According to the authors, these results do not mean a high BMI is not a conclusive indicator of low dementia risk. They wrote: “BMI may not be a reliable measure of underweight, overweight and obesity, and the use of other parameters such as waist circumference may have allowed more accurate analyses.”
Furthermore, they also added there were other limitations to the study such as the fact that “BMI was unavailable for the majority of patients followed in general practices, and this may have biased the study findings” and “there was no information in the database on physical activity and diet, although these two factors are associated with both BMI and dementia”.
As a result, the authors concluded more studies were needed in order to “corroborate or invalidate these findings in other countries and settings”. This means that this study cannot be used to draw a conclusion of the impact of BMI on dementia risk.
Alongside the lack of evidence and need for further investigation, it is important to note this was an observational rather than a causational study.
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