Figure 2.

Proposed theoretical model for the environmental factors associated with “Childhood Asthma Symptoms” during the prenatal period and the first 1000 days of life: BRISA cohort, São Luís, Brazil, 2010–2013. The Socioeconomic Status (SES) would be a more distal determinant (exogenous variable) exerting its effects on the development of “Childhood Asthma Symptoms” in early childhood³⁸ and on the remaining dependent variables of the model. Maternal age potentially affects pregestational body mass index (BMI)³⁹ and “Childhood Asthma Symptoms”⁸. Maternal respiratory infections may be associated with “Childhood Asthma Symptoms”¹⁴. Smoking during pregnancy may result in “Childhood Asthma Symptoms”⁷ and may also result in low birth weight (LBW)⁴⁰; soft drink and junk food consumption potentially affect blood pressure^41,42 and diabetes⁴³, which may lead to caesarean delivery, which has been associated with “Childhood Asthma Symptoms”^9,10, LBW¹¹ and preterm birth (PTB)^12,13. Girls have a lower risk of “Childhood Asthma Symptoms” and black race is associated with an increased risk of “Childhood Asthma Symptoms”^3,44. Exclusive breastfeeding may have a protective effect on “Childhood Asthma Symptoms”¹⁴. Child’s respiratory infections during the first year of life may be associated with “Childhood Asthma Symptoms”¹⁴, while higher child’s BMI z-score has been associated with “Childhood Asthma Symptoms”^12,13. Environmental stimuli in early childhood (exposure to carpet covered floor, pets and mold/mildew), including exposure to tobacco have been associated with “Childhood Asthma Symptoms”^7,14,23.