Table 1

Sample characteristics

Population Bipolar disorder
Characteristics n (%) n (%) Incidence rate per 100 000 person-years 95% CI
a. Categorised according to the Swedish system used by Statistics Sweden.
Total sample 713 596 280 4.10 3.64-4.61
Gender
     Male 364 839 (51.0) 128 (45.7) 3.71 3.12-4.40
     Female 348 757 (49.0) 152 (54.3) 4.51 3.84-5.30
Parent over 40 years at birth
     Father 25 837 (3.6) 15 (5.4) 6.09 3.67-10.11
     Mother 3 684 (0.5) 1 (0.4) 2.89 0.41-20.48
Season of birth: January to April 249 518 (34.8) 112 (40.0) 4.54 3.78-5.47
Highest parental socioeconomic groupa
     Self-employed/company owner 60 024 (8.4) 25 (8.9) 4.37 2.95-6.46
     White collar higher 108 933 (15.3) 41 (14.6) 4.00 2.95-5.43
     White collar middle 92 678 (13.0) 26 (9.3) 2.96 2.02-4.35
     White collar lower 168 694 (23.6) 74 (26.4) 4.56 3.63-5.74
     Blue collar higher 153 708 (21.5) 74 (26.4) 5.01 3.98-6.30
     Blue collar lower 125 147 (17.5) 36 (12.9) 2.98 2.15-4.13
     Missing 4 412 (0.6) 4 (1.4) 9.51 3.57-25.34
Highest parental educationa
     Higher education ≥3 years 166 757 (23.4) 89 (31.8) 5.68 4.61-7.00
     Higher education <3 years 117 984 (16.5) 46 (16.4) 4.10 3.06-5.49
     High school 3 years 110 147 (15.4) 39 (13.9) 3.71 2.71-5.08
     High school 2 years 238 593 (33.4) 78 (28.0) 3.42 2.74-4.27
     Compulsory school only 76 644 (10.7) 25 (8.9) 3.24 2.19-4.79
     Missing 3 471 (0.5) 3 (1.1) 8.68 2.80-26.92