Introduction:
The evidence for the relation between diabetes mellitus and risk of dementia in Asian population has been limited. This study investigated the association between diabetes mellitus and risk of dementia in community-based samples of Japanese.
Hypothesis:
There is an association between diabetes mellitus and risk of disabling dementia
Methods:
We performed a nested case-control study based on a cohort of about 6,000 Japanese aged 45-69 at baseline between 1984 and 1994. The information of the status of diabetes at baseline was collected for 174 disabling dementia cases incident between 1999 and 2004 and 348 controls matched with cases by age±3, sex and baseline-year. Incident disabling dementia was defined as dependent individuals who had moderate to severe dementia-related behavioral disturbance or cognitive impairment. This criterion was previously validated with 5-cog test. Dementia cases were further classified according to presence of history of stroke. The conditional odds ratio (OR) for dementia was calculated according to the status of (1) glucose intolerance; fasting serum glucose 110-125mg/dl or non-fasting serum glucose 140-199 mg/dl; and (2) diabetes; fasting serum glucose ≥126 mg/dl, non-fasting serum glucose ≥200 mg/dl, and/or the use of glucose-lowering medication or insulin therapy. Variables for multivariable adjustment were body mass index, smoking status, total cholesterol and hypertension status (140≤SBP<160 mmHg, 90≤DBP<95 mmHg for hypertension of grade 1, SBP ≥160 mmHg, DBP ≥95mmHg for hypertension of grade 2 and 3, and the treatment with an antihypertensive drug). Sex-specific analysis was also conducted as subanalysis.
Results and Conclusions:
Mean follow-up year was 11.4 years. The proportion of men was 32.8% and the prevalence of glucose intolerance and diabetes among controls were 16.7% and 5.8%, respectively. Of dementia cases, 44.8% had history of stroke. Compared with persons with normal glucose level, ORs (95%CI) for glucose intolerance and diabetes were 1.12 (0.68-1.84) and 2.18 (1.13-4.22), and multivariable ORs were 0.98 (0.58-1.65) and 2.04 (1.03-4.03), respectively. For sex stratified analysis, ORs for diabetes were 1.39 (0.45-4.31) for men, and 2.79 (1.20-6.50) for women. The association of diabetes was primarily observed in dementia cases with stroke history [OR=3.19 (1.04-9.82)], but not in those without it [OR=1.78 (0.78-4.07)]. In conclusion, we found an association between diabetes mellitus and risk of disabling dementia. The association was confined to women, and dementia with stroke history.
Calcium channel blocker use is associated with lower fasting serum glucose among adults with diabetes from the REGARDS study
