People who pass out after heavy drinking may have double the risk of developing dementia later in life: Study
Heavy alcohol intake can cause people to pass out. This pattern of drinking is likely to double an individual's risk of dementia in later life, according to researchers who reviewed previous studies on the link between binge drinking and dementia.
Dementia robs people of their memory and their ability to think and carry out everyday activities. According to the World Health Organization (WHO), around 50 million people have dementia across the globe, with nearly 10 million new cases emerging every year. Alzheimer's disease is the most common form of dementia and may contribute to 60–70% of cases.
Previous studies have linked alcohol intake with a higher risk of developing dementia. But not much was known on the effects of alcohol-induced passing out until now, the researchers said. "The findings of this study suggest that alcohol-induced loss of consciousness, irrespective of overall alcohol consumption, is associated with a subsequent increase in the risk of dementia," the researchers wrote in their study. According to the team, in addition to the weekly intake quantity, drinking pattern is also crucial.
Drinking hits the brain and the effects include difficulty walking, blurred vision, slurred speech, slowed reaction times, and impaired memory. Large quantities of alcohol, when consumed quickly and on an empty stomach, can produce a blackout, according to experts. It occurs when inebriated people experience memory loss as they fail to recall events while binging.
The study involved 131, 415 participants, who were free of dementia when the research began. Of them, about 96, 000 reportedly passed out during drinking, and about 10,000 said they had experienced it in the last 12 months. Overall, 1081 individuals developed dementia. "Those who reported having lost consciousness due to alcohol consumption, regardless of their overall weekly consumption, had a 2-fold increased risk of dementia compared with people who had not lost consciousness and were moderate drinkers," the researchers wrote. "Those who reported having lost consciousness during the past 12 months had twice the risk of dementia [compared to] moderate drinkers who had not lost consciousness," they added.
The risk applied to both men and women, and other forms of the condition, such as all-cause dementia, early-onset dementia, late-onset dementia, and Alzheimer's disease. The study found that heavy drinkers (individuals consuming more than 14 units in a week) were more likely to develop dementia later in life than moderate drinkers (those consuming between 1 and 14 units of alcohol in a week).
So how could alcohol raise the risk of dementia? It could happen either directly or indirectly, according to the researchers. Ethanol is toxic to the brain: it crosses the blood-brain barrier to reach the brain, and in high concentrations, it can lead to the loss of brain cells. Alternatively, it could indirectly act by causing liver and kidney disease, diabetes, hypertension, arrhythmias, coronary heart disease, and stroke. These conditions, in turn, are risk factors for dementia.
However, it is important to remember that the study only brings out a link and does not prove that alcohol-induced loss of consciousness causes dementia. The findings are published in JAMA.