Table 1

Studies showing a relation between family size and atopic disease that could not be included in figures 1 to 4 (no frequencies/odds ratio reported or outcome did not fit in one of the four categories)

Author and yearOutcome measuredFindingsMeasure of association
Bråbäck et al, 199545
 n=2232SPTThe number of siblings and domestic crowding were inversely related to sensitisationOR=0.58 (0.43 to 0.77) for number of persons per room
Burr et al, 199747
 n=437 for SPT
 n=338 for IgESPT, IgE, wheezing, eczema, hay fever (children with family history of atopy)There was a non-significant negative association of SPT and IgE with number of older siblingsp=0.13 for SPT
 p=0.12 for IgE
Mattes et al, 19989
 n=3165Atopic disorder (asthma, hay fever, or eczema)Inverse relation between number of older siblings and atopic diseaseOR=0.4 (0.19 to 0.83) for +3 older siblings
 OR=1.14 (0.70 to 1.85) for +3 younger siblings
Strachan et al, 19975
 n=11042Inhalant allergy (cat, pollen, or dust) and non-inhalant allergy (insect bites or something else)Inhalant allergy was inversely related with the number of siblingsOR=0.76 (0.59 to 0.97)
 (not adjusted)
Tariq et al, 199853
 n=1215 for atopic illness
 n=981 for SPTAtopic disorder (asthma, eczema, or hay fever)
 SPTWeak inverse relation of number of siblings with atopic illness and SPTPR=0.41 for atopic illness (not significant)
 PR=0.61 for SPT (not significant), 4 siblings v no
Taylor et al, 198319
 n=12743Eczema, hay fever, wheezing, and asthmaHaving older siblings was inversely associated with hay fever, no associations with eczema of asthmaPR=0.56 of having older siblings v no older siblings for hay fever (no CI or p value provided)
Weitzman et al, 199041
 n=15224Asthma and use of asthma medicationAsthma was positively associated with having a large family size (more than 6 members)OR=1.9 (1.2 to 3.1) for 6 or more family members v less than six
Attena et al, 199928Medical diagnosis of asthmaFirstborn had 1.89 times more asthma than other siblingsOR=1.89 for firstborn (p=0.048)
Lewis et al, 1998
 n=716217EczemaSignificant trend of increased risk of eczema at the age of 16 in firstborn compared with subsequent children.Graphical presentation: OR≊0.92 for the third child, and OR≊0.78 for the fourth child compared with the first.
Moyes et al, 1995
 n=57724Cough and wheezeCough and wheeze was more common in primary childrenCough: primary children OR=1.3 (1 to 1.7), wheeze: OR=1.5 (1 to 2.3)