Table 2—

Independent associations of perinatal factors and asthmatic symptoms (wheeze, noctural dyspnoea) and bronchitic symptoms (cough, phlegm, dyspnoea grade 3) at a young adult age, with adjustment for other potential risk factors

	Asthmatic symptoms	Wheeze	Nocturnal dyspnoea	Bronchitic symptoms	Cough	Phlegm	Dyspnoea grade 3
Perinatal factors
Mother smoked during pregnancy	0.91 (0.54–1.51)	0.73 (0.28–1.90)	0.60 (0.27–1.31)	0.98 (0.77–1.25)	1.09 (0.71–1.84)	1.15 (0.72–1.86)	0.91 (0.16–5.16)
Being first‐born	0.58 (0.35–0.95)*	0.66 (0.27–1.65)	0.74 (0.35–1.57)	0.93 (0.64–1.36)	1.19 (0.80–1.79)	0.80 (0.51–1.27)	4.75 (0.54–41.78)
Birth weight, per 100 g increase	1.00 (0.95–1.04)	0.96 (0.88–1.05)	0.60 (0.27–1.31)	1.00 (0.96–1.03)	1.00 (0.97–1.04)	0.99 (0.95–1.03)	0.98 (0.84–1.14)
Other potential risk factors
Severe respiratory tract infection^#	2.76 (1.51–5.04)*	0.83 (0.30–2.29)	2.27 (0.93–5.53)^¶	1.57 (0.92–2.71)	1.90 (1.08–3.33)*	2.04 (1.12–3.72)*	4.60 (0.77–27.48)^¶
Current smoking	1.70 (1.02–2.84)*	1.01 (0.38–2.68)	1.75 (0.80–3.82)	2.23 (1.50–3.31)*	2.22 (1.46–3.37)*	1.80 (1.12–2.89)*	1.17 (0.20–7.06)
Family history asthma	2.07 (1.18–3.64)*	2.07 (0.71–6.08)	1.80 (0.77–4.20)	1.30 (0.80–2.12)	1.13 (0.67–1.90)	1.51 (0.97–2.64)	0.00 (0.00–1.89)
Family history allergy	1.84 (1.09–3.10)*	1.04 (0.41–2.66)	2.86 (1.18–6.91)*	1.36 (0.92–2.0)	1.24 (0.82–1.87)	1.07 (0.67–1.71)	1.61 (0.28–9.26)

Data are presented as odds ratio (95% confidence interval)
COPD: chronic obstructive pulmonary disease
Multiple logistic regression analysis estimating the effect of perinatal factors (mother smoked during pregnancy, being first-born and birth weight) on respiratory symptoms, with adjustment for other potential risk factors (severe respiratory tract infection in the first year of life, current smoking habits, family history of asthma or allergy, sex (not shown), age (not shown)
*: p<0.05
^¶: p<0.10
^#: in the first year of life. n=1,568