Guadalupe Ramírez-López

Influence of CRP, IL6, and TNFA gene polymorphisms on circulating levels of C-reactive protein in Mexican adolescents.

BACKGROUND AND AIMS Obesity correlates with a chronic and low-grade inflammation status. C-reactive protein (CRP) measurement has been used as an independent risk marker for future cardiovascular events. CRP level shows interindividual variability due to environmental and genetic factors. The aim of this study was to assess the association of functional polymorphisms on CRP, IL6, and TNFA genes with serum CRP levels in Mexican mestizo adolescents. METHODS Body mass index (BMI), serum high-sensitivity C-reactive protein (hsCRP) levels, and genotypes for CRP+1444C>T, IL6-174G>C, and TNFA-308G>A polymorphisms were obtained from 418 unrelated Mexican adolescents. Genetic association with hsCRP levels was evaluated by means of a dominant genetic model with uni- and multivariate analysis. RESULTS Genotype frequencies for all three polymorphisms were according to Hardy-Weinberg equilibrium (HWE). CRP+1444T, TNFA-308A, and IL6-174C allele frequencies were 37, 7, and 10%, respectively. CRP+1444T was associated with higher mean CRP levels independent of age, gender and BMI (β = 0.21; 95% confidence interval [95% CI] = 0.02-0.39); p = 0.030). IL6-174C was associated with low CRP levels in the overweight group (p = 0.005). IL6-174G>C and TNFA-308G>A allele frequencies observed from this Mexican sample were similar to data for other Mexican populations. CONCLUSIONS The CRP+1444C>T polymorphism was associated with CRP levels in Mexican adolescents and could be used as a genetic marker for the early detection of individuals at risk for developing obesity-related conditions such as cardiovascular disease or type 2 diabetes mellitus in early adulthood.

Weight, Physical Activity, and Smoking as Determinants of Insulinemia in Adolescents

BACKGROUND It is known that insulinemia is the result of the interaction among several factors, such as weight, body fat pattern distribution, and physical activity as well as ethnicity. There is little information regarding this question among Mexican adolescents. The association among fasting insulin levels, weight, fat distribution, physical activity, and cigarette smoking was studied in Mexican adolescents. METHODS Cross-sectional data were collected from 352 Mexican adolescents aged 14-19 years (response rate 41.5%). Fasting insulin levels were measured by microparticle enzyme immunoassay; body mass index (BMI), waist-to-hip ratio (WHR), and waist circumference (WC) were determined using standardized techniques, while physical activity was determined by 7-day Stanford physical activity inventory. Cigarette smoking was defined as number of cigarettes/year. RESULTS Increased BMI and waist circumference, low physical activity, younger age, and non-smoking were associated with high insulin levels. Non-smokers had higher fasting insulin levels compared to smokers (57.8 pmol +/- 1.84 vs. 49.7 pmol/L +/- 2.8; p = 0.034). However, adjusted odds ratio (OR) between insulin and smoking status was not significant. Multivariate analysis showed the following: insulin increased 1.06 pmol/L for each unit of change in BMI; increased 1.02 pmol/L for each unit of change in waist circumference; increased 1.16 pmol/L for non-smoking, and decreased 1.07 pmol/L for each 250 kcal/day of energy expenditure. CONCLUSIONS Our results support the concept that Mexican adolescents who are overweight have abdominal fat distribution and physical inactivity, and significant hyperinsulinemia. The relationship between smoking and lower insulinemia found in this research warrants further study.

Interleukin-6 Polymorphisms Are Associated with Obesity and Hyperglycemia in Mexican Adolescents

BACKGROUND AND AIMS Interleukin-6 is an inflammatory response mediator used as a metabolic marker of obesity. Polymorphisms IL6 -597C>A, -572G>C, and -174G>C modify the production of this protein. The associations between these haplotypes and obesity or metabolic markers have not been studied in adolescents, so an analysis of these associations was performed. METHODS The cross-sectional study included 745 apparently healthy 14- to 19-year-old adolescents. Obesity, serum glucose, insulin, triglycerides, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol (HDL-C), and high-sensitivity C-reactive protein (hs-CRP) were evaluated, and IL6 -597G>A, -572G>C and -174G>C polymorphisms determined. The associations were analyzed using multivariate logistic regression models. RESULTS The allele frequencies were 0.15 for -597A and -174C and 0.30 for -572C. Genotypes were in Hardy-Weinberg equilibrium. IL-6(-597/-572/-174) haplotypes GGG, GCG, and AGC comprised 99.74% of the total haplotypes. The associations were significant between genotype GCG/GCG and hyperglycemia (OR = 2.86, 95% CI = 1.02-7.97); between GCG/GCG and high hs-CRP (OR = 6.17, 95% CI = 1.13-33.77); between AGC/AGC and obesity (OR = 4.42, 95% CI = 1.40-14.01); and between GGG/GCG and low HDL-C (OR = 1.53, 95% CI = 1.03-2.28). CONCLUSIONS Genotypes of the IL6(-597/-572/-174) polymorphisms are associated with metabolic risk factors in Mexican adolescents.

Actividad física, conductas sedentarias y calidad de vida en adolescentes universitarios de Ciudad Guzmán, Jalisco, México

With the aim of evaluating the association between physical activity and sedentary behavior with quality of life (QoL) in undergraduate students of Ciudad Guzman, state of Jalisco, Mexico, a total of 881 adolescents aged between 17 and 19 were studied. Online questionnaires were used, namely the research version of the Youth Quality of Life Instrument and the Youth Risk Behavior Survey. Odd ratios (OR) were obtained using simple and multivariate logistic regression analysis. The number of days with physical activity was related to a higher total perceptual score, higher general QoL domain, higher self domain as well as higher environment domain. Playing in > 2 sports teams was related to a higher total perceptual score, higher general QoL domain, higher self domain as well as higher environment domain. Having 4-5 physical education classes/week was related with a higher general QoL domain. Limiting recreational screen time to < 2 hours/day was related with a higher relationship domain. In conclusion, in Mexican undergraduate adolescent students, higher QoL was associated with: physical activity at least 4 days/week; physical education classes 4 or more days/week; playing in 2 or more sports teams and limiting recreational screen time to 2 hours or less.

Triglycerides and high-density lipoprotein cholesterol are associated with insulinemia in adolescents

OBJECTIVE The aim of this study was to evaluate the association between lipids and insulin concentration in adolescents. MATERIAL AND METHODS A cross-sectional study of 350 adolescents aged 14-19 years old from a public high school in Guadalajara, in the state of Jalisco, Mexico, was conducted. Fasting insulin concentration was determined using microparticle enzyme immunoassay; total cholesterol and triglycerides were detected by standard enzymatic procedures;and low- and high-density lipoproteins were found using standard precipitation methods. Statistical analysis included linear multivariate regression. RESULTS Serum triglycerides were associated positively with insulin fasting (beta = 0.003, p = 0.0001) and high-density lipoprotein cholesterol was negatively associated with insulin fasting in male adolescents 18-19 years old (beta = -0.03, p = 0.012). CONCLUSIONS The relationships between triglycerides and insulin and between high-density lipoprotein cholesterol and insulin are already present in adolescence.

Association of Polymorphisms of Genes Involved in Lipid Metabolism with Blood Pressure and Lipid Values in Mexican Hypertensive Individuals

Hypertension and dyslipidemia exhibit an important clinical relationship because an increase in blood lipids yields an increase in blood pressure (BP). We analyzed the associations of seven polymorphisms of genes involved in lipid metabolism (APOA5 rs3135506, APOB rs1042031, FABP2 rs1799883, LDLR rs5925, LIPC rs1800588, LPL rs328, and MTTP rs1800591) with blood pressure and lipid values in Mexican hypertensive (HT) patients. A total of 160 HT patients and 160 normotensive individuals were included. Genotyping was performed through PCR-RFLP, PCR-AIRS, and sequencing. The results showed significant associations in the HT group and HT subgroups classified as normolipemic and hyperlipemic. The alleles FABP2 p.55T, LIPC −514T, and MTTP −493T were associated with elevated systolic BP. Five alleles were associated with lipids. LPL p.474X and FABP2 p.55T were associated with decreased total cholesterol and LDL-C, respectively; APOA5 p.19W with increased HDL-C; APOA5 p.19W and FABP2 p.55T with increased triglycerides; and APOB p.4181K and LDLR c.1959T with decreased triglycerides. The APOB p.E4181K polymorphism increases the risk for HT (OR = 1.85, 95% CI: 1.17–2.93; P = 0.001) under the dominant model. These findings indicate that polymorphisms of lipid metabolism genes modify systolic BP and lipid levels and may be important in the development of essential hypertension and dyslipidemia in Mexican HT patients.

The effects of social networks on tobacco use among high-school adolescents in Mexico

OBJECTIVE To identify the effect of centrality in social network positions on tobacco-use among high-school adolescents in Tonala, Jalisco, Mexico. MATERIALS AND METHODS Longitudinal sociometric social network data were collected among 486 high-school adolescents in 2003 and 399 in 2004. The survey included: social network components, smoking and sociodemographic characteristics. Social network measures of centrality were calculated and multivariate logistic regression was used. RESULTS Ever used tobacco (OR= 44.98), marginalized-low stratum (OR= 2.16) and in-degree (OR=1.10) predicted tobacco use. Out-degree (OR= 0 .89) and out-in-degree (OR= 0.90) protected against tobacco use. CONCLUSION Nominating more friends rather than receiving such nominations was protective for tobacco use. Popular students, those receiving many nominations, were at higher risk for tobacco use. Involvement of leaders with capacity to influence might be an efficient strategy for dissemination of preventive messages.

Analysis of cytokine gene polymorphisms in Mestizo and native populations from Mexico

To determine whether the well‐known genetic structure of the Mexican population observed with other multiallelic markers can be detected by analyzing functional polymorphisms of cytokine and other inflammatory‐response‐related genes.

Metabolic and genetic markers’ associations with elevated levels of alanine aminotransferase in adolescents

Abstract Background: Non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease in adolescents, is a feature of metabolic syndrome (MetS). Obesity and insulin resistance (IR) are risk factors for NAFLD, as well as inflammation-related genetic markers. The relationship between metabolic or inflammation-related genetic markers and alanine aminotransferase (ALT) is not fully understood. We examined the relationship of MetS, metabolic and inflammation-related genetic markers with elevated ALT in adolescents. Methods: A total of 674 adolescents participated in a cross-sectional study in Guadalajara, Mexico. Elevated ALT (>40 IU/L), a surrogate marker of NAFLD, and MetS (International Diabetes Federation definition) were evaluated. Obesity, IR, lipids, C-reactive protein (CRP) and genetic markers (TNFA-308G>A, CRP+1444C>T, IL1RN and IL6-597/-572/-174 haplotype) were evaluated. Multivariate logistic regression was performed. Results: Elevated ALT was observed in 3% and 14.1% (total and obese, respectively) of the adolescents. Obesity (odds ratio [OR], 5.86; 95% confidence interval [95% CI], 1.16–25.89), insulin (OR, 8.51; 95% CI, 2.61–27.71), IR (OR, 9.10; 95% CI, 2.82–29.38), total cholesterol (TC) (OR, 3.67; 95% CI, 1.25–10.72), low-density lipoprotein-cholesterol (LDL-C) (OR, 3.06; 95% CI, 1.06–8.33), non-high-density lipoprotein-cholesterol (HDL-C) (OR, 3.88; 95% CI, 1.27–11.90) and IL1RN (OR, 4.64; 95% CI, 1.10–19.53) were associated with elevated ALT. Among males, ≥2 MetS criteria were associated with elevated ALT (OR, 4.22; 95% CI, 1.14–15.71). Conclusions: Obesity, insulin, IR, high TC, high LDL-C, high non-HDL-C and IL1RN polymorphism were associated with elevated ALT. Among males, ≥2 MetS criteria were associated with elevated ALT. There is an urgent need to reduce obesity and IR in adolescents to prevent NAFLD.

Bullying and health-related quality of life in children and adolescent Mexican students

Previous studies have reported a relationship between being a victim of bullying, but no studies have been carried out with Mexican students; notwithstanding the high scores of bullying in Mexico in international rankings. The objective of this study was to analyze the association between being a victim of bullying and lower HRQoL among schoolchildren and adolescents in Mexico. This cross-sectional and correlational study involved 2225 students from 22 elementary, middle and high schools. HRQoL was assessed with the KIDSCREEN-10 questionnaire and bullying with the social adaptation dimension of KIDSCREEN-52. Bivariate associations were evaluated, and a multivariate logistic regression was utilized. The prevalence of victims of bullying was 17.3%. Being a victim of bullying was double the risk of having a lower HRQoL than not being a victim after adjusting for health perception, gender and age, OR 2.3 (1.7-3.1). As the Wilson and Cleary Model of Quality of Life explains, individual characteristics, such as, being a victim of bullying are associated with quality of life. Similar findings in the existing literature imply that bullying is a global phenomenon that impacts the victimized child or adolescents life in different ways.