment for CVD risk factors, we found a lower plaque presence in South-Asian Surinamese (0.63, 95% CI 0.48; 0.82). In both Moroccan and South-Asian Surinamese individuals, adjustment for socioeconomic status did not materially change the results. cIMT was lower in South-Asian Surinamese compared to the Dutch (-17.9 µm, 95% CI -27.9; -7.9) and partly explained by ethnic differences in body height as South-Asian Surinamese individuals were, on average, shorter than the Dutch population. No differences in cIMT between Moroccans and Dutch were found. Conclusions cIMT and plaque prevalence differ between ethnic groups independent of CVD risk. Lower plaque prevalence in Moroccans was partly attributable to a lower prevalence of traditional CVD risk factors, while body height was an important contributor to differences in cIMT in South-Asians. This study emphasizes the need for ethnic-specific cut-off values for plaque presence and cIMT.

Relative contributions of pre-pandemic factors and intra-pandemic activities to differential COVID-19 risk among migrant and non-migrant populations in the Netherlands: lessons for future pandemic preparedness.

BACKGROUND: Although risk factors for differences in SARS-CoV-2 infections between migrant and non-migrant populations in high income countries have been identified, their relative contributions to these SARS-CoV-2 infections, which could aid in the preparation for future viral pandemics, remain unknown. We investigated the relative contributions of pre-pandemic factors and intra-pandemic activities to differential SARS-CoV-2 infections in the Netherlands by migration background (Dutch, African Surinamese, South-Asian Surinamese, Ghanaians, Turkish, and Moroccan origin). METHODS: We utilized pre-pandemic (2011-2015) and intra-pandemic (2020-2021) data from the HELIUS cohort, linked to SARS-CoV-2 PCR test results from Public Health Service of Amsterdam (GGD Amsterdam). Pre-pandemic factors included socio-demographic, medical, and lifestyle factors. Intra-pandemic activities included COVID-19 risk aggravating and mitigating activities such as physical distancing, use of face masks, and other similar activities. We calculated prevalence ratios (PRs) in the HELIUS population that was merged with GGD Amsterdam PCR test data using robust Poisson regression (SARS-CoV-2 PCR test result as outcome, migration background as predictor). We then obtained the distribution of migrant and non-migrant populations in Amsterdam as of January 2021 from Statistics Netherlands. The migrant populations included people who have migrated themselves as well as their offspring. We used PRs and the population distributions to calculate population attributable fractions (PAFs) using the standard formula. We used age and sex adjusted models to introduce pre-pandemic factors and intra-pandemic activities, noting the relative changes in PAFs. RESULTS: From 20,359 eligible HELIUS participants, 8,595 were linked to GGD Amsterdam PCR test data and included in the study. Pre-pandemic socio-demographic factors (especially education, occupation, and household size) resulted in the largest changes in PAFs when introduced in age and sex adjusted models (up to 45%), followed by pre-pandemic lifestyle factors (up to 23%, especially alcohol consumption). Intra-pandemic activities resulted in the least changes in PAFs when introduced in age and sex adjusted models (up to 16%). CONCLUSION: Interventions that target pre-pandemic socio-economic status and other drivers of health inequalities between migrant and non-migrant populations are urgently needed at present to better prevent infection disparities in future viral pandemics.

Does the socioeconomic positioned neighbourhood matter? Norwegian adolescents' perceptions of barriers and facilitators for physical activity.

BACKGROUND AND AIMS: A higher proportion of adolescents from lower socioeconomic position families tend to be less physically active than their counterparts from higher socioeconomic position families. More research is needed to understand the causes of these differences, particularly the influence of the neighbourhood environment. This qualitative study aims to explore how adolescents and their parents from higher and lower socioeconomic neighbourhoods perceive the social, organisational and physical environment influencing adolescents' physical activity behaviours. METHOD: We conducted six semi-structured focus groups with 35 13-14-year-olds and eight interviews with some of their parents. The interviewees were recruited from one higher and two lower socioeconomic neighbourhoods in Oslo, Norway. Theme-based coding was used for analysis, and the results discussed in light of an ecological framework. RESULTS: The results indicate that factors like social norms in a neighbourhood could shape adolescents' physical activity behaviour, and a social norm of an active lifestyle seemed to be an essential facilitator in the higher socioeconomic neighbourhood. Higher availability of physical activity and high parental engagement seemed to facilitate higher physical activity in this neighbourhood. In the lower socioeconomic neighbourhoods, the availability of local organised physical activity and volunteer engagement from parents varied. Programmes from the municipality and volunteer organisations seemed to influence and be essential for adolescents' physical activity behaviour in these neighbourhoods. CONCLUSIONS: The results illustrate the complexity of behaviour and environment interaction, and a limitation in explaining the phenomenon by focusing primarily on the individual level rather than an ecological perspective.

The ENCOMPASS framework: a practical guide for the evaluation of public health programmes in complex adaptive systems.

BACKGROUND: Systems thinking embraces the complexity of public health problems, including childhood overweight and obesity. It aids in understanding how factors are interrelated, and it can be targeted to produce favourable changes in a system. There is a growing call for systems approaches in public health research, yet limited practical guidance is available on how to evaluate public health programmes within complex adaptive systems. The aim of this paper is to present an evaluation framework that supports researchers in designing systems evaluations in a comprehensive and practical way. METHODS: We searched the literature for existing public health systems evaluation studies. Key characteristics on how to conduct a systems evaluation were extracted and compared across studies. Next, we overlaid the identified characteristics to the context of the Lifestyle Innovations Based on Youth Knowledge and Experience (LIKE) programme evaluation and analyzed which characteristics were essential to carry out the LIKE evaluation. This resulted in the Evaluation of Programmes in Complex Adaptive Systems (ENCOMPASS) framework. RESULTS: The ENCOMPASS framework includes five iterative stages: (1) adopting a system dynamics perspective on the overall evaluation design; (2) defining the system boundaries; (3) understanding the pre-existing system to inform system changes; (4) monitoring dynamic programme output at different system levels; and (5) measuring programme outcome and impact in terms of system changes. CONCLUSIONS: The value of ENCOMPASS lies in the integration of key characteristics from existing systems evaluation studies, as well as in its practical, applied focus. It can be employed in evaluating public health programmes in complex adaptive systems. Furthermore, ENCOMPASS provides guidance for the entire evaluation process, all the way from understanding the system to developing actions to change it and to measuring system changes. By the nature of systems thinking, the ENCOMPASS framework will likely evolve further over time, as the field expands with more completed studies.

The association between gender-related characteristics and type 2 diabetes risk in a multi-ethnic population: The HELIUS study.

BACKGROUND AND AIMS: Men and women have different type 2 diabetes mellitus (T2DM) risks, which have been reported across populations of different ethnicity. Where differences in T2DM risk for sex (biological) have been studied, research on gender (socio-cultural) and T2DM risk is lacking. We explored, in a multi-ethnic population, the association of six gender-related characteristics with incident T2DM over 3 years, and the mediation by known risk factors for T2DM. METHODS AND RESULTS: We included 9605 women and 7080 men of the multi-ethnic HELIUS study (Amsterdam, the Netherlands). We studied associations between gender-related characteristics and incident T2DM, using Cox regression. After a median of 3.0 years (IQR 2.0; 4.0), 198 (2.1%) women and 137 (1.9%) men developed T2DM. A lower T2DM risk was observed in those not being the primary earner (HR 0.67; 95% CI 0.47; 0.93) and a higher desired level of social support (HR 0.62; 95% CI 0.44; 0.87). Hours spent on household work, home repairs, type of employment and male- or female-dominated occupation were not associated with T2DM incidence. No evidence for effect modification by biological sex or ethnicity was found. Known risk factors of T2DM did not mediate the observed associations. CONCLUSION: Gender-related characteristics, not being the primary earner and a higher desired social support were associated with reduced T2DM risk, and this was not mediated by known risk factors for T2DM.

The potential of food environment policies to reduce socioeconomic inequalities in diets and to improve healthy diets among lower socioeconomic groups: an umbrella review.

Socioeconomic inequalities in diets need to be tackled to improve population diets and prevent obesity and diet-related non-communicable diseases. The potential of food environment policies to reduce such inequalities has to date however not been appraised. The objective of this umbrella review was to assess the impact of food environment policies on socioeconomic inequalities in diets and to identify knowledge gaps in the existing literature, using the Healthy Food Environment Policy Index as a conceptual framework. The policies considered in the umbrella review are within six domains: 1) food composition 2) food labelling 3) food promotion 4) food provision 5) food retail 6) food pricing. A systematic search for systematic literature reviews on the effect of food environment policies on dietary-related outcomes across socioeconomic groups and published in English between 2004 and 2019 was conducted. Sixteen systematic literature reviews encompassing 159 primary studies were included, covering food composition (n = 2), food labelling (n = 3), food provision (n = 2), food prices (n = 13) and food in retail (n = 4). Quality assessment using the "Assessing the Methodological Quality of Systematic Reviews" quality rating scale showed that review quality was mainly low or critically low. Results suggest that food taxation may reduce socioeconomic inequalities in diets. For all other policy areas, the evidence base was poor. Current research largely fails to provide good quality evidence on impacts of food environment policies on socioeconomic inequalities in diets. Research to fill this knowledge gap is urgently needed.

How theory can help to understand the potential impact of food environment policies on socioeconomic inequalities in diet: an application of Bourdieu's capital theory and the scarcity theory.

Government policies that promote healthy food environments are considered promising to reduce socioeconomic inequalities in diet. Empirical evidence of effects on these inequalities, however, is relatively scarce and, with a few exceptions, tends to be inconclusive. We use two contemporary theories that help to understand socioeconomic inequalities in health and health-related behaviours (Bourdieu's capital theory and Mullainathan and Shafir's scarcity theory) to reason how policies influencing food environments may differentially impact lower and higher socioeconomic groups. In essence, these theories enable us to understand how specific elements of broader daily living conditions (e.g. social practices that lead to habitus formation, material conditions that shape experiences of scarcity) may lead to a greater benefit of certain food environment policies for the healthfulness of diets of lower or higher socioeconomic groups. We conclude that the application of theories on the mechanisms underlying socioeconomic inequalities in health can help to guide future empirical studies in testing theory-based hypotheses on differential effects of policies, and thereby enhance the development of effective policies tackling socioeconomic inequalities in dietary intakes.

Participatory research in health promotion: a critical review and illustration of rationales.

In health promotion research, enthusiasm for patient and public involvement (PPI) is growing. However, a lack of conceptual clarity leads to ambiguities in participatory processes and purposes, and hampers efforts to achieve and evaluate PPI in research. This study provides an overview of its underlying reasons-or rationales-so as to better understand, guide and interpret PPI in research practice. We conducted a critical review to identify typologies of rationales for PPI. We re-categorized the different types of rationales from these typologies based on their content. We illustrated the resulting categories of rationales with examples from a case study on PPI in research on Lyme disease. Five categories of rationales for PPI were identified. The democratic rationale reflects the normative right of citizens to have a voice in research. The consumerist rationale refers to the economic right of stakeholders with interests to have a say. Rooted in social justice, the transformative rationale seeks to empower marginalized groups. The substantive rationale starts from epistemic considerations and aims to improve the quality of knowledge that research generates. The instrumental rationale is of pragmatic origin and refers to improved efficiency and effectiveness of the research. Our overview of categories of rationales can be used as a frame of reference for PPI in health promotion research. Exploring, stating explicitly and reflecting on the underlying reasons for PPI may help to define realistic purposes, select matching approaches and design appropriate evaluation studies. This might also contribute to the conceptualization of PPI.

Enthusiasm for patient and public involvement in health promotion research is growing. However, it often remains unclear why this involvement is being organized. This lack of clarity makes it difficult to implement such participatory research and to evaluate its added value. We searched for reasons that were given for starting patient and public involvement in research. We found five different reasons. The first is the right of all citizens to have a say in research that affects them. The second is the right of individuals to demand the best research. The third is the desire to involve and empower marginalized groups. The fourth aims to improve the quality of the knowledge generated by the research. The fifth is to achieve more effective and efficient research. Together, these reasons may help researchers get more clarity about why patients or the public should be involved in their studies. This may in turn help to define realistic purposes, design a good participatory process, and conduct appropriate evaluations. All in all, using these five reasons as a frame of reference might lead to a better understanding of what good participatory research in health promotion should look like.

Understanding the impact of exposure to adverse socioeconomic conditions on chronic stress from a complexity science perspective.

BACKGROUND: Chronic stress increases chronic disease risk and may underlie the association between exposure to adverse socioeconomic conditions and adverse health outcomes. The relationship between exposure to such conditions and chronic stress is complex due to feedback loops between stressor exposure and psychological processes, encompassing different temporal (acute stress response to repeated exposure over the life course) and spatial (biological/psychological/social) scales. We examined the mechanisms underlying the relationship between exposure to adverse socioeconomic conditions and chronic stress from a complexity science perspective, focusing on amplifying feedback loops across different scales. METHODS: We developed a causal loop diagram (CLD) to interpret available evidence from this perspective. The CLD was drafted by an interdisciplinary group of researchers. Evidence from literature was used to confirm/contest the variables and causal links included in the conceptual framework and refine their conceptualisation. Our findings were evaluated by eight independent researchers. RESULTS: Adverse socioeconomic conditions imply an accumulation of stressors and increase the likelihood of exposure to uncontrollable childhood and life course stressors. Repetition of such stressors may activate mechanisms that can affect coping resources and coping strategies and stimulate appraisal of subsequent stressors as uncontrollable. We identified five feedback loops describing these mechanisms: (1) progressive deterioration of access to coping resources because of repeated insolvability of stressors; (2) perception of stressors as uncontrollable due to learned helplessness; (3) tax on cognitive bandwidth caused by stress; (4) stimulation of problem avoidance to provide relief from the stress response and free up cognitive bandwidth; and (5) susceptibility to appraising stimuli as stressors against a background of stress. CONCLUSIONS: Taking a complexity science perspective reveals that exposure to adverse socioeconomic conditions implies recurrent stressor exposure which impacts chronic stress via amplifying feedback loops that together could be conceptualised as one vicious cycle. This means that in order for individual-level psychological interventions to be effective, the context of exposure to adverse socioeconomic conditions also needs to be addressed.

Developing a realist informed framework for cultural adaptation of lifestyle interventions for the prevention of type 2 diabetes in South Asian populations in Europe.

AIMS: Selected lifestyle interventions proven effective for White-European populations have been culturally adapted for South Asian populations living in Europe, who are at higher risk of type 2 diabetes. However, a limited theoretical basis underpins how cultural adaptations are believed to augment intervention effectiveness. We undertook a realist review to synthesise existing literature on culturally adapted type 2 diabetes prevention interventions, to develop a framework that shows 'how' cultural adaptation works, for 'whom' and in 'what contexts'. METHODS: We followed the stepped methodological approach of realist review. Our work concluded a European-wide project (EuroDHYAN), and core studies were identified from the preceding EuroDHYAN reviews. Data were extracted, coded into themes and synthesised to create 'Context-Mechanism-Outcome' configurations and to generate a refined explanatory framework. RESULTS: We identified eight core intervention papers. From this evidence, and supporting literature, we examined the 'Team' domain of cultural adaptation and identified a mechanism of shared cultural identity which we theorised as contributing to strong team-participant relationships. We also identified four key contexts which influenced intervention outcomes: 'research setting' and 'heterogeneous populations' (intrinsic to the intervention) and 'broader environment' and 'socio-cultural stress' (extrinsic barriers). CONCLUSIONS: This work instigates research into the mechanisms of cultural adaptation which, if pursued, will allow a more nuanced understanding of how to apply adaptations, and for whom. In practice we recommend greater consideration of heterogeneous and intersecting population characteristics; how intervention design can safeguard sustainability; and how the four key contexts identified influence how, and whether, these interventions work.

Dynamics of the complex food environment underlying dietary intake in low-income groups: a systems map of associations extracted from a systematic umbrella literature review.

BACKGROUND: Inequalities in obesity pertain in part to differences in dietary intake in different socioeconomic groups. Examining the economic, social, physical and political food environment of low-income groups as a complex adaptive system - i.e. a system of multiple, interconnected factors exerting non-linear influence on an outcome, can enhance the development and assessment of effective policies and interventions by honouring the complexity of lived reality. We aimed to develop and apply novel causal loop diagramming methods in order to construct an evidence-based map of the underlying system of environmental factors that drives dietary intake in low-income groups. METHODS: A systematic umbrella review was conducted on literature examining determinants of dietary intake and food environments in low-income youths and adults in high/upper-middle income countries. Information on the determinants and associations between determinants was extracted from reviews of quantitative and qualitative studies. Determinants were organised using the Determinants of Nutrition and Eating (DONE) framework. Associations were synthesised into causal loop diagrams that were subsequently used to interpret the dynamics underlying the food environment and dietary intake. The map was reviewed by an expert panel and systems-based analysis identified the system paradigm, structure, feedback loops and goals. RESULTS: Findings from forty-three reviews and expert consensus were synthesised in an evidence-based map of the complex adaptive system underlying the food environment influencing dietary intake in low-income groups. The system was interpreted as operating within a supply-and-demand, economic paradigm. Five sub-systems ('geographical accessibility', 'household finances', 'household resources', 'individual influences', 'social and cultural influences') were presented as causal loop diagrams comprising 60 variables, conveying goals which undermine healthy dietary intake. CONCLUSIONS: Our findings reveal how poor dietary intake in low-income groups can be presented as an emergent property of a complex adaptive system that sustains a food environment that increases the accessibility, availability, affordability and acceptability of unhealthy foods. In order to reshape system dynamics driving unhealthy food environments, simultaneous, diverse and innovative strategies are needed to facilitate longer-term management of household finances and socially-oriented practices around healthy food production, supply and intake. Ultimately, such strategies must be supported by a system paradigm which prioritises health.

Does the neighbourhood food environment contribute to ethnic differences in diet quality? Results from the HELIUS study in Amsterdam, the Netherlands.

OBJECTIVE: The aim of the current study was to establish whether the neighbourhood food environment, characterised by the healthiness of food outlets, the diversity of food outlets and fast-food outlet density within a 500 m or 1000 m street network buffer around the home address, contributed to ethnic differences in diet quality. DESIGN: Cross-sectional cohort study. SETTING: Amsterdam, the Netherlands. PARTICIPANTS: Data on adult participants of Dutch, South-Asian Surinamese, African Surinamese, Turkish and Moroccan descent (n total 4728) in the HELIUS study were analysed. RESULTS: The neighbourhood food environment of ethnic minority groups living in Amsterdam is less supportive of a healthy diet and of less diversity than that of participants of Dutch origin. For example, participants of Turkish, Moroccan and South-Asian Surinamese descent reside in a neighbourhood with a significantly higher fast-food outlet density (≤1000 m) than participants of Dutch descent. However, we found no evidence that neighbourhood food environment characteristics directly contributed to ethnic differences in diet quality. CONCLUSION: Although ethnic minority groups lived in less healthy food environments than participants of ethnic Dutch origin, this did not contribute to ethnic differences in diet quality. Future research should investigate other direct or indirect consequences of residing in less supportive food environments and gain a better understanding of how different ethnic groups make use of their neighbourhood food environment.

Perceptions of the social and physical environment of adolescents' dietary behaviour in neighbourhoods of different socioeconomic position.

A higher proportion of adolescents from families in a lower socioeconomic position (SEP) tends to have more unhealthy dietary behaviours, and overweight and obesity, than their counterparts in higher SEPs. More research is needed to understand the causes of these differences, in particular the influence of the neighbourhood environment, which has been explored less. The presented qualitative study explores how adolescents and their parents from higher and lower SEP neighbourhoods perceive the social and physical environment influencing adolescents' dietary behaviours. We conducted 6 semi-structured focus groups with 35 13-14 year olds and 8 interviews with some of their parents. The interviewees were recruited from one higher and two lower SEP neighbourhoods in Oslo, Norway. Theme-based inductive coding was used for analysis, and the results discussed in light of an ecological framework. The results indicate that all the adolescents experience several barriers to healthy dietary behaviours. For adolescents in the lower SEP neighbourhood, one or both parents desired their cultural cuisine served at home, whereas the adolescents wanted and often consumed western dishes. Fast-food restaurants or hanging out at the mall was perceived as the preferred social arena, often due to lack of involvement in either leisure-time physical activities or youth clubs as a safe, engaging option. The adolescents in the higher SEP neighbourhood perceived social norms which accentuated healthy dietary choices. When more possibilities for activities were present and the adolescents expressed being highly engaged in leisure-time physical activity, this also seemed to facilitate healthier dietary behaviours. These findings indicate how several factors simultaneously can influence dietary behaviour. Use of a multi-layered approach when exploring the environmental influences could increase knowledge about tackling social inequalities in dietary behaviours among adolescents.