Prevalence of impaired glucose tolerance and other types of dysglycaemia among young twins and singletons in Guinea-Bissau

Background Twins 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. Methods The 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. Results Median 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. Conclusions Twins 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.