Table 1.
Characteristics of cases and their matched cancer-free controls at time of first cognitive assessment
| Characteristic | Study population |
P† | |
|---|---|---|---|
| Case patients (n = 2059) | Control subjects (n = 7403)* | ||
| Age, median (IQR), y | 64.7 (60.2–71.5) | 62.5 (58.3–70.6) | <.001 |
| Sex, No. (%) | <.001 | ||
| Women | 980 (47.6) | 4446 (60.1) | |
| Men | 1079 (52.4) | 2957 (39.9) | |
| Education, No. (%) | <.001 | ||
| Primary | 349 (16.9) | 1067 (14.4) | |
| Lower | 847 (41.1) | 3155 (42.6) | |
| Intermediate | 607 (29.5) | 2040 (27.6) | |
| Higher | 256 (12.4) | 1141 (15.4) | |
| Smoking, No. (%) | <.001 | ||
| Never | 452 (22.0) | 2149 (29.0) | |
| Current | 500 (24.3) | 1458 (19.7) | |
| Former | 1107 (53.8) | 3796 (51.3) | |
| Alcohol use, No. (%) | .99 | ||
| No | 374 (18.2) | 1344 (18.2) | |
| Yes | 1685 (81.8) | 6059 (81.8) | |
| CES-D sum-score, mean (SD) | 13.0 (4.0) | 13.8 (4.1) | <.001 |
| BMI, median (IQR), kg/m2 | 26.7 (24.5–29.2) | 27.0 (24.6–29.7) | <.001 |
| Age at time of cancer diagnosis, mean (SD), y | 73.8 (8.3) | ||
Control subjects were matched to case patients per individual cognitive test. Some control subjects were matched to case patients for different cognitive tests, whereas other control subjects were only matched to case patients for one cognitive test. The control subjects in this table represent all individual control subjects used for the different cognitive test analyses. BMI = body mass index; CES-D = Center for Epidemiol Studies Depression scale; IQR = interquartile range.
Two-sided P values were calculated using the independent samples t test (for continuous variables with a normal distribution), the Wilcoxon signed-rank test (for continuous variables with a skewed distribution), and the χ2test (for categorical variables) to investigate differences in characteristics between case patients and control subjects. A P value <.05 was considered statistically significant.