The more stressors experienced in midlife, such as money problems and job pressure, the higher the risk for subsequent dementia, new research shows. The study was presented here at the Alzheimer's Association International Conference (AAIC) 2018.

"These findings suggest that problems related to sparse resources may impact brain health over the long term and may contribute to inequalities in dementia risk," said author Paola Gilsanz, ScD, staff scientist at the Kaiser Permanente Northern California Division of Research.

Midlife Stress a Major Culprit

Dementia rates differ by race and ethnicity, Gilsanz told meeting delegates. African Americans have the highest rates, while Asian Americans have the lowest. 

"However, the underlying causes and drivers of these inequalities are unclear. And identifying them, understanding what these possible drivers are, is an important step in diminishing these racial and ethnic inequalities," she said. Stress is a risk factor for cognitive decline, and studies are uncovering evidence that points to midlife stress, in particular, as a culprit, said Gilsanz. 

Stress may be related to dementia through some possible pathways. These include activation of the hypothalamic-pituitary-adrenal axis, an increase in the level of glucocorticoids, hypertension and other health conditions, and health behaviors, said Gilsanz.

For this new study, the researchers used data from Kaiser Permanente Northern California, an integrated healthcare delivery system. In the 1960s and 1970s, Kaiser incorporated questionnaires into routine clinical care.

The 1972 and 1973 questionnaires asked respondents if they were experiencing serious or disturbing problems with their marriage, family, or employment or had financial problems, used drugs, or had other concerns.

The study included 12,263 persons aged 40 to 55 years at the time of the 1972 or 1973 checkup who remained a Kaiser member until 1996. The sample was 63% white, 17% African American, 8% Asian, 5% Hispanic, and 3% from another ethnic category.

Researchers adjusted for demographics, including sex, race, and education. Some models also adjusted for midlife health indicators, for example, body mass index, the presence of hypertension, smoking status, and late-life health indicators, such as stroke, heart failure, and diabetes.

Stressors by Race

The investigators found that overall for all individual ethnic/racial groups, most participants reported no stressors. "This was especially true for Asians, among whom 84% reported no stressors," said Gilsanz.

About 24% of the sample reported at least one stressor. Blacks (27%) and Hispanics (28%) were more likely to report at least one stressor compared to Asians (16%) and whites (23%). As for the type of stressor, overall, few participants reported drug use as a problem, but about 7% reported financial stress, and 6% reported job stress.

Some stressors were more common among the different groups. For example, marital stress was reported by about 8% of blacks and Hispanics but by fewer than 3% of Asians, whereas Hispanics most often reported family stressors. Financial problems were more common among blacks and Hispanics than among whites or Asians.