Association of fat mass and obesity-associated (FTO) gene rs9939609 with obesity-related traits and glucose intolerance in an indigenous population, the Xavante.

BACKGROUND AND AIMS: Common variants in fat mass and obesity-associated (FTO) gene have been implicated as a susceptibility locus for obesity and type 2 diabetes in different populations. Here, in an indigenous population-based study, we examined whether FTO rs9939609 has a role in susceptibility to glucose intolerance and obesity. METHODS: The study population comprised 949 full Xavante indigenous people (465 men) aged 18-99 years. The participants were submitted to clinical examination, anthropometrical measures and basal and 2-h post 75g oral glucose load capillary glucose measurements. FTO rs9939609 was genotyped and logistic regression was carried out to test the additive effect of the risk allele. RESULTS: The frequency of the minor allele of the FTO rs9939609 (0.06) was lower in Xavante than observed in some populations. A significant association between the variant and overweight was observed (OR = 1.56 (95% CI:1.06-2.29, p = 0.02), using an additive model of inheritance, adjusted by age and gender and considering the family structure. We found no associations with obesity or glucose intolerance. CONCLUSIONS: The FTO rs9939609 is associated with overweight, but not with obesity or glucose intolerance. The low frequency of the A allele suggests that it is not an important risk determinant for these conditions in Xavante indigenous people.

Serum 25-hydroxyvitamin D concentration and its association with glucose intolerance in an indigenous population.

BACKGROUND AND AIMS: Type 2 diabetes is a multifactorial disease resulting from diverse genetic and environmental factors as well as the interaction between them. Low levels of 25-hydroxyvitamin D [25(OH)D], an indicator of vitamin D status, have been associated with an increased risk of type 2 diabetes, but not consistently. Also, it remains to be determined if this association differs among ethnic groups. Therefore, we aimed to evaluate vitamin D status and its association with glucose intolerance in a Brazilian indigenous population, the Xavante Indians. METHODS: The study population consisted of 819 full Xavante Indians (410 women), aged ≥18 years and living in two indigenous reserves located in Mato Grosso State, central region of Brazil. Clinical examination and anthropometrical measurements were made, blood samples were obtained for total cholesterol, HDL-cholesterol, triglycerides and 25(OH)D measurement. Fasting and 2-h post 75 g oral glucose load capillary glucose was measured. Vitamin D status was defined by serum 25(OH)D levels: vitamin D sufficiency (25(OH)D: 30-100 ng/mL), vitamin D insufficiency (25(OH)D: 20- <30 ng/mL) and vitamin D deficiency (25(OH)D: < 20 ng/mL). Multiple logistic regression was performed to identify independent associations between 25(OH)D levels and impaired glucose tolerance or diabetes mellitus. RESULTS: Analyses stratified by 25(OH)D levels shows that 65.5% of the population had vitamin D deficiency/insufficiency (25(OH)D < 30 ng/mL). 25(OH)D concentrations were lower in individuals with impaired glucose tolerance or diabetes mellitus than in normal glucose tolerant individuals. Multiple logistic regression analysis showed an inverse association between increments of 25(OH)D and presence of diabetes mellitus (OR per 1 ng/mL increase in 25(OH)D: 0.97; 95% confidence interval: 0.95-0.99), or impaired glucose tolerance (OR per 1 ng/mL increase in 25(OH)D: 0.87; 95% confidence interval: 0.85-0.89), in an age, sex, BMI and season of sampling-adjusted model. CONCLUSIONS: The present population-based study found a high prevalence of hypovitaminosis D among Xavante Indians. In this at-risk population of type 2 diabetes, a significant association of higher serum 25(OH)D with a decreased prevalence of diabetes mellitus and impaired glucose tolerance was observed.

Diabetic retinopathy among Brazilian Xavante Indians.

BACKGROUND: To describe the frequency of diabetic retinopathy (DR) and its associated variables in Brazilian Xavante Indians. METHODS: A population-based survey carried out in two Xavante Reservations between 2008 and 2012, included 948 Indians aged 20 years or more, identified 246 individuals with type 2 diabetes. A non-probabilistic cluster sample of 140 diabetic individuals were submitted to ophthalmologic examination. Due to operational conditions and to optimize the field work, only the larger Xavante villages were included. Ophthalmologic examinations were performed during one trip to each reservation, in their villages and consisted of measurement visual acuity, anterior segment biomicroscopy, applanation tonometry, and direct and indirect ophthalmoscopy. RESULTS: The frequency of DR was 19.3%, distributed as follows: mild non-proliferative retinopathy in nine (33.3%) subjects, moderate in nine (33.3%), severe in six (22.3%), very severe in two (7.4%), and high-risk proliferative DR in one (3.7%). The occurrence of DR was higher among those with a longer duration of diabetes, higher levels of glycated hemoglobin (HbA1c) and fasting glucose, papillary excavation ≥ 0.5, and among individuals in older age group. Using the log-binomial regression model, diabetes duration > 24 months and HbA1c ≥ 6.5% were significantly associated with the occurrence of DR. CONCLUSIONS: The presence of DR (19.3%) in Xavante Indians is an alert for health care providers for this population, since diabetes is a new disease among them. Its association with disease duration, high levels of HbA1c and blood glucose calls attention for the necessity of more actions to improve diabetes control in this recently contacted ethnic group that needs particular attention.

High prevalence of type 2 diabetes mellitus in Xavante Indians from Mato Grosso, Brazil.

OBJECTIVE: To estimate the prevalence of diabetes, hypertension, obesity, and describe demographic, anthropometric and medical characteristics, in a genetically distinct population: the Brazilian Xavante Indians. DESIGN: Population-based survey carried out among 948 Xavante from Mato Grosso, Brazil. Fasting and 2-hour after 75 g glucose capillary glycemia were measured by a portable glucometer (HemoCue Glucose201+). Diabetes was defined according to WHO criteria. Anthropometric data and medical characteristics were measured, and fat mass (%) was evaluated using bioelectrical impedance. Blood pressure was measured by an automated device (OMRON 742INTC), and hypertension was defined according to WHO criteria. RESULTS: Age-adjusted prevalence rates with 95% confidence intervals were diabetes: 28.2% (25.3-31.1) in general, 18.4% (14.9-22.2) in men and 40.6% (36.2-45.1) in women (P<.001); impaired glucose tolerance: 32.3% (20.5-26.0) in general, 29.7% (25.4-33.9) in men and 34.4% (30.2-38.8) in women (P>.05); hypertension: 17.5% (15.1-19.9) in general. Obesity was found in 50.8% of the individuals. Fat mass (%) was associated with diabetes in men (P<.05) and women (P<.05). Thigh circumference and waist/ thigh ratio were lower in those with diabetes, in men and women (P<.001). CONCLUSIONS: The high prevalence of diabetes and obesity in Xavante is likely related to their recent change in food habits and physical activities. Our results should raise awareness about the magnitude of this health problem and also indicate that it could increase dramatically in the future if no preventive actions are adopted.

Prevalence of the metabolic syndrome using two proposed definitions in a Japanese-Brazilians community.

Metabolic Syndrome (MetS) is associated with increased risk of morbi-mortality, thus the characterization of the population magnitude of this syndrome is critical for allocating health care. However, prevalence estimates of MetS in the same population could differ depending on the definition used. Therefore, we compared the prevalence of the MetS using definitions proposed by: National Cholesterol Education Panel Revised (NCEP) and International Diabetes Federation (IDF) 2009 in a Japanese-Brazilians community (131 individuals, age 57 ± 16 years, 1st and 2nd generation). All individuals went through a clinical and laboratorial evaluation for assessment of weigh, height, waist circumference, blood pressure, triglycerides, HDL-cholesterol and fasting plasma glucose. The prevalence of MetS was 26.7% (n = 35) and 37.4% (n = 49) under the NCEP and IDF definitions, respectively. Despite higher blood pressure measurements, waist circumference and serum triglyceride levels and lower HDL cholesterol levels (p < 0.01), individuals identified with MetS did not show increased blood glucose levels. IDF definition classified 14 individuals (10.7%) with MetS that were not classified under the NCEP and 35 individuals were identified with MetS by both criteria. We observed, in this group, more severe lipid disorders, compared to individuals identified only under the IDF definition, and the BMI and waist circumference (p = 0.01; p = 0.006, respectively) were lower. In conclusion, the IDF revised criteria, probably because of the ethnic specific values of waist circumference, was able to identify a larger number of individuals with MetS. However, our data suggesting that additional studies are necessary to define best MetS diagnostic criteria in this population.