A large prospective study examining 146,046 participants in Mexico City found that diabetes mellitus is associated with a far worse prognosis in this population than in populations that were analyzed in previous studies conducted primarily in high-income countries. Around a quarter of participants aged 60–74 years were diagnosed with diabetes mellitus. Individuals with diabetes mellitus had a fourfold higher all-cause mortality than participants without diabetes mellitus, in contrast to patients with diabetes mellitus from high-income countries, who have a less-than-twofold increased mortality. The team suggest that inadequate medical care contributes to this difference; participants with diabetes mellitus had poor glycaemic control, with a baseline HbA1c >10% in 36% of patients, and rates of treatment with antihypertensive and lipid-lowering drugs were low.