Table 1.

Characteristics of the Study Sample According to Glycemic Status, AGES-Reykjavik Study, 2002–2006^a

	Normoglycemia (n = 955)	Impaired Fasting Glucose (n = 744)	Diagnosed Type 2 Diabetes Mellitus (n = 163)	Undiagnosed Type 2 Diabetes Mellitus (n = 55)
Age, years	76.0 (5.7)	75.3 (5.4)	75.6 (5.4)	75.9 (4.9)
Low education, %	22.8	21.0	21.5	10.9**
Female sex, %	64.4	54.4***	44.2**	45.5**
Depressive symptomatology, %	7.8	5.5	6.0	2.0*
Memory (z score)	0.08 (0.89)	0.11 (0.90)	0.01 (0.76)	−0.18 (0.71)*
Speed of processing (z score)	0.05 (0.72)	0.12 (0.72)	−0.08 (0.73)*	−0.13 (0.81)*
Executive function (z score)	0.04 (0.65)	0.06 (0.66)	0.02 (0.64)	−0.07 (0.55)
Ever smoking, %	54.3	54.4	63.8*	50.9
Body mass indexb	25.9 (4.1)	27.8 (4.4)***	28.7 (4.3)***	29.4 (5.3)***
Hypertension, %	73.9	80.5**	92.0***	90.9***
Being in top quartile of white matter lesion load, %	20.5	19.0	29.5*	27.3*
MRI cerebral infarct, %	24.6	27.8	39.3***	30.9
Visual acuity of 20/20, %	27.0	27.7	27.0	20.4
Retinopathy, %	19.1	16.0	39.7***	21.2
Apolipoprotein E ϵ4 genotype, %	27.6	26.9	21.5	23.6
Total cholesterol level, mmol/L	5.8 (1.1)	5.8 (1.2)	5.2 (1.1)***	5.7 (1.2)
Insulin level, μU/mL	7.4 (4.5)	11.5 (7.3)***	17.4 (21.1)***	16.8 (10.9)***
Median hemoglobin A1c level, %	5.6 (5.4–5.8)c	5.7 (5.5–5.9)	6.4 (6.0–7.1)***	6.2 (5.8–6.5)***
Median fasting glucose level, mmol/L	5.2 (5.0–5.4)	5.9 (5.7–6.2)***	7.3 (6.3–8.9)***	7.6 (7.2–8.1)***

Abbreviations: AGES-Reykjavik, Age, Gene/Environment Susceptibility–Reykjavik; MRI, magnetic resonance imaging.

^*P < 0.05; **P < 0.01; ***P < 0.001 (age-adjusted comparison with normoglycemic group).

^aGlycemic groups were based on current American Diabetes Association criteria (18). All values are means with standard deviations in parentheses, unless otherwise noted.

^bWeight (kg)/height (m)².

^cNumbers in parentheses, interquartile range.