Diabetes, prediabetes, and mild cognitive impairment among older adults: the Hitachi Health Study II.

AIM: We examined associations of diabetes, prediabetes, and glycemic markers with mild cognitive impairment (MCI) in older adults, and whether these associations are modified by treatment status, diabetes duration, and glycemic control.

METHODS

We used data from 2486 adults (mean age: 65 years) undergoing health check-ups and cognitive screening. Prediabetes and diabetes were defined by fasting plasma glucose (FPG), HbA1c, or history/medication use. Diabetes was divided into screen-detected and treated cases. Cognitive function was tested using a computerized test battery evaluating immediate memory, temporal orientation, delayed recall, and three-dimensional visual-spatial perception. Participants scoring ≤ 13 (range, 0-15) were considered to have MCI.

RESULTS

Overall, 251 participants (10.1%) were classified with MCI. Compared with normoglycemia, odds ratios (95% CIs) were 1.45 (0.90, 2.33) for prediabetes and 1.67 (0.99, 2.81) for diabetes. When stratified by treatment status, the odds ratios were larger in treated diabetes than in screen-detected diabetes (1.77 [1.03, 3.06] vs. 1.48 [0.77, 2.84]). Larger odds ratios were also found among those with diabetes duration ≥ 10 years (2.26, 95% CI: 1.27, 4.02) and HbA1c ≥ 7% (1.90, 95% CI: 1.00, 3.60). Diabetes was associated with lower scores in temporal orientation and visual-spatial perception. Among participants without diabetes, higher FPG was associated with higher odds of MCI; the odds ratio for FPG 110-125 vs. <100 mg/dL was 1.85 (95% CI: 1.18, 2.89).

CONCLUSION

Older adults with diabetes, particularly those with treated, longstanding, or uncontrolled diabetes, had a higher prevalence of MCI. Among those without diabetes, higher FPG was associated with MCI.