Analysis of type 2 diabetes and obesity genetic variants in Mexican Pima Indians: Marked allelic differentiation among Amerindians at HLA

Connecting the dots in the associations between diet, obesity, cancer, and microRNAs

The prevalence of obesity has reached pandemic levels worldwide, leading to a lower quality of life and higher health costs. Obesity is a major risk factor for noncommunicable diseases, including cancer, although obesity is one of the major preventable causes of cancer. Lifestyle factors, such as dietary quality and patterns, are also closely related to the onset and development of obesity and cancer. However, the mechanisms underlying the complex association between diet, obesity, and cancer remain unclear. In the past few decades, microRNAs (miRNAs), a class of small non-coding RNAs, have been demonstrated to play critical roles in biological processes such as cell differentiation, proliferation, and metabolism, highlighting their importance in disease development and suppression and as therapeutic targets. miRNA expression levels can be modulated by diet and are involved in cancer and obesity-related diseases. Circulating miRNAs can also mediate cell-to-cell communications. These multiple aspects of miRNAs present challenges in understanding and integrating their mechanism of action. Here, we introduce a general consideration of the associations between diet, obesity, and cancer and review the current knowledge of the molecular functions of miRNA in each context. A comprehensive understanding of the interplay between diet, obesity, and cancer could be valuable for the development of effective preventive and therapeutic strategies in future.

Psychometric properties of the Arabic versions of the Three-Item Short Form of the modified Weight Bias Internalization Scale (WBIS-3) and the Muscularity Bias Internalization Scale (MBIS)

BACKGROUND

There is a lack of psychometrically sound measures to assess internalized weight and muscularity biases among Arabic-speaking people. To fill this gap, we sought to investigate the psychometric properties of Arabic translations of the Three-Item Short Form of the Modified Weight Bias Internalization Scale (WBIS-3) and the Muscularity Bias Internalization Scale (MBIS) in a sample of community adults.

METHODS

A total of 402 Lebanese citizens and residents enrolled in this cross-sectional study (mean age: 24.46 years (SD = 6.60); 55.2% females). Exploratory Factor Analysis (EFA) was conducted using the principal-axis factoring and oblimin rotation to estimate parameters and the parallel analysis to determine the number of factors. CFA was conducted using the weighted least square mean and variance adjusted estimator which was recommended for ordinal CFA.

RESULTS

An Exploratory Factor Analysis of the WBIS-3 resulted in a robust single-factor solution for the three items. An examination of the factorial structure of the MBIS revealed a two-factor structure, which showed adequate model fit. We obtained excellent internal consistency as indicated by McDonald's ω coefficients of .87 for the WBIS-3 total score and ranging between .92 and .95 for the MBIS two factor scores. Cross-sex invariance of the MBIS was confirmed at the configural, metric, and scalar levels. Convergent validity was supported by significant correlations between the WBIS-3 and MBIS. Divergent and concurrent validity were approved by showing small to medium correlations between MBIS/WBIS-3 scores and muscle dysmorphia, disordered eating symptoms, and body image concerns.

CONCLUSION

Findings suggest that the Arabic versions of the WBIS-3 and MBIS are suitable for use in Arabic-speaking adults.

Diagnostic criteria and etiopathogenesis of type 2 diabetes and its complications: Lessons from the Pima Indians

The Phoenix Epidemiology and Clinical Research Branch of the National Institute of Diabetes and Digestive and Kidney Diseases has conducted prospective studies of diabetes and its complications in the Pima Indians living in Arizona, USA for over 50 years. In this review we highlight areas in which these studies provided vital insights into the criteria used to diagnose type 2 diabetes, the pathophysiologic changes that accompany the development of type 2 diabetes, and the course and determinants of diabetes complications-focusing specifically on diabetic kidney disease. We include data from our longitudinal population-based study of diabetes and its complications, studies on the role of insulin resistance and insulin secretion in the pathophysiology of type 2 diabetes, and in-depth studies of diabetic kidney disease that include measures of glomerular function and research kidney biopsies. We also focus on the emerging health threat posed by youth-onset type 2 diabetes, which was first seen in the Pima Indians in the 1960s and is becoming an increasing issue worldwide.

A review of ancestrality and admixture in Latin America and the caribbean focusing on native American and African descendant populations

Genomics can reveal essential features about the demographic evolution of a population that may not be apparent from historical elements. In recent years, there has been a significant increase in the number of studies applying genomic epidemiological approaches to understand the genetic structure and diversity of human populations in the context of demographic history and for implementing precision medicine. These efforts have traditionally been applied predominantly to populations of European origin. More recently, initiatives in the United States and Africa are including more diverse populations, establishing new horizons for research in human populations with African and/or Native ancestries. Still, even in the most recent projects, the under-representation of genomic data from Latin America and the Caribbean (LAC) is remarkable. In addition, because the region presents the most recent global miscegenation, genomics data from LAC may add relevant information to understand population admixture better. Admixture in LAC started during the colonial period, in the 15th century, with intense miscegenation between European settlers, mainly from Portugal and Spain, with local indigenous and sub-Saharan Africans brought through the slave trade. Since, there are descendants of formerly enslaved and Native American populations in the LAC territory; they are considered vulnerable populations because of their history and current living conditions. In this context, studying LAC Native American and African descendant populations is important for several reasons. First, studying human populations from different origins makes it possible to understand the diversity of the human genome better. Second, it also has an immediate application to these populations, such as empowering communities with the knowledge of their ancestral origins. Furthermore, because knowledge of the population genomic structure is an essential requirement for implementing genomic medicine and precision health practices, population genomics studies may ensure that these communities have access to genomic information for risk assessment, prevention, and the delivery of optimized treatment; thus, helping to reduce inequalities in the Western Hemisphere. Hoping to set the stage for future studies, we review different aspects related to genetic and genomic research in vulnerable populations from LAC countries.

The history behind the mosaic of the Americas

Focusing on literature published in 2018-2020, we review inferences about: (i) how ancient DNA is contributing to clarify the peopling of the Americas and the dispersal of its first inhabitants, (ii) how the interplay between environmental diversity and culture has influenced the genetic structure and adaptation of Andean and Amazon populations, (iii) how genetics has contributed to our understanding of the Pre-Columbian Tupi expansion in Eastern South America, (iv) the subcontinental origins and dynamics of Post-Columbian admixture in the Americas, and finally, (v) episodes of adaptive natural selection in the American continent, particularly in the high altitudes of the Andes.

Obesity: global epidemiology and pathogenesis

The prevalence of obesity has increased worldwide in the past ~50 years, reaching pandemic levels. Obesity represents a major health challenge because it substantially increases the risk of diseases such as type 2 diabetes mellitus, fatty liver disease, hypertension, myocardial infarction, stroke, dementia, osteoarthritis, obstructive sleep apnoea and several cancers, thereby contributing to a decline in both quality of life and life expectancy. Obesity is also associated with unemployment, social disadvantages and reduced socio-economic productivity, thus increasingly creating an economic burden. Thus far, obesity prevention and treatment strategies - both at the individual and population level - have not been successful in the long term. Lifestyle and behavioural interventions aimed at reducing calorie intake and increasing energy expenditure have limited effectiveness because complex and persistent hormonal, metabolic and neurochemical adaptations defend against weight loss and promote weight regain. Reducing the obesity burden requires approaches that combine individual interventions with changes in the environment and society. Therefore, a better understanding of the remarkable regional differences in obesity prevalence and trends might help to identify societal causes of obesity and provide guidance on which are the most promising intervention strategies.