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The minor allele (A) of the rs373863828 variant (p.Arg457Gln) in CREBRF is restricted to indigenous peoples of the Pacific islands (including New Zealand Māori and peoples of Polynesia), with a frequency up to 25% in these populations. This allele associates with a large increase in body mass index (BMI) but with significantly lower risk of type-2 diabetes (T2D). It is unclear whether the increased BMI is driven by increased adiposity or by increased lean mass. Hence, we undertook body composition analysis using DXA in 189 young men of Māori and Pacific descent living in Aotearoa New Zealand. The rs373863828 A allele was associated with a trend toward increased relative lean mass although this was not statistically significant (p=0.06). Notably though this allele was associated with significantly lower circulating levels of the muscle inhibitory hormone myostatin (p

AimThe minor A allele of rs373863828 (CREBRF p.Arg457Gln) is associated with increased body mass index (BMI), but reduced risk of type 2 and gestational diabetes in Polynesian (Pacific peoples and Aotearoa New Zealand Māori) populations. This study investigates the effect of the A allele on insulin release and sensitivity in overweight/obese men without diabetes.MethodsA mixed meal tolerance test was completed by 172 men (56 with the A allele) of Māori or Pacific ancestry, and 44 (24 with the A allele) had a frequently sampled intravenous glucose tolerance test and hyperinsulinemic-euglycemic clamp. Mixed linear models with covariates age, ancestry and BMI were used to analyse the association between the A allele of rs373863828 and markers of insulin release and blood glucose regulation.ResultsThe A allele of rs373863828 is associated with a greater increase in plasma insulin 30 min following a meal challenge without affecting the elevation in plasma glucose or incretins GLP-1 or GIP. Consistent with this point, following an intravenous infusion of a glucose bolus, participants with an A allele had higher early (prs373863828 genotype was not associated with a significant difference (p>0.05) in insulin sensitivity index or glucose disposal during hyperinsulinemic-euglycemic clamp.Conclusion/interpretationrs373863828-A allele associates with increased glucose-stimulated insulin release without affecting insulin sensitivity, suggesting that CREBRF p.Arg457Gln may increase maximal ability for β-cells to release insulin to reduce the risk of type 2 diabetes.

INTRODUCTION: Patients with irritable bowel syndrome (IBS) identify food as a trigger for the onset or worsening of gastrointestinal symptoms. Despite this, there is no published validated contemporaneous food and symptom diary to investigate the association between diet and IBS symptoms. The objective of this prospective observational study was to assess the construct validity of a novel food diary and symptom questionnaire, the Food and Symptom Times (FAST) diary, and the predictive validity of the food diary component with relation to fiber and fermentable oligosaccharides, disaccharides, monosaccharides, and polyols consumption and subsequent gastrointestinal symptoms. METHODS: Fifty-one participants with IBS completed the FAST diary and several legacy instruments. The relationship between the FAST gastroenterological symptoms and legacy instruments was examined using Spearman correlation coefficients. Further statistical analysis investigated the relationship between diet and postprandial gastrointestinal symptoms. RESULTS: Consistent with a priori predictions, the FAST symptoms showed moderate correlations with the most similar Patient-Reported Outcome Measurement Information System gastrointestinal scales (0.328–0.483, P < 0.05) and the most similar Gastrointestinal Symptom Rating Scale questions (0.303–0.453, P < 0.05), with the exception of the weakly correlated subscale constipation for both instruments (−0.050 to −0.119, P > 0.05). The IBS-Quality of Life instrument showed moderate correlations with the FAST symptom abdominal swelling/distension (0.313–0.416, P < 0.05). The consumption of a high fermentable oligosaccharides, disaccharides, monosaccharides, and polyols meal was associated with participants with IBS-D experiencing abdominal bloating and participants with IBS-C not experiencing abdominal swelling (P < 0.05). The consumption of fiber was correlated with abdominal fullness and bloating in participants with IBS-C (P < 0.05). DISCUSSION: The FAST diary validly measures gastrointestinal symptoms as they occur in people with IBS and correlates these symptoms with specific aspects of diet.