Skip to main content

Table 1 Studies of dyslipidemia and cognitive function in type 2 diabetes

From: The impact of diabetes on cognitive decline: potential vascular, metabolic, and psychosocial risk factors

Study

Sample

Design

Number

Baseline mean age

Lipids

Cognitive measures

Adjustment variables

Association with cognitive function

Bruce et al. [14] (2008)

Patients with type 2 diabetes participating in the Fremantle Diabetes Study; Australia

8-year retrospective, observational

302

Mean 76 ± 5 years

Total cholesterol and HDL at baseline and 8 years earlier

Dementia and MCI identified from screening instruments/clinical interview

Waist-hip ratio

No associations in unadjusted cross-sectional or prospective analyses. Higher total cholesterol 8 years earlier protective of cognitive impairment short of dementia (but not dementia or all cognitive impairment) at baseline (finding independent of waist-hip ratio)

Chen et al. [9] (2011)

Patients with type 2 diabetes; China

Cross-sectional, observational

101

Mean 63 ± 8 years

Total cholesterol, LDL, and HDL

MCI identified on the basis of cognitive screening instrument

None

Higher triglycerides, total cholesterol, and LDL in MCI group compared with group free of MCI. Negative correlation of total cholesterol with scores on cognitive screening instrument in patients with MCI. No finding for HDL.

Chen et al. [11] (2012)

Patients with type 2 diabetes; China

Cross-sectional, observational

157

Mean 55 ± 7 years

Triglycerides, total cholesterol, LDL, and HDL

MCI identified on the basis of cognitive screening instrument

None

No association

Cukierman-Yaffe et al. [13] (2009)

Patients with type 2 diabetes participating in ACCORD-MIND; North America

Cross-sectional analysis of trial on blood pressure, lipids, and glycemic control

2,977

Mean 63 ± 6 years

Hyperlipidemia defined as use of lipid-lowering medication or untreated LDL cholesterol

Digit Symbol Coding (primary outcome), MMSE, Rey Auditory Verbal Learning, and Stroop (secondary outcomes)

Age

Association of hyperlipidemia with better performance on Digit Symbol Coding. No findings for other cognitive tests.

Perlmutter et al. [10] (1988)

Patients with type 2 diabetes; USA

Cross-sectional, observational

246

Range 55-74 years

Triglycerides and total cholesterol

Digit Symbol Coding, Digit Span, and simple reaction time

Plasma glucose, HbA1c, body mass index, and history of hypertension

Lower cognitive function in ‘high’ compared with ‘low’ triglyceride groups (fully adjusted analysis); association of cholesterol with triglyceride (unadjusted analysis).

Umegaki et al. [16] (2014)

Patients with type 2 diabetes; Japan

Six-year prospective, observational

79

Mean 74 ± 5 years

Mean of HDL and LDL measured at baseline and annual follow-ups

Composite score from MMSE, Digit Symbol Coding, Stroop, and word recall. Analyses of ‘decliners’ versus ‘non-decliners’ on the basis of composite score and individual cognitive tests.

Age, education, estimated glomerular filtration rate, renin-angiotensin system inhibitor use, paraventricular hyperintensities, and deep white matter hyperintensities

Lower mean 6-year HDL in ‘decliners’ compared with ‘non-decliners’ on composite score and Stroop (unadjusted analysis). No finding for LDL. Mean 6-year HDL significant predictor in model of risk of decline on composite score (fully adjusted analysis).

Williamson et al. [17] (2014)

Patients with type 2 diabetes participating in ACCORD-MIND lipid arm, receiving simvastatin + fenofibrate or simvastatin + placebo; North America

40-month trial on blood pressure, lipids, and glycemic control

1,538

Mean 62 ± 6 years

Successful manipulation of cholesterol levels (groups differed on cholesterol following intervention).

Total brain volume at baseline and 40 months, Digit Symbol Coding (primary outcome), MMSE, Rey Auditory Verbal Learning, and Stroop (secondary outcomes) at baseline and 20 and 40 months

Glycemia treatment arm, visit effect, clinical center, and history of cardiovascular disease

No difference in 20- or 40-month cognitive decline or 40-month change in total brain volume between intervention and control groups of lipid trial

Van Harten et al. [12] (2007)

Patients with type 2 diabetes; The Netherlands

Cross-sectional, observational

92

Mean 73 ± 6 years

Total cholesterol/HDL ratio

Cognitive screening instruments, composite scores of four cognitive domains derived from scores on battery of 10 cognitive tests

Duration of diabetes, HbA1c, insulin use, hypertension, and polyneuropathy

No association

Yanagawa et al. [15] (2011)

Patients with diabetes receiving exercise program four times per week versus none; Japan

12-week trial on physical exercise intervention

16

Mean 71 ± 4 years

HDL and LDL (no intervention effect on HDL and LDL)

MMSE, word recall, Digit Symbol Coding, Stroop, and Trail-Making Test

Age, education, and body mass index

No difference in cognitive function between treatment groups following intervention

  1. ACCORD-MIND, Action to Control Cardiovascular Risk in Diabetes-Memory in Diabetes; HDL, high-density lipoprotein; LDL, low-density lipoprotein; MCI, mild cognitive impairment; MMSE, Mini-Mental State Examination