Social Determinants of Health as Potential Mild Cognitive Impairment Risk Factors

Social determinants of health (SDOHs), including Area Deprivation Index (ADI) scores, greenspace, and homicide rates, may be considered mild cognitive impairment (MCI) risk factors, according to a study published in the Journal of the American Geriatrics Society.

Researchers conducted a community-based study using data from 2 cohorts to assess the associations between SDOHs and the risk for mild cognitive impairment:

• Monongahela-Youghiogheny Healthy Aging Team (MYHAT) cohort: Individuals aged 65 years and older living in southwestern Pennsylvania screened at study entry with the age-education-correction Mini-Mental State Examination (MMSE)
• Seniors Project 15,104 (SP15104): Individuals meeting similar inclusion criteria to the MYHAT cohort from a single postal code in the same geographic area with an overall 60% Black population.

Individual and community-level data were collected from both cohorts to characterize SDOHs, including ADI, fine particulate matter (PM^2.5) exposure, greenspace, walkability index, and availability of health care services. MCI was defined as a rating of 0.5 on the Clinical Dementia Rating Staging Instrument^®. Logistic regression models were employed for statistical analysis.

A total of 2830 individuals were included in the analysis (aged 65-74 years, 52.8%; women, 60.5%; educational level >high school, 48.3%; self-reported Black race, 9.6%). Overall, 4.3% were born in a Southern US state, and 2.3% completed schooling in a Southern US state. Distribution of SDOH variables included:

• ADI, 85th percentile (IQR, 72.8-94.0)
• PM^2.5, 13.16 μg/m³ (IQR, 13.1-13.2)
• Greenspace (open developed and undeveloped landcover), 40.23% (IQR, 27.3-53.5)
• Walkability index (score range, 1-20), 12.2 (IQR, 8.0-14.5)
• Number of ambulatory health care specialists per square mile, 4.80 (IQR, 2.6-12.4)
• Average homicides per 100,000 people, 4.4 (IQR, 0.0-13.8)

Higher ADI, higher PM^2.5, lesser greenspace, higher homicide rate per 100,000 people, and having completed schooling in a Southern US state were associated with MCI. After adjusting for all 4 demographic variables, only ADI remained significantly associated with MCI (odds ratio [OR], 1.036; 95% CI, 1.011-1.064; P =.006); the inclusion of 4 covariates had the potential to reduce statistical power. Significant interactions were observed between race, PM^2.5, and schooling in a Southern state.

Higher PM^2.5 was significantly associated with MCI in those aged between 75 and 84 years, and lesser greenspace area and higher homicide rate were associated with MCI in those aged between 65 and 74 years.

Among those with less than a high school education, ADI, PM^2.5, Southern birth, and Southern schooling were associated with MCI. PM^2.5 and homicide rate were associated with MCI in those with high school education, and the presence of more primary health care services per square mile was associated with MCI in those with a greater than high school education.

Higher ADI was associated with MCI among men, while all SDOH variables except for the availability of ambulatory health care were associated with MCI among women. Higher ADI, higher PM^2.5, and lesser greenspace area were associated with MCI among those of White race, while higher PM^2.5, Southern birth, and Southern schooling were associated with MCI in those of Black race.

Study strengths included a community-based, ethnoracially diverse, well-characterized study cohort; limitations included a lack of various public data availability and unmeasured potential SDOHs.

“In this cohort, several community-wide social/environmental factors were associated with MCI. While clinicians should continue to encourage older adults to modify their individual risk factors, policy changes are needed to mitigate social determinants of health in the community,” the researchers concluded.