OBJECTIVETwins in Africa may be at increased risk of metabolic disorders due to strained conditions in utero, including high exposure to infections. We studied metabolic syndrome (MS) and diabetes mellitus (DM) among young twins and singletons in Guinea-Bissau.RESEARCH DESIGN AND METHODSThe study was cross-sectional and occurred from October 2009 until August 2011 at the Bandim Health Project, a demographic surveillance site in the capital Bissau. Twins and singleton controls between 5 and 32 years were visited at home. Fasting blood samples for metabolic measurements were collected. Zygosity was established genetically for a subset. DM was defined as HbA1c ≥6.5% (48 mmol/mol) and MS by the International Diabetes Federation criteria.RESULTSHbA1c was available for 574 twins and 463 singletons. Mean age was 15.3 years versus 15.8 years, respectively. Eighteen percent of twins were monozygotic. There were no DM cases among twins but one among singletons. A total of 1.4% (8 of 574) of twins had elevated HbA1c (6.0–6.4%, 42–46 mmol/mol) compared with 2.4% (11 of 463) of singletons (P = 0.28). Mean HbA1c was 5.3% (34 mmol/mol) for both groups. MS data were available for 364 twins and 360 singletons. The MS prevalence was 3.0% (11 of 364) among twins and 3.6% (13 of 360) among singletons (P = 0.66). The prevalence of fasting blood glucose (F-glucose) ≥5.6 mmol/L was 34.9% (127 of 364) for twins versus 24.7% (89 of 360) for singletons (P = 0.003). Median homeostasis model assessment–insulin resistance did not differ (P = 0.34).CONCLUSIONSThe MS and DM prevalences among young individuals in Guinea-Bissau were low. Twins did not have a higher MS and DM burden than singletons, though elevated F-glucose was more common among twins.

BackgroundTwins may be at increased risk of dysglycaemic disorders due to adverse fetal conditions. Data from Africa regarding this association is limited. We studied impaired glucose tolerance (IGT) and other types of dysglycemia among twins and singletons in Guinea-Bissau.MethodsThe study was conducted from February 2011 until March 2012 at the Bandim Health Project, a health and demographic surveillance system site in the capital Bissau. Twins (n = 209) and singletons (n = 182) were recruited from a previously established cohort. Oral glucose tolerance tests (OGTT) were performed, along with anthropometrics and collection of clinical and dietary data.ResultsMedian age was 16.6 and 14.2 years between twins and singletons, respectively (P = 0.08). Mean birth weight was 2410 vs. 3090 g, respectively (P < 0.001). Twins had higher median fasting- and two hour capillary plasma glucose, 5.4(3.2–8.2) vs. 5.0(3.2–11.5) mmol/L (P < 0.001) and 6.8(3.4–11.3) vs. 6.2(3.2–12.1) mmol/L (P < 0.001), respectively, compared to singletons. The prevalence of IGT was 2.5 % (5/209) vs. 3.5 % (6/182) (RR = 0.73, 95 % CI: 0.20–2.64). 12 % (25/209) of twins had impaired fasting glucose (IFG), compared to 3.5 % (6/182) of singletons (3.63, 1.53–8.62). Dysglycemia (IGT and/or IFG or overt diabetes) was found in 17 % (35/209) vs. 9 % (16/182) (1.90, 1.08–3.37), respectively.ConclusionsTwins had higher glucose levels in both the fasting and postprandial state. This may indicate a detrimental effect of the twin fetal environment on glucose metabolism later in life, a result contrary to Scandinavian register studies. The IGT burden was low in this young age group and the risk was similar in twins and singletons.Electronic supplementary materialThe online version of this article (doi:10.1186/s12902-016-0126-6) contains supplementary material, which is available to authorized users.

Sub-Saharan Africa has the highest natural twinning rate in the world. Unfortunately, due to lack of adequate care during pregnancy, labor and postnatally, twin mortality in Sub-Saharan Africa also remains very high. Thus, it has been estimated that one in five twins dies during the childhood years. In spite of this, surprisingly few twin studies have been conducted in the region, making additional epidemiological data much needed. In 2009, we established one of the first twin registries in Sub-Saharan Africa at the Bandim Health Project in Guinea-Bissau. The registry had two main objectives. First, we wanted to describe the twinning rate and mortality patterns among newborn twins, including mortality risk factors and hospitalization patterns. Such studies can help the local clinicians improve twin health by identifying the most vulnerable children. Second, and in light of the rapidly increasing diabetes rates in Africa, we wanted to use the registry to particularly focus on metabolic disorders. Twins are often born with low birth weight, which according to the ‘thrifty phenotype hypothesis’ could predispose them to metabolic disorders later in life. Yet, no such ‘fetal programming’ data have previously been available from African twins despite the fact that nutritional patterns and influences from other factors (e.g., infections) could be markedly different here compared to high-income settings. In this article, we summarize the findings and current status of the Guinea-Bissau twin registry.