Objective To estimate the risk for adverse perinatal outcomes for women who met the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria but not the two‐step criteria for gestational diabetes mellitus (GDM). Design Population‐level cross‐sectional study. Setting Ontario, Canada. Population A total of 90 140 women who underwent a 75‐g oral glucose tolerance test. Methods Women were divided into those who met the diagnostic thresholds for GDM by two‐step criteria and were therefore treated, those who met only the IADPSG criteria for GDM and so were not treated, and those who did not have GDM by either criteria. Main outcome measures Hypertensive disorders of pregnancy, preterm delivery, primary caesarean section, large‐for‐gestational‐age, shoulder dystocia and neonatal intensive care unit admission. Results Women who met the IADPSG criteria had an increased risk for all adverse perinatal outcomes compared with women who did not have GDM. Women with GDM by two‐step criteria also had an increased risk of most outcomes. However, their risk for large‐for‐gestational‐age neonates and for shoulder dystocia was actually lower than that of women who met IADPSG criteria. Conclusion Women who met IADPSG criteria but who were not diagnosed with GDM based on the current two‐step diagnostic strategy, and were therefore not treated, had an increased risk for adverse perinatal outcomes compared with women who do not have GDM. The current strategy for diagnosing GDM may be leaving women who are at risk for adverse events without the dietary and pharmacological treatments that could improve their pregnancy outcomes. Tweetable abstract Women who meet IADPSG criteria for GDM have an increased risk for adverse perinatal outcomes compared with women without GDM.

We report the incidence of cardiovascular events, mortality and risk factors (diabetes and hypertension) in immigrants from Iran and in non-Iranian immigrants from the Middle East. Using population-based healthcare administrative data, all immigrants from the Middle East and the non-immigrant population of Ontario, Canada as of July 2012 were identified. Baseline differences in diabetes and hypertension prevalence were compared. Outcomes were ascertained through March 2016 and included the incidence of acute coronary events, ischemic heart disease mortality, all-cause mortality, and incident diabetes and hypertension. The study population included 55,539 Iranian immigrants, 106,926 non-Iranian Middle Eastern immigrants, and 6,967,132 non-immigrants. Non-immigrants had the highest crude baseline prevalence of diabetes and hypertension. Compared to non-immigrants, Iranian and non-Iranian Middle Eastern immigrants had significantly lower incidence rate of acute coronary events, ischemic heart disease mortality and all-cause mortality. Both Iranian and non-Iranian Middle Eastern immigrants had better cardiovascular health status than non-immigrants.