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P1–182: Glycemic control and risk of dementia in a cohort of patients with type 2 diabetes
Author(s) -
Whitmer Rachel A.,
Selby Joseph V.,
Van Den Eeden Steven K.,
Haan Mary N.,
Quesenberry Charles P.,
Minkoff Jerome,
Yaffe Kristine
Publication year - 2006
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2006.05.557
Subject(s) - medicine , dementia , glycemic , diabetes mellitus , cohort , type 2 diabetes , cohort study , disease , gerontology , endocrinology
Background: Type 2 diabetes is associated with an increased risk of dementia, Alzheimer’s Disease, and cognitive decline, although the exact mechanisms remain unclear. Recent evidence has suggested that hyperinsulinemia, a consequence of poor glycemic control, is implicated in the deposition of amyloid beta plaques. Effective glycemic control lowers risk of several diabetes-associated complications including stroke and neuropathy. Yet, whether glycemic control is associated with dementia risk is unknown. Objective(s): The goal of this study was to determine whether level of glycemic control, measured as glycosylated hemoglobin (HbA1c), is associated with risk of incident dementia in a diverse cohort of type 2 diabetic men and women. Methods: We studied 22,852 members of the Kaiser Permanente of Northern California Diabetes Registry (66% caucasian, 10 % black, 11 % asian, 10 % latino, 3% native-american or other, 44% female), all whom took a survey between 1994-1996, were above age 50 at time of survey (mean age 66), and had at least one HbA1c measured between 1994-1996. Incident dementia was identified through outpatient and inpatient medical records from January 1, 1997-May 30, 2005. Time to dementia diagnosis was analyzed with Cox proportional hazards models adjusted for age, education, race, sex, BMI, diabetes duration, diabetes treatment, and cardiovascular disease. Patients were censored at time of dementia diagnosis, loss to membership, death or end of study period May 30, 2005. Results: 2488 participants ( 11%) were diagnosed with incident dementia. HbA1c was associated with dementia (continuous HR 1.03, 95% CI 1.01-1.05). Compared to those with a HbA1c less than 10 (N 19318 ) those with levels between 10 and 11.9 (N 2286 ) were 16% more likely to have dementia ( HR 1.16, 95% CI 1.01-1.32); those with levels between 12 and 14.9 (N 1143 ) were 25% more likely (HR 1.25 95% CI 1.03-1.53); and those with levels greater than 15 (N 105 ) were 83% more likely (HR 1.83, 95% CI 1.01-3.65). Conclusions: These results suggest a graded association of higher HbA1c levels with risk for dementia, with a possible threshold at approximately 9.9% Future studies are needed to confirm that interventions which lower HbA1c lead to lower risk for dementia.