Analysing data from a whopping 1.3 million people, new research has found that a higher BMI (during midlife) can be associated with an increased risk of dementia in later life.
What is BMI?
BMI is a calculated score based on dividing your weight (in kilograms) by your height (in metres squared) – a score of between 18 to 25 is generally considered acceptable. However, the Heart Foundation does state that BMI is only an estimate and it doesn’t consider age, ethnicity, gender and body composition.
How are BMI and dementia linked?
This new research, published in the Journal Alzheimer’s and Dementia, examined the medical records of 1,349,857 dementia-free participants who were involved in 39 different medical studies across Europe, the USA and Asia.
Each participant had their BMI checked when they first participated in a study. Based on this, the researchers wanted to assess how many of the participants went on to develop dementia. Two interesting results were found:
The first – a higher BMI was associated with increased dementia risk when weight was measured more than 20 years’ before the dementia diagnosis.
The second – a higher BMI was not linked to dementia when assessed ‘less than 10 years’ before dementia diagnosis.
Firstly, the researchers suggest that a higher BMI during midlife is generally correlated with poorer health, nutrition and increased risk of multiple diseases such as heart disease and diabetes, etc. These are all known risk factors for dementia, so this result really just reiterates what research has been showcasing for many years. It is another important study showcasing that a healthy lifestyle will reduce your dementia risk.
However, the second result is slightly harder to define. The researchers have put an interesting hypothesis forward suggesting that those participants who had a higher BMI in later life were likely to have passed away from other diseases, not dementia related. This could be one reason why this result was seen.
It is important to note, however, that the study does not suggest that a low BMI is protective against dementia.
Researchers would like to further examine the underlying mechanisms for weight loss during the preclinical stages of dementia. They also suggest future studies should examine whether the role of BMI in dementia varies between dementia subtypes, such as, Alzheimer’s disease, vascular dementia, frontotemporal dementia, and Lewy body disease.
Read the full story study via Alzheimer’s and Dementia.