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Table 1 Demographic characteristics

From: Genetic and environmental influences on circulating NK and T cells and their relation to bipolar disorder

  Bipolar twins (BD) Control twins (HC)
Total (n = 52) MZ (n = 22) DZ (n = 30) Index (n = 26) Co-twin (n = 26) Total (n = 54) MZ (n = 30) DZ (n = 24)
Age, mean (SD), range, y 49.6 (10.2), 29–69 47.5 (11.0), 29–62 51.1 (9.5), 37–69 49.6 (10.2), 29–69 47.5, (11.0), 29–62 48.3 (8.4), 32–72 48.5 (10.2), 32–72 48.1 (6.0), 39–57
Female, n (%) 37 (71.2) 18 (81.8) 19 (63.3) 19 (73.1) 18 (69.2) 38 (70.3) 24 (80.0) 14 (58.3)
Diagnosis
 Bipolar disorder I 20 7 13 20
 Bipolar disorder II 9 6 3 6 3
 Bipolar Disorder 1 1 1
NOS
 Unipolar disorder 4 3 1 4 2 0 2
 Psychotic disorder 3 1 2 3
 Other disorder 4 1 3 4 8 4 4
 No disorder 11 4 7 11 45 27 18
Mood
 Euthymic 17 8 9 14 3    
 Mood episode 11 5 6 10 1    
 Missing data 24 9 15 2 22    
 Age at onset, mean (SD), range, y 26.9 (10.3), 13–57 24.4 (7.8), 13–40 29.4 (11.9), 14–57 29.6 (10.7), 16–57 22.3 (7.5), 13–40    
 Smoking, n (%) 28 (53.8) 10 (45.5) 18 (60.0) 17 (65.4) 11 (42.3) 27 (50.0) 15 (50.0) 12 (50.0)
 Body mass index, mean (SD) range 25.1 (4.4), 17–42 25.5 (4.7), 18–42 24.9 (4.1), 17–28 26.1 (5.0), 17–42 24.2 (3.4), 18–31 25.2 (4.7), 18–40 24.4 (3.4), 19–30 26.2 (5.9), 18–40
Psychotropic medication
 Lithium 16 7 9 14 2 0 0 0
 Anticonvulsants 3 1 2 2 1 0 0 0
 Antipsychotics 18 5 13 13 5 0 0 0
 Antidepressants 10 4 6 7 3 1 1 0
 Benzodiazepines 8 4 4 7 1 1 1 0
  1. BD bipolar disorder, HC healthy controls, DZ dizygotic, MZ monozygotic
  2. Mood episode, defined as YMRS > 13 and/or IDS > 7. Euthymic, defined as YMRS ≤ 13 and/or IDS ≤ 7. Current use of psychotropic medication is reported. No significant differences between different groups, except for use of psychotropic medication (p < 0.001)