Heavy daily alcohol intake at the population level predicts the weight of alcohol in cirrhosis burden worldwide

Background & Aims

Studies assessing alcohol as a population level risk factor for cirrhosis typically focus on per capita consumption. However, clinical studies indicate that daily intake is a strong predictor of alcoholic cirrhosis. We aimed to identify the determinants of alcohol’s contribution to the global cirrhosis burden and to evaluate the influence of daily drinking on a population level.

Methods

We performed a comprehensive analysis of the WHO 2014 Global Status Report on Alcohol and Health. We categorized countries by heavy or moderate drinking based on daily consumption, using U.S. Department of Agriculture definitions of heavy drinking. Additional data on cirrhosis cofactors were also obtained. Uni- and multivariate models were fitted to identify independent predictors of the alcohol-attributable fraction of cirrhosis.

Results

The WHO 2014 Report found that half of cirrhosis mortality worldwide is attributable to alcohol, approximating 60% in North America and Europe. In an integrative multivariate model, the designation of countries by moderate or heavy daily drinking had the strongest influence on the weight of alcohol in the cirrhosis burden. The relative contribution from alcohol increased by 11% with a transition from the moderate to heavy classification (p <0.001). Importantly, drinking patterns such as heavy episodic drinking and the type of alcohol did not independently predict the alcohol-attributable fraction of cirrhosis.

Conclusions

Heavy daily drinking on a population level significantly influences the weight of alcohol in the cirrhosis burden. Reducing heavy drinking should be considered as an important target for public health monitoring and policies.

Lay summary

We carried out an analysis of the WHO 2014 Global Status Report on Alcohol and Health, and categorized countries by their level of drinking (heavy or moderate). We found that half of the global cirrhosis cases, and 60% in both North America and Europe are associated with alcohol intake. We concluded that on a population level heavy daily drinking significantly influences the impact of alcohol on the cirrhosis burden.

Introduction

Excessive use of alcohol is a main cause of global mortality, contributing to deaths through cancers, toxic organ damage, and accidents and injuries [1]. Detailed data on the burden of alcohol-associated mortality were released in the 2014 World Health Organization (WHO) Global Status Report on Alcohol and Health, which is the most detailed and comprehensive report of this kind [2]. This publication emphasizes the significant contribution alcohol use makes to the global cirrhosis burden, with approximately half of global cirrhosis deaths attributed to alcohol use. Attention should be placed on detrimental patterns and levels of alcohol use that lead to cirrhosis in order to reduce associated mortality.

Previous studies have demonstrated a dose-response relationship between alcohol intake and an individual’s risk for developing cirrhosis [3], [4], [5], [6]. There is also substantial support for a threshold effect, wherein the risk for developing cirrhosis is constant over time if a threshold of intake is surpassed [7], [8], [9]. For a given level of total consumption, the pattern of drinking may confer higher risk for cirrhosis; for example, drinking on a daily basis has been shown to be associated with higher risk [6], [7], [9]. Some studies have investigated the potential influences of factors including binge drinking [10], [11], duration of consumption over lifetime [7], [9], and alcohol type [6], [12], [13]. Cofactors that have been shown to increase risk of alcoholic cirrhosis include cigarette smoking [14], [15], excess weight [16], and viral hepatitis [17]. Consumption of certain substances, such as coffee and tea, may provide a protective effect against the development of liver disease [18], [19]. For all variables discussed, the potential for significant geographical variation exists, due to cultural and socioeconomic differences in exposure to risk or protective factors. The economics and policies of alcohol sale can also be expected to vary considerably across the globe and to influence the way it is consumed [20].

On a population level, an association between alcohol consumption and cirrhosis mortality has been well documented, reflecting the risk relationship demonstrated on the individual level [21], [22], [23], [24]. Most population level studies have assessed the effect of per capita drinking on the death rate from cirrhosis, primarily in Europe and the U.S. One study compared the effect of per capita consumption on cirrhosis mortality in European countries that predominantly consume spirits as opposed to wine and beer [21]. Moreover, it has been hypothesized that differences in population drinking patterns (e.g., heavy episodic vs. daily drinking) shape the relationship between alcohol consumption and cirrhosis mortality [22]. However, to our knowledge, there are no studies assessing the influence of daily drinking patterns on cirrhosis mortality at the population level, or on the burden of alcoholic cirrhosis specifically. In this study, we aimed to identify the main determinants of cirrhosis mortality and the weight of alcohol in the global cirrhosis burden. We used recent data reported in the WHO 2014 Global Status Report on Alcohol and Health to evaluate associations between population drinking, cirrhosis cofactors, and economic indicators and the burden of alcoholic cirrhosis.