Table 1.
The study population characteristics at baseline in 2000 and at follow-up 2014 – 2016 in participants with normal (IR-) insulin tolerance and with insulin resistance (IR+) in 2000 (n = 60)
| N | IR– 30 | IR+ 30 | p |
| Baseline in 2000 | |||
| age, mean (SD) | 55.6 (3.8) | 55.2 (2.8) | 0.65 |
| women, n/% | 17/56.7 | 16/53.3 | 0.80 |
| men, n/% | 13/43.3 | 14/46.7 | 0.80 |
| Fasting time (h:min), median (range) | 6:15 (5:30–7:59) | 6:58 (5:38–12:51) | 0.24 |
| HOMA-IR, median (range) | 0.90 (0.46–1.22) | 2.82 (2.20–5.24) | <0.0001 |
| APOE ɛ4 genotype, n | 15 | 15 | 1.0 |
| Level of education, n/% | 0.04 | ||
| Primary school | 5/16.7 | 15/50.0 | |
| Middle school or comprehensive school | 12/40.0 | 9/30.0 | |
| High school | 5/16.7 | 3/10.0 | |
| College or university | 8/26.7 | 3/10.0 | |
| BMI (kg/m2), mean (SD) | 25.1 (2.9) | 29.9 (3.4) | <0.001 |
| Hypertension, n/% | 10/33.3 | 21/70.0 | 0.005 |
| HDL cholesterol (mmol/L), mean (SD) | 1.55 (0.43) | 1.23 (0.27) | 0.001 |
| Triglycerides (mmol/L), mean (SD) | 1.24 (0.46) | 1.74 (0.95) | 0.002 |
| Current smoking, n/% | 5/16.7 | 4/13.3 | 0.72 |
| CERAD | |||
| verbal fluency, mean (SD) | 28.7 (6.3) | 23.3 (5.1) | 0.0007 |
| word-list learning sum, mean (SD) | 21.8 (3.8) | 20.9 (3.1) | 0.32 |
| delayed recall, mean (SD) | 7.3 (1.7) | 6.8 (1.4) | 0.26 |
| Follow-up in 2014–2016 | |||
| age at time of MRI-scan, mean (SD) | 71.1 (3.7) | 70.8 (2.8) | 0.72 |
| HOMA-IR, median (range) | 1.73 (0.22–5.13) | 3.31 (1.2–21.4) | <0.0001 |
| Fazekas score, n/% | 0.78 | ||
| 0 | 9/30.0 | 15/50.0 | |
| 1 | 16/53.3 | 6/20.0 | |
| 2 | 3/10.0 | 7/23.3 | |
| 3 | 2/6.7 | 2/6.7 | |
| PIB-positive, n/% | 10/33.3 | 18/60.0 | 0.04 |
| PIB-negative, n/% | 20/66.7 | 12/40.0 | 0.04 |
IR–, HOMA-IR in the lowest tertile of the Health 2000 study population (HOMA-IR < 1.25); IR+, HOMA-IR in the highest tertile of the Health 2000 study population (HOMA-IR > 2.17). p-values for the differences between the IR groups assessed with Student’s t-test for continuous variables and with Pearson’s Chi-Squared test for categorical variables except for the length of the fasting time in 2000 which was assessed with Wilcoxon rank sums test and Fazekas score which was assessed with a Cochran Armitage Trend Test. Fazekas scores were obtained by rounding the computed Fazekas score to the nearest whole number. A logarithmic transformation is used for triglycerides and HOMA-IR at follow-up in order to achieve normal distribution. PIB-PET scan was considered PIB positive when PIB composite score was >1.5.