Lower State-Level Educational Quality Heightens Dementia Risk Later in Life

In the United States, lower state-level educational quality in childhood, which disproportionally affects Black individuals, is associated with a higher risk for dementia later in life, according to study findings published in JAMA Neurology.

Numerous studies have found significant associations between lower levels of education and higher risk for dementia. However, most of this evidence has been based on years of education attained and not on educational quality. For the study, researchers sought to assess the association between state-level educational quality and dementia risk.

In this study, researchers evaluated data from Kaiser Permanente Northern California (KPNC) and historical state-level administrative databases. The subset of patients (N=20,778) who completed a survey between 1964 and 1972, were born in the US, were not of Hispanic ethnicity, did not have a diagnosis of dementia as of December 1996, and were aged 65 and older as of January 1996 were eligible for this study. Risk for dementia through 2019 was evaluated on the basis of school term length, student-teacher ratio, and attendance rate in the state that each individual lived as a youth.

The included individuals were:

• mean age 74.7 (SD, 6.5);
• 56.5% women;
• 81.2% White, 18.8% Black;
• 41.0% achieved up to high school education; and
• 43.8% were born in the West, 23.8% in the South, 21.4% in the Midwest, and 11.0% in the Northeast.

The study cohort was well-balanced for each of the 3 educational quality indexes, in which roughly one-third of the sample attended a school in a state with lowest, medium, or highest quality student-to-teacher ratios, attendance rates, and term lengths. However, stratified by race, most Black individuals, but not White individuals, attended schools with the lowest student-to-teacher ratio (84.6% vs 21.3%), attendance rates (76.2% vs 23.3%), and term lengths (86.1% vs 20.8%), respectively.

In the pooled sample, compared with low-quality education, medium- (hazard ratio [HR], 0.83) and high- (HR, 0.88) quality student-to-teacher ratios, medium- (HR, 0.85) and high- (HR, 0.80) quality attendance rates, and medium- (HR, 0.92) and high- (HR, 0.79) quality term lengths were associated with lower risk for dementia.

Stratified by race, trends were consistent among White individuals but high-quality student-to-teacher ratios (HR, 0.98; 95% CI, 0.81-1.18) and attendance rates (HR, 0.82; 95% CI, 0.65-1.04) and medium-quality term lengths (HR, 1.07; 95% CI, 0.89-1.28) were not associated with lower dementia risk compared with the low-quality groups.

In sensitivity analyses which adjusted for educational attainment, similar trends were observed.

Study limitations included the generalization of educational quality across an entire state and the fact that rates of dementia ascertained from medical records tend to be an underestimation.

These data indicated that Black individuals tended to receive poorer quality education compared with White individuals and that poorer quality education was associated with increased dementia risk.

Researchers concluded, “More studies are needed to disentangle how historical and modern forms of segregation are associated with dementia risk, particularly among racial and ethnic minority groups. These findings have important policy relevance, suggesting that state-level investments to improve educational quality matter.”