Having a particular genetic variant (A-allele of ADH1B rs1229984) is associated with non-drinking and lower alcohol consumption. This variant is also associated with favorable cardiovascular profile and a reduced risk of coronary heart disease compared to those without the genetic variant, but it is unknown whether this may be caused by differences in alcohol consumption or by additional confounding effects of the genetic variant itself.

Drinking in moderation has been found to help those who have suffered a heart attack survive it. However, excessive alcohol consumption leads to an increased risk of heart failure. A review of the literature found that half a drink of alcohol offered the best level of protection. However, they noted that at present there have been no randomised trials to confirm the evidence which suggests a protective role of low doses of alcohol against heart attacks. However, moderate alcohol consumption is associated with hypertension. There is an increased risk of hypertriglyceridemia, cardiomyopathy, hypertension, and stroke if 3 or more standard drinks of alcohol are taken per day.

Chronic excessive alcohol abuse is associated with a wide range of skin disorders including urticaria, porphyria cutanea tarda, flushing, cutaneous stigmata of cirrhosis, psoriasis, pruritus, seborrheic dermatitis and rosacea.

A 2010 study concluded, "Nonlight beer intake is associated with an increased risk of developing psoriasis among women. Other alcoholic beverages did not increase the risk of psoriasis in this study."

While little detailed genetic research has been done, it has been shown that alcoholism tends to run in families with possible involvement of differences in alcohol metabolism and the genotype of alcohol-metabolizing enzymes.

Acute intoxication, such as binge drinking and alcoholism, are known potent risk factors for suicide. Binge drinking is also associated with an increased risk of unplanned sex, unprotected sex, unplanned pregnancies, and an increased risk of HIV infection. 10 percent of women and 19 percent of men have reported being assaulted as a result of alcohol. Males who drink more than 35 units of alcohol per week report being physically hurt as a result of alcohol, and 15 percent report physically hurting others as a result of their drinking. Almost 16 percent of binge drinkers report being taken advantage of sexually, and 8 percent report taking advantage of another person sexually as a result of alcohol within a 1-year period. Heavy drinkers cause approximately 183,000 rapes and sexual assaults, 197,000 robberies, 661,000 aggravated assaults, and 1.7 million simple assaults each year. Binge drinking has been associated with high odds of divorce, spousal abuse, and poor job performance. Binge drinking can cause adverse effects on the body including effects on blood homeostasis and its circadian variation, cardiac rhythm, ischaemic heart disease, blood pressure, white blood cell activity, female reproductive hormone levels as well as adverse effects on the fetus. There is also evidence from animal studies that binge drinking causes brain damage. Binge drinking has been associated with lower abdominal pain in women. Ketoacidosis can occur in individuals who chronically abuse alcohol and have a recent history of binge drinking. Alcohol affects brain development quite significantly especially during adolescence when the brain is still developing. The main lobes that are involved in decision making and complex thought processes are undergoing their final development phase during adolescence and binge drinking can negatively stunt the growth of these frontal lobes.

The high levels of binge drinking among young people and the adverse consequences that include increased risk of alcoholism as an adult and liver disease make binge drinking a major public health issue. Recent research has found that young college binge drinkers who drink 4/5+ drinks on more than 3 occasions in the past 2 weeks are statistically 19 times more likely to develop alcoholism than non-binge drinkers, though the direction of causality remains unclear. This is particularly interesting as drinking for the sole purpose of getting drunk, remains a major health and social problem on college campuses across the United States. Heavy and regular binge drinking during adolescence is associated with an increased risk of alcoholism. Approximately 40 percent of alcoholics report heavy drinking during adolescence. Repeated episodes of excessive drinking, especially at an early age, are thought to cause a profound increase in the risk of developing an alcohol-related disorder (ICD-10, harmful use/dependence syndrome). Heavy drinking is also closely associated with depression. Those with severe depression have higher rates of alcohol abuse than those with low depression. College students who are depressed are more susceptible to use alcohol than college students who are not depressed. In a study conducted by Harvard University it was found that about 32% of students surveyed were diagnosable for alcohol abuse and about 6% were diagnosed as alcohol dependent. Binge drinking is also becoming an increasing problem in Australian adolescents, the Australian School Students Alcohol and Drug survey conducted by the National Cancer Council discovered that around 33 percent of students between Years 7 and 11 consumed alcohol in the week leading up to the survey, they also found that 10 percent of the students participated in binge drinking at a consumption level which is considered dangerous to adults. When the survey results were separated into age groups the findings were that 13 percent of 15-year-old's and 22 percent of 17-year-old's had alcohol consumption levels above the daily maximum suggested to adults and that 20 percent of 17-year-old's had a consumption level of alcohol considered risky to adults.

Other risk factors that influence the development of alcohol abuse or alcoholism include social and genetic factors. Several researchers have found that starting drinking before the age of 15 is associated with a fourfold increased risk for developing alcoholism compared to people that delay drinking until age 20 or later. It has been estimated by some that if the age at which people started drinking could be delayed to age 20, there would be a 50 percent reduction in the number of cases of alcohol use disorder. However, it is unclear whether this is a causal relationship, or a function of confounding familial (and other) factors associated with both age at first drink and propensity for alcoholism.

The main cause of death among adolescents as a result of binge drinking is road traffic accidents; a third of all fatal road traffic accidents among 15- to 20-year-olds are associated with drinking alcohol. Cyclists and pedestrians are likely to have less spatial awareness and concentration while travelling after binge drinking and, also, it is more common that adolescents that binge-drink drive drunk or are the passenger of a drunk driver. It has been found that 50 percent of all head injuries in adolescents in the US are associated with alcohol consumption. Violence and suicide combine to become the third-most-common cause of death associated with binge drinking among adolescents. The suicide risk in adolescents is more than 4 times higher among binge drinkers than non-binge drinking adolescents.

Earlier sexual activity, increased changing of sexual partners, higher rate of unwanted (teenage) pregnancy, higher rate of sexually transmitted diseases, infertility, and alcohol-related damage to the fetus during pregnancy is associated with binge drinking. Female binge drinkers are three times more likely to be victims of sexual assault; 50 percent of adolescent girls reporting sexual assault were under the influence of alcohol or another psychotropic substance at the time.

Adolescents who regularly participated in binge drinking for several years show a smaller hippocampus brain region, in particular those who began drinking in early adolescence. Heavy binge drinking is associated with neurocognitive deficits of frontal lobe processing and impaired working memory as well as delayed auditory and verbal memory deficits. Animal studies suggest that the neurodegenerative effects of alcohol abuse during adolescence can be permanent. Research in humans, which utilised sophisticated brain scanning technology suggests that in adolescent teenagers, drinking more than 4 or 5 drinks once or twice a month results in subtle damage to the teenagers developing brain tissue, in particular the white matter. However, this research is primarily cross-sectional and done with fairly small sample sizes, making causality less certain.

Several studies have been conducted to discover if there is a link between binge drinking in adolescent years and becoming a chronic alcohol consumer when they transition into adulthood. A particular study conducted by the National Longitudinal Survey of Youth found that harmful drinking during adolescent years was significantly associated with the continuance of dangerous levels of alcohol consumption into adulthood years.

The relationship between alcohol and weight is the subject of inconclusive studies. Findings of these studies range from increase in body weight to a small decrease among women who begin consuming alcohol. Some of these studies are conducted with a large number of subjects; one involved nearly 80,000 and another 140,000 subjects.

Findings are inconclusive because alcohol itself contains 7 calories per gram, but research suggests that alcohol energy is not efficiently used. Alcohol also appears to increase metabolic rate significantly, thus causing more calories to be burned rather than stored in the body as fat (Klesges "et al.", 1994). Other research has found consumption of sugar to decrease as consumption of alcohol increases.

According to Dr. Kent Bunting, the research results do not necessarily mean that people who wish to lose weight should continue to consume alcohol because consumption is known to have an enhancing effect on appetite. Due to these discrepancies in findings, the relationship between alcohol and weight remains unresolved and requires further research.

Biological and environmental factors are thought to contribute to alcoholism and obesity. The physiologic commonalities between excessive eating and excessive alcohol drinking shed light on intervention strategies, such as pharmaceutical compounds that may help those who suffer from both.

Some of the brain signaling proteins that mediate excessive eating and weight gain also mediate uncontrolled alcohol consumption. Some physiological substrates that underlie food intake and alcohol intake have been identified. Melanocortins, a group of signaling proteins, are found to be involved in both excessive food intake and alcohol intake.

Alcohol may contribute to obesity. A study found frequent, light drinkers (three to seven drinking days per week, one drink per drinking day) had lower BMIs than infrequent, but heavier drinkers. Although calories in liquids containing ethanol may fail to trigger the physiologic mechanism that produces the feeling of fullness in the short term, long-term, frequent drinkers may compensate for energy derived from ethanol by eating less.

The International Agency for Research on Cancer of the World Health Organization has classified alcohol as a Group 1 carcinogen.

Studies have shown that heavy drinkers put themselves at greater risk for heart disease and developing potentially fatal cardiac arrhythmias. Excessive alcohol consumption can cause higher blood pressure, increase cholesterol levels and weakened heart muscles. Studies have shown that moderate wine drinking can improve the balance of low-density lipoprotein (LDL or "bad" cholesterol) to high-density lipoprotein (HDL "good" cholesterol), which has been theorized as to clean up or remove LDL from blocking arteries. The main cause of heart attacks and the pain of angina is the lack of oxygen caused by blood clots and atheromatous plaque build up in the arteries. The alcohol in wine has anticoagulant properties that limits blood clotting by making the platelets in the blood less prone to stick together and reducing the levels of fibrin protein that binds them together.

Professional cardiology associations recommend that people who are currently nondrinkers should not start drinking alcohol.

The combination of self-starvation and alcohol abuse can lead to an array of physical and psychological consequences. For example, drinking in a state of malnutrition can predispose individuals to a higher rate of blackouts, alcohol poisoning, alcohol-related injury, violence, or illness. Drinking on an empty stomach allows ethanol to reach the blood system at a swifter pace and raises one's blood alcohol content with an often dangerous speed. This can render the drinker more vulnerable to alcohol-related brain damage. In addition, alcohol abuse can have a detrimental impact on hydration and the body's retention of minerals and nutrients, further exacerbating the consequences of malnutrition and denigrating an individual's cognitive faculties. This can ultimately have a negative impact on academic performance.

These harmful consequences can be more easily induced in women, as women are oftentimes less capable of metabolizing alcohol than men. On CBS News, Carrie Wilkins, PhD, of the Center for Motivation and Change (a private practice group based in New York City) describes how women are more vulnerable to particular toxic side effects of alcohol consumption.

Drunkorexia can lead to short term and long term cognitive problems including difficulty concentrating and difficulty making decisions. It also increases the risk of developing more serious eating disorders or alcohol abuse problems. As binge drinking is involved there is a greater risk for violence, risky sexual behavior, alcohol poisoning, substance abuse and chronic disease later in life.

Drunkorexia consists of 3 major aspects: alcohol use/abuse, food intake restriction, and excessive physical activity. It is commonly summarised in the following activities:

- Counting daily calorie intake (commonly known as "calorie counting") to ensure no weight will be gained when consuming alcohol.

- Missing or skipping meals to conserve calories for consumption of alcoholic beverages.

- Over exercising to counterweigh for calories consumed from alcoholic beverages.

- Consuming an extreme amount of alcohol to vomit previously digested food.

Extensive epidemiological studies have demonstrated the cardioprotective effect of alcohol consumption. However the mechanism by which this occurs is not fully understood. Research has suggested several possible mechanisms, including the following.

There is a lack of medical consensus about whether moderate consumption of beer, wine, or distilled spirits has a stronger association with heart disease. Studies suggest that each is effective, with none having a clear advantage. Most researchers now believe that the most important ingredient is the alcohol itself.

The American Heart Association has reported that "More than a dozen prospective studies have demonstrated a consistent, strong, dose-response relation between increasing alcohol consumption and decreasing incidence of CHD (coronary heart disease). The data are similar in men and women in a number of different geographic and ethnic groups. Consumption of one or two drinks per day is associated with a reduction in risk of approximately 30% to 50%".

Heart disease is the largest cause of mortality in the United States and many other countries. Therefore, some physicians have suggested that patients be informed of the potential health benefits of drinking alcohol in moderation, especially if they abstain and alcohol is not contraindicated. Others, however, argue against the practice in fear that it might lead to heavy or abusive alcohol consumption. Heavy drinking is associated with a number of health and safety problems.

Based on combined data from SAMHSA's 2004–2005 National Surveys on Drug Use & Health, the rate of past-year alcohol dependence or abuse among persons aged 12 or older varied by level of alcohol use: 44.7% of past month heavy drinkers, 18.5% binge drinkers, 3.8% past month non-binge drinkers, and 1.3% of those who did not drink alcohol in the past month met the criteria for alcohol dependence or abuse in the past year. Males had higher rates than females for all measures of drinking in the past month: any alcohol use (57.5% vs. 45%), binge drinking (30.8% vs. 15.1%), and heavy alcohol use (10.5% vs. 3.3%), and males were twice as likely as females to have met the criteria for alcohol dependence or abuse in the past year (10.5% vs. 5.1%).

A logical possibility is that some of the alcohol abstainers in research studies previously drank excessively and had undermined their health, thus explaining their high levels of risk. To test this hypothesis, some studies have excluded all but those who had avoided alcohol for their entire lives. The conclusion remained the same in some studies: moderate drinkers are less likely to suffer heart disease. A paper concludes, "In this population of light to moderate drinkers, alcohol consumption in general was associated with decreased MI [myocardial infarction ] risk in women; however, episodic intoxication was related to a substantial increase in risk."

An analysis by Dr. Kaye Fillmore and colleagues failed to find significant support. Analyzing 54 prospective studies, the authors found that those studies which were free of the potential error (including former drinkers in the abstaining group) did not demonstrate significant cardiac protection from alcohol, although they continued to exhibit a J-shaped relationship in which moderate drinkers were less likely (but not at a statistically significantly level of confidence) to suffer cardiac disease than lifelong abstainers.

Dr. Arthur Klatsky noted that the flaw pointed out by Fillmore existed in one of his early studies of alcohol consumption, but that his later studies illustrating a protective effect of moderate alcohol consumption did not contain this flaw. To overcome the inherent weaknesses of all epidemiological studies, even when properly conducted, he calls for a randomized trial in which some subjects are assigned to abstain while others are assigned to drink alcohol in moderation and the health of all is monitored for a period of years.

This question of confusion of abstainers with previously heavy drinkers in epidemiologic studies is overcome with studies showing dose response effects. That is, higher amounts of alcohol consumption seem associated with greater cardiovascular benefit. Cardiology associations recommend that people who are currently nondrinkers should not start drinking alcohol.

Alcohol abuse is said to be most common in people aged between 15 and 24 years, according to Moreira 2009. However, this particular study of 7275 college students in England collected no comparative data from other age groups or countries.

Causes of alcohol abuse are complex and are likely the combination of many factors, from coping with stress to childhood development. The US Department of Health & Human Services identifies several factors influencing adolescent alcohol use, such as risk-taking, expectancies, sensitivity and tolerance, personality and psychiatric comorbidity, hereditary factors, and environmental aspects. Studies show that child maltreatment such as neglect, physical, and/or sexual abuse, as well as having parents with alcohol abuse problems, increases the likelihood of that child developing alcohol use disorders later in life. According to Shin, Edwards, Heeren, & Amodeo (2009), underage drinking is more prevalent among teens that experienced multiple types of childhood maltreatment regardless of parental alcohol abuse, putting them at a greater risk for alcohol use disorders. Genetic and environmental factors play a role in the development of alcohol use disorders, depending on age. The influence of genetic risk factors in developing alcohol use disorders increase with age ranging from 28% in adolescence and 58% in adults.

Alcohol is the most available, widely consumed, and widely abused recreational drug. Beer alone is the world's most widely consumed alcoholic beverage; it is the third-most popular drink overall, after water and tea. It is thought by some to be the oldest fermented beverage.

Direct alcohol tolerance is largely dependent on body size. Large-bodied people will require more alcohol to reach insobriety than lightly built people. Thus men, being larger than women on average, will have a higher alcohol tolerance. The alcohol tolerance is also connected with activity of "alcohol dehydrogenases" (a group of enzymes responsible for the breakdown of alcohol) in the liver, and in the bloodstream.

High level of alcohol dehydrogenase activity results in fast transformation of ethanol to more toxic acetaldehyde. Such atypical alcohol dehydrogenase levels are less frequent in alcoholics than in nonalcoholics and, alongside other symptoms, can indicate various forms of liver disease. Furthermore, among alcoholics, the carriers of this atypical enzyme consume lower ethanol doses, compared to the individuals without the allele.

The tolerance to alcohol is not equally distributed throughout the world's population, and genetics of alcohol dehydrogenase indicate resistance has arisen independently in different cultures. In North America, Native Americans have the highest probability of developing alcoholism compared to Europeans and Asians.

Higher body masses and the prevalence of high levels of alcohol dehydrogenase in an individual increase alcohol tolerance.

Not all differences in tolerance can be traced to biochemistry. Differences in tolerance levels are also influenced by socio-economic and cultural difference including diet, average body weight and patterns of consumption.

An estimated one out of twenty people have an alcohol flush reaction. It is not in any way an indicator for the drunkenness of an individual. It is colloquially known as "face flush", a condition where the body metabolizes alcohol nearly 100-times less efficiently into acetaldehyde, a toxic metabolite. Flushing, or blushing, is associated with the erythema (reddening caused by dilation of capillaries) of the face, neck, and shoulder, after consumption of alcohol.

Researchers from the NIH's National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) conducted a study and found that early-onset paternal obesity is connected with an increased risk of liver disease in their kin. Researchers found that obese fathers had an elevated level of serum alanine aminotransferase (ALT), a liver enzyme, compared to fathers who were not obese. They did a secondary analysis that excluded obese offspring. Children who were a normal weight but had obese fathers still had elevated ALT levels, which indicated that a child's ALT levels are not dependent upon the child's own BMI.

Obese women have an increased risk of pregnancy-related complications, including hypertension, gestational diabetes, and blood clots. Also, the mother is at risk of going into preterm labor. Maternal obesity is also known to be associated with increased rates of complications in late pregnancy such as cesarean delivery, and shoulder dystocia. A meta-analysis estimated that Cesarean delivery rates increased with odds ratios of 1.5 among overweight, 2 among obese, and 3 among severely obese women, compared with normal weight pregnant women. In addition, morbidly obese women who have not had children before are at increased risk of all–cause preterm deliveries. It is well recognized that obese women are at increased risk of preeclampsia and that women who have never been pregnant are at higher risk of preeclampsia than women who have had children in the past.

One out of 67 women who drink alcohol during pregnancy will have a child with a birth defect. The five countries with the highest prevalence of alcohol use during pregnancy were Ireland (about 60%), Belarus (47%), Denmark (46%), the UK (41%) and the Russian Federation (37%). The lowest prevalence is in those nations whose religious beliefs govern their alcohol consumption. Birth defects caused by alcohol consumption may be up to 1% in many places. This may mean that FASD may be higher than anencephaly, Down syndrome, spina bifida and trisomy 18. Globally, one in 10 women drink alcohol during pregnancy. Out of this population, 20% binge drink and have four or more alcoholic drinks per single occasion.

"Binge drinking is the direct cause of FAS or FASD. These findings are alarming because half of the pregnancies in developed countries and over 80% in developing countries are unplanned. That means that many women don’t realize they are pregnant during the early stages and that they continue drinking when pregnant."

The cause of alcohol abuse is complex. Alcohol abuse is related to economic and biological origins and is associated with adverse health consequences. Peer pressure influences individuals to abuse alcohol; however, most of the influence of peers is due to inaccurate perceptions of the risks of alcohol abuse. According to Gelder, Mayou and Geddes (2005) easy accessibility of alcohol is one of the reasons people engage in alcohol abuse as this substance is easily obtained in shops. Another influencing factor among adolescents and college students are the perceptions of social norms for drinking; people will often drink more to keep up with their peers, as they believe their peers drink more than they actually do. They might also expect to drink more given the context (e.g. sporting event, fraternity party, etc.). This perception of norms results in higher alcohol consumption than is normal.

Alcohol abuse is also associated with acculturation, because social and cultural factors such as an ethnic group’s norms and attitudes can influence alcohol abuse.

Conditions of fatigue correlate positively with increased alcohol consumption.

Starting in 1981, the surgeon general of the United States started releasing a warning asking pregnant women to abstain from alcohol for the remainder of gestation.

Low doses of alcohol (one beer) appear to increase total sleep time and reduce awakening during the night. The sleep-promoting benefits of alcohol dissipate at moderate and higher doses of alcohol. Previous experience with alcohol also influences the extent to which alcohol positively or negatively affects sleep. Under free-choice conditions, in which subjects chose between drinking alcohol or water, inexperienced drinkers were sedated while experienced drinkers were stimulated following alcohol consumption. In insomniacs, moderate doses of alcohol improve sleep maintenance.