Abstinence and heavy drinking associated with increased dementia risk

01 August 2018

The BMJ: Alcohol consumption and risk of dementia: 23-year follow-up of Whitehall II cohort study

A new study has examined the links between alcohol consumption in midlife and later life dementia risk, finding that abstaining from drinking or drinking over 14 units a week was associated with a higher dementia risk than drinking 1-14 units per week. The findings are published today (Wednesday 1 August 2018) in The BMJ.

Many studies have looked at the links between different levels of drinking and how this impacts dementia risk, but most rely on a single snapshot in time, meaning we don’t know how changing patterns of drinking could affect people’s risk.

The new findings are based on data collected from 9,087 members of the Whitehall II study, a long-term study into factors that can affect health. Beginning in 1985, the Whitehall II study recruited members of the Civil Service between the ages of 35 and 55, who went on to provide information about their health and lifestyle through regular assessments roughly five years apart.

In this study, the researchers looked at self-reported levels of alcohol intake at two or more assessment points between 1985 and 1993. They classed people who had fully abstained from alcohol, people who stopped drinking early in the study and those who only occasionally drank during the study period as abstainers. Those who did drink were split into two groups, those who drank between 1-14 units a week and those who drank over 14 units a week. They then looked at who was recorded as having dementia, using data from national hospital statistics, the Mental Health Services Data Set and mortality statistics.

They found a 47% increased dementia risk in those classed as abstaining from drinking, which was 45% after adjusting for social and economic factors (age, sex, ethnicity, marital status, occupational position and education), health behaviours (smoking, physical activity, dietary behaviour) and health-related factors (systolic blood pressure, total cholesterol, diabetes, BMI, cardiovascular diseases, drug use, anxiety and depression). Among those drinking more than 14 units a week, every additional 7 units a week was associated with 18% increase in dementia risk.

When the researchers looked at how drinking habits changed over the course of the study, people who reported drinking over 14 units a week throughout the study had a 36% increased risk compared to people who consistently reported drinking 1-14 units a week. Those who reduced their alcohol consumption during the study had a 50% increased risk of dementia, and those who were classed as abstainers throughout had a 67% increased risk. The study didn’t look at participants’ alcohol intake before mid-life.

Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:

“Past studies of alcohol and dementia risk have tended to record how much people drink at a single point in time, but the strength of this study is that the researchers have been able to track changes in people’s drinking over a number of years during midlife.

“As this study only looked at people’s drinking in midlife, we don’t know about their drinking habits earlier in adulthood, and it is possible that this may contribute to their later life dementia risk. People who completely abstain from alcohol may have a history of heavy drinking and this can make it difficult to interpret the links between drinking and health. Future research will need to examine drinking habits across a whole lifetime, and this will help to shed more light on the relationship between alcohol and dementia.

“The researchers relied on participants reporting their own drinking levels, meaning people may have underestimated how much alcohol they regularly drink. While the Whitehall II Study has provided valuable insights into health and ageing, we don’t know the extent to which findings from this group of civil servants apply to the population as a whole.

“Current alcohol guidelines recommend not regularly drinking more than 14 units a week for both men and women, and drinking over this amount impacts on a number of health conditions, not only dementia. We know that a healthy lifestyle, including cutting down on too much alcohol, can improve health and reduce dementia risk, and a good motto tends to be, what is good for your heart is good for your brain. Not smoking, eating a healthy balanced diet, staying mentally and physically active and keeping blood pressure and cholesterol in check are all ways to support healthy brain ageing.”