Alcohol use influences the development, course, and outcomes of diseases, and it has been estimated that in 2016, around 3 million deaths globally were attributed to the harmful use of alcohol (World Health Organisation, 2018). The adverse health effects of alcohol use are mainly dependent on the volume and pattern of drinking (Rehm et al., 2003), but also on the type of alcoholic beverage consumed (Mäkelä, Mustonen & Österberg, 2007).
2.2.1 Harmful effects of alcohol use
There is a considerable amount of evidence demonstrating that alcohol use causes many communicable and non-communicable diseases, as well as injuries (intentional and unintentional) (Rehm et al., 2010b; Rehm et al., 2017a). Reports confirm a causal association of alcohol use with many diseases, suggesting that higher levels of alcohol use can lead to an exponential increase in the risk of diseases. Studies have pointed out a detrimental causal association of alcohol use with some communicable diseases, such as tuberculosis (Rehm et al., 2009), human immunodeficiency virus infection (Rehm et al., 2017c), and pneumonia (Samokhvalov, Irving & Rehm, 2010).
Previous research has concluded that the use of alcohol is causally associated with many gastrointestinal diseases, such as liver cirrhosis (Rehm et al., 2010a) and pancreatitis (Samokhvalov, Rehm & Roerecke, 2015), as well as injuries (Cherpitel, 2009). Likewise, alcohol use has been causally linked with many neuropsychiatric conditions, for example, epilepsy (Leach, Mohanraj & Borland, 2012) and Alzheimer or other dementia conditions (Daulatzai, 2015). Because alcohol use is a risk for many cancers—for example, the cancer of the pharynx, larynx, mouth, esophagus, and liver, to name just a few—the International Agency for Research on Cancer (IARC) has recognized it as a carcinogen (IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2012). Some other non-communicable diseases, such as cardiovascular diseases including hypertension (Briasoulis, Agarwal & Messerli, 2012), ischemic heart disease (Roerecke, Rehm, 2014), and cardiomyopathy (Rehm et al., 2017b), are also associated with chronic alcohol use.
It is worth noting that most of these above-mentioned effects are attributed to the effects of volume of alcohol consumed, except for injuries and ischemic heart diseases, for which both the volume of alcohol consumed and drinking patterns are important (Rehm et al., 2010b). Beyond the detrimental health effects of alcohol use, the often-debated beneficial effects of alcohol use needs to be mentioned. A low-risk drinking pattern has been reported to have some beneficial effects, notably in the case of diabetes (Baliunas et al., 2009), ischemic heart disease, ischemic stroke, and Alzheimer or other dementia conditions (Collins et al., 2009). A meta-analysis reported that light-to-moderate wine intake has cardio-protective effects (Di Castelnuovo et al., 2002), suggesting that the type of beverage could explain the cardio-protective effect of alcohol. Another report also suggested that moderate wine intake has a beneficial effect on diabetes, osteoporosis, and neurological diseases
(Artero et al., 2015). However, a question about the risks and benefits of different alcoholic beverages on health remains unanswered.
2.2.2 Conceptual models for alcohol effects on health
The effects of the total volume and pattern of drinking imply that both these factors contribute to the burden of chronic diseases. Considering this, Rehm and colleagues included these factors in their conceptual model (Rehm et al., 2010b). In addition to these factors, the role of societal and individual (sociodemographic and socioeconomic) factors in the harmful effects of alcohol use on health has been emphasized (Blas & Kurup, 2010). Societal factors include drinking culture, alcohol policy, drinking environment, and the healthcare system. Individual factors include age, gender, genetics, and socioeconomic position (Blas & Kurup, 2010). In addition to the total volume and pattern of drinking, another pathway proposed by Mäkelä et al. includes the effects of the type of beverage consumed on the health outcomes (Mäkelä, Mustonen & Österberg, 2007). The type of beverage may have a marginal effect compared with other measures of alcohol use (Figure 3; modified from Mäkelä, Mustonen & Österberg, 2007; Rehm et al., 2010b; Blas & Kurup, 2010). The harmful effects caused by alcohol use are explained by multiple mechanisms including, (a) detrimental effects on organs and tissues; (b) injuries or poisoning due to acute intoxication; and (c) self-harm due to dependence (Rehm et al., 2003).
SOCIETAL FACTORS
Drinking culture Alcohol policyINDIVIDUAL FACTORS
Age Gender Genetics
ALCOHOL USE Needs and
preferences
Volume Pattern Beverage type
2.2.3 Alcohol effects on health by age, gender, genetics, and socioeconomic position (SEP)
As noted earlier, individual characteristics may influence alcohol-related health outcomes. Studies have reported that alcohol effects differ by age, gender, and SEP.
It has been reported that both young and older individuals are more prone to the adverse effects of alcohol than other age groups (Mustonen, 2000), but the underlying reasons may be different for these groups (young and older). One of the reasons for this could be a difference in drinking behaviors, as it is known that heavy episodic drinking occasions are common among young individuals, for example (General, 2007), while, in older individuals, frequent drinking (Wilsnack et al., 2009) and the inability to handle the same volume/pattern of alcohol use with increasing age can increase their susceptibility to the consequences of alcohol intake.
Likewise, alcohol-related harm has been reported in both men and women. The increased alcohol-related harm among men has been suggested to be related to their high-risk and frequent drinking behavior (Wilsnack et al., 2009), whereas it can be assumed that this harm is more pronounced among women due to the biological differences between genders (Wilsnack, Wilsnack & Kantor, 2013). Current evidence suggests that alcohol affects men and women disproportionately. It has been reported by Rehm et al. that women suffer more from alcohol-related cardiovascular diseases and cancers than men (Rehm et al., 2010b), whereas, on the other hand, it is estimated that alcohol-related mortality is higher among men than women (World Health Organisation, 2014). Additionally, ethnic differences with regard to alcohol intake and alcohol tolerance may also distinguish the experience of adverse effects among different populations (Joslyn et al., 2010).
Socioeconomic position can also affect the consequences of alcohol intake. For example, earlier research suggests that people belonging to a lower SEP are more prone to the harmful effects of alcohol use (Grittner et al., 2012). This susceptibility among individuals with a lower SEP can most likely be attributed to their risky drinking behavior and limited or lack of access to healthcare services (Schmidt et al., 2010). The disproportionate effect of alcohol that causes greater harm in vulnerable populations who consume an equal amount of alcohol compared to well-off populations is termed the ´alcohol harm paradox´ (Jones et al., 2015). The exact mechanism for this phenomenon is unclear, but several explanations have been proposed. Some of these include the clustering of risk factors or unhealthy behaviors, such as, smoking and alcohol; the difference in drinking patterns (Huckle, You &
Casswell, 2010); the choice of beverage (Mortensen et al., 2001); differences in drinking behavior with regard to SEP (Bloomfield et al., 2006); and lastly differences in access to healthcare.