Table 1 Participant demographics and characteristics.

Monozygotic
(n = 46 pairs)
Dizygotic
Same sex
(n = 23 pairs)
Opposite sex
(n = 20 pairs)
Number of individuals or twin pairs (%)
Age (years)
  50–5412 (26.1)0 (0.0)0 (0.0)
  55–5913 (28.3)0 (0.0)0 (0.0)
  60–647 (15.2)4 (17.4)1 (5.0)
  65–699 (19.6)4 (17.4)11 (55.0)
  70–743 (6.5)12 (52.2)7 (35.0)
  75–792 (4.4)3 (13.0)1 (5.0)
Sex
  Female25 (54.4)16 (69.6)20 (100.0)
  Male21 (45.6)7 (30.4)
Smoking
  Smoker14 (15.2)9 (19.6)10 (25.0)
  Concordance40 (87.0)16 (69.6)12 (60.0)
History of atopic disease*
  Yes27 (29.3)14 (30.4)13 (32.5)
  Concordance29 (63.0)15 (65.2)11 (55.0)
History of psoriasis
  Yes8 (8.7)2 (4.3)5 (12.5)
  Unknown2 (2.2)1 (2.2)2 (5.0)
  Concordance38 (82.6)20 (87.0)13 (65.0)
Farm exposure
  Yes1 (1.1)2 (4.3)1 (2.5)
  Unknown0 (0.0)2 (4.3)0 (0.0)
  Concordance45 (97.8)21 (91.3)19 (95.0)

*Atopic diseases include asthma, atopic dermatitis, and allergy.