Income-related inequities in the progression from gestational to type 2 diabetes

Aims: Previous studies suggest that individuals from low-income households are at a higher risk of developing type 2 diabetes (T2D), but it remains unclear whether lower socioeconomic status affects the risk of postpartum T2D in women with gestational diabetes mellitus (GDM). This study aimed to explore whether the risk of T2D differs among women with a history of GDM across income levels. Materials and methods: Using data from the Taiwan Maternal and Child Health Database, we identified 154 631 mothers with GDM between 1 January 2009 and 31 December 2017. We applied crude and multivariable-adjusted logistic regression models to assess the risk of postpartum T2D across different income levels. Results: Among 154 631 mothers with GDM, 701 (0.45%) had very low income, 51 990 (33.62%) had low income, 81 575 (52.75%) had middle income, and 20 365 (13.17%) had high income. The mean maternal age was 31.95 years (SD = 4.73 years). Compared to the middle-income group, mothers with GDM and very low income had a higher risk of postpartum T2D (adjusted hazard ratio [aHR]: 1.86; 95% CI: 1.28–2.71), as did those with low income (aHR: 1.20; 95% CI: 1.12–1.29). Conversely, those with high income had a lower risk (aHR: 0.74; 95% CI: 0.66–0.83). Kaplan–Meier analysis showed a higher risk of postpartum T2D in lower-income groups (log-rank p < 0.0001). Conclusions: This study demonstrates that women with GDM and low family income have a significantly increased risk of postpartum T2D. These findings highlight the need for targeted prevention and follow-up care for this high-risk group.