Table 2.

Characteristics of Included Studies

Study	Setting	Study design	Recruitment setting and methods	Cohort size	Length of follow-up	Confounders	Funding sources
Håberg et al.25	Norway	Prospective birth cohort	Norwegian Mother and Child Cohort Study: Routine ultrasound appointment at 13–17 weeks gestation; questionnaires at the ages of 6, 12, and 18 months.	33,192	Age of 18 months	From questionnaires: Maternal asthma; educational level; income; age; marital status; parity; and smoking during pregnancy, smoking after birth, breastfeeding, and daycare attendance versus care at home. From birth records: child's sex, caesarean delivery, birthweight, gestational age, diabetes, gestational diabetes, hypertension, and pre-eclampsia.	Norwegian Ministry of Health, Division of Intramural Research, National Institute of Environmental Health Sciences, NIH.
Chen et al.26	Taiwan	Prospective birth cohort	Taiwan Birth Cohort Study: Random sampling from national birth registry and interviews; interviews at age of 6 months.	24,400	Age of 6 months	Prenatal conditions: Medication use during pregnancy, pregravid BMI, gestational weight gain, morbidities of gestation, tobacco smoking, betel nut chewing, shift work, and exposure to environmental tobacco smoking. Postnatal conditions: Sex of the baby, gestational age, birth weight, vaccination of Hemophilus influenzae type B, parental education level, family income level, number of siblings at home, and congenital cardiopulmonary disease. Environmental conditions: Exposure to cockroaches, water damage, visible mold on walls of home, carpeted flooring, incense burning, and pet ownership	Not available
Cameron et al.27	Australia	Prospective birth cohort	Environments for Healthy Living Cohort: Surveys during routine antenatal appointments in third trimester from 3 public maternity hospitals and admitted patient data from Queensland Hospital.	2,778	Age of 5 years	Maternal factors: Education, marital status, age, diabetes (pre-existing or gestational), cigarette smoking, recreational drug use and/or high-level alcohol consumption, number of other children living in the household, partner's employment status, and income quintile. Child and birth factors: Sex, plurality, gestational age, mode of delivery, newborn admission to intensive or special care, and birth weight.	Griffith University
Rajappan et al.28	United Kingdom	Prospective birth cohort	Southampton Women's Survey Cohort: Interviews at preconception, 11 and 34 weeks of pregnancy, and 6, 3, and 12 months after birth.	2,799	Age of 12 months	Maternal factors: Age, height, parity, education, late-pregnancy 25-hydroxyvitamin D status, smoking in pregnancy, smoking in child's infancy, and asthma. Paternal factors: Age, height, and asthma. Child and birth factors: Birthweight, gestation, age at last breastfeed, exposure to smokers in the home other than the mother, and adiposity gain between birth and 6 age of months.	Medical Research Council, British Heart Foundation, Food Standards Agency, Dunhill Medical Trust, the European Union's Seventh Framework Program, projects Early Nutrition and Dr Katharine Pike was supported by a grant from the British Lung Foundation.
Videholm et al.29	Sweden	Population-based retrospective cohort	Data from the Swedish Medical Birth Register, the National Inpatient Register, the Cause of Death Register, the Total Population Register, and the Longitudinal integration database for health insurance and labor market studies.	838,756	Age of 5 years	Maternal age, maternal education level, maternal smoking, parity, geographic region, and time trends (year of birth).	This study was supported by a grant from the Oskarsfonden (Box 36, 932 51 Bureå, Sweden).
Gutvirtz et al.30	Israel	Population-based retrospective cohort	Singleton deliveries from a single regional tertiary medical center (Soroka University Medical Center).	249,840	Up to first hospitalization for infection morbidity or 18 years of age.	Maternal age, maternal hypertensive disorders of pregnancy (chronic hypertension, gestational or pre-eclampsia with or without severe features, and eclampsia), maternal diabetes mellitus (pregestational and gestational), chorioamnionitis during labor, preterm delivery, birthweight, lack of prenatal care, and mode of delivery	Not available
Gutierrez et al.31	U.S.	Prospective birth cohort	Boston Birth Cohort: Predominantly urban, low-income minority cohort recruited at birth in the Boston Medical Centre. Data points sourced from epidemiologic questionnaires, EMR, and clinical measurements at all primary care visits.	2,790	Age of 12 months	Maternal factors: Maternal age at delivery, race/ethnicity, parity, maternal smoking during pregnancy, education level, and cardiometabolic conditions during pregnancy (chronic and gestational diabetes, hypertensive disorders of pregnancy). Child and birth factors: Gestational age at birth, season of birth, delivery type, and breastfeeding (ever breastfed versus never breastfed) during the first year of life.	Johns Hopkins School of Medicine; the Academy of Allergy, Asthma and Immunology Foundation; NIH

EMR, electronic medical record.