Assessing the trend of diabetes mellitus by analyzing metformin as a biomarker in wastewater

Abstract According to International Diabetes Federation estimates, China has the highest rate of diabetes in the world. To monitor the prevalence of diabetes mellitus (DM) in near real-time, a first-line medication for the treatment of type 2 diabetes, metformin, was used. Wastewater-based epidemiology (WBE) was applied to estimate the consumption of metformin in Dalian from 2015 to 2018. Quantification of metformin was undertaken using solid-phase extraction (SPE) and N -methyl-bis (trifluoroacetamide) derivatization prior to GC–MS analysis. The concentrations of metformin in eleven wastewater treatment plants (WWTPs) ranged from 1.7 μg/L to 239.0 μg/L, with an average value of 68.3 μg/L. For metformin consumption, there was a gradual increase from 12.1 mg/d/capita in 2015 to 28.4 mg/d/capita in 2018. Meanwhile, the prevalence of metformin in the Dalian population ranged from 1.6% in 2015 to 3.8% in 2018. Similarly, the prevalence of DM showed an increasing trend from 12.2% in 2015 to 21.6% in 2018, which is consistent with the data predicted by traditional surveys (15.2–19.8%). Additionally, the prevalence of DM in 2015 estimated based on WBE was 12.2%, which agreed with the results from the traditional survey (12.3%). These results indicated that the proposed method provided a feasible way to reveal the prevalence of DM through metformin monitoring by the WBE approach.