Small-world connectivity dictates collective endothelial cell signaling.

Every blood vessel is lined by a single layer of highly specialized, yet adaptable and multifunctional endothelial cells. These cells, the endothelium, control vascular contractility, hemostasis, and inflammation and regulate the exchange of oxygen, nutrients, and waste products between circulating blood and tissue. To control each function, the endothelium processes endlessly arriving requests from multiple sources using separate clusters of cells specialized to detect specific stimuli. A well-developed but poorly understood communication system operates between cells to integrate multiple lines of information and coordinate endothelial responses. Here, the nature of the communication network has been addressed using single-cell Ca2+ imaging across thousands of endothelial cells in intact blood vessels. Cell activities were cross-correlated and compared to a stochastic model to determine network connections. Highly correlated Ca2+ activities occurred in scattered cell clusters, and network communication links between them exhibited unexpectedly short path lengths. The number of connections between cells (degree distribution) followed a power-law relationship revealing a scale-free network topology. The path length and degree distribution revealed an endothelial network with a "small-world" configuration. The small-world configuration confers particularly dynamic endothelial properties including high signal-propagation speed, stability, and a high degree of synchronizability. Local activation of small clusters of cells revealed that the short path lengths and rapid signal transmission were achieved by shortcuts via connecting extensions to nonlocal cells. These findings reveal that the endothelial network design is effective for local and global efficiency in the interaction of the cells and rapid and robust communication between endothelial cells in order to efficiently control cardiovascular activity.

Commentary on Antosz et al. (2023): The role of macro-micro-macro frameworks and critical realism in agent-based modelling.

Antosz and colleagues' review of the role of theory in agent-based modelling (ABM) makes important recommendations for modelling practitioners. However, macro-micro-macro frameworks are not necessarily as reliant on existing theory as the review suggests. Adopting a critical realist perspective to ABM design would help to deliver the recommendations, within which macro-micro-macro frameworks can play an important enabling role.

Endothelial PAR2 activation evokes resistance artery relaxation.

Protease-activated receptor-1 & -2 (PAR1 and PAR2) are expressed widely in cardiovascular tissues including endothelial and smooth muscle cells. PAR1 and PAR2 may regulate blood pressure via changes in vascular contraction or relaxation mediated by endothelial Ca2+ signaling, but the mechanisms are incompletely understood. By using single-cell Ca2+ imaging across hundreds of endothelial cells in intact blood vessels, we explored PAR-mediated regulation of blood vessel function using PAR1 and PAR2 activators. We show that PAR2 activation evoked multicellular Ca2+ waves that propagated across the endothelium. The PAR2-evoked Ca2+ waves were temporally distinct from those generated by muscarinic receptor activation. PAR2 activated distinct clusters of endothelial cells, and these cells were different from those activated by muscarinic receptor stimulation. These results indicate that distinct cell clusters facilitate spatial segregation of endothelial signal processing. We also demonstrate that PAR2 is a phospholipase C-coupled receptor that evokes Ca2+ release from the IP3 -sensitive store in endothelial cells. A physiological consequence of this PAR2 signaling system is endothelium-dependent relaxation. Conversely, PAR1 activation did not trigger endothelial cell Ca2+ signaling nor relax or contract mesenteric arteries. Neither did PAR1 activators alter the response to PAR2 or muscarinic receptor activation. Collectively, these results suggest that endothelial PAR2 but not PAR1 evokes mesenteric artery relaxation by evoking IP3 -mediated Ca2+ release from the internal store. Sensing mediated by PAR2 receptors is distributed to spatially separated clusters of endothelial cells.

Simulation of Alcohol Control Policies for Health Equity (SIMAH) Project: Study Design and First Results.

Since about 2010, life expectancy at birth in the United States has stagnated and begun to decline, with concurrent increases in the socioeconomic divide in life expectancy. The Simulation of Alcohol Control Policies for Health Equity (SIMAH) Project uses a novel microsimulation approach to investigate the extent to which alcohol use, socioeconomic status (SES), and race/ethnicity contribute to unequal developments in US life expectancy and how alcohol control interventions could reduce such inequalities. Representative, secondary data from several sources will be integrated into one coherent, dynamic microsimulation to model life-course changes in SES and alcohol use and cause-specific mortality attributable to alcohol use by SES, race/ethnicity, age, and sex. Markov models will be used to inform transition intensities between levels of SES and drinking patterns. The model will be used to compare a baseline scenario with multiple counterfactual intervention scenarios. The preliminary results indicate that the crucial microsimulation component provides a good fit to observed demographic changes in the population, providing a robust baseline model for further simulation work. By demonstrating the feasibility of this novel approach, the SIMAH Project promises to offer superior integration of relevant empirical evidence to inform public health policy for a more equitable future.

Can lifestyle factors explain racial and ethnic inequalities in all-cause mortality among US adults?

BACKGROUND: Racial and ethnic inequalities in all-cause mortality exist, and individual-level lifestyle factors have been proposed to contribute to these inequalities. In this study, we evaluate the extent to which the association between race and ethnicity and all-cause mortality can be explained by differences in the exposure and vulnerability to harmful effects of different lifestyle factors. METHODS: The 1997-2014 cross-sectional, annual US National Health Interview Survey (NHIS) linked to the 2015 National Death Index was used. NHIS reported on race and ethnicity (non-Hispanic White, non-Hispanic Black, and Hispanic/Latinx), lifestyle factors (alcohol use, smoking, body mass index, physical activity), and covariates (sex, age, education, marital status, survey year). Causal mediation using an additive hazard and marginal structural approach was used. RESULTS: 465,073 adults (18-85 years) were followed 8.9 years (SD: 5.3); 49,804 deaths were observed. Relative to White adults, Black adults experienced 21.7 (men; 95%CI: 19.9, 23.5) and 11.5 (women; 95%CI: 10.1, 12.9) additional deaths per 10,000 person-years whereas Hispanic/Latinx women experienced 9.3 (95%CI: 8.1, 10.5) fewer deaths per 10,000 person-years; no statistically significant differences were identified between White and Hispanic/Latinx men. Notably, these differences in mortality were partially explained by both differential exposure and differential vulnerability to the lifestyle factors among Black women, while different effects of individual lifestyle factors canceled each other out among Black men and Hispanic/Latinx women. CONCLUSIONS: Lifestyle factors provide some explanation for racial and ethnic inequalities in all-cause mortality. Greater attention to structural, life course, healthcare, and other factors is needed to understand determinants of inequalities in mortality and to advance health equity.

Can Social Norms Explain Long-Term Trends in Alcohol Use? Insights from Inverse Generative Social Science.

Social psychological theory posits entities and mechanisms that attempt to explain observable differences in behavior. For example, dual process theory suggests that an agent's behavior is influenced by intentional (arising from reasoning involving attitudes and perceived norms) and unintentional (i.e., habitual) processes. In order to pass the generative sufficiency test as an explanation of alcohol use, we argue that the theory should be able to explain notable patterns in alcohol use that exist in the population, e.g., the distinct differences in drinking prevalence and average quantities consumed by males and females. In this study, we further develop and apply inverse generative social science (iGSS) methods to an existing agent-based model of dual process theory of alcohol use. Using iGSS, implemented within a multi-objective grammar-based genetic program, we search through the space of model structures to identify whether a single parsimonious model can best explain both male and female drinking, or whether separate and more complex models are needed. Focusing on alcohol use trends in New York State, we identify an interpretable model structure that achieves high goodness-of-fit for both male and female drinking patterns simultaneously, and which also validates successfully against reserved trend data. This structure offers a novel interpretation of the role of norms in formulating drinking intentions, but the structure's theoretical validity is questioned by its suggestion that individuals with low autonomy would act against perceived descriptive norms. Improved evidence on the distribution of autonomy in the population is needed to understand whether this finding is substantive or is a modeling artefact.

Trends in mortality from alcohol, opioid, and combined alcohol and opioid poisonings by sex, educational attainment, and race and ethnicity for the United States 2000-2019.

BACKGROUND: The ongoing opioid epidemic and increases in alcohol-related mortality are key public health concerns in the USA, with well-documented inequalities in the degree to which groups with low and high education are affected. This study aimed to quantify disparities over time between educational and racial and ethnic groups in sex-specific mortality rates for opioid, alcohol, and combined alcohol and opioid poisonings in the USA. METHODS: The 2000-2019 Multiple Cause of Death Files from the National Vital Statistics System (NVSS) were used alongside population counts from the Current Population Survey 2000-2019. Alcohol, opioid, and combined alcohol and opioid poisonings were assigned using ICD-10 codes. Sex-stratified generalized least square regression models quantified differences between educational and racial and ethnic groups and changes in educational inequalities over time. RESULTS: Between 2000 and 2019, there was a 6.4-fold increase in opioid poisoning deaths, a 4.6-fold increase in combined alcohol and opioid poisoning deaths, and a 2.1-fold increase in alcohol poisoning deaths. Educational inequalities were observed for all poisoning outcomes, increasing over time for opioid-only and combined alcohol and opioid mortality. For non-Hispanic White Americans, the largest educational inequalities were observed for opioid poisonings and rates were 7.5 (men) and 7.2 (women) times higher in low compared to high education groups. Combined alcohol and opioid poisonings had larger educational inequalities for non-Hispanic Black men and women (relative to non-Hispanic White), with rates 8.9 (men) and 10.9 (women) times higher in low compared to high education groups. CONCLUSIONS: For all types of poisoning, our analysis indicates wide and increasing gaps between those with low and high education with the largest inequalities observed for opioid-involved poisonings for non-Hispanic Black and White men and women. This study highlights population sub-groups such as individuals with low education who may be at the highest risk of increasing mortality from combined alcohol and opioid poisonings. Thereby the findings are crucial for the development of targeted public health interventions to reduce poisoning mortality and the socioeconomic inequalities related to it.

Glucocorticoids regulate mitochondrial fatty acid oxidation in fetal cardiomyocytes.

The late gestational rise in glucocorticoids contributes to the structural and functional maturation of the perinatal heart. Here, we hypothesized that glucocorticoid action contributes to the metabolic switch in perinatal cardiomyocytes from carbohydrate to fatty acid oxidation. In primary mouse fetal cardiomyocytes, dexamethasone treatment induced expression of genes involved in fatty acid oxidation and increased mitochondrial oxidation of palmitate, dependent upon a glucocorticoid receptor (GR). Dexamethasone did not, however, induce mitophagy or alter the morphology of the mitochondrial network. In vivo, in neonatal mice, dexamethasone treatment induced cardiac expression of fatty acid oxidation genes. However, dexamethasone treatment of pregnant C57Bl/6 mice at embryonic day (E)13.5 or E16.5 failed to induce fatty acid oxidation genes in fetal hearts assessed 24 h later. Instead, at E17.5, fatty acid oxidation genes were downregulated by dexamethasone, as was GR itself. PGC-1α, required for glucocorticoid-induced maturation of primary mouse fetal cardiomyocytes in vitro, was also downregulated in fetal hearts at E17.5, 24 h after dexamethasone administration. Similarly, following a course of antenatal corticosteroids in a translational sheep model of preterm birth, both GR and PGC-1α were downregulated in heart. These data suggest that endogenous glucocorticoids support the perinatal switch to fatty acid oxidation in cardiomyocytes through changes in gene expression rather than gross changes in mitochondrial volume or mitochondrial turnover. Moreover, our data suggest that treatment with exogenous glucocorticoids may interfere with normal fetal heart maturation, possibly by downregulating GR. This has implications for clinical use of antenatal corticosteroids when preterm birth is considered a possibility. KEY POINTS: Glucocorticoids are steroid hormones that play a vital role in late pregnancy in maturing fetal organs, including the heart. In fetal cardiomyocytes in culture, glucocorticoids promote mitochondrial fatty acid oxidation, suggesting they facilitate the perinatal switch from carbohydrates to fatty acids as the predominant energy substrate. Administration of a synthetic glucocorticoid in late pregnancy in mice downregulates the glucocorticoid receptor and interferes with the normal increase in genes involved in fatty acid metabolism in the heart. In a sheep model of preterm birth, antenatal corticosteroids (synthetic glucocorticoid) downregulates the glucocorticoid receptor and the gene encoding PGC-1α, a master regulator of energy metabolism. These experiments suggest that administration of antenatal corticosteroids in anticipation of preterm delivery may interfere with fetal heart maturation by downregulating the ability to respond to glucocorticoids.

Mitochondrial ATP production provides long-range control of endothelial inositol trisphosphate-evoked calcium signaling.

Endothelial cells are reported to be glycolytic and to minimally rely on mitochondria for ATP generation. Rather than providing energy, mitochondria in endothelial cells may act as signaling organelles that control cytosolic Ca2+ signaling or modify reactive oxygen species (ROS). To control Ca2+ signaling, these organelles are often observed close to influx and release sites and may be tethered near Ca2+ transporters. In this study, we used high-resolution, wide-field fluorescence imaging to investigate the regulation of Ca2+ signaling by mitochondria in large numbers of endothelial cells (∼50 per field) in intact arteries from rats. We observed that mitochondria were mostly spherical or short-rod structures and were distributed widely throughout the cytoplasm. The density of these organelles did not increase near contact sites with smooth muscle cells. However, local inositol trisphosphate (IP3)-mediated Ca2+ signaling predominated near these contact sites and required polarized mitochondria. Of note, mitochondrial control of Ca2+ signals occurred even when mitochondria were far from Ca2+ release sites. Indeed, the endothelial mitochondria were mobile and moved throughout the cytoplasm. Mitochondrial control of Ca2+ signaling was mediated by ATP production, which, when reduced by mitochondrial depolarization or ATP synthase inhibition, eliminated local IP3-mediated Ca2+ release events. ROS buffering did not significantly alter local Ca2+ release events. These results highlight the importance of mitochondrial ATP production in providing long-range control of endothelial signaling via IP3-evoked local Ca2+ release in intact endothelium.

A software architecture for mechanism-based social systems modelling in agent-based simulation models.

This paper introduces the MBSSM (Mechanism-Based Social Systems Modelling) software architecture that is designed for expressing mechanisms of social theories with individual behaviour components in a unified way and implementing these mechanisms in an agent-based simulation model. The MBSSM architecture is based on a middle-range theory approach most recently expounded by analytical sociology and is designed in the object-oriented programming paradigm with Unified Modelling Language diagrams. This paper presents two worked examples of using the architecture for modelling individual behaviour mechanisms that give rise to the dynamics of population-level alcohol use: a single-theory model of norm theory and a multi-theory model that combines norm theory with role theory. The MBSSM architecture provides a computational environment within which theories based on social mechanisms can be represented, compared, and integrated. The architecture plays a fundamental enabling role within a wider simulation model-based framework of abductive reasoning in which families of theories are tested for their ability to explain concrete social phenomena.

Phenotypic dissection of the mouse Ren1d knockout by complementation with human renin.

Normal renin synthesis and secretion is important for the maintenance of juxtaglomerular apparatus architecture. Mice lacking a functional Ren1d gene are devoid of renal juxtaglomerular cell granules and exhibit an altered macula densa morphology. Due to the species-specificity of renin activity, transgenic mice are ideal models for experimentally investigating and manipulating expression patterns of the human renin gene in a native cellular environment without confounding renin-angiotensin system interactions. A 55-kb transgene encompassing the human renin locus was crossed onto the mouse Ren1d-null background, restoring granulation in juxtaglomerular cells. Correct processing of human renin in dense core granules was confirmed by immunogold labeling. After stimulation of the renin-angiotensin system, juxtaglomerular cells contained rhomboid protogranules with paracrystalline contents, dilated rough endoplasmic reticulum, and electron-lucent granular structures. However, complementation of Ren1d-/- mice with human renin was unable to rescue the abnormality seen in macula densa structure. The juxtaglomerular apparatus was still able to respond to tubuloglomerular feedback in isolated perfused juxtaglomerular apparatus preparations, although minor differences in glomerular tuft contractility and macula densa cell calcium handling were observed. This study reveals that the human renin protein is able to complement the mouse Ren1d-/- non-granulated defect and suggests that granulopoiesis requires a structural motif that is conserved between the mouse Ren1d and human renin proteins. It also suggests that the altered macula densa phenotype is related to the activity of the renin-1d enzyme in a local juxtaglomerular renin-angiotensin system.

Protein Valuation in Food Choice Is Positively Associated with Lean Mass in Older Adults.

BACKGROUND: Calorie for calorie, protein is more satiating than carbohydrate or fat. However, it remains unclear whether humans perceive calories derived from these macronutrients equally and whether lean mass is associated with a tendency to "value" protein when dietary decisions are made. OBJECTIVES: This study aimed to determine the test-retest reliability of a novel method for quantifying macronutrient valuations in human volunteers and to determine whether "protein valuation" is associated with a higher fat-free mass index (FFMI) in older adults. METHODS: A 2-alternative, forced-choice task in which 25 foods were compared in 300 trials was undertaken in 2 studies. In study 1, participants (age range 19-71 y, n = 92) attended 2 test sessions, spaced 1 wk apart. In study 2, older adults (age range 40-85 y; n = 91) completed the food-choice task and assessed the test foods for liking, expected satiety, and perceived healthiness. Body composition and habitual protein intake were assessed in both studies. Data were analyzed through the use of individual binomial logistic regressions and multilevel binomial logistic regressions. RESULTS: In study 1, measures of macronutrient valuation showed excellent test-retest reliability; responses in the forced-choice task were highly correlated (week 1 compared with week 2; protein, r = 0.83, P < 0.001; carbohydrate, r = 0.90, P < 0.001; fat, r = 0.90, P < 0.001). Calorie for calorie, protein and carbohydrate were stronger predictors of choice than fat (P < 0.001). In study 2, protein was a stronger predictor than both carbohydrate (P = 0.039) and fat (P = 0.003), and a positive interaction was observed between protein valuation and FFMI (OR = 1.64; 95% CI: 1.38, 1.95; P < 0.001). This was the case after controlling for age, gender, liking for foods, and habitual protein consumption. CONCLUSIONS: Together, these findings demonstrate that adult humans value calories derived from protein, carbohydrate, and fat differently, and that the tendency to value protein is associated with greater lean mass in older adults.

Investigating the RAS can be a fishy business: interdisciplinary opportunities using Zebrafish.

The renin-angiotensin system (RAS) is highly conserved, and components of the RAS are present in all vertebrates to some degree. Although the RAS has been studied since the discovery of renin, its biological role continues to broaden with the identification and characterization of new peptides. The evolutionarily distant zebrafish is a remarkable model for studying the kidney due to its genetic tractability and accessibility for in vivo imaging. The zebrafish pronephros is an especially useful kidney model due to its structural simplicity yet complex functionality, including capacity for glomerular and tubular filtration. Both the pronephros and mesonephros contain renin-expressing perivascular cells, which respond to RAS inhibition, making the zebrafish an excellent model for studying the RAS. This review summarizes the physiological and genetic tools currently available for studying the zebrafish kidney with regards to functionality of the RAS, using novel imaging techniques such as SPIM microscopy coupled with targeted single cell ablation and synthesis of vasoactive RAS peptides.

Muscle strength, functional endurance, and health-related quality of life in active older female golfers.

BACKGROUND: Grip strength is a reliable predictor of whole body strength in older adults, but muscle characteristics of people with different activity levels have not been studied previously. The present study examined the relationship between grip strength (GS), quadriceps peak torque (QPT), functional endurance, and health-related quality of life (HRQoL) in older female golfers. METHODS: Twenty-nine healthy female golfers (mean age 69.1 years, SD 3.4) participated. The ISOCOM and JAMAR dynamometers were used to assess QPT and GS, respectively. Functional endurance tests included 1-min sit-to-stand test (1MSTS), 30-s wall press (30SWP), and 2-min stair climb (2MSC). HRQol was assessed using the SF-36 questionnaire. RESULTS: Mean GS and QPT were 27.5 ± 4 kg/f and 103.7 ± 25.1 N m, respectively. Mean scores for the 1MSTS, 30SWP, and 2MSC were 31 ± 7.7, 17.4 ± 3.5, and 237.5 ± 48.6 repetitions, respectively. GS was moderately correlated with QPT (r = 0.44), 1MSTS (r = 0.36), and 2MSC (r = 0.36), but had weak correlation with 30SWP (r = 0.003). Moderate correlation was observed between quadriceps peak torque and the 1MSTS (r = 0.50; p = 0.01), 2MSC (r = 0.44; p = 0.02) and 30SWP (r = 0.33). 30SWP and 2MSC had moderate correlations with PF r = 0.41 (p = 0.03) and r = 0.61 (p < 0.0005) and general physical well-being r = 0.47 (p = 0.01) and r = 0.39 (p = 0.04), respectively. CONCLUSION: Quadriceps strength was more closely associated with functional endurance than grip strength. A single strength measure may not reflect overall muscle characteristics in active older females, and hence, assessment of both upper and lower limb strengths may be appropriate.

Bimodal dynamics of granular organelles in primary renin-expressing cells revealed using TIRF microscopy.

Renin is the initiator and rate-limiting factor in the renin-angiotensin blood pressure regulation system. Although renin is not exclusively produced in the kidney, in nonmurine species the synthesis and secretion of the active circulatory enzyme is confined almost exclusively to the dense core granules of juxtaglomerular (JG) cells, where prorenin is processed and stored for release via a regulated pathway. Despite its importance, the structural organization and regulation of granules within these cells is not well understood, in part due to the difficulty in culturing primary JG cells in vitro and the lack of appropriate cell lines. We have streamlined the isolation and culture of primary renin-expressing cells suitable for high-speed, high-resolution live imaging using a Percoll gradient-based procedure to purify cells from RenGFP+ transgenic mice. Fibronectin-coated glass coverslips proved optimal for the adhesion of renin-expressing cells and facilitated live cell imaging at the plasma membrane of primary renin cells using total internal reflection fluorescence microscopy (TIRFM). To obtain quantitative data on intracellular function, we stained mixed granule and lysosome populations with Lysotracker Red and stimulated cells using 100 nM isoproterenol. Analysis of membrane-proximal acidic granular organelle dynamics and behavior within renin-expressing cells revealed the existence of two populations of granular organelles with distinct functional responses following isoproterenol stimulation. The application of high-resolution techniques for imaging JG and other specialized kidney cells provides new opportunities for investigating renal cell biology.

Human kidney pericytes produce renin.

Pericytes, perivascular cells embedded in the microvascular wall, are crucial for vascular homeostasis. These cells also play diverse roles in tissue development and regeneration as multi-lineage progenitors, immunomodulatory cells and as sources of trophic factors. Here, we establish that pericytes are renin producing cells in the human kidney. Renin was localized by immunohistochemistry in CD146 and NG2 expressing pericytes, surrounding juxtaglomerular and afferent arterioles. Similar to pericytes from other organs, CD146+CD34-CD45-CD56- renal fetal pericytes, sorted by flow cytometry, exhibited tri-lineage mesodermal differentiation potential in vitro. Additionally, renin expression was triggered in cultured kidney pericytes by cyclic AMP as confirmed by immuno-electron microscopy, and secretion of enzymatically functional renin, capable of generating angiotensin I. Pericytes derived from second trimester human placenta also expressed renin in an inducible fashion although the renin activity was much lower than in renal pericytes. Thus, our results confirm and extend the recently discovered developmental plasticity of microvascular pericytes, and may open new perspectives to the therapeutic regulation of the renin-angiotensin system.

Signalling switches maintain intercellular communication in the vascular endothelium.

BACKGROUND AND PURPOSE: The single layer of cells lining all blood vessels, the endothelium, is a sophisticated signal co-ordination centre that controls a wide range of vascular functions including the regulation of blood pressure and blood flow. To co-ordinate activities, communication among cells is required for tissue level responses to emerge. While a significant form of communication occurs by the propagation of signals between cells, the mechanism of propagation in the intact endothelium is unresolved. EXPERIMENTAL APPROACH: Precision signal generation and targeted cellular manipulation was used in conjunction with high spatiotemporal mesoscale Ca2+ imaging in the endothelium of intact blood vessels. KEY RESULTS: Multiple mechanisms maintain communication so that Ca2+ wave propagation occurs irrespective of the status of connectivity among cells. Between adjoining cells, regenerative IP3-induced IP3 production transmits Ca2+ signals and explains the propagated vasodilation that underlies the increased blood flow accompanying tissue activity. The inositide is itself sufficient to evoke regenerative phospholipase C-dependent Ca2+ waves across coupled cells. None of gap junctions, Ca2+ diffusion or the release of extracellular messengers is required to support this type of intercellular Ca2+ signalling. In contrast, when discontinuities exist between cells, ATP released as a diffusible extracellular messenger transmits Ca2+ signals across the discontinuity and drives propagated vasodilation. CONCLUSION AND IMPLICATIONS: These results show that signalling switches underlie endothelial cell-to-cell signal transmission and reveal how communication is maintained in the face of endothelial damage. The findings provide a new framework for understanding wave propagation and cell signalling in the endothelium.

How can agent-based modelling provide new insights into the impact of minimum unit pricing in Scotland?

In recent years we have gained insight into the impact of minimum unit pricing (MUP)-a legal floor price below which a given volume of alcohol cannot be sold-on population-level reductions in alcohol sales, consumption and harm. However, several questions remain unanswered including how individual-level purchasing changes impact the local economy (e.g., balance between on-licence and off-licence outlets), lead to long-term population-level trends (e.g., youth drinking) and social harms (e.g., violence). Agent-based modelling captures heterogeneity, emergence, feedback loops and adaptive and dynamic features, which provides an opportunity to understand the nuanced effects of MUP. Agent-based models (ABM) simulate heterogeneous agents (e.g., individuals, organisations) often situated in space and time that interact with other agents and/or with their environment, allowing us to identify the mechanisms underlying social phenomena. ABMs are particularly useful for theory development, and testing and simulating the impacts of policies and interventions. We illustrate how ABMs could be applied to generate novel insights and provide best estimates of social network effects, and changes in purchasing behaviour and social harms, due to the implementation of MUP. ABMs like other modelling approaches can simulate alternative implementations of MUP (e.g., policy intensity [£0.50, £0.60] or spatial scales [local, national]) but can also provide an understanding of the potential impact of MUP on different population groups (e.g., alcohol exposure of young people who are not yet drinking). Using ABMs to understand the impact of MUP would provide new insights to complement those from traditional epidemiological and other modelling methods.

How does alcohol use impact morbidity and mortality of liver cirrhosis? A systematic review and dose-response meta-analysis.

BACKGROUND: Alcohol consumption is the most important risk factor responsible for the disease burden of liver cirrhosis (LC). Estimates of risk relationships available usually neither distinguish between different causes such as alcohol-related LC or hepatitis-related LC, nor differentiate between morbidity and mortality as outcome. We aimed to address this research gap and identify dose-response relationships between alcohol consumption and LC, by cause and outcome. METHODS: A systematic review using PubMed/Medline and Embase was conducted, identifying studies that reported an association between level of alcohol use and LC. Meta-regression models were used to estimate the dose-response relationships and control for heterogeneity. RESULTS: Totally, 44 studies, and 1 secondary data source, with a total of 5,122,534 participants and 15,150 cases were included. Non-linear dose-response relationships were identified, attenuated for higher levels of consumption. For morbidity, drinking 25 g/day was associated with a RR of 1.81 (95% CI 1.68-1.94) compared to lifetime abstention; 50 g/day and 100 g/day corresponded to 3.54 (95% CI 3.29-3.81) and 8.15 (95% CI 7.46-8.91), respectively. For mortality, for 25 g/day, a RR of 2.65 (95% CI 2.22-3.16); for 50 g/day, a RR of 6.83 (95% CI 5.84-7.97); for 100 g/day, a RR of 16.38 (95% CI 13.81-19.42) were identified. A higher risk for alcohol-related and all-cause LC as compared to hepatitis C-related LC was found. CONCLUSION: Our results demonstrated higher acceleration for mortality compared to morbidity. The current findings will inform the way we quantify the burden due to LC attributable to alcohol use.

Alcoholic beverage types consumed by population subgroups in the United States: Implications for alcohol policy to address health disparities.

INTRODUCTION: We aimed to identify alcoholic beverage types more likely to be consumed by demographic subgroups with greater alcohol-related health risk than others, mainly individuals with low socio-economic status, racial/ethnic minority status and high drinking levels. METHODS: Fractional logit modelling was performed using a nationally representative sample of US adult drinkers (analytic N = 37,657) from the National Epidemiologic Survey on Alcohol and Related Conditions Waves 2 (2004-2005) and 3 (2012-2013). The outcomes were the proportions of pure alcohol consumed as beer, wine, liquor and coolers (defined as wine-/malt-/liquor-based coolers, hard lemonade, hard cider and any prepackaged cocktails of alcohol and mixer). RESULTS: Adults with lower education and low or medium income were more likely to drink beer, liquor and coolers, while those with a 4-year college/advanced degree and those with high income preferred wine. Excepting Asian adults, racial/ethnic minority adults were more likely to drink beer (Hispanics) and liquor (Blacks), compared with White adults. High- or very-high-level drinkers were more likely to consume liquor and beer and less likely to consume wine (and coolers), compared with low-level drinkers. High-level and very-high-level drinkers, who were less than 10% of all drinkers, consumed over half of the total volume of beer, liquor and coolers consumed by all adults. DISCUSSION AND CONCLUSIONS: Individuals with low socio-economic status, racial/ethnic minority status or high drinking level prefer liquor and beer. As alcohol taxes, sales and marketing practices all are beverage-specific, targeted approaches to reduce consumption of these beverages, particularly among individuals with these profiles, are warranted.