Table 2.

Confounders and risk factors evaluated in studies of included studies

Variables	Haervig et al, 2014[49]	Pottegard et al, 2014[52]	Bro et al, 2015[46]	Diav-Citrin et al, 2016[48]	Cohen et al, 2017[47]	Nörby et al, 2017[51]	Huybrechts et al, 2018[50]	Poulton et al, 2018[53]
Maternal age	×	×	×	×	×	×	×	×
Region	×				×	×
Ethnicity	×	×			×		×
Education		×	×
Body Mass Index, BMI		×			×	×
Cohabitation			×			×
Year of conception					×
Year of delivery						×	×	×
Year at initial contact				×
Gestational age				×
Parity/multiparty			×		×	×	×	×
Multifetal pregnancy					×		×	×
Smoking status		×	×		×	×		×
Alcohol use					×
Other drug abuse or dependence					×	×
Psychiatric conditions			×		×		×
Chronic comorbid medical conditions			×		×		×	×
Marker of general comorbidity					×		×
Prescribed medications/co-medications		×	×		×	×	×
Proxies for health care utilization intensity					×