Associations of insulin resistance with cognition in individuals without diagnosed diabetes: Results from the Hispanic Community Health Study/Study of Latinos

Diabetes Res Clin Pract. 2019 Apr;150:38-47. doi: 10.1016/j.diabres.2019.01.030. Epub 2019 Feb 16.

Abstract

Aims: Insulin resistance (IR) adversely impacts memory and executive functioning in non-Hispanic whites without diabetes. Less is known in Hispanics/Latinos, despite the fact that Hispanics/Latinos have higher rates of insulin resistance than non-Hispanic whites. We investigated the association between IR and cognition and its variation by age.

Methods: Data from 5987 participants 45-74 years old without diabetes from the Hispanic Community Health Study/Study of Latinos. IR was considered continuously using homeostasis model assessment for insulin resistance (HOMA-IR) and also dichotomized based on clinically relevant thresholds for hyperinsulinemia (fasting insulin > 84.73 pmol/L or HOMA-IR > 2.6) and sample-based norms (75th percentile of fasting insulin or HOMA-IR). Cognitive testing included the Brief Spanish English Verbal Learning Test (B-SEVLT), Verbal Fluency, and Digit Symbol Substitution.

Results: There was 90% overlap in participant categorization comparing clinically relevant and sample-based thresholds. In separate fully-adjusted linear regression models, age modified the association between HOMA-IR and Digit Symbol Substitution (p = 0.02); advancing age combined with higher HOMA-IR levels resulted in higher scores. Age also modified the association between clinically relevant hyperinsulinemia and B-SEVLT recall (p = 0.03); with increasing age came worse performance for individuals with hyperinsulinemia.

Conclusion: The relationship of IR with cognition in Hispanics/Latinos without diabetes may reflect an age- and test-dependent state.

Keywords: Aging; Cognition; Epidemiology; Hispanics; Insulin resistance; Latinos.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Cognition Disorders / etiology*
  • Cognition Disorders / psychology
  • Community Health Services*
  • Diabetes Mellitus*
  • Female
  • Hispanic or Latino / psychology*
  • Humans
  • Hyperinsulinism / complications*
  • Insulin Resistance*
  • Male
  • Middle Aged
  • Prognosis
  • Prospective Studies
  • Young Adult