Megan Brooks

July 16, 2013

BOSTON, Massachusetts — Socioeconomic disparities may, in large part, explain racial and ethnic differences in dementia rates, a new study suggests.

"Differences in socioeconomic status (SES), such as lower income and reduced quality of education, may account for higher dementia rates among black compared to white elders," said study investigator Kristine Yaffe, MD, from the University of California, San Francisco, and the San Francisco Veterans Affairs Medical Center. "Improving SES, particularly education, may help reduce dementia risk."

She reported the findings here at the Alzheimer's Association International Conference (AAIC) 2013.

Twice the Risk

Dr. Yaffe noted that older African Americans are about twice as likely to develop Alzheimer's disease and other dementias as their white peers. SES has been shown to affect cognition in late life. However, "few studies have really looked at SES as maybe one of the explanations for why nonwhites have a higher rate of dementia," Dr. Yaffe said.

Dr. Kristine Yaffe

Her team evaluated dementia risk among 3075 black and white individuals 70 to 79 years old at baseline participating in the ongoing prospective Health, Aging and Body Composition Study and were free of dementia at baseline.

During 12 years of follow-up, 575 (18.7%) participants developed dementia. In unadjusted analysis, African Americans were significantly (P < .001) more likely to develop dementia than whites (21.9% vs 16.4%; hazard ratio [HR], 1.57; 95% confidence interval [CI], 1.33 - 1.84).

The HR lessened somewhat but remained significant after adjustment for demographic characteristics, presence or absence of the APOE &espilon;4 risk allele, comorbid conditions, and lifestyle factors (HR, 1.40; 95% CI, 1.17 - 1.68).

However, it was greatly reduced and no longer statistically significant when SES was added to the model (HR, 1.08; 95% CI, 0.86 - 1.36), Dr. Yaffe said.

SES "Can't Be Ignored"

"This suggests that SES explains the difference in risk," she said. "Other risk factors, such as comorbidities and lifestyle factors, did not seem to influence risk as much," Dr. Yaffe said.

Socioeconomic factors included education level, literacy, income, and perceived financial adequacy.

These findings are "important because differences in SES such as lower income and reduced quality of education may account for higher dementia rates among blacks compared to whites. It's not so easy to improve SES but in terms of education, from a public health point of view, for all racial groups, I think we really need to be thinking about quality of education," Dr. Yaffe said.

Briefing moderator David S. Knopman, MD, from the Mayo Clinic, Rochester, Minnesota, said the issue of SES "has a bearing on the ability of the brain to withstand the onslaught of Alzheimer's disease. It can't be ignored."

The study was funded by the National Institutes of Health, National Institute on Aging. Dr. Yaffe is co-chair of the AAIC 2013 Program Committee.

Alzheimer's Association International Conference (AAIC) 2013. Oral Presentation O2-13-3. Presented July 15, 2013.


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