TABLE 1.

Studies with a long-term follow-up asthma (minimum 10 years) and breastfeeding.

Author and Year	Definition of asthma	Assessed at ages	Duration of breastfeeding	Breastfeeding (BF) effects	Smoking	Respiratory tract infections (RTI)
Saarinen et al. 19954	Asthma defined as either: • allergic asthma diagnosed • ≥ 3 episodes of wheezing (at 3–10 years) • wheezing history + ≥3 respirat. Infect, (at 3–5 yrs) • wheezing history + rhinoconjuctival symptoms	3 years 5 years 10 years 17 years	≤ 1 months 1–6 months ≥ 6 months	Protective against infections; Protective against respiratory allergy at 17 years (BF > 1 month)	Controlled for the effect of smoking; smoking for 5 yrs post-delivery is not associated with atopic disease in adolescence.	No association between susceptibility to RTI in infancy and atopic disease in adolescence.
Wright et al. 20017	• Physician diagnosis of asthma + symptoms on ≥2 questionnaires • Recurrent wheeze (≥ 4 episodes during past yr)	6 years 9 years 11 years 13 years	0 < 4 months ≥ 4 months	Children ≤ 3 years: lower prevalence of recurrent wheeze (BF ≥4 months); Children >3 years: higher prevalence of recurrent wheeze if the mother had asthma.	Controlled for the effect of smoking	Predominately infectious wheeze until 6 years included. The authors acknowledge a wheeze-asthma overlap.
Takemura et al. 20019	Questionnaire: • Ever asthma • Attack of wheezing • Physician diagnosis	Age 6–13 years	0–3 months	Increased risk of asthma in children who were breastfed.	Smoking at the time of the survey, not in pre- or postnatal.	Not included
Sears et al. 20026	• Questionnaires • Pulmonary function tests • Bronchial challenge tests • Allergy skin tests	From age 9–26 yrs, every 2–5 yrs	0 ≥ 1 months	Increased risk of asthma (BF ≥ 1 month);	Controlled for the effect of smoking	Not included
Burgess et al. 20068	Questionnaire: • Child asthma last 6 mths • Asthma medications • Days missed in school • Asthma-related hospital admission	14 years	0 <3 weeks 3–6 weeks 7 weeks-3 months ≥ 4 months	Increased asthma prevalence in BF children of asthmatic women; no association with asthma at 14 years	Maternal smoking was not included in the multivariate analyses; it was associated with the decision and duration of BF.	Not included
Matheson et al. 200710	Questionnaire: • Attacks of asthma or wheezy breathing last 12 months	13 years 20 years 31 years	First 3 months	BF reduced the risk for asthma in children with atopic mothers at 7 years, but increased at >7 years; no effect in children of non-atopic mothers.	Maternal smoking was controlled for; it was related to not exclusive breastfeeding.	Controlled for pleurisy & pneumonia. Exclusive BF was protective against pneumonia or pleurisy and bronchitis.