Risk factors and population attributable fraction for dementia in American Indians: The Strong Heart Study.

INTRODUCTION

Previous works implicate 14 modifiable risk factors as underlying 45% of dementia cases. Population attributable fraction (PAF) is population-specific, limiting generalizability. Little is known about the risk and PAF of dementia in American Indians.

METHODS

American Indians from the Southwest, Southern Plains, and Northern Plains made multiple visits from mid- to late-life (1989 to 2019). Cognitive status was adjudicated by panel consensus (ages 70 to 95). Logistic regression models assessed relative risk and PAF for dementia.

RESULTS

American Indians had distinctive patterns of factor prevalence. The proportion with limited education and social isolation was similar. Mid-life depression, head injury, smoking, hypertension, obesity, and diabetes were more common. High low-density lipoprotein levels, sedentary/inactivity, and consumption of ≥21 units of alcohol/week were less common. We did not assess hearing loss, vision loss, or air pollution. Significant risk factors for dementia with PAF percentage were as follows: education (19%), hypertension (11%), isolation (13%), and depression (60%).

DISCUSSION: Important, unique risk patterns were detected for American Indians, in contrast to prior models.