The role of a traditional and western diet on glucose homeostasis in Greenlandic Inuit carriers and non-carriers of type 2 diabetes variant in the TBC1D4 gene: A protocol for a randomized clinical trial

Abstract

Introduction The lifestyle of Inuit in Greenland and worldwide is undergoing a transition from a fisher-hunter to a westernized society and meanwhile the prevalence of type-2 diabetes (T2D) has increased dramatically. Studies have shown that a common nonsense p.Arg684Ter variant in TBC1D4, which is frequent in Greenland, confers genetic susceptibility towards high risk of T2D. The aim of the study is to investigate whether a traditional marine diet, with high fat and low carbohydrate, will improve glycemic control in Greenland Inuit compared to a western diet. Moreover, we want to examine if the response is more pronounced in carriers of the p.Arg684Ter variant. Materials and methods We will conduct a randomized, clinical cross-over trial with two dietary intervention periods of four weeks duration. The diet intervention comprise provision of >20E% and instruction for the remaining part of the diet. We expect to include 30 homozygous carriers and 30 homozygous non-carriers of the p.Arg684Ter variant, aged 18–80 years, across three Greenlandic towns. The primary outcome is plasma (p)-glucose 2 h post an oral glucose tolerance test and we aim to have 80% power, at α = 0.05, to detect a difference of 1.1 mmol/L. We will also include supporting measures of glucose homeostasis, assess other markers of the metabolic syndrome and perform metabolome and microbiome profiling. The statistical analysis will be performed as complete case analyses using linear mixed models. Ethics and dissemination The study received approval by the Ethics Committee of Greenland (KVUG 2018-26) and will be disseminated via international peer-reviewed journal articles and conferences. Trial registration number Clinicaltrials.gov identifier no. NCT04011904.

Food Reward after a Traditional Inuit or a Westernised Diet in an Inuit Population in Greenland

“…The strengths of this study include the novelty of examining food reward in a remote area of the world as part of the first and largest interventional study on the effects of a TID on glucose homeostasis and metabolic health markers [ 17 ]. Conducting health-related studies in this population is challenging due to the infrastructure across the country, limited access to health care resources, technology, and devices, as well as language and cultural barriers, which makes this a unique opportune dataset to study.…”

“…This analysis included only participants who performed the LFPQ after the first intervention period. The trial is registered at ClinicalTrials.gov (NCT04011904), approved by the Ethics Committee of Greenland (KVUG 2018-26), and described in detail elsewhere [ 17 ]. Out of three study locations (Nuuk, Qaanaaq, and Qasigiannguit) in Greenland, this subgroup included participants from Qaanaaq and Qasigiannguit in north-western and western Greenland, respectively.…”

The effect of traditional diet on glucose homoeostasis in carriers and non-carriers of a common TBC1D4 variant in Greenlandic Inuit: a randomised crossover study

“…Written consent was obtained from participants after receiving written and oral study information in Greenlandic or Danish, as appropriate. The study was registered at ClinicalTrials.gov (NCT04011904), although after enrollment began due to administrative error, and the study protocol has been published (17) .…”

“…Following informed consent, participants were screened according to inclusion and exclusion criteria (see protocol article (17) ). Briefly, they were required to be aged 18 to 80 years and speak Greenlandic and/or Danish.…”

“…For the remaining dietary intake, participants were provided with basic written instructions encouraging adherence to the appropriate dietary pattern. For further details on the diets, refer to the protocol article (17) . In both periods, participants were asked to limit alcohol intake and maintain a basic food log to assess dietary adherence.…”