Table 1

 Included studies

ReferencePrimary exposure measurePlace of study, nEffect size (95% CI)Primary outcome measureAge at follow upNotes
CI, confidence interval; OR, odds ratio; RR, relative risk.
Bolte, 200435Birth weight ⩾4 kgMunich, n = 534OR 1.52 (0.51 to 4.51)Physician diagnosed asthma5–7 y
Sin, 200436Birth weight ⩾4.5 kgAlberta, n = 83 595RR 1.16 (1.04 to 1.29)Asthma Emergency Department visit10 y
Yuan, 200237Ponderal index ⩾2.5 g/cm3Denmark, n = 10 440RR 1.53 (1.11 to 2.13)Asthma hospitalisation12 y
Gilliland, 200331BMI in 4th, 7th, and 10th gradesSouthern California, n = 3792RR 1.52 (1.14 to 2.03)Physician diagnosed asthma11–22 y (4 y after enrolled)
Xu, 200224Ponderal index ⩾2.83 g/cm3Finland, n = 4719Effect of birth weight: OR 1.26 (0.88 to 1.82)Physician diagnosed asthma31 yEffect of high childhood BMI: OR 1.32 (0.82 to 2.4)
Chinn, 200132BMI age 5–6UK, n = 6744OR 1.24 (0.82 to 1.88)Physician diagnosed asthma9–10 yResults for boys and girls were pooled to get total. Also contained info on risk per additional gram of birth weight, but this continuous outcome was not able to be combined with the dichotomous outcomes of the other studies
Castro-Rodriguez, 200133BMI age 11Tucson, n = 448 (222 boys and 226 girls)OR 2.7 (0.9 to 8.2) for boys; OR 3.2 (1.1 to 8.8) for girlsFrequent wheeze at age 1313 yNot enough incidence information given to pool results for gender; each gender entered separately into meta-analysis
Rasanen, 200038Ponderal index ⩾27 kg/m3Finland, n = 4578OR 1.86 (1.13 to 3.07)Physician diagnosed asthma16 y
Leadbitter, 199939Birth weight ⩾4 kgDunedin, New Zealand, n = 735OR 1.0 (0.4 to 2.4)Physician diagnosed asthma13 y
Gregory, 199940Birth weight ⩾4 kgSouthampton, UK, n = 249OR 1.3 (0.4 to 4.4)Current wheeze or current use of asthma medication11–14 y
Fergusson, 199741Birth weight ⩾4 kgChristchurch, New Zealand, n = 891RR 0.89 (0.51 to 1.6)Physician diagnosed asthma16 y
Schwartz42Birth weight ⩾3.8 kgUSA, n = 4661RR 0.92 (0.62 to 1.37)Physician diagnosed asthma6 m–11 yData on childhood BMI cross-sectional