UK health records point to midlife obesity link to dementia risk

18 December 2019

Scientists from the University of Oxford, using NHS health records, have found obesity in women’s midlife is associated with increased dementia risk. The researchers published the findings in the scientific journal, Neurology.

What did the researchers do?

The researchers looked at over one million volunteers taking part in the Million Women study –  a group originally set up to investigate cancer risk.

The women, all living in the UK, recorded their height and weight to calculate their Body Mass Index (BMI) at the start of the study. Participants were also asked how often they were exercising at the beginning of the study.

Researchers then followed the women for up to 20 years and used their NHS records to identify cases where volunteers were admitted to hospital with a mention of dementia in their health record, and at what age this took place.

What did the scientists find?

The team found that women in midlife who were classified as obese, as defined by a BMI of over 30, were at an increased risk of dementia 15 years after the beginning of the study.

They also found that women with a low-calorie diet and who were less physically active during midlife were at slightly higher risk of dementia within 10 years from the beginning of the study.

Our expert’s reaction

Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:
“This new study confirms obesity as a strong risk factor for dementia and underlines the importance of action to tackle obesity. We will continue to call on Government to lead an awareness campaign to increase public understanding about dementia risk factors, which could help reduce the number of people developing condition.

“The diseases that cause dementia begin decades before memory problems start to show and this study also hints to factors like physical inactivity and weight loss in midlife as potential indicators of the condition. If we are to limit the growing impact of diseases like Alzheimer’s, its vital that research investigates the role of risk factors throughout life, and the best time for people to take action to reduce their risk.

“While this is a large study using NHS health records, at this stage we cannot generalise these findings to men or to whole of the UK population. BMI can be a crude measure and is not necessarily a good indication of our general health but keeping tabs on the amount of body fat we carry is important for a healthy body and a healthy brain.

“As well as maintaining a healthy weight, the best evidence suggests that staying mentally and physically active, not smoking, drinking within the recommended limits, eating a healthy diet, and keeping blood pressure and cholesterol in check can all help us to keep our brains healthy as we get older.”

Neurology: Body mass index, diet, physical inactivity, and the incidence of dementia in 1 million UK women