Table 3. Adjusted associations of perinatal characteristics with wheezing phenotypes in ALSPAC.

	Adjusted Relative Risk Ratio (95% CI) for*
Perinatal characteristicsadjusted by other demographic,maternal, pregnancy, childand perinatal characteristics(N = 8,107)	Transient early(N = 788)	Prolonged early(N = 533)	Intermediateonset (N = 198)	Late onset(N = 375)	Persistent(N = 571)	Heterogeneity P-value+
Maternal age at delivery(per-5-years)	0.92 (0.84, 1.00)	0.87 (0.79, 0.96)	0.91 (0.76, 1.09)	0.98 (0.88, 1.10)	0.90 (0.81, 1.01)	0.58
Birth weight (per-1 Kg)±	1.04 (0.88, 1.22)	0.97 (0.81, 1.16)	0.99 (0.71, 1.39)	0.95 (0.77, 1.18)	0.94 (0.77, 1.16)	0.93
Low birth weight (<2.5 Kg)±	1.00 (0.67, 1.50)	1.05 (0.68, 1.63)	2.40 (1.21, 4.75)	1.31 (0.80, 2.17)	1.04 (0.64, 1.69)	0.20
Pregnancy duration (per-1week)‡	0.98 (0.94, 1.02)	0.97 (0.92, 1.01)	1.04 (0.95, 1.14)	1.02 (0.96, 1.08)	0.93 (0.88, 0.98)	0.08
Preterm delivery (<37 weeks)‡	1.21 (0.89, 1.66)	1.47 (1.05, 2.04)	1.14 (0.59, 2.22)	0.86 (0.54, 1.37)	1.49 (1.03, 2.16)	0.30
Caesarean section	1.02 (0.81, 1.29)	0.99 (0.76, 1.29)	0.94 (0.57, 1.56)	1.19 (0.89, 1.59)	1.03 (0.76, 1.38)	0.87

^*compared with never/infrequent wheezing (N = 5642) and using each child’s phenotype probability as weights.

^±Not adjusted for each other but adjusted for preterm delivery (<37 weeks).

^‡Not adjusted for each other and not adjusted for birth weight/low birth weight (since birth weight does not influence gestational age).

⁺Chi-squared test across phenotypes.