title: Incidence of dementia is increased in type 2 diabetes and reduced by the use of sulfonylureas and metformin.
abstract: To determine incidence of dementia in type 2 diabetic (T2DM) patients, and whether there are adverse or favorable effects of oral agents (OA) in DM, we obtained a representative cohort of 800,000 from Taiwan’s National Health Insurance database. Those who, as of on January 1, 2000, were 50 years or older and dementia free (n = 127,209) were followed until December 31, 2007, in relation to absence (n = 101,816) or presence (n = 25,393) of T2DM, and whether any OA was used. Dementia was ascertained by ICD9-CM or A-code. Dementia incidence densities (DID) and fully adjusted Cox proportional hazard models were used to estimate association between dementia, DM, and OA. Notably, DID (per 10,000 person-years)was markedly increased with DM (without medication), compared to DM free subjects (119 versus 46). Using non-DM as reference, the adjusted hazard ratios (HRs) (95% confidence interval) for DM without and with OA were 2.41 (2.17–2.66) and 1.62 (1.49–1.77), respectively. For T2DM, compared with no medication, sulfonylureas alone reduced the HR from 1 to 0.85 (0.71–1.01), metformin alone to 0.76 (0.58–0.98), while with combined oral therapy the HR was 0.65 (0.56–0.74). Adjustments included cerebrovascular diseases so that non-stroke related dementias were found to be decreased in DM with sulfonylurea and metformin therapy. T2DM increases the risk of dementia more than 2-fold. On the other hand, sulfonylureas may decrease the risk of dementia, as does metformin; together, these 2 OAs decrease the risk of dementia in T2DM patients by 35% over 8 years.
authors.affiliation: Division of Health Policy Research and Development, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC. cch@nhri.org.tw
authors.forename: Chih-Cheng
authors.initials: CC
authors.lastname: Hsu
authors.forename: Mark L
authors.initials: ML
authors.lastname: Wahlqvist
authors.forename: Meei-Shyuan
authors.initials: MS
authors.lastname: Lee
authors.forename: Hsin-Ni
authors.initials: HN
authors.lastname: Tsai
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015331:Cohort Studies; D003704:Dementia / Q000453:epidemiology*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D015994:Incidence; D007348:Insurance, Health / Q000706:statistics & numerical data; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D013453:Sulfonylurea Compounds / Q000627:therapeutic use*; D013624:Taiwan / Q000453:epidemiology
chemical_list: D007004:Hypoglycemic Agents; D013453:Sulfonylurea Compounds; D008687:Metformin