BackgroundFor more than half a century, there has been much research and controversies on how to accurately screen for and diagnose gestational diabetes mellitus (GDM). There is a paucity of updated research among the Emirati population in the United Arab Emirates (UAE). The lack of a uniform GDM diagnostic criteria results in the inability to accurately combine or compare the disease burden worldwide and locally. This study aimed to compare the incidence of GDM in the Emirati population using six diagnostic criteria for GDM.MethodsThe Mutaba’ah study is the largest multi-center mother and child cohort study in the UAE with an 18-year follow-up. We included singleton pregnancies from the Mutaba’ah cohort screened with the oral glucose tolerance test (OGTT) at 24–32 weeks from May 2017 to March 2021. We excluded patients with known diabetes and with newly diagnosed diabetes. GDM cumulative incidence was determined using the six specified criteria. GDM risk factors were compared using chi-square and t-tests. Agreements among the six criteria were assessed using kappa statistics.ResultsA total of 2,546 women were included with a mean age of 30.5 ± 6.0 years. Mean gravidity was 3.5 ± 2.1, and mean body mass index (BMI) at booking was 27.7 ± 5.6 kg/m2. GDM incidence as diagnosed by any of the six criteria collectively was 27.1%. It ranged from 8.4% according to the EASD 1996 criteria to 21.5% according to the NICE 2015 criteria. The two most inclusive criteria were the NICE 2015 and the IADPSG criteria with GDM incidence rates of 21.5% (95% CI: 19.9, 23.1) and 21.3% (95% CI: 19.8, 23.0), respectively. Agreement between the two criteria was moderate (k = 0.66; p < 0.001). The least inclusive was the EASD 1996 criteria [8.4% (95% CI: 7.3, 9.6)]. The locally recommended IADPSG/WHO 2013 criteria had weak to moderate agreement with the other criteria, with Cohen’s kappa coefficient ranging from (k = 0.51; p < 0.001) to (k = 0.71; p < 0.001). Most of the GDM risk factors assessed were significantly higher among those with GDM (p < 0.005) identified by all criteria.ConclusionsThe findings indicate discrepancies among the diagnostic criteria in identifying GDM cases. This emphasizes the need to unify GDM diagnostic criteria in this population to provide accurate and reliable incidence estimates for healthcare planning, especially because the agreement with the recommended criteria was not optimal.

Focus of Presentation There has been a lot of confusion among epidemiologists, especially students and early career epidemiologists, on definitions of prospective and retrospective cohort studies versus the actual practice. Many retrospective studies are reported and reviewed as prospective studies, and this is expected to lead to drawing wrong conclusions from studies, as well as leading to the disruption of the evidence-based hierarchy especially when it comes to systematic reviews and meta-analysis. There is a need, therefore, for consensus by the expert community to clarify every aspect of this issue. Findings Most epidemiological textbooks define prospective cohort study as a type of cohort study where researchers develop and conduct the study on all subjects before they start developing outcomes while in retrospective cohort study, the researchers go back in time to study exposure history for subjects whom at least some of them have developed the outcomes. Some experts, though, define both study types based on the time of development of the hypothesis or research question in relation to data collection. That is, those who develop the research question before data collection are considered to be conducting a prospective study and it is a retrospective study when developed after data collection (Miettinen, O.S. 1985). In some cases, retrospective studies are defined as the cohort studies whose data collections are from the records or historical data, while prospective studies are when data are collected prospectively (Setia M.S. 2016). Meanwhile, some experts consider any follow up study to be prospective even if historical data is used while they define retrospective studies as case control studies (Last, J.M. 2000, Doll, R. and Hill, A.B. 1954) These disparities in definitions lead to confusion among young epidemiologists as to which study type, they are conducting. This leads to the question of how important it is to differentiate the two study types. Is it really necessary? Does it affect my study results? Some experts are of the opinion that the need to differentiate between the two is minimal, as a retrospective cohort study conducted very well could be superior to an average prospective one in terms of evidence-based hierarchy. And due to the ambiguity and inconsistent nature of these labels, some even recommend abandoning the labels all together (Wylie C. E. 2015, Vandenbroucke, J.P. 1991). However, we are aware that data collected in retrospective studies might be prone to issues like incomplete records, recall bias and confounding, thereby leading to decreased internal validity of studies. This could be averted if the same study were conducted retrospectively. Conclusions/Implications It has become apparent that it is very essential for the expert community to address this methodological issue in Epidemiology and try to reach some consensus on this matter with regards to whether these subdivisions should be maintained and if so, how they should be uniformly defined and also to have a standard uniform methodological guideline that could be used internationally. This could serve as a guide for young epidemiologists and could ensure the uniformity of research worldwide. Key messages There is a confusion, especially among young epidemiologist on the definitions and use of prospective and retrospective cohort studies Expert community, especially the International Association of Epidemiology, should address these concerns and if possible, have a consensus to form a standard guideline.

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Gestational diabetes mellitus (GDM) burden is burgeoning globally. Correct knowledge about GDM among young people is paramount for timely prevention. This study assesses GDM knowledge and identifies factors associated with it among United Arab Emirates (UAE) University students. A validated self-administered questionnaire collected data from the university students. We analyzed the data for GDM knowledge status (ever heard of GDM) and GDM knowledge levels (poor, fair, and good) and conducted ordinal logistic regressions to assess for associated factors. A total of 735 students were surveyed with a mean age of 21.0 years. Of these, 72.8% had heard of GDM, and 52.9% of males versus 20.3% of female students had never heard of the condition before. Higher age (p = 0.019) and being a postgraduate student (p = 0.026) were associated with higher GDM knowledge status in males. GDM knowledge level analysis showed that 24.0%, 58.5%, and 17.5% had poor, fair, and good knowledge. The mean GDM-knowledge score was 6.3 ± 2.4 (out of 12). Being married [aOR-1.82 (95%CI 1.10–3.03)] and knowing someone who had GDM [aOR-1.78 (95%CI 1.23–2.60)] were independently associated with higher GDM knowledge levels among students. Students’ primary source of GDM knowledge was family/friends. There is an observed knowledge gap related to GDM among the students, especially males. This study urges the need to accelerate targeted GDM awareness campaigns among university students and the general population in the UAE.

Focus of Presentation There is a confusion among epidemiologists, especially early-career epidemiologists, on the different definitions and use of prospective and retrospective cohort studies. There is a need for consensus by the expert community on this methodological dilemma. Findings Different Epidemiology experts define prospective and retrospective cohort studies differently. Most textbooks define prospective cohort study as one conducted when all the subjects are outcome-free while in retrospective cohort study, at least some of them have developed the outcomes, then researchers go back in time to study exposures. However, some experts define both study types based on the time of development of the research hypothesis or question in relation to data collection. Some experts consider retrospective studies to be only from records. Meanwhile, some consider any follow up study to be prospective even if historical data is used. These disparities in definitions lead to confusion among young epidemiologists. Some experts state that there is no need to differentiate between the two studies, however, we are aware of the possible bias and confounding that could occur from retrospective studies. Conclusions/Implications It has become essential for the expert community to address this methodological dilemma and to reach consensus on it. This could serve as a guide for young epidemiologists and ensure the uniformity of research worldwide. Key messages There are disparities in definitions and use of prospective and retrospective cohort studies. Hence, the expert community, especially the International Association of Epidemiology, should address this dilemma and reach a consensus to form standard guidelines.