The myostatin rs1805086 variant is associated with obesity in Mexican adults, independently of metabolic risk factors.

AIM: To determine whether rs1805086 is associated with obesity and metabolic disturbances in a Mexican adult population. SUBJECTS AND METHODS: We genotyped rs1805086 in 1024 men and women aged 18-58 years. Anthropometric and body fat data were used to estimate obesity. Biochemical parameters were measured and DNA was used to determine the rs1805086 genotype. RESULTS: rs1805086 heterozygous AG frequency was 5.4%, and the homozygous for the risk allele GG was absent. Heterozygous had higher levels of body mass index (BMI) and waist/height ratio (WHtR). Heterozygous subjects showed a greater total and central obesity compared to the homozygous for ancestral allele AA (OR BMI > 30 kg/m2 = 2.35, 95% CI 1.29-4.29; OR WHtR > 0.5 = 2.03, 95% CI 1.19-3.45; OR elevated fat mass (EFM) %= 1.72, 95% CI 1.01-2.92; OR fat mass index (FMI)>p85 = 1.96, 95% CI 1.05-3.68). rs1805086 was not associated with metabolic alterations. CONCLUSION: Heterozygosity for rs1805086 showed a predisposition to having elevated overall and central obesity parameters. This association with adiposity seems to be independent of metabolic risk.

Effect of 15 BMI-Associated Polymorphisms, Reported for Europeans, across Ethnicities and Degrees of Amerindian Ancestry in Mexican Children.

In Mexico, the genetic mechanisms underlying childhood obesity are poorly known. We evaluated the effect of loci, known to be associated with childhood body mass index (BMI) in Europeans, in Mexican children from different ethnic groups. We performed linear and logistic analyses of BMI and obesity, respectively, in Mestizos and Amerindians (Seris, Yaquis and Nahuatl speakers) from Northern (n = 369) and Central Mexico (n = 8545). We used linear models to understand the effect of degree of Amerindian ancestry (AMA) and genetic risk score (GRS) on BMI z-score. Northern Mexican Mestizos showed the highest overweight-obesity prevalence (47.4%), followed by Seri (36.2%) and Central Mexican (31.5%) children. Eleven loci (SEC16B/rs543874, OLFM4/rs12429545/rs9568856, FTO/rs9939609, MC4R/rs6567160, GNPDA2/rs13130484, FAIM2/rs7132908, FAM120AOS/rs944990, LMX1B/rs3829849, ADAM23/rs13387838, HOXB5/rs9299) were associated with BMI and seven (SEC16B/rs543874, OLFM4/rs12429545/rs9568856, FTO/rs9939609, MC4R/rs6567160, GNPDA2 rs13130484, LMX1B/rs3829849) were associated with obesity in Central Mexican children. One SNP was associated with obesity in Northern Mexicans and Yaquis (SEC16B/rs543874). We found higher BMI z-score at higher GRS (ß = 0.11, p = 0.2 × 10-16) and at lower AMA (ß = -0.05, p = 6.8 × 10-7). The GRS interacts with AMA to increase BMI (ß = 0.03, p = 6.08 × 10-3). High genetic BMI susceptibility increase the risk of higher BMI, including in Amerindian children.

Association of the PSRC1 rs599839 Variant with Coronary Artery Disease in a Mexican Population.

Background and Objectives: Coronary artery disease (CAD) is a major health problem in México. The identification of modifiable risk factors and genetic biomarkers is crucial for an integrative and personalized CAD risk evaluation. In this work, we aimed to validate in a Mexican population a set of eight selected polymorphisms previously associated with CAD, myocardial infarction (MI), or dyslipidemia. Materials and Methods: A sample of 907 subjects (394 CAD cases and 513 controls) 40-80 years old was genotyped for eight loci: PSRC1 (rs599839), MRAS (rs9818870), BTN2A1 (rs6929846), MTHFD1L (rs6922269), CDKN2B (rs1333049), KIAA1462 (rs3739998), CXCL12 (rs501120), and HNF1A (rs2259816). The association between single nucleotide polymorphisms (SNPs) and CAD was evaluated by logistic regression models. Results: Multiple logistic regression analysis with adjustment by age, gender, and body mass index showed that rs599839 was significantly associated with CAD (ORADD = 0.72, p = 0.009; ORDOM = 0.66, p = 0.007). Conclusions: The PSRC1 rs599839 polymorphism shows a significant protective association with CAD in this sample of the Mexican population.

Effect of multi-component school-based program on body mass index, cardiovascular and diabetes risks in a multi-ethnic study.

BACKGROUND: Mexico occupies one of the first places worldwide in childhood obesity. Its Mestizo and Indigenous communities present different levels of westernization which have triggered different epidemiological diseases. We assessed the effects of a multi-component school-based intervention program on obesity, cardiovascular and diabetes risk factors. METHODS: A physical activity, health education and parent involvement (PAHEPI) program was developed and applied in six urban (Mestizo ethnic group) and indigenous (Seri and Yaqui ethnic groups) primary schools for 12 weeks. A total of 320 children aged 4-12 years participated in intervention program; 203 under Treatment 1 (PAHEPI program) and 117, only from Mestizo groups, under Treatment 2 (PAHEPI+ school meals). For Body Mass Index (BMI), cardiovascular and diabetes factors, pairwise comparisons of values at baseline and after treatments were done using Wilcoxon signed rank test. Generalized linear models were applied to assess the intervention effect by age, sex and nutritional status in relation to ethnicity and treatment. RESULTS: We observed improvements on BMI in children with overweight-obesity and in triglycerides in the three ethnic groups. The Mestizo ethnic group showed the largest improvements under Treatment 2. While Seris showed improvements only in cardiovascular risk factors, Yaquis also showed improvements in diabetes risk factors, though not in BMI. CONCLUSIONS: This study showed that the same intervention may have positive but different effects in different ethnic groups depending on their lifestyle and their emerging epidemiological disease. Including this type of intervention as part of the school curriculum would allow to adapt to ethnic group in order to contribute more efficiently to child welfare. TRIAL REGISTRATION: This study was retrospectively registered under the identifier NCT03768245 .

Common Polymorphisms Linked to Obesity and Cardiovascular Disease in Europeans and Asians are Associated with Type 2 Diabetes in Mexican Mestizos.

Background and objectives: Type 2 diabetes (T2D) is a major problem of public health in Mexico. We investigated the influence of five polymorphisms, previously associated with obesity and cardiovascular disease in Europeans and Asians, on T2D in Mexican Mestizos. Materials and Methods: A total of 1358 subjects from 30 to 85 years old were genotyped for five loci: CXCL12 rs501120; CDNK2A/B rs1333049; HNF-1α rs2259816; FTO rs9939609; and LEP rs7799039. We used logistic regressions to test the effect of each locus on T2D in two case⁻control groups with obesity and without obesity. Also, linear regression models on glucose and glycated hemoglobin (HbA1c) were carried out on the whole sample, adjusted by age, gender, and body mass index. Results: The CXCL12 rs501120 C allele (OR = 1.96, p = 0.02), the FTO rs9939609 A allele (OR = 2.20, p = 0.04) and the LEP rs7799039 A allele (OR = 0.6, p = 0.03) were significantly associated with T2D in obesity case⁻control group. No significant association was found in the non-obesity case⁻control group. The linear regression model showed that CDNK2A/B rs1333049 C allele (ß = 0.4, p = 0.03) and FTO rs9939609 A allele (ß = 0.5, p = 0.03), were significantly associated with HbA1c, but no association was found among the loci with the glucose levels. Conclusions: Polymorphisms previously linked with obesity and cardiovascular events were also associated with T2D and high levels of HbA1c. Furthermore, we must point at the fact that this is the first report where polymorphisms CXCL12 rs501120 and LEP rs7799039 are associated with T2D in subjects with obesity.

Genetic Obesity Risk and Attenuation Effect of Physical Fitness in Mexican-Mestizo Population: a Case-Control Study.

We analyzed commonly reported European and Asian obesity-related gene variants in a Mexican-Mestizo population through each single nucleotide polymorphism (SNP) and a genetic risk score (GRS) based on 23 selected SNPs. Study subjects were physically active Mexican-Mestizo adults (n = 608) with body mass index (BMI) values from 18 to 55 kg/m2 . For each SNP and for the GRS, logistic models were performed to test for simple SNP associations with BMI, fat mass percentage (FMP), waist circumference (WC), and the interaction with VO2max and muscular endurance (ME). To further understand the SNP or GRS*physical fitness components, generalized linear models were performed. Obesity risk was significantly associated to 6 SNPs (ADRB2 rs1042713, APOB rs512535, PPARA rs1800206, TNFA rs361525, TRHR rs7832552 and rs16892496) after adjustment by gender, age, ancestry, VO2max , and ME. ME attenuated the influence of APOB rs512535 and TNFA rs361525 on obesity risk in FMP. WC was significantly associated to GRS. Both ME and VO2max attenuated GRS effect on WC. We report associations for 6 out of 23 SNPs and for the GRS, which confer obesity risk, a novel finding for Mexican-Mestizo physically active population. Also, the importance of including physical fitness components variables in obesity genetic risk studies is highlighted, with special regard to intervention purposes.

Sex beyond species: the first genetically analyzed case of intergeneric fertile hybridization in pinnipeds.

A species, according to the biological concept, is a natural group of potentially interbreeding individuals isolated by diverse mechanisms. Hybridization is considered the production of offspring resulting from the interbreeding of two genetically distinct taxa. It has been documented in over 10% of wild animals, and at least in 34 cases for Artic marine mammals. In Otariids, intergeneric hybridization has been reported though neither confirming it through genetic analyses nor presenting evidence of fertile offspring. In this study, we report the finding of a hybrid adult female between a South American fur seal (Arctocephalus australis) and a South American sea lion (Otaria byronia), and its offspring, a male pup, in Uruguay. Further based on morphological constraints and breeding seasons, sex-biased hybridization between the two species is hypothesized. Morphological and genetic (nuclear and mitochondrial) results confirm de hybrid nature of the female-pup pair. Here we discuss a genetic dilution effect, considering other hybridization events must be occurring, and how isolation mechanisms could be circumvented. Moreover, the results obtained from stable isotope analysis suggest feeding habits may be a trait transmitted maternally, leading to consider broader issues regarding hybridization as an evolutionary innovation phenomenon.

Population genetic structure and social kin associations of franciscana dolphin, Pontoporia blainvillei.

We investigated population and social structure of the franciscana dolphin, Pontoporia blainvillei, an endemic and the most endangered cetacean of the southwestern Atlantic Ocean. We analyzed samples from the Rio de la Plata estuary obtained in Uruguayan waters and from the Atlantic Ocean obtained in both Uruguayan and Brazilian waters. Mitochondrial and microsatellite DNA markers were used to study differentiation between the estuary and the ocean and the association between kinship and social group structure. Although multilocus analyses suggested that franciscanas are structured into 2 subpopulations (K = 2, divergence among clusters: F(ST) = 0.06, P = 0.002; R(ST) = 0.3, P = 0.001), mitochondrial markers did not support such divergence (F(ST) = 0.02, P = 0.12; Ф(ST) = 0.06, P =0.06). However, these units are not entirely segregated geographically. Regarding social structure, some groups are composed by first-order related individuals (R ≥ 0.5, P < 0.5). Overall, the data suggest that matrilines could be the social unit in this species. We argue that the divergence found could be associated to local adaptation and social structure, resulting from either feature leading to a recent divergence or reflecting equilibrium between local differentiation and gene flow. This evidence supports considering franciscanas from the Rio de la Plata estuary a discrete management unit.

Economic burden of severe asthma treatment: A real-life study.

Background: Individuals with severe asthma represent 5%-10% of the general asthmatic population. Despite the use of biologic drugs during clinical management, inadequate control of the disease has translated into high economic impact. In Mexico, however, these costs have not yet been assessed. Methods: A retrospective cohort study was carried out in 2018 and 2019 at Regional Hospital Lic. Adolfo López Mateos, ISSSTE. The assessment of direct costs included pharmacological treatment, clinical tests, days of hospitalization, admissions to the emergency room, and scheduled consultations. The evaluation involved 2 groups of patients-with controlled severe asthma (CSA) and uncontrolled severe asthma (UCSA)-according to presence of exacerbations. Results: 60 patients (18-75 years old, 51 women) were included in the study. In 2018, 23 of them (38.3%) were categorized as belonging to the UCSA group; in 2019, 22 patients (36.7%) were in this condition (exacerbations: median = 1.5, maximum = 6). Of the 60 patients, 12 (20%) presented between 2 and 9 exacerbations in the study's two-year period (median = 3) after between 4 and 10 years (median = 7.8) of complementary anti-immunoglobulin E (IgE) therapy with omalizumab. The cost for all patients in the 2018-2019 period was 993,289.60 USD. The mean cost per patient was higher for those with UCSA (16,392 USD) than for those with CSA (16,246 USD, p = 0.02). We found a positive association between cost and exacerbations, with an increase of 350 USD per exacerbation (p˂0.0001). Our results indicate that 62% of patients respond to complementary anti-IgE treatment, while 38%-and especially 20%-do not respond optimally to this treatment. Conclusions: Poor asthma control in this latter group of 38% of patients leads to lower quality of life and higher costs associated with pharmacological treatment.

Dyslipidemia, Obesity, and Ethnicity in Mexican Children.

The aim of this study was to assess lipid disorders in children from five ethnic groups, both urban and indigenous, from northern and central Mexico. We measured the lipid profile to determine the ability of the body mass index (BMI) to discriminate an abnormally high lipid level using receiving operating characteristics (ROC). We analyzed the association and interaction of obesity and ethnicity with lipid disorders using generalized linear models in 977 children. The highest prevalence of lipid disorders (high TG, high TC, high LDL, high APOB, and dyslipidemia) was found in central Mexico-Mexico City and urban northern Mexico. The BMI performed better at predicting low HDL in Seris, a northern indigenous group (0.95, CI: 0.69-0.85), and Mexico City (0.75, CI: 0.69-0.82), and high LDL in Puebla (central Mexico, 0.80, CI: 0.69-0.85). Obesity significantly (p < 0.05) increases lipid disorders by around two times (OR~2) for almost all lipid markers. Obesity and ethnic interaction increase the lipid disorders by more than five times for different lipid markers and ethnic groups (high total cholesterol OR = 5.31; low HDL OR = 5.11, and dyslipidemia OR = 5.68). Lipid disorders are not restricted to children with high BMIs, but obesity exacerbates these. The emerging lipid disorder risk depends on the ethnic group.

Antioxidant Enzymes Haplotypes and Polymorphisms Associated with Obesity in Mexican Children.

Obesity is a major health problem worldwide and constitutes a sanitary emergency in Mexico, especially childhood obesity. Several studies have proved the relationship between obesity and oxidative stress and the influence of genetic predisposition. This work was aimed to analyze the association of antioxidant enzyme polymorphisms with overweight and obesity in Mexican children and adolescents. A case-control study was performed in 585 children and adolescents aged 3 to 17 years, using two criteria to classify obesity: body mass index (BMI) and body fat percentage (BFP). Anthropometric and biochemical measurements were carried out, and malondialdehyde serum levels were determined. Genotyping was done with the Axiom Genome-Wide LAT microarray, including 68 single nucleotide polymorphisms (SNPs) of the glutathione peroxidase (GPX) and paraoxonase (PON) families. We found six haplotypes associated with obesity-two of them (one in GPX3 and the other in GPX5 and GPX6) in a protective direction when obesity was classified by BMI. The other four haplotypes were associated with obesity when classification was based on BFP-one of them in GPX3 in a protective direction and the others in PON genes conferring obesity risk. In addition, two SNPs, GPX3 rs922429 and GPX4 rs2074451 showed protection against obesity classified by BFP. This study showed genetic susceptibility to oxidative stress in relation to obesity in Mexican children and opens up the possibility that some genetic loci related to obesity are not identified when weight classification is based on BMI.

Polymorphisms in Adipokines in Mexican Children with Obesity.

The high prevalence of childhood obesity in Mexico is alarming in the health-science field. We propose to investigate the contribution of adipokines and cytokines polymorphisms and common BMI/obesity-associated loci, revealed in genome-wide association studies in Caucasian adult cohorts, with childhood obesity. This study included 773 Mexican-Mestizo children (5-15 years old) in a case-control study. The polymorphisms included were ADIPOQ (rs6444174), TNF-α (rs1800750), IL-1ß (rs1143643), IL-6 (rs1524107; rs2069845), NEGR1 (rs34305371), SEC16B-RASAL2 (rs10913469), TMEM18 (rs6548238; rs7561317), GNPDA2 (rs16857402), LEP (rs2167270), MTCH2 (rs10838738), LGR4-LIN7C-BDNF (rs925946), BCDIN3D-FAIM2 (rs7138803), FTO (rs62033400), MC4R (rs11872992), MC4R (rs17782313), and KCTD15 (rs29942). No significant contribution was found with adipokines and cytokines polymorphisms in this study. Only both TMEM18 (rs6548238; rs7561317) polymorphisms were found associated with obesity (OR=0.5, P=0.008) and were in linkage disequilibrium (r2=0.87). The linear regression showed that the rs7561317 polymorphism of TMEM18 is negatively associated with obesity. This report highlights the influence of TMEM18 in Mexican-Mestizo children obesity, while adipokine and cytokine polymorphisms were not associated with it.

Genome-Wide Association Study of Body Mass Index and Body Fat in Mexican-Mestizo Children.

BACKGROUND: Childhood obesity is a major health problem in Mexico. Obesity prevalence estimated by body mass index (BMI) is almost half than that estimated by percent body fat (%BF) in the Childhood Obesity pediatric cohort (COIPIS). OBJECTIVE: We performed a genome-wide association study (GWAS) of BMI and %BF in 828 children from the COIPIS to identify markers of predisposition to high values for both phenotypes used for obesity classification. METHODS: For the GWAS we used the LAT Axiom 1, Affymetrix and 2.5 million single loci from the 1000 Genomes Phase 3 imputation panel. We used a linear model, adjusted by age, sex, and Amerindian ancestry assuming an additive inheritance model. RESULTS: Genome-wide significance (p ≤ 5.0 × 10-8) and 80% of statistical power was reached for associations of two loci in two genes (CERS3 and CYP2E1) to BMI. Also, 11 loci in six genes (ANKS1B, ARNTL2, KCNS3, LMNB1, SRGAP3, TRPC7) reached genome-wide significance for associations to %BF, though not 80% of statistical power. DISCUSSION: None of the SNPs were previously reported as being associated to BMI or %BF. In addition, different loci were found for BMI and %BF. These results highlight the importance of gaining deeper understanding of genetic markers of predisposition to high values for the phenotypes used for obesity diagnosis.

Obesity measured as percent body fat, relationship with body mass index, and percentile curves for Mexican pediatric population.

In Mexico, the increase in childhood obesity is alarming. Thus, improving the precision of its diagnosis is expected to impact on disease prevention. We estimated obesity prevalence by bioimpedance-based percent body fat (%BF) and body mass index (BMI) in 1061 girls and 1121 boys, from 3 to 17 years old. Multiple regressions and area under receiver operating curves (AUC) were used to determine the predictive value of BMI on %BF and percentile curves were constructed. Overall obesity prevalence estimated by %BF was 43.7%, and by BMI it was 20.1%; it means that the diagnosis by BMI underestimated around 50% of children diagnosed with obesity by %BF (≥30% for girls, ≥25% for boys). The fat mass excess is further underestimated in boys than in girls when using the standard BMI classification. The relationship between %BF and BMI was strong in school children and adolescents (all cases R2>0.70), but not in preschool children (girls R2 = 0.57, boys R2 = 0.23). AUCs showed greater discriminative power of BMI to detect %BF obesity in school children and adolescents (all cases AUC≥0.90) than in preschool children (girls AUC = 0.86; boys AUC = 0.70). Growth percentile charts showed that girls aged 9-17 years and boys aged 8-17 years presented fat excess from the 50th percentile and above. We suggested to change the BMI cut-off for them, considering values at the 75th percentile as overweight, and values at the 85th percentile as obesity, as previously recommended for Mexican children. Improving obesity diagnosis will allow greater efficiency when searching for comorbidities in clinical practice.

Genetic susceptibility to pre diabetes mellitus and related association with obesity and physical fitness components in Mexican-Mestizos.

Pre diabetes mellitus (pre-DM) is considered an early-reversible condition that can progress to Type 2 diabetes mellitus (T2DM) which is the main cause of death for adult Mexican population. Gene variants influencing fasting glucose levels may constitute helpful tool for prevention purposes in pre-DM condition. Physically active Mexican-Mestizo adults (n=565) were genotyped for 6 single nucleotide polymorphisms (SNPs) (ADIPOQ rs2241766, ACSL1 rs9997745, LIPC rs1800588, PPARA rs1800206, PPARG rs1801282 and PPARGC1A rs8192678) related to lipid and carbohydrate metabolism. Fasting glucose was measured and values classified as pre-DM (≥100mg/dL) or normal fasting glucose. Logistic models were used to test associations between pre-DM condition and SNPs, and interaction with Body Mass Index (BMI) and physical fitness components. The A allele of ASCL1 rs9997745 conferred increased risk (OR=3.39, p=0.001) of pre-DM which is modulated by BMI. The A allele of the PPARGC1A rs8192678 showed significant SNP*BMI (OR=1.10, p=0.008) interaction effect for pre-DM risk, meaning that obese subjects showed higher pre-DM risk but normal weight subjects showed lower risk. The effect increased with age and was attenuated by higher cardiorespiratory values. We found that both ACSL1 rs9997745 and PPARGC1A rs8192678 are associated with pre-DM, and that BMI significantly modified their association.

Fine-scale population structure of blue whale wintering aggregations in the Gulf of California.

Population differentiation in environments without well-defined geographical barriers represents a challenge for wildlife management. Based on a comprehensive database of individual sighting records (1988-2009) of blue whales from the winter/calving Gulf of California, we assessed the fine-scale genetic and spatial structure of the population using individual-based approaches. Skin samples of 187 individuals were analyzed for nine microsatellite loci. A single population with no divergence among years and months and no isolation by distance (Rxy = 0.1-0.001, p>0.05) were found. We ran two bayesian clustering methods using Structure and Geneland softwares in two different ways: 1) a general analysis including all individuals in which a single cluster was identified with both softwares; 2) a specific analysis of females only in which two main clusters (Loreto Bay and northern areas, and San Jose-La Paz Bay area) were revealed by Geneland program. This study provides information indicating that blue whales wintering in the Gulf of California are part of a single population unit and showed a fine-scale structure among females, possibly associated with their high site fidelity, particularly when attending calves. It is likely that the loss of genetic variation is minimized by male mediated gene flow, which may reduce the genetic drift effect. Opportunities for kin selection may also influence calf survival and, in consequence, have a positive impact on population demography in this small and endangered population.