Alzheimer's linked to cancer

By JImmy Downs

People who have Alzheimer’s disease may be less likely to have cancer and vice versa, according to a new study in the Dec 23, 2009 online issue of Neurology.

According to a press release by the American Academy of Neurology, the Cardiovascular Health Study involved 3,000 people aged 65 and older who were followed for an average of five years to see whether they developed dementia and followed for an average of eight years to see if they developed cancer.

At the start of the study, 5.4 percent had Alzheimer's and 17.3 percent of participants had a diagnosed cancer.  During the follow-up, 478 people acquired dementia and 376 people developed invasive cancer.

Researchers of Washington University School of Medicine in St. Louis found the risk of hospitalization due to cancer was 69 percent lower in those who had Alzheimer’s disease at baseline compared to those who did not have Alzheimer's disease.

For Caucasian people who had cancer when entering the study, the risk of Alzheimer’s disease was 43 percent lower compared to those who did not have cancer.

"Discovering the links between these two conditions may help us better understand both diseases and open up avenues for possible treatments," said study author Catherine M. Roe.

Sex hormones may be the missing link between Alzheimer's disease to cancer, according to a scientist who is not part of the research team and does not want to be named.   He said previous studies have already found people who have lower sex hormones are at high risk of dementia or Alzheimer's disease while people who have high levels of sex hormones are at high risk of cancer such as breast cancer and prostate cancer.