I question whether the researchers had a control group with loads of mercury fillings in their mouths, or they researched whether or not their subjects were vaccine enthusiasts.
"Laboratory studies suggest that exposure to methylmercury at a level similar to those found in fish may induce pancreatic islet β-cell dysfunction. Few, if any, human studies have examined the association between mercury exposure and diabetes incidence. We examined whether toenail mercury levels are associated with incidence of diabetes in a large prospective cohort. RESEARCH DESIGN AND METHODS: A prospective cohort of 3,875 American young adults, aged 20-32 years, free of diabetes in 1987 (baseline), were enrolled and followed six times until 2005. Baseline toenail mercury levels were measured with instrumental neutron-activation analysis. Incident diabetes was identified by plasma glucose levels, oral glucose tolerance tests, hemoglobin A1C levels, and/or antidiabetes medications."
http://www.ncbi.nlm.nih.gov/pubmed/23423697
"Laboratory studies suggest that exposure to methylmercury at a level similar to those found in fish may induce pancreatic islet β-cell dysfunction. Few, if any, human studies have examined the association between mercury exposure and diabetes incidence. We examined whether toenail mercury levels are associated with incidence of diabetes in a large prospective cohort. RESEARCH DESIGN AND METHODS: A prospective cohort of 3,875 American young adults, aged 20-32 years, free of diabetes in 1987 (baseline), were enrolled and followed six times until 2005. Baseline toenail mercury levels were measured with instrumental neutron-activation analysis. Incident diabetes was identified by plasma glucose levels, oral glucose tolerance tests, hemoglobin A1C levels, and/or antidiabetes medications."
http://www.ncbi.nlm.nih.gov/pubmed/23423697