Does Obesity Prevent or Increase Dementia Risk?
Several dementia advocacy organizations recommend maintaining a healthy weight to lower the risk of dementia. However, certain studies have proposed that obesity could potentially offer protection against dementia. What does scientific research reveal about this matter?
The link between obesity and dementia appears strong initially, as obesity in middle age is associated with a higher risk of dementia later in life. However, complexities arise. Despite rising obesity rates, dementia rates in the West have declined. Moreover, an “obesity paradox” suggests obesity may reduce dementia risk.
Addressing Causality Challenges with Limited Data
Determining causality is challenging due to data limitations. Randomized trials would clarify, but they’re impractical and unethical. Thus, researchers rely on observational studies, which have biases like reverse causation and confounding.
Recent findings highlight childhood intelligence’s role. Lower childhood intelligence correlates with higher obesity risk and poorer cognitive skills in midlife. Therefore, the link between midlife obesity and cognitive decline may be influenced by childhood intelligence, emphasizing the need for a nuanced understanding.
So, how can we address these bias issues? One innovative approach is conducting Mendelian randomization studies, often dubbed “nature’s randomized trial.”
In these studies, researchers divide a large population into two groups solely based on whether they possess a gene (or genes) associated with obesity. As these genes are randomly inherited, this naturally randomizes the population into two groups balanced for all factors except obesity status.
While not without potential biases, any differences in dementia risk are attributed directly to obesity.
Several studies, at least ten, have employed this method to investigate if obesity influences Alzheimer’s disease, the most prevalent form of dementia. Only one study has hinted at a connection between the two.
Thus, returning to the question: does obesity truly elevate dementia risk? As scientists caution, the absence of evidence doesn’t imply evidence of absence. In other words, lacking sufficient data to confirm the link doesn’t necessarily disprove it.
Science progresses gradually. With continued data collection and advancements in techniques, a more definitive answer to this question will eventually surface.
In the meantime, it’s prudent to heed the advice of dementia charities and strive to maintain a healthy weight. Doing so not only lowers the risk of various other significant health issues but might also mitigate the risk of dementia.
Read the original article on: Science Alert
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