Environmental Risks for Alzheimer's
Your racial or ethnic background, how long you go to school, and the work you do all influence your risk for dementia.
People with fewer years of education appear to be at greater risk for AD and other dementias. No one is quite sure why, but a slew of studies show that someone who did not complete high school is more likely to develop dementia than is someone who graduated from college. Some experts say that learning itself stimulates brain cell growth. They speculate that years spent in college or graduate school may help build up individual cognitive reserve, which may help protect against Alzheimer's or keep it at bay longer.
Highly educated people are also likely to have more mentally stimulating jobs, better overall physical health, and more disposable income to spend on exercise, travel and other activities that are believed to enhance brain health.
In addition, it may be difficult to detect Alzheimer's disease in people with sixteen or more years of education, who can often compensate for — or hide — early symptoms of memory loss, clinicians say. Better-educated people tend to be diagnosed with dementia later in the course of the disease, once their symptoms become impossible to ignore. They tend to decline quickly following diagnoses made relatively late in the course of the disease.
Latinos with diabetes, high blood pressure, or heart disease are less likely to receive services to help monitor and control those conditions, according to a report by the Alzheimer's Association. Barriers to the health care system can delay identification and diagnosis of dementia, leading to higher levels of impairment among people with the disease.
Better educated people also score higher on a standard screening test for cognitive function, the mini-mental state examination (MMSE), according to a large study reported in the July 2008 Archives of Neurology. Researchers and Texas Tech University and Mayo Clinic Medical School recommended that older patients who score less than a 27 out of 30 on the MMSE should receive further evaluations if they have a college or graduate education. This differs from the standard MMSE recommendations, which set a score of 24 or below as the threshold for prompting further evaluations.
Class, Race, and Ethnicity
Low education levels are closely linked with poverty, poor diet, and malnutrition; high levels of hypertension, cardiovascular disease, and diabetes; and restricted access to health and medical care. People who struggle to feed, house, and support their families often don't have the money, time, or exposure to health education. African Americans and Latinos who are under-educated, impoverished, and in poor health appear to be at extremely high risk for dementia.
STATISTICS OF CAREGIVERS
African-American and Hispanic caregivers were more likely than caregivers of other races to think Alzheimer's is a normal part of aging, according to a 2007 survey conducted by the Alzheimer's Foundation of America. Thirty-seven percent of African-American, 33 percent of Latino, and 23 percent of Caucasian caregivers said they considered AD part and parcel of old age. Seventy percent of African-American and 67 percent of Hispanic caregivers were more likely to dismiss the symptoms of Alzheimer's as old age, compared with 53 percent of caregivers of other races.
In addition, 67 percent of African-American and 63 percent of Hispanic caregivers were also more likely to say they didn't know enough about Alzheimer's to recognize its symptoms, compared with 49 percent of caregivers of other races. However, 33 percent of African-American and 26 percent of Hispanic caregivers thought they were at higher risk for Alzheimer's than did caregivers of other races, only 12 percent of whom considered themselves at risk.
As a group, African Americans are more likely to suffer heart disease and stroke than is the rest of the American population. They also appear to be at increased risk for diabetes, high blood pressure, high cholesterol, and cardiovascular complications. Alzheimer's Association researchers point out, however, that these worrisome statistics describe African Americans of all educational levels and socioeconomic backgrounds, and that educated middle-class and upper-middle-class African Americans seem to face much the same risks for Alzheimer's and dementia as do Caucasians.
A vast, enormously diverse population that includes people of all races and from 25 countries of origin, Latinos are not genetically predisposed to Alzheimer's. However, they do face many risk factors for AD.
A disproportionate number of Hispanic Americans are 65 and older, an age that categorically puts them at greater risk for Alzheimer's disease. Low-income, less educated Hispanic Americans also appear to be at elevated risk for vascular disease, including diabetes, which has been linked to dementia.
Public health surveys show that Hispanics are less likely than other Americans to see doctors, in part because of financial and language barriers. They more often mistake dementia symptoms for normal aging, delaying diagnosis and inadvertently exacerbating the effects of the disease.
THE SCHOOL SISTERS OF NOTRE DAME
Some of the earliest evidence that keeping your brain active and engaged may guard against dementia emerged not in a test lab or academic research center, but from a community of Catholic religious women, the School Sisters of Notre Dame in Mankato, Minnesota. Epidemiologist David Snowdon happened upon the evidence while studying healthy aging among the sisters during the mid-1980s. As he gathered information on the sisters' life histories and lifelong habits, his research confirmed what earlier studies had suggested: that having a college education and active intellectual life appear to protect some people against the ravages of AD. While all the aging sisters had some intellectual decline, Snowdon found that those who had gone to college and taught most of their lives declined less than did sisters who did service jobs.
But Snowdon was able to go further than other epidemiologists in linking intellectual activity in younger adulthood to brain health in old age thanks to an archive at the convent. The sisters in Mankato community had all written autobiographies when they entered the convent as young women, in their twenties.
Working with linguistics experts, Snowdon compared autobiographies with their cognitive health in late life and found a remarkable correlation between the sophistication of thought and optimism expressed and cognitive health later in life. The nuns who had written the most verbally expressive, upbeat essays showed fewer signs of intellectual decline half a century later.
However, this study raises a chicken-and-egg question that continues to dominate epidemiological research about intellectual activity and dementia: Were the sisters who wrote the lower-scoring essays hobbled even in young adulthood by early signs of cognitive decline? Or were those who wrote richer, more complex youthful biographies protected from developing symptoms of dementia?