Brett Smith for redOrbit.com- -Your Universe Online
Alzheimer’s disease affects millions of Americans and two new studies have uncovered interesting information about the disease.
In one study of almost 500,000 French men and women, people who delayed retirement were found to have less of a risk of developing Alzheimer’s or other types of dementia. In the other study of 3.5 million US military veterans, those diagnosed with cancer were less likely to have Alzheimer’s and those who received chemotherapy were even less likely.
The French study is said to be the largest to look at the connection between delayed retirement and dementia. It appears to be consistent with previous findings that encourage older people to stay mentally stimulated and socially active.
“For each additional year of work, the risk of getting dementia is reduced by 3.2 percent,” study author Carole Dufouil of INSERM told CBS News.
Alzheimer’s research was emphasized by former French president Nicolas Sarkozy, and the country’s integrated medical system made for a more robust study, according to reports. The researchers used those comprehensive medical records to look at health outcomes for around 429,000 workers.
The French team found that almost three percent of those in the study had developed dementia, but the risk of this was lower for each year of age at retirement. To eliminate the possibility that the retirement was caused by dementia, the French team ruled out anyone who was diagnosed with dementia within five or ten years of retirement.
“The trend is exactly the same,” Dufouil said.
The US military study echoes the findings of a similar study on older Italians released last week â€“ those diagnosed with cancer are less likely to also be diagnosed with Alzheimer’s.
“With these large-cohort studies and others, we are beginning to see the outlines of a broad picture of Alzheimer’s disease risk and prevention factors,” said Maria Carrillo, vice president of medical and scientific relations at the Alzheimer’s Association.
“However, we need to know even more about what specific factors actually raise and lower risk for cognitive decline and Alzheimer’s,” Carrillo said. “To do that, we need longer-term studies in larger and more diverse populations, and more research funding is required to make that happen. Alzheimer’s research would benefit from its own version of the Framingham Study, which has taught us so very much about preventable risk factors for heart disease and stroke.”
Providing a wider scope than the Italian study which did not look at individual cancers, the US military study found that reduced risk was greatest among survivors of liver cancer (51 percent lower risk), cancer of the pancreas (44 percent), lung cancer (25 percent) and leukemia (23 percent).
The study also found that treatment with chemotherapy, but not radiation, reduced Alzheimer’s risk by 20 to 45 percent among veterans with a cancer history.
“The potential protective effect of chemotherapy is supported by recent experimental studies,” said study co-author Dr. Laura Frain, a geriatrician at VA Boston Healthcare System. “The results of this study are interesting because they could help focus future research onto the specific pathways and treatment agents involved in the individual cancers that are associated with a reduced risk of Alzheimer’s. This could potentially open new therapeutic strategies for Alzheimer’s prevention and treatment.”