Strange Inverse Relationship Between Cancer and Neurodegenerative Diseases

A very peculiar and not well understood finding has shown that older people with Alzheimer’s disease have a significantly lower risk of developing cancer than those without memory and thinking problems. Dr. Benito-León and his team concluded that patients suffering from Alzheimer’s were half as likely to develop cancer than older people with normal memory.


Their study involved 2,627 people aged 65 and above that took tests measuring their memory and thinking skills. The tests were repeated three years after the initial tests and then participants were followed for about 13 years. The results were split into three groups: scores that were declining fast, scores that had improved, and those in the middle. Out of the 1,003 participants that died over the 12 year period, only 21% of the participants whose scores rapidly declined had died of cancer. Even when the results were adjusted for factors such as smoking, diabetes, and heart disease, the rapidly declining test score group was still at a 30% lower risk of dying from cancer.

The strange inverse relationship is still something that researchers do not understand. Nobody knows if the properties of one illness counteracts the other or if the symptoms of one masks the other. One previously thought theory was that cancer is under diagnosed for people suffering from Alzheimer’s because they are less likely to mention symptoms. However, this study disproves this theory and the misunderstanding continues.

Source: Faster cognitive decline in elders without dementia and decreased risk of cancer mortality.Julián Benito-León, MD, PhD, Juan Pablo Romero, MD, Elan D. Louis, MD, MSc and Félix Bermejo-Pareja, MD, PhD. April 9, 2014, doi: 10.1212/WNL.0000000000000350Neurology 10.1212/WNL.0000000000000350



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