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Table 1 Baseline characteristics of subjects in the total sample

From: Age dependency of risk factors for cognitive decline

Characteristic Total sample ≤70 years > 70–80 years > 80 years P -value b
Sample sizea 2527 1292 794 441  
Age, y 70.1 (8.8) 62.6 (4.2) 75.5 (2.9) 82.6 (1.5)  
Female, % 51.2 52.3 50.0 50.3 0.48
Education, y 9.1 (3.4) 9.5 (3.3) 8.7 (3.2) 8.6 (3.7) < 0.01
Follow-up, y (median, IQR) 9.1 (3.2–19.0) 13.3 (8.9–19.2) 6.2 (3.0–13.0) 4.9 (3.3–8.9) < 0.01
MMSE, points (median, IQR) 28 (27–29) 29 (26–30) 28 (24–30) 27 (24–30) < 0.01
Change in MMSE per year (SE) −0.11 (0.00) − 0.06 (0.00) − 0.18 (0.01) − 0.25 (0.02) < 0.01
15WT immediate recall, words 8.1 (2.5) 8.9 (2.3) 7.6 (2.4) 6.3 (2.1) < 0.01
Change in 15WT immediate recall per year (SE) −0.11 (0.00) −0.07 (0.00) − 0.11 (0.01) −0.07 (0.02) < 0.01
15WT delayed recall, words 5.3 (2.7) 6.2 (2.6) 4.7 (2.5) 3.5 (2.2) < 0.01
Change in 15WT delayed recall per year (SE) −0.11 (0.00) −0.05 (0.01) − 0.10 (0.01) −0.06 (0.02) < 0.01
APOE ε4, %c 26.3 27.8 25.2 23.6 0.29
Total cholesterol, mmol/L 5.7 (1.0) 5.9 (1.0) 5.6 (1.0) 5.3 (1.1) < 0.01
LDL cholesterol, mmol/L 3.7 (1.0) 3.8 (0.9) 3.6 (0.9) 3.4 (1.1) < 0.01
HDL cholesterol, mmol/L 1.3 (0.4) 1.3 (0.4) 1.4 (0.4) 1.3 (0.4) 0.48
Homocysteine, mmol/L 14.5 (6.1) 13.5 (5.2) 14.7 (5.0) 17.2 (9.2) < 0.01
Vitamin B12, pMol/L (median, IR) 266 (212–333) 268 (219–335) 264 (213–331) 249 (196–333) 0.12
Hypertension, % 76.7 72.9 82.2 73.7 < 0.01
Myocardial infarction, % 8.8 6.4 11.1 11.7 < 0.01
Diabetes mellitus, % 7.0 4.3 8.6 12.3 < 0.01
Stroke, % 4.4 1.6 6.7 8.7 < 0.01
CES-D total score (median, IQR) 5 (2–11) 5 (2–9) 6 (3–11) 7 (3–12) < 0.01
IL-6, pg/ml (median, IQR) 1.4 (0.6–2.5) 1.3 (0.6–2.4) 1.6 (0.7–2.7) 1.8 (1.0–3.1) < 0.01
CRP, ug/ml (median, IQR) 2.2 (1.0–4.7) 2.0 (0.9–3.9) 2.5 (1.3–5.6) 2.8 (1.4–5.7) < 0.01
ACT, % of NHP 173.6 (57.6) 169.6 (53.0) 179.3 (66.1) 177.2 (54.1) 0.01
Alcohol consumption, %
 None 20.1 15.6 25.3 24.7 < 0.01
 Minimald 20.6 17.8 23.6 23.6
 Moderatee 59.4 66.6 51.1 51.7
Smokers, % 24.6 30.4 23.1 19.8 < 0.01
Total physical activity, min per day 169.2 (114.2) 188.4 (121.3) 160.0 (103.7) 126.8 (95.3) < 0.01
  1. 15WT 15 Words Test, ACT a1-antichymotrypsin, APOE apolipoprotein E, CES-D Center for Epidemiologic Studies Depression scale, CRP C-reactive protein, HDL High-Density Lipoprotein, IL-6 interleukin-6, IQR interquartile range, LASA Longitudinal Aging Study Amsterdam, LDL Low-Density Lipoprotein, MMSE Mini-Mental State Examination, NHP normal human plasma, SE standard error
  2. aSample size varies per characteristic (Additional file 1: Table S2). bDifferences between the three age groups tested with ANOVA for continuous variables, chi-square for categorical variables, Kruskal-Wallis test for non-parametric variables and mixed model analysis for the change in cognitive test scores per year. cPercentage of subjects with an apolipoprotein E ε4 isoform as proxy for an APOE ε4 allele. dWomen:1 drink/day, men: 1–2 drinks/day. eWomen: > 1 drink/day, men: > 2 drinks/day. Values are means (SD) unless stated otherwise