Association of ALT and the metabolic syndrome among Mexican children.

Nonalcoholic fatty liver disease (NAFLD) is emerging as a component of the metabolic syndrome (MetS); Hispanics being particularly predisposed. Alanine aminotransferase (ALT) is considered a marker of NAFLD. The aim of this study was to determine the prevalence and associations between ALT elevations and MetS in normal-weight, overweight and obese Mexican children and adolescents, since data in Mexico is scarce. Body mass index (BMI), waist circumference (WC), percentage body fat, blood pressure, glucose, lipid profiles, ALT and aspartate aminotransferase (AST) were measured in 236, 6-12yo normal-weight, overweight and obese Mexicans from eight public schools. The results showed that elevated ALT (>40 IU/L) was found in 17.7% of the obese and overweight population, with no gender difference. The prevalence of elevated ALT increased linearly across BMI categories (p = 0.001), from 0.0% for the normal-weight group (95%CI 0.0-€“8.0) to 22.4% for the obese one (95%CI 16.2-€“30.2). AST/ALT ratio <1 also increased linearly, as did the prevalence of MetS (p = 0.001), from 0.0% for the normal-weight group to 40.3% for the obese one. The prevalence of MetS was strongly associated with elevated ALT (p = 0.002), 50% in the elevated ALT group (95%CI 34.1-€“65.9) and 24.1% in the normal ALT one (95%CI 18.1-€“31.3). There was also a strong association between MetS and an AST/ALT ratio <1. WC was the best predictor of elevated ALT (AOR = 7.13). Pearson correlation showed that MetS components were significantly correlated with elevated ALT. Therefore elevated ALT levels were highly prevalent and strongly associated with MetS in Mexican children, it should be screened in overweight and obese children.

Clinical and epidemiological features of 2009 pandemic H1N1 influenza differ slightly according to seroprevalence status during the second wave in the general population in México.

BACKGROUND: Clinical features of pandemic H1N1 have been derived from lab-confirmed, hospitalized, or critically ill subjects. This report describes the clinical features of H1N1 and their prevalence from non-confirmed subjects according to seroprevalence status in México. The objective was to determine the prevalence of these clinical features from non-confirmed cases of pandemic H1N1 and to compare them according to seroprevalence status in northern Monterrey, México, during 2009, and to identify the predictive signs and symptoms; there have been no prior serologic studies in México. METHODS: During November-December 2009, 2,222 volunteers, ages 6-99 years, were categorized into 3 symptomatic groups: influenza-like illness, respiratory illness, and non-respiratory illness. Antibodies against influenza A/H1N1/2009 were determined by a virus-free enzyme-linked immunosorbent assay (ELISA) method. Demographics and clinical presentation were assessed through face-to-face questionnaire, and the association with seroprevalence status was determined and compared. RESULTS: Overall seroprevalence was 39%. Of the seropositive subjects, 67% were symptomatic and 33% were asymptomatic. Seventy-one percent of seropositive symptomatic subjects reported respiratory illness, 17% reported non-respiratory symptoms, and 12% reported influenza-like illness. The most common symptoms were rhinorrhea/nasal congestion (93%) and headache (83%). No significant difference was found between the symptom profiles of the seropositive group, compared to the seronegative one, nor of the median duration of symptoms. The seropositive group had a significantly elevated proportion of influenza-like illness (12%), compared to the seronegative group (8%). The proportion of subjects who took days off and who sought medical attention was significantly higher in the seropositive group. No single symptom was associated as a predictor of seropositiveness. CONCLUSIONS: One third of the seropositive subjects were asymptomatic, and few had an influenza-like illness. No difference was found in the symptom profiles of the seropositive and seronegative groups. No single symptom predicted seropositiveness. Large scale population studies are needed, especially in México, to characterize clinical syndromes.

Seroprevalence of antibodies to influenza A/H1N1/2009 among transmission risk groups after the second wave in Mexico, by a virus-free ELISA method.

OBJECTIVE: No serological studies have been performed in Mexico to assess the seroprevalence of influenza A/H1N1/2009 in groups of people according to the potential risk of transmission. The aim of this study was to determine the seroprevalence of antibodies against influenza A/H1N1/2009 in subjects in Mexico grouped by risk of transmission. METHODS: Two thousand two hundred and twenty-two subjects were categorized into one of five occupation groups according to the potential risk of transmission: (1) students, (2) teachers, (3) healthcare workers, (4) institutional home residents aged >60 years, and (5) general population. Seroprevalence by potential transmission group and by age grouped into decades was determined by a virus-free ELISA method based on the recombinant receptor-binding domain of the hemagglutinin of influenza A/H1N1/2009 virus as antigen (85% sensitivity; 95% specificity). The Wilson score, Chi-square test, and logistic regression models were used for the statistical analyses. RESULTS: Seroprevalence for students was 47.3%, for teachers was 33.9%, for older adults was 36.5%, and for the general population was 33.0%, however it was only 24.6% for healthcare workers (p=0.011). Of the students, 56.6% of those at middle school, 56.4% of those at high school, 52.7% of those at elementary school, and 31.1% of college students showed positive antibodies (p<0.001). Seroprevalence was 44.6% for college teachers, 31.6% for middle school teachers, and 29.8% for elementary school teachers, but was only 20.3% for high school teachers (p=0.002). CONCLUSIONS: The student group was the group most affected by influenza A/H1N1/2009, while the healthcare worker group showed the lowest prevalence. Students represent a key target for preventive measures.

Waist-to-height: cutoff matters in predicting metabolic syndrome in Mexican children.

BACKGROUND: Body-mass index (BMI), waist circumference (WC), and, recently, waist-to-height ratio (WHtR) have been proposed as clinical indexes to identify children at cardiometabolic risk. The aim was to identify the usefulness of WHtR cutoffs, WC, and BMI as predictors of metabolic syndrome in Mexican children, according to BMI z-scores, and the severity of obesity to cardiometabolic risk factors and metabolic syndrome. METHODS: This was a cross-sectional study of 214 overweight/obese and 47 normal-weight Mexican children 6-12 years old. Children were divided in groups according to BMI z-scores. Anthropometric and biochemical measurements were determined. Receiver-operating characteristic (ROC) curves and areas under the curves were calculated to compare the abilities of the anthropometric measurements to predict metabolic syndrome. RESULTS: The overall prevalence of metabolic syndrome was 23.3%, ranging from 11.0% in the overweight group to 73.9% in the severely obese one. Children with metabolic syndrome had significantly higher WHtR, WC, BMI, percentage of body fat, triglycerides, total cholesterol, low-density lipoprotein cholesterol (LDL-C), systolic and diastolic blood pressure, and lower high-density lipoprotein cholesterol (HDL-C). A WHtR cutoff point of 0.59 from the ROC curve was identified as strong predictor of metabolic syndrome in our population, whereas a cutoff of 0.5 showed very poor specificity (22.7%). WC predicted metabolic syndrome as well. CONCLUSION: Cutoff values for WHtR make a difference in predicting metabolic syndrome. A cutoff of 0.59 for WHtR strongly predicted metabolic syndrome; it might be a simpler to use screening tools and counters for short people. Further studies are required to determine the cutoff points for an accurate prediction, because there are few in children and none in Mexico.

Plasma phospholipid fatty acids in obese male and female Mexican children.

AIM: To assess the plasma phospholipid (PL) fatty acid composition in obese Mexican children and evaluate gender differences and predisposition to health risks. METHODS: This was a case-control study of 100 obese and 100 normal-weight children aged 6-12 years. BMI, waist circumference, triceps skinfold, and percentage of body fat were determined. PL fatty acids were measured by gas chromatography. RESULTS: Compared to normal-weight children, obese children had significantly higher proportions of 18:0, 16:1n-7, 20:3n-6, saturated fatty acids (SFA), total highly unsaturated fatty acids (UFAs), and total n-3 but lower proportions of 18:1n-9, 18:2n-6, 22:5n-6, monounsaturated fatty acids, and total n-9. Obese children had significantly higher ratios of 20:3n-6/18:2n-6 and 18:3n-6 + 20:3n-6/18:2n-6, and they had lower ratios of 20:4n-6/20:3n-6 and n-6/n-3. The predictors positively associated with obesity, in decreasing association strength, were 16:1n-7, 20:3n-6, and SFA. Obese boys showed significantly higher 20:4n-6, 20:5n-3, 20:3n-6/18:2 n-6, 18:3n-6 + 20:3n-6/18:2n-6, and 20:5n-3/20:4n-6, higher UFAs, and lower 18:2n-6 and 22:6n-3/20:4n-6 compared to obese girls (p < 0.05). CONCLUSION: Significant alterations in the proportions of plasma PL fatty acids were found in obese children, especially in male subjects, which might place them in danger of early cardiovascular risk; however, an insulin-resistant state might be responsible for their fatty acid composition. More studies are needed since there are none in Mexican children.

Metabolic syndrome risk factors among a sample of overweight and obese Mexican children.

The objective of this study was to estimate the prevalence and correlations of components of the metabolic syndrome (MetS) using the International Diabetes Federation (IDF) pediatric definition in a cross-sectional study of 215 overweight/obese Mexican children aged 6 to 12. There are no previous studies of this kind in Mexican children. Clinical, anthropometric, and laboratory measurements were performed. The prevalence of MetS using the pediatric IDF criteria was 6.7% (95% confidence interval, 4.0-11.1). A higher proportion of children in the younger age group had waist circumference above the cutoff, while a higher proportion in the older age group had hyperglycemia. Children with MetS had higher percentages of body fat, body mass index, total cholesterol, and low-density lipoprotein cholesterol. Increased triglycerides, decreased high-density lipoprotein cholesterol, and waist circumference were most highly associated with MetS. This has significant implications for public health.

Serum 25-hydroxyvitamin d concentration, life factors and obesity in Mexican children.

Although current evidence emphasizes a high prevalence of vitamin D deficiency and an inverse association between serum 25-hydroxyvitamin D (25-OHD) concentration and obesity, no studies have been conducted in Mexican children. The objective was to determine the prevalence of vitamin D deficiency and its association with obesity and lifestyle factors in a sample of school-aged Mexican children. A cross-sectional study of 99 obese and 99 nonobese 6-12 year-old children, skin phototypes III-V, from six public schools was conducted during summer at latitude 25 degrees 40', in northeastern Mexico. Anthropometric measurements were determined. Serum 25-OHD was measured by immunoluminometric direct assay. Consumption of foods rich in vitamin D, sunscreen use and vitamin consumption were assessed through applied questionnaires. 62.1% of the subjects had insufficiency of 25-OHD (21-29 ng/ml) and 20.2% had deficiency (<20 ng/ml). Obese subjects (BMI >or=95th percentile for age and gender) had significantly lower concentration of 25-OHD than nonobese. Predictors of 25-OHD concentration were, in order of significance: percentage of body fat, BMI, triceps skin fold, and waist circumference (WC). A significantly higher rate of 25-OHD deficiency was observed in children with inadequate milk/yoghurt consumption, but no difference was found for other foods, physical activity (PA) or screen-time. In a multivariate model, being obese was significantly associated with the risk of 25-OHD deficiency, after adjustment for PA, screen-time, skin phototype, ingestion of milk/yoghurt, fish, cheese, and carbonated beverages. A high prevalence of vitamin D deficiency and an inverse association between serum 25-OHD concentration and obesity was found.