Dementia study links four habits to cognitive decline with 'biggest risk factor'

Dementia can lead to problems with memory, language, understanding and judgement
-Credit: (Image: Getty Images/iStockphoto)


It's a condition that affects one in 11 people over the age of 65 in the UK - and new research has found that there could be four key ways to reduce our chances of developing it as we get older.

Dementia is a group of symptoms associated with an ongoing decline of brain functioning, with Alzheimer's disease and vascular dementia making up the majority of cases. As well as memory loss, the condition can affect the way a person speaks, thinks, feels and behaves, and in its late stage can leave people unable to take care of themselves.

With more than 1 million people in the UK expected to suffer from dementia by 2030 due to an ageing population, there is ongoing research about how the condition can be prevented, treated and perhaps even cured. Previous research has suggested that around 40% of dementia cases could be avoided by making certain lifestyle changes - and one recent study has uncovered evidence to support this, Gloucestershire Live reports.

Research published in the Nature Communications journal has indicated that the most damaging habit a person can have when it comes to their cognitive health is smoking. The study also found that combining smoking with drinking large amounts of alcohol, not exercising and having limited social contact further raises your chances of developing dementia.

The team of scientists from University College London (UCL) looked at 16 different lifestyle combinations in order to isolate the effects of smoking, alcohol consumption, physical activity, and social contact on cognitive decline. As part of the study, researchers followed more than 32,000 adults between 50 and 104 over 14 countries for up to 15 years.

The findings revealed that non-smokers consistently showed slower rates of cognitive decline compared to smokers, regardless of other lifestyle factors. This suggests that giving up smoking, or never starting, could be the most vital step in preserving brain function as we age.

When focusing on these lifestyle factors, study participants were categorised as either current or non-smokers, no-to-moderate or heavy drinkers, weekly moderate-plus-vigorous activity or less exercisers and people who had weekly or less than weekly social contact. Their cognitive function was measured using two tests including a memory test and a verbal fluency test.

These tests were repeated at multiple time points over the years, allowing researchers to track how cognitive function changed over time for each lifestyle profile. Overall it was found that smokers who drank heavily, infrequently exercised, and had limited social contact showed the fastest rate of cognitive decline.

However, the most significant finding of the study was that smokers who followed all other healthy behaviours still showed faster cognitive decline than non-smokers. Among non-smokers, the differences in other lifestyle factors had much smaller effects on the brain.

Dr Mikaela Bloomberg, from UCL, explained: "Our findings suggest that among the healthy behaviours we examined, not smoking may be among the most important in terms of maintaining cognitive function. For people who aren't able to stop smoking, our results suggest that engaging in other healthy behaviours such as regular exercise, moderate alcohol consumption and being socially active may help offset adverse cognitive effects associated with smoking."

The NHS website says that while there's no certain way to prevent all types of dementia, there is "good evidence" that a healthy lifestyle can help to reduce your risk as you get older. As well as your age and certain genetic factors, there are several other risk factors that can be modified.

According to the NHS, you can help reduce your risk of dementia by:

  • Eating a balanced diet

  • Maintaining a healthy weight

  • Exercising regularly

  • Keeping alcohol within recommended limits

  • Stopping smoking

  • Keeping your blood pressure at a healthy level

"The research concluded that by modifying the risk factors we are able to change, around four in 10 cases of dementia could be prevented," the health service says. "Experts agree that what's good for your heart is also good for your brain."