Worms or sugar? Mass deworming treatment doubles the probability to suffer from diabetes ten to fifteen years later

Mass deworming has long been promoted as a cost-effective device to improve health status and educational attainment of children. Recent contributions suggest that they would in addition increase lifetime earnings of individuals. However, recent medical research emphasizes the role played by the gut microbiome and helminths in particular – colloquially termed worms – on the prevention of metabolic syndromes and inflammatory diseases including Type-2 diabetes. We use publicly available data from the Kenya Life Panel Survey (rounds 2 and 3) that follows a representative sample of children initially part of the Primary School Deworming Project randomized experiment 10 and 15 years after the intervention and study the impact of deworming on diabetes. We find that children who were enrolled in early treated schools and received two to three additional years of deworming treatment are twice more likely to declare suffering from diabetes 10 to 15 years later (n=31 for 6,390 treated individuals) than individuals in the control group (n=7 for 3,284 individuals). Our results are consistent with a protective effect of worm infection against diabetes and suggest potential adverse long-term health impacts of mass deworming administration. Given the cost of diabetes treatment in low and middle-income countries, the cost-benefit balance of mass deworming may need to be reevaluated.