Researchers have unmasked the relationship between two deadly illnesses: cancer and Alzheimer's disease.

A study discovered that people with cancer have less chances of getting Alzheimer’s disease and those having Alzheimer's disease may not contract cancer.

Dr. Catherine M. Roe and her team studied 3,020 people which were aged 65 and older. And these people were checked for five years to see whether they developed dementia and eight years to see whether they developed cancer.

Out of these, 164 people already had Alzheimer's disease and 522 people had cancer. During the study 478 people developed dementia and 376 people developed cancer. For those who had Alzheimer's disease there was a lower risk of getting cancer to about by 69 percent and those having cancer meant a 43 percent reduced risk for Alzheimer's disease. No link was found between vascular dementia and cancer.

"Alzheimer's was associated with a rather dramatic reduction in cancer risk", said Dr. Richard Lipton, an attending neurologist at Montefiore Medical Center and professor of neurology at Albert Einstein College of Medicine in New York City. "From my perspective, the strengths of the findings are very striking and somewhat unexpected”.