Analysis of how a complex systems perspective is applied in studies on socioeconomic inequalities in health and health behaviour-a call for reporting guidelines

BACKGROUND

A complex systems perspective is gaining popularity in research on socioeconomic inequalities in health and health behaviour, though there may be a gap between its popularity and the way it is implemented. Building on our recent systematic scoping review, we aim to analyse the application of and reporting on complex systems methods in the literature on socioeconomic inequalities in health and health behaviour.

METHODS

Selected methods and results from the review are presented as a basis for in-depth critical reflection. A traffic light-based instrument was used to assess the extent to which eight key concepts of a complex systems perspective (e.g. feedback loops) were applied. Study characteristics related to the applied value of the models were also extracted, including the model evidence base, the depiction of the model structure, and which characteristics of model relationships (e.g. polarity) were reported on.

RESULTS

Studies that applied more key concepts of a complex systems perspective were also more likely to report the direction and polarity of relationships. The system paradigm, its deepest held beliefs, is seldom identified but may be key to recognize when designing interventions. A clear, complete depiction of the full model structure is also needed to convey the functioning of a complex system. We recommend that authors include these characteristics and level of detail in their reporting.

CONCLUSIONS

Above all, we call for the development of reporting guidelines to increase the transparency and applied value of complex systems models on socioeconomic inequalities in health, health behaviour and beyond.

The current state of complex systems research on socioeconomic inequalities in health and health behavior-a systematic scoping review

BACKGROUND

Interest in applying a complex systems approach to understanding socioeconomic inequalities in health is growing, but an overview of existing research on this topic is lacking. In this systematic scoping review, we summarize the current state of the literature, identify shared drivers of multiple health and health behavior outcomes, and highlight areas ripe for future research.

METHODS

SCOPUS, Web of Science, and PubMed databases were searched in April 2023 for peer-reviewed, English-language studies in high-income OECD countries containing a conceptual systems model or simulation model of socioeconomic inequalities in health or health behavior in the adult general population. Two independent reviewers screened abstracts and full texts. Data on study aim, type of model, all model elements, and all relationships were extracted. Model elements were categorized based on the Commission on Social Determinants of Health framework, and relationships between grouped elements were visualized in a summary conceptual systems map.

RESULTS

A total of 42 publications were included; 18 only contained a simulation model, 20 only contained a conceptual model, and 4 contained both types of models. General health outcomes (e.g., health status, well-being) were modeled more often than specific outcomes like obesity. Dietary behavior and physical activity were by far the most commonly modeled health behaviors. Intermediary determinants of health (e.g., material circumstances, social cohesion) were included in nearly all models, whereas structural determinants (e.g., policies, societal values) were included in about a third of models. Using the summary conceptual systems map, we identified 15 shared drivers of socioeconomic inequalities in multiple health and health behavior outcomes.

CONCLUSIONS

The interconnectedness of socioeconomic position, multiple health and health behavior outcomes, and determinants of socioeconomic inequalities in health is clear from this review. Factors central to the complex system as it is currently understood in the literature (e.g., financial strain) may be both efficient and effective policy levers, and factors less well represented in the literature (e.g., sleep, structural determinants) may warrant more research. Our systematic, comprehensive synthesis of the literature may serve as a basis for, among other things, a complex systems framework for socioeconomic inequalities in health.

A scoping review of smoking cessation pharmacogenetic studies to advance future research across racial, ethnic, and ancestral populations

Abstinence rates among smokers attempting to quit remain low despite the wide availability and accessibility of pharmacological smoking cessation treatments. In addition, the prevalence of cessation attempts and abstinence differs by individual-level social factors such as race and ethnicity. Clinical treatment of nicotine dependence also continues to be challenged by individual-level variability in effectiveness to promote abstinence. The use of tailored smoking cessation strategies that incorporate information on individual-level social and genetic factors hold promise, although additional pharmacogenomic knowledge is still needed. In particular, genetic variants associated with pharmacological responses to smoking cessation treatment have generally been conducted in populations with participants that self-identify as White race or who are determined to be of European genetic ancestry. These results may not adequately capture the variability across all smokers as a result of understudied differences in allele frequencies across genetic ancestry populations. This suggests that much of the current pharmacogenetic study results for smoking cessation may not apply to all populations. Therefore, clinical application of pharmacogenetic results may exacerbate health inequities by racial and ethnic groups. This scoping review examines the extent to which racial, ethnic, and ancestral groups that experience differences in smoking rates and smoking cessation are represented in the existing body of published pharmacogenetic studies of smoking cessation. We will summarize results by race, ethnicity, and ancestry across pharmacological treatments and study designs. We will also explore current opportunities and challenges in conducting pharmacogenomic research on smoking cessation that encourages greater participant diversity, including practical barriers to clinical utilization of pharmacological smoking cessation treatment and clinical implementation of pharmacogenetic knowledge.

CHRNA5-A3-B4 and DRD2 Genes and Smoking Cessation Throughout Adulthood: A Longitudinal Study of Women

INTRODUCTION

Smoking cessation is more than 50% heritable. Genetic studies of smoking cessation have been limited by short-term follow-up or cross-sectional design.

AIMS AND METHODS

This study tests single nucleotide polymorphism (SNP) associations with cessation during long-term follow-up throughout adulthood in women. The secondary aim tests whether genetic associations differ by smoking intensity. Associations between 10 SNPs in CHRNA5, CHRNA3, CHRNB2, CHRNB4, DRD2, and COMT and the probability of smoking cessation over time were evaluated in two longitudinal cohort studies of female nurses, the Nurses' Health Study (NHS) (n = 10 017) and NHS-2 (n = 2793). Participant follow-up ranged from 2 to 38 years with data collected every 2 years.

RESULTS

Women with the minor allele of either CHRNA5 SNP rs16969968 or CHRNA3 SNP rs1051730 had lower odds of cessation throughout adulthood [OR = 0.93, p-value = .003]. Women had increased odds of cessation if they had the minor allele of CHRNA3 SNP rs578776 [OR = 1.17, p-value = .002]. The minor allele of DRD2 SNP rs1800497 was associated with lower odds of cessation in moderate-to-heavy smokers [OR = 0.92, p-value = .0183] but increased odds in light smokers [OR = 1.24, p-value = .096].

CONCLUSIONS

Some SNP associations with short-term smoking abstinence observed in prior studies were shown in the present study to persist throughout adulthood over decades of follow-up. Other SNP associations with short-term abstinence did not persist long-term. The secondary aim findings suggest genetic associations may differ by smoking intensity.

IMPLICATIONS

The results of the present study expand on previous studies of SNP associations in relation to short-term smoking cessation to demonstrate some of these SNPs were associated with smoking cessation throughout decades of follow-up, whereas other SNP associations with short-term abstinence did not persist long-term. The rate of relapse to smoking remains high for several years after quitting smoking, and many smokers experience multiple quit attempts and relapse episodes throughout adulthood. Understanding genetic associations with long-term cessation has potential importance for precision medicine approaches to long-term cessation management.

Factors associated with the desire to quit tobacco smoking in Saudi Arabia: Evidence from the 2019 Global Adult Tobacco Survey

INTRODUCTION

Saudi Arabia is expected to witness a slight reduction in tobacco use. The Saudi government offers free-of-charge smoking cessation services. Yet, factors influencing the desire to quit smoking are not comprehensively investigated in Saudi Arabia. This study examines the factors influencing the desire to quit among smoking adults in Saudi Arabia and investigates whether using alternative tobacco products, such as e-cigarettes, is associated with the desire to quit smoking.

METHODS

Data from the 2019 nationally representative Global Adults Tobacco Survey (GATS) was used. GATS utilized a face-to-face household cross-sectional survey that collected data from adults aged ≥15 years. Several factors including, sociodemographic characteristics, use of alternative tobacco products, attitude toward tobacco control, and awareness of smoking cessation clinics (SCCs), were examined to predict the desire to quit. Logistic regression analysis was conducted.

RESULTS

A total of 11381 individuals completed the survey. Of the total sample, 1667 participants were tobacco smokers. The majority of the tobacco smokers were interested in quitting smoking (82.4%); 58% of cigarette smokers and 17.1% of waterpipe smokers were interested in quitting smoking. The desire to quit smoking was positively associated with the awareness of SCCs (AOR=3; 95% CI: 1.8-5), attitude toward raising tobacco taxes (AOR=2.3; 95% CI: 1.4-3.8), and a strict rule of smoking inside the home (AOR=2; 95% CI: 1.1-3.9). No statistical association was found between the desire to quit smoking and the use of e-cigarettes.

CONCLUSIONS

The desire to quit tobacco smoking among Saudi smokers increased with awareness of SCCs, favoring taxes on tobacco products, and implementing strict rules of smoking inside the home. The study reveals valuable insights into the main factors that could inform the development of more effective policy interventions targeting smokers in Saudi Arabia.

Variation in Patient Smoking Cessation Rates Among Health-Care Providers: An Observational Study

BACKGROUND

Physicians play a crucial role in providing smoking cessation counseling and medications. However, it is unknown whether individual physicians' approaches affect whether patients quit.

RESEARCH QUESTION

This study assessed patient quit rates within a national quality-improvement learning collaborative to document variation in quit rates at the physician, practice, and health system levels.

STUDY DESIGN AND METHODS

A retrospective cohort study was conducted of primary care patients identified from the Optum analytics database containing longitudinal ambulatory data for patients from 22 health-care organizations between January 2012 and December 2018. The study included smokers aged ≥ 18 years who attended at least three ambulatory visits, with two visits at least 1 year apart. The primary study outcome was abstinence for ≥ 1 year. A mixed effects logistic regression model was used to predict the probability of quitting as a function of patient variables. Quit rates were then adjusted by patient factors and calculated at the level of clinician, clinic/practice, and health system.

RESULTS

Across all systems, 56% of patients had a documented smoking status in 2017. Among nearly 1 million smokers, 24% quit smoking. In the regression model, patient characteristics associated with quitting included older age, Hispanic ethnicity, being married, urban residence, commercial insurance, pregnancy, and a diagnosis of pneumonia, myocardial infarction, ischemic heart disease, cataract, or asthma. Medicaid insurance, low income, high BMI, peripheral vascular disease, alcohol-related diagnosis, and COPD were negatively associated with smoking cessation. Adjusted quit rates ranged from 14.3% to 34.5% across 20 health systems, 5% to 66% among 1,399 practice sites, and 4% to 87% among 3,803 health-care providers. Of smokers, 10.2% were prescribed smoking deterrents, and 3.9% were referred for counseling.

INTERPRETATION

Smoking cessation rates varied substantially at the practitioner, practice site, and health system levels. It is likely that individual physician approaches to smoking cessation influence patients' likelihood of quitting.

Self-regulation mechanisms in health behavior change: a systematic meta-review of meta-analyses, 2006-2017

Self-regulation is one primary mechanism in interventions for health behavior change and has been examined in numerous recent meta-analyses. This pre-registered meta-review (PROSPERO CRD42017074018) examined Mmeta-analyses of any intervention and health behavior/outcome were eligible if they quantitatively assessed self-regulation and appeared between January 2006 and August 2017. In total, 66 meta-analyses were ultimately eligible; 27% reported a protocol, 11% used GRADE; 58% focused on RCTs. Reviews satisfied only a moderate number of items on the AMSTAR 2 (M = 45.45%, SD = 29.57%). Only 6% of meta-analyses directly examined whether changes in self-regulation predicted the behavior change (i.e., self-efficacy and physical activity, l = 2; frequency of self-monitoring and goal attainment, l = 1; cognitive bias modification and addiction, l = 1). Meta-analyses more routinely assessed self-regulation by comparing the efficacy of intervention components (97%), such as those from behavior change taxonomies. Meta-analyses that focused on intervention components identified several as successful, including personalized feedback, goal setting, and self-monitoring; however, none were consistently successful in that each worked only for some health behaviors and with particular populations. Some components had inconclusive evidence, given that they were only examined in low- quality reviews. Future reviewers should utilize advanced methods to assess mechanisms, and study authors should report hypothesized mechanisms to facilitate synthesis.

Association Between rs1051730 and Smoking During Pregnancy in Dutch Women

INTRODUCTION

The common genetic variant (rs1051730) in the 15q24 nicotinic acetylcholine receptor gene cluster CHRNA5-CHRNA3-CHRNB4 was associated with smoking quantity and has been reported to be associated also with reduced ability to quit smoking in pregnant women but results were inconsistent in nonpregnant women. The aim of this study was to explore the association between rs1051730 and smoking cessation during pregnancy in a sample of Dutch women.

METHODS

Data on smoking during pregnancy were available from 1337 women, who ever smoked, registered at the Netherlands Twin Register (NTR). Logistic regression was used to assess evidence for the association of rs1051730 genotype on smoking during pregnancy. In a subsample of 561 women, we investigated the influence of partner's smoking. Educational attainment and year of birth were used as covariates in both analyses.

RESULTS

There was evidence for a significant association between having one or more T alleles of the rs1051730 polymorphism and the likelihood of smoking during pregnancy (p = .03, odds ratio = 1.28, 95% CI = 1.02 to 1.61). However, this association attenuated when adjusting for birth cohort and educational attainment (p = .37, odds ratio = 1.12, 95% CI = 0.87 to 1.43). In the subsample, smoking spouse was highly associated with smoking during pregnancy, even when educational attainment and birth cohort were included in the model.

CONCLUSIONS

Our results did not support a strong association between this genetic variant and smoking during pregnancy. However, a strong association was observed with the smoking behavior of the partner, regardless of the genotype of the women.

IMPLICATIONS

The present study emphasizes the importance of social influences like spousal smoking on the smoking behavior of pregnant women. Further research is needed to address the role of rs1051730 genetic variant in influencing smoking cessation and the interaction with important environmental factors like the smoking behavior of the partner.

Comparative study of seven commercial kits for human DNA extraction from urine samples suitable for DNA biomarker-based public health studies

Human genomic DNA extracted from urine could be an interesting tool for large-scale public health studies involving characterization of genetic variations or DNA biomarkers as a result of the simple and noninvasive collection method. These studies, involving many samples, require a rapid, easy, and standardized extraction protocol. Moreover, for practicability, there is a necessity to collect urine at a moment different from the first void and to store it appropriately until analysis. The present study compared seven commercial kits to select the most appropriate urinary human DNA extraction procedure for epidemiological studies. DNA yield has been determined using different quantification methods: two classical, i.e., NanoDrop and PicoGreen, and two species-specific real-time quantitative (q)PCR assays, as DNA extracted from urine contains, besides human, microbial DNA also, which largely contributes to the total DNA yield. In addition, the kits giving a good yield were also tested for the presence of PCR inhibitors. Further comparisons were performed regarding the sampling time and the storage conditions. Finally, as a proof-of-concept, an important gene related to smoking has been genotyped using the developed tools. We could select one well-performing kit for the human DNA extraction from urine suitable for molecular diagnostic real-time qPCR-based assays targeting genetic variations, applicable to large-scale studies. In addition, successful genotyping was possible using DNA extracted from urine stored at -20°C for several months, and an acceptable yield could also be obtained from urine collected at different moments during the day, which is particularly important for public health studies.

The association of affective temperaments with smoking initiation and maintenance in adult primary care patients

BACKGROUND

Smoking behaviour and its course is influenced by personality factors. Affective temperaments could allow a more specific framework of the role trait affectivity plays in this seriously harmful health-behaviour. The aim of our study was to investigate if such an association exists in an ageing population with a special emphasis on gender differences.

METHODS

459 primary care patients completed the TEMPS-A, Beck Depression Inventory (BDI) and Hamilton Anxiety Rating Scale (HAM-A). Subjects were characterized according to their smoking behaviour as current, former or never smokers. Univariate analysis ANOVA and logistic regression were performed to analyse differences in the three smoking subgroups to predict smoking initiation and maintenance.

RESULTS

Current smokers were younger and less educated than former or never smokers. Males were more likely to try tobacco during their lifetime and were more successful in cessation. Depressive, cyclothymic and irritable temperament scores showed significant differences between the three smoking subgroups. Irritable temperament was a predictor of smoking initiation in females whereas depressive temperament predicted smoking maintenance in males with a small, opposite effect of HAM-A scores independent of age, education, lifetime depression and BDI scores. Whereas smoking initiation was exclusively predicted by a higher BDI score in males, smoking maintenance was predicted by younger age and lower education in females.

LIMITATIONS

The cross-sectional nature of the study design may lead to selective survival bias and hinder drawing causal relationships.

CONCLUSIONS

Affective temperaments contribute to smoking initiation and maintenance independently of age, education, and depression. The significant contribution of depressive temperament in males and irritable temperament in females may highlight the role of gender-discordant temperaments in vulnerable subgroups.

Genetic similarities between tobacco use disorder and related comorbidities: an exploratory study

Background

Tobacco use disorder (TUD), defined as the use of tobacco to the detriment of a person’s health or social functioning, is associated with various disorders. We hypothesized that mutual variation in genes may partly explain this link. The aims of this study were to make a non-exhaustive inventory of the disorders using (partially) the same genetic pathways as TUD, and to describe the genetic similarities between TUD and the selected disorders.

Methods

We developed a 3 stage approach: (i) selection of genes influencing TUD using Gene2Mesh and Ingenuity Pathway Analysis (IPA), (ii) selection of disorders associated with the selected genes using IPA and (iii) genetic similarities between disorders associated with TUD using Jaccard distance and cluster analyses.

Results

Fourteen disorders and thirty-two genes met our inclusion criteria. The Jaccard distance between pairs of disorders ranged from 0.00 (e.g. oesophageal cancer and malignant hypertension) to 0.45 (e.g. bladder cancer and addiction). A lower number in the Jaccard distance indicates a higher similarity between the two disorders. Two main clusters of genetically similar disorders were observed, one including coexisting disorders (e.g. addiction and alcoholism) and the other one with the side-effects of smoking (e.g. gastric cancer and malignant hypertension).

Conclusions

This exploratory study partly explains the potential genetic components linking TUD to other disorders. Two principle clusters of disorders were observed (i) coexisting disorders of TUD and (ii) side-effects of TUD disorders. A further deepening of this observation in a real life study should allow strengthening this hypothesis.