Table 1.
Study population characteristics by generation
| All participants (n = 6486) | G0 (n = 2025) | G1 (n = 2030) | G2 (n = 2431) | |||||
|---|---|---|---|---|---|---|---|---|
| Age, years | 45.3 (7.0–92.0) | 72.7 (59.0–92.0) | 48.7 (41.0–56.0) | 19.7 (7.0–37.0) | ||||
| Sex, male | 2803 (43.3) | 799 (39.5) | 914 (45.0) | 1090 (45.0) | ||||
| Education, years | 14.3 (4.0) | 11.9 (4.1) | 15.8 (3.7) | 15.2 (3.3) | ||||
| Data on cognitive performance | N (%) | Mean (SD) | N (%) | Mean (SD) | N (%) | Mean (SD) | N (%) | Mean (SD) |
| Overall cognitive performance | 5570 | − 1.12 (1.51) | 1422 | − 2.87 (0.97) | 1867 | − 0.92 (1.17) | 2281 | − 0.19 (1.02) |
| Learning and memory (PAL test) | 6215 | − 1.05 (1.48) | 1870 | − 2.51 (1.03) | 1951 | − 0.92 (1.16) | 2394 | − 0.00 (1.01) |
| Working memory (SWM test) | 6386 | − 0.86 (1.19) | 1937 | − 1.84 (0.75) | 2022 | − 0.61 (1.13) | 2427 | − 0.27 (1.02) |
| Information processing (RVP test) | 5773 | − 0.46 (1.27) | 1534 | − 1.33 (1.24) | 1932 | 0.15 (1.03) | 2307 | − 0.40 (1.14) |
| Reaction time (RTI test)* | 6366 | 0.55 (1.15) | 1937 | 0.75 (0.61) | 2016 | 0.62 (0.37) | 2413 | 0.40 (1.54) |
The numbers are presented as the means (ranges) for continuous variables and as numbers of participants and percentages for categorical variables. Self-reported education years were considered for the G1 and G0 participants. For the G2 participants, self-reported education years were applied for all participants aged ≥ 28 years. For the participants aged ≤ 18 years, a maximum of parental education years was applied. For the G2 participants aged 19–28 years, parental education years were applied if the participant reported that he/she was studying; otherwise, self-reported education years were used. The cognitive performance variables are standardized domain specifically in relation to participants aged 20–29 years. Hence, the means (SD) describe how many standard deviations the given principal component differs from the highest values reached at age 20–29 years
*Due to its nonnormal distribution, the median (interquartile range) is reported for the reaction time (RTI test)