September 23, 2005

Complex work may help ward off Alzheimer’s

By Amy Norton

NEW YORK (Reuters Health) - People with challenging jobs
may have to work hard, but the payoff could be some protection
against Alzheimer's disease later in life, new research

In a study of more than 10,000 older Swedish adults who
were part of a twin registry, researchers found that people
with a history of "complex" work had a lower risk of
Alzheimer's disease. The same held true even among twin pairs
in which one was affected by Alzheimer's but the other was not
-- a situation that factors in the influence of genes and

The findings suggest that complex jobs may "provide some
mental exercise" that helps delay the onset of dementia later
in life, said the study's lead author, Dr. Ross Andel of the
University of South Florida in Tampa. And that does not mean
you need to be a rocket scientist, Andel told Reuters Health.

The study found that the complexity of a worker's
interactions with other people - with teaching as an example of
higher complexity -- showed the strongest link to a lower
Alzheimer's risk. Men and women with the most challenging jobs
in this regard were 22 percent less likely to develop the
disease compared with those with the least complex work.

These individuals also had a slightly lower risk of all
forms of dementia, according to findings published in the
Journal of Gerontology: Psychological Sciences.

The findings fit in with other research that has linked
higher education, as well as mentally stimulating leisure
activities like reading and doing crossword puzzles, to a lower
risk of Alzheimer's disease.

Although it's not clear that these are cause-and-effect
relationships, scientists speculate that people who stay
mentally engaged throughout their lives may have a greater
"cognitive reserve" that allows them to withstand more of the
brain damage seen in Alzheimer's disease before symptoms begin.

The physical-fitness principle of "use it or lose it" may
apply, in a fashion, to the brain as well, Andel said.

His team's study included 10,079 men and women from the
Swedish Twin Registry who were at least 65 years old in 1998.
Of these, 225 had been diagnosed with dementia, most (146
cases) had Alzheimer's disease. There were 55 twin pairs who
were discordant for dementia, meaning one was affected but the
other was not.

Overall, people whose main lifetime occupation required
more complex interpersonal relationships -- such as managing
people, making negotiations or dealing with customers -- were
less likely to have Alzheimer's disease.

Among twins discordant for dementia, there was some
evidence that complex work with data -- compiling, organizing
or analyzing information, for instance -- was protective.

Complex work was related to lower Alzheimer's risk
regardless of a person's education, the researchers found.

One of the strengths of the study, Andel said, was its
separate analysis of twin pairs in which one had dementia and
the other did not. Among these twins, the protective effect of
complex work with people was even stronger than it was among
the whole study population.

"This gives us more confidence that we're really onto
something," Andel said.

SOURCE: Journal of Gerontology: Psychological Sciences,
September 2005.