Indicators of socio-economic status and risk of gestational diabetes mellitus in pregnant women in urban Tianjin, China

Aims: To examine associations between the indicators of socio-economic status (SES) and gestational diabetes mellitus (GDM). Methods: From 2010 to 2012, 17 659 women underwent glucose challenge test (GCT) and oral glucose tolerance test if GCT ≥ 7.8 mmol/L at 24–28 gestational weeks in 6 urban districts of Tianjin, China. Binary logistic regression was used to obtain adjusted odds ratio (OR) of SES for GDM, as defined by education attainment and family monthly income. Results: A total of 1264 women (7.2%) were found to have GDM. If the women with low-middle income and high school or below used as the reference group, the middle-high income group and the high income group were associated with decreased risks of GDM (OR: 0.85, 95%CI: 0.71–1.00 & 0.80, 0.65–0.98) while tertiary education attainment was associated with decreased risk of GDM (0.75, 0.58–0.97). Women with higher income and/or higher education attainment tended to have a decreased risk of GDM (P for trend: 0.0105). All these significant ORs were attenuated to be non-significant by adjustment for pre-pregnancy body mass index (BMI), but not by adjustment for gestational weight gain (GWG). Conclusions: In urban Tianjin, indicators of high SES were associated with decreased risk of GDM via decreased pre-pregnancy BMI.