Table 2

Clinical characteristics of the French-Canadian family study
Probandsa Family members
n = 253 n = 1031
Male: Female ratio 1 : 1.1 1 : 1.2
Mean age, yr (range) 18 (3–50) 44 (2–93)
Smoking status, n (%)
 Never 211 (85) 473 (47)
 Ex-smoker 12 (5) 342 (34)
 Smoker 25 (10) 197 (19)
FEV1, % predicted (SD) b 92.7 (15.7) 94.6 (20.3)
PC20, mg/ml (SD) c 2.53 (3.51) 10.06 (4.97)
Serum IgE in μg/l (SD) d 254.2 (4.9) 112.4 (4.4)
Number of persons with subphenotypes (%)
 Asthma e 253 (100) 378 (37)
 Atopy f 200 (79) 509 (49)
 Atopic asthma (Asthma + Atopy) 200 (79) 257 (25)

a Probands are first affected family member recruited in the familial collection and family members refers to other family members who joined the study.

b FEV1 = Mean calculated for the forced expiratory volume in one second evaluated for 217 probands and 770 family members.

c PC20 = Provocative concentration of methacholine that induces a 20% fall in FEV1. Geometric mean and SD evaluated for 192 probands and 711 family members.

d IgE = Immunoglobulin E serum concentration. Geometric mean and SD evaluated for 237 probands and 820 family members.

e Present asthma or past documented clinical history of asthma. The reported mean age of onset is 7 years among the probands and 22 years among the asthmatic family members. Asthma phenotype was evaluated for 1022 subjects.

f Defined as at least one positive response on skin prick test (wheal diameter > 3 mm at 10 minutes). Atopy phenotype was evaluated for 997 subjects.

Vaillancourt et al.

Vaillancourt et al. BMC Research Notes 2012 5:630   doi:10.1186/1756-0500-5-630

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