Table 1.

Demographic characteristics of the national sample and genotyped subsample

Swedish national sample	Cases	Controls	Statistical comparison
Subjects	14,230	3,816,264	NA
Birth year, mean (SD)	1969 (8.6)	1975 (10.5)	t3,830,492 = 72.3, P<1×10−300
Male sex, N (%)	8,762 (61.6%)	1,959,215 (51.3%)	${\chi }_1^2$ = 594.2, P=3.12×10−131
Premorbid cognitive ability (males), mean (SD)	−0.51 (1.07)	0.00 (1.00)	t1,422,976 = 40.2, P<1×10−300
Educational attainment, mean (SD)	−0.59 (0.90)	0.00 (1.00)	t3,706,109 = 69.5, P<1×10−300
Intellectual disability, N (%)	923 (6.5%)	23,692 (0.6%)	${\chi }_1^2$ = 7630.1, P<1×10−300
Genotyped subsample	Cases	Controls	Statistical comparison
Subjects	4,992	6,009	NA
Birth year, mean (SD)	1954 (11.8)	1952 (11.3)	t10,999 = −9.7, P=2.72×10−22
Male sex, N (%)	3,021 (60.5%)	3,052 (50.8%)	${\chi }_1^2$ = 103.9, P= 2.11×10−24
Premorbid cognitive ability (males), mean (SD)	−0.34 (0.97)	0.31 (0.91)	t2,544 = 17.4, P= 2.60×10−64
Educational attainment, mean (SD)	−0.34 (0.87)	0.28 (1.00)	t10,770 = 33.7, P= 2.18×10−237
Intellectual disability, N (%)	351 (7.0%)	5 (0.1%)	${\chi }_1^2$ = 418.2, P= 6.14×10−93

Premorbid cognitive ability is Z-score standardized by birth year in each sample. Educational attainment is Z-score standardized by birth year and sex in each sample. All continuous variables are described by mean and standard deviation (SD). Categorical variables are described by sample size (N) and percentage (%). Statistical comparisons are t-test for continuous variables and chi-square test for categorical variables. All statistical comparisons exceed Bonferroni correction (N=10, P < 0.005).NA: not applicable.