An integrated dual process simulation model of alcohol use behaviours in individuals, with application to US population-level consumption, 1984–2012

Introduction The Theory of Planned Behaviour (TPB) describes how attitudes, norms and perceived behavioural control guide health behaviour, including alcohol consumption. Dual Process Theories (DPT) suggest that alongside these reasoned pathways, behaviour is influenced by automatic processes that are determined by the frequency of engagement in the health behaviour in the past. We present a computational model integrating TPB and DPT to determine drinking decisions for simulated individuals. We explore whether this model can reproduce historical patterns in US population alcohol use and simulate a hypothetical scenario, “Dry January”, to demonstrate the utility of the model for appraising the impact of policy interventions on population alcohol use. Method Constructs from the TPB pathway were computed using equations from an existing individual-level dynamic simulation model of alcohol use. The DPT pathway was initialised by simulating individuals’ past drinking using data from a large US survey. Individuals in the model were from a US population microsimulation that accounts for births, deaths and migration (1984–2015). On each modelled day, for each individual, we calculated standard drinks consumed using the TPB or DPT pathway. In each year we computed total population alcohol use prevalence, frequency and quantity. The model was calibrated to alcohol use data from the Behavioral Risk Factor Surveillance System (1984–2004). Results The model was a good fit to prevalence and frequency but a poorer fit to quantity of alcohol consumption, particularly in males. Simulating Dry January in each year led to a small to moderate reduction in annual population drinking. Conclusion This study provides further evidence, at the whole population level, that a combination of reasoned and implicit processes are important for alcohol use. Alcohol misuse interventions should target both processes. The integrated TPB-DPT simulation model is a useful tool for estimating changes in alcohol consumption following hypothetical population interventions

The role of alcohol use in the aetiology and progression of liver disease: a narrative review and a quantification

Issues Alcohol use has been shown to impact on various forms of liver disease, not restricted to alcoholic liver disease. Approach We developed a conceptual framework based on a narrative review of the literature to identify causal associations between alcohol use and various forms of liver disease including the complex interactions of alcohol with other major risk factors. Based on this framework, we estimate the identified relations for 2017 for the USA. Key Findings The following pathways were identified and modelled for the USA for the year 2017. Alcohol use caused 35 200 (95% uncertainty interval 32 800–37 800) incident cases of alcoholic liver cirrhosis. There were 1700 (uncertainty interval 1100–2500) acute hepatitis B and C virus (HBV and HCV) infections attributable to heavy‐drinking occasions, and 14 000 (uncertainty interval 5900–19 500) chronic HBV and 1700 (uncertainty interval 700–2400) chronic HCV infections due to heavy alcohol use interfering with spontaneous clearance. Alcohol use and its interactions with other risk factors (HBV, HCV, obesity) led to 54 500 (uncertainty interval 50 900–58 400) new cases of liver cirrhosis. In addition, alcohol use caused 6600 (uncertainty interval 4200–9300) liver cancer deaths and 40 700 (uncertainty interval 36 600–44 600) liver cirrhosis deaths. Implications Alcohol use causes a substantial number of incident cases and deaths from chronic liver disease, often in interaction with other risk factors. Conclusion This additional disease burden is not reflected in the current alcoholic liver disease categories. Clinical work and prevention policies need to take this into consideration