Maternal and Offspring Fatty Acid Desaturase Variants, Prenatal DHA Supplementation, and Dietary n-6:n-3 Fatty Acid Ratio in Relation to Cardiometabolic Health in Mexican Children.

BACKGROUND: Single-nucleotide polymorphisms (SNPs) in fatty acid desaturase (FADS) genes may modify dietary fatty acid requirements and influence cardiometabolic health (CMH). OBJECTIVES: We evaluated the role of selected variants in maternal and offspring FADS genes on offspring CMH at the age of 11 y and assessed interactions of genotype with diet quality and prenatal docosahexaenoic acid (DHA) supplementation. METHODS: We used data from offspring (n = 203) born to females who participated in a randomized controlled trial of DHA supplementation (400 mg/d) from midgestation to delivery. We generated a metabolic syndrome (MetS) score from body mass index, high-density lipoprotein cholesterol, triglycerides, systolic blood pressure, and fasting glucose and identified 6 distinct haplotypes from 5 offspring FADS SNPs. Dietary n-6 (ω-6):n-3 fatty acid ratios were derived from 24-h recall data (n = 141). We used generalized linear models to test associations of offspring diet and FADS haplotypes with MetS score and interactions of maternal and offspring FADS SNP rs174602 with prenatal treatment group and dietary n-6:n-3 ratio on MetS score. RESULTS: Associations between FADS haplotypes and MetS score were null. Offspring SNP rs174602 did not modify the association of prenatal DHA supplementation with MetS score. Among children with TT or TC genotype for SNP rs174602 (n = 88), those in the highest n-6:n-3 ratio tertile (>8.61) had higher MetS score relative to the lowest tertile [<6.67) (Δ= 0.36; 95% confidence interval (CI): 0.03, 0.69]. Among children with CC genotype (n = 53), those in the highest n-6:n-3 ratio tertile had a lower MetS score relative to the lowest tertile (Δ= -0.23; 95% CI: -0.61, 0.16). CONCLUSIONS: There was evidence of an interaction of offspring FADS SNP rs174602 with current dietary polyunsaturated fatty acid intake, but not with prenatal DHA supplementation, on MetS score. Further studies may help to determine the utility of targeted supplementation strategies and dietary recommendations based on genetic profile.

Breastfeeding Duration and Cardiometabolic Health during Adolescence: A Longitudinal Analysis.

OBJECTIVE: To investigate the longitudinal association between breastfeeding duration and cardiometabolic health, using repeated measures study design among children and adolescents. STUDY DESIGN: This study included 634 offsprings aged 10 to 21 years (52% female) from the Early Life Exposure in Mexico to Environmental Toxicants birth cohort followed up to four time points during adolescence. Breastfeeding duration was prospectively quantified using questionnaires during early childhood. Cardiometabolic risk factors, body composition, and weight-related biomarkers were assessed as outcomes during adolescent follow-up visits. Sex-stratified linear mixed-effects models were used to model the association between quartiles of breastfeeding duration and outcomes, adjusting for age and additional covariates. RESULTS: Median breastfeeding duration was 7 months (minimum = 0, maximum = 36). Boys in the second quartile (median breastfeeding = 5 months) had lower total fat mass % (ß (SE) -3.2 (1.5) P = .037), and higher lean mass % (3.1 (1.6) P = .049) and skeletal muscle mass % (1.8 (0.8) P = .031) compared with the reference group (median breastfeeding = 2 months). A positive linear trend between breastfeeding duration and trunk lean mass % (0.1 (0.04) P = .035) was found among girls. No association was found with other cardiometabolic indicators. CONCLUSION: Despite sex-specific associations of breastfeeding duration with body composition, there was a lack of substantial evidence for the protective effects of breastfeeding against impaired cardiometabolic health during adolescence among Mexican youth. Further longitudinal studies with a robust assessment of breastfeeding are recommended.

Effects of prenatal docosahexaenoic acid supplementation on offspring cardiometabolic health at 11 years differs by maternal single nucleotide polymorphism rs174602: follow-up of a randomized controlled trial in Mexico.

BACKGROUND: There is limited evidence regarding long-term effects of prenatal docosahexaenoic acid (DHA) supplementation on offspring cardiometabolic health (CMH). Inconsistent results may be attributable to variants of fatty acid desaturase (FADS) genes. OBJECTIVE: We aimed to evaluate the effect of prenatal DHA supplementation on offspring CMH and investigate effect modification by maternal FADS2 single nucleotide polymorphism (SNP) rs174602. METHODS: We used follow-up data from a double-blind, randomized controlled trial in Mexico in which pregnant females received 400 mg/d of algal DHA or placebo from midgestation until delivery. The study sample included 314 offspring with data at age 11 y and maternal FADS genetic data (DHA: n = 160; Placebo: n = 154). We derived a Metabolic Syndrome (MetS) score from body mass index, HDL, triglycerides, fasting glucose concentrations, and systolic blood pressure. Generalized linear models were used to evaluate the effect of the intervention on offspring MetS score and test interactions between treatment group and genotype, adjusting for maternal, offspring, and household factors. RESULTS: Offspring MetS score did not differ significantly by treatment group. We observed evidence of effect modification by maternal SNP rs174602 (P = 0.001); offspring of maternal TT genotype who received DHA had lower MetS score relative to the placebo group (DHA (mean ± standard error of the mean (SEM)): -0.21 ± 0.11, n = 21; Placebo: 0.05 ± 0.11, n = 23; Δ= -0.26 (95% CI: -0.55, 0.04), P = 0.09); among CC maternal genotype carriers, offspring of mothers who received DHA had higher MetS score (0.18 ± 0.06, n = 62) relative to the placebo group (-0.05 ± 0.06, n = 65, Δ=0.24 (0.06, 0.41), P < 0.01). CONCLUSION: The effect of prenatal DHA supplementation on offspring MetS score differed by maternal FADS SNP rs174602. These findings further support incorporating genetic analysis of FADS polymorphisms in DHA supplementation trials. CLINICAL TRIAL DETAILS: This trial was registered at clinicaltrials.gov as NCT00646360.

Clustering of cardiometabolic risk factors in Mexican pre-adolescents.

OBJECTIVE: To examine clustering of cardiometabolic markers in Mexican children at age 11 years and compare a metabolic syndrome (MetS) score to an exploratory cardiometabolic health (CMH) score. METHODS: We used data from children enrolled in the POSGRAD birth cohort with cardiometabolic data available (n = 413). We used principal component analysis (PCA) to derive a Metabolic Syndrome (MetS) score and an exploratory cardiometabolic health (CMH) score, which additionally included adipokines, lipids, inflammatory markers, and adiposity. We assessed reliability of individual cardiometabolic risk as defined by MetS and CMH by calculating % agreement and Cohen's kappa statistic. RESULTS: At least one cardiometabolic risk factor was present in 42 % of study participants; the most common risk factors were low High-Density Lipoprotein (HDL) cholesterol (31.9 %) and elevated triglycerides (18.2 %). Measures of adiposity and lipids explained the most variation in cardiometabolic measures for both MetS and CMH scores. Two-thirds of individuals were categorized in the same risk category by both MetS and CMH scores (κ = 0.42). CONCLUSIONS: MetS and CMH scores capture a similar amount of variation. Additional follow-up studies comparing predictive abilities of MetS and CMH scores may enable improved identification of children at risk for cardiometabolic disease.

Design and Validation of a Food Frequency Questionnaire to Evaluate the Consumption of Trans Fatty Acids in the Adult Population (FFQ-TFA).

Instruments for estimating the intake of food components can be useful in the prevention and/or treatment of diseases related to improper diet. There is, at present, no scientifically validated instrument for estimating consumption of trans fatty acids (TFA) in the Mexican population. The objective of this study was to design and validate such an instrument: a questionnaire that can be used to estimate consumption of TFA from food products. The questionnaire was applied to 162 students from the Autonomous University of Querétaro (UAQ). There were two phases to the study: (1) design of a food frequency questionnaire to assess consumption of trans fatty acids (FFQ-TFA) and an eating practices questionnaire (EPQ-TFA); (2) validation of the instrument. Content validity was measured by expert review and by Aiken's V method, obtaining an overall score of 0.895. As final tests for the FFQ-TFA analysis, criterion validity was measured using Spearman's correlation (r = 0.717, p < 0.01) and a linear regression (B = 0.668), considering the results of the 24-h dietary recall (24 HR); and reproducibility or temporal stability was measured using Pearson's correlation (r = 0.406, p < 0.01). Subsequently, a Pearson correlation was applied between TFA consumption estimated by the FFQ-TFA-2 and the global score from the EPQ-TFA-2 (r = 0.351, p < 0.01). A Pearson correlation was applied between the EPQ-TFA-1 and the EPQ-TFA-2 (r = 0.575, p < 0.01). TFA consumption per day was 2.49 ± 1.32 g in the participating population, which was 1.04 ± 0.51% of their total kcal consumption.

Conducta de apetito-saciedad y estado nutricio en lactantes menores de 6 meses de edad / Behavior of appetite-satiety and nutritional status in infants under 6 months of age

Resumen La prevalencia de la obesidad infantil ha aumentado alarmantemente a nivel mundial. En lactantes, la etiología es multicausal, destacando la ingesta como un determinante clave para el aumento de peso. El comportamiento alimentano del lactante y que algunas madres perciban pobremente las señales de hambre y saciedad de su hijo, dificultan la autorregulación de la conducta de apetito-saciedad y puede favorecer el desarrollo de la obesidad. Sin embargo, las investigaciones aún son limitadas. El objetivo del presente trabajo fue identificar cómo percibe la madre la conducta de alimentación de su hijo y cómo se relaciona con el estado nutricio" del lactante menor de seis meses de edad. El diseño fue descriptivo correlacionai, se estudiaron 40 diadas (madre-hijo menor de seis meses de edad) que asistieron al programa Control de Nino Sano de una institución de salud pública. Se exploraron las características sociodemográficas de la diada y mediciones antropométricas de peso y talla. Se utilizó el Baby Eating Behavior Questionnarie para medir a través de cuatro subescalas la. conducta alimentaria del lactante. La media de edad de los lactantes fue de 4.03 meses (DE = 1.16). El 37.5 % presentaron sobrepeso y el 62.5 % eran varones. La conducta alimentaría más percibida por la madre fue "disfrute de alimentos" ( x -= 4.85; DE = 0.34), la conducta menos percibida fue respuesta de saciedad" ( x -= 2.06; DE = 0.83). La conducta de "mi bebé tiene un gran apetito" se correlacionó con el IMC del lactante (rs = 0.299, p < 0.05). Las madres fueron más sensibles para percibir las señales de hambre de su hijo, no así con las señales de saciedad, lo cual pűede favorecer el aumento de peso rápido en el lactante y por ende el desarrollo de la obesidad a edad temprana.

Abstract The prevalence of childhood obesity has increased alarmingly worldwide. In infants, the etiology is multi-causal, highlighting the intake as a determinant for weight gain. The alimentary behavior of the infant and the poor perception of hunger and satiety signals of their children perceived by some mothers difficult the self-regulation of the appetite-satiety behavior and may favor the development of obesity. However, research is still limited. The objective of this study was to identify how the mother peceives the eating behavior of her child and how it relates to the nutritional status of the infant. The design was descriptive correlational. 40 dyads were studied (mother-son under the age of 6 months) who attended the Healthy Child Control program of a public health institution. The sociodemographic characteristics of the dyad and anthropometric measurements of height and weight were explored. The Baby Eating Behavior Questionnaire was used to measure the feeding behavior of the infant through four scales. The mean age of the infants was 4.03 months. (DE = 1.16). The 37.5 % were overweight and the 62.5 % were males. The mother's most often perceived feeding behavior was "enjoyment of food" ( x - = 4.85; DE = 0.34) and the least frequently perceived was "safety responsiveness"( x -= 2.06; DE = 0.83). The "My baby has a good appetite" perception was correlated" to the BMI of the infant (rs = 0.299, p < 0.05). Mothers were more sensitiive to perceive their child s hunger signals, but not with satiety signals, which may favor the rapid weight gain in infants and thus the obesity development at early age.

Prevalence of anemia in children 1 to 12 years of age. Results from a nationwide probabilistic survey in Mexico.

OBJECTIVE: To describe the epidemiology and analyze factors associated with iron deficiency anemia in a probabilistic sample of the Encuesta Nacional de Nutrición 1999 (ENN-99) [National Nutritional Survey 1999 (NNS-99)]. MATERIAL AND METHODS: The sample included 8,111 children aged 1 to 12 years, and was nationally representative by rural and urban strata and by four geographical regions. Capillary hemoglobin was measured using a portable photometer (HemoCue). The analysis of the determining factors of anemia was performed by odds ratios derived from a logistic regression model and multiple regression models. RESULTS: The prevalence of anemia was 50% in infants < 2 years of age, with no significant differences between urban and rural strata or among regions. It varied between 14 and 22% in 6-11 year-old children and was higher in the South region and among the indigenous children. Dietary intake of iron was 50% of the recommended daily allowance in children < 2 years of age, but not in older children. Phytate ( approximately 500-800 mg/d) and tannin (approximately 19 mg/d) intakes were very high in children over 7 years of age. Hemoglobin was positively associated with nutritional status of children (p = 0.01), socioeconomic status (p range 0.05-0.001), duration of lactation in children under 2 years of age (p = 0.1), and iron and calcium intake (p = 0.02), but not with folic acid or vitamin B12 intake. Hemoglobin was negatively associated with maternal education (p = 0.01) in older children, but not in those under 2 years of age. CONCLUSIONS: We present evidence of an alarming national epidemic of anemia, particularly marked in children 12 to 24 months of age. The control of anemia should be considered as an urgent national concern given its grave consequences on the physical and mental development of these children and on their long-term health. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Vitamins A, and C and folate status in Mexican children under 12 years and women 12-49 years: a probabilistic national survey.

OBJECTIVE: To describe the epidemiology of Vitamin A and C and folic acid deficiencies and their association with sociodemographic and dietary factors in a national probabilistic sample of Mexican women and children. MATERIAL AND METHODS: This is a probabilistic sample from the National Nutrition Survey 1999 (ENN-99) including 1,966 children and 920 women. Vitamins A and C were measured in serum by high-performance liquid chromatography, and folic acid in total blood by a microbiological method. Determinants for such deficiencies were explored by multiple regression models. RESULTS: Vitamin A deficiency (retinol < 10 micrograms/dl) was rare in both children and women. But subclinical deficiency (retinol > 10 and < 20 micrograms/dl) was present in 25% of children. The likelihood of subclinical deficiency of vitamin A was less in older children (OR = 0.98, p = 0.01) and in women with higher body mass index (OR = 0.93, p = 0.01). About 30% of children < 2 years of age and 40% of women were vitamin C deficient. The likelihood of vitamin C deficiency was less in children and women as socioeconomic level increased (OR = 0.69, p = 0.03, and OR = 0.80, p = 0.04), and higher in older women (OR = 1.02, p = 0.05). The prevalence of folate deficiency varied in children (2.3 to 11.2), in women it was 5%. Folate deficiency was less in children of higher socioeconomic level (OR = 0.62, p = 0.01), and in those eating more vegetables (OR = 0.22, p = 0.01). CONCLUSIONS: The high prevalence of subclinical deficiency of vitamin A in children is indicative of risk of further deterioration under adverse circumstances. Vitamin C deficiency in both children and women implies in addition diminished ability for iron absorption. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Iron, zinc and iodide status in Mexican children under 12 years and women 12-49 years of age. A probabilistic national survey.

OBJECTIVE: To describe the epidemiology of iron, zinc and iodide deficiencies in a probabilistic sample of Mexican women and children and explore its association with some dietary and socio-demographic variables. MATERIAL AND METHODS: We carried out in 1999 an epidemiological description of iron (percent transferrin saturation, PTS, < 16%), serum zinc (< 65 ug/dl) and iodide (< 50 ug/l urine) deficiencies in a probabilistic sample of 1,363 Mexican children under 12 years and of 731 women of child-bearing age. Serum iron, Total Iron Binding Capacity (TIBC) and zinc were measured by atomic absorption spectrometry, and urinary iodide by a colorimetric method. Logistic regression models explored determinants for such micromineral deficiencies. RESULTS: Iron deficiency was higher (67%) in infants < 2 years of age. Prevalence declined (34-39%) at school age. The prevalence for iron deficiency in women was 40%. Zinc deficiency was higher in infants < 2 years of age (34%) than in school-age children (19-24%). Prevalence in women was 30%, with no rural/urban difference. In women the likelihood of iron deficiency decreased as SEL improved (p = 0.04) and increased with the intake of cereals (p = 0.01). The likelihood of low serum zinc levels was greater in women and children of low socioeconomic level (SEL) (p < 0.02 and p = 0.001) iodide deficiency was negligible in both children and women. CONCLUSIONS: The data shows high prevalence of iron deficiency-specially in infants 12 to 24 months of age. It is suggested that in older children and women 12 to 49 years of age that iron bioavailability is low. The prevalence of zinc deficiency was also very high. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Factors associated with overweight and obesity in Mexican school-age children: results from the National Nutrition Survey 1999.

OBJECTIVE: The objective of the study was to measure the prevalence of overweight and obesity in Mexican school-age children (5-11 years) in the National Nutrition Survey 1999 (NNS-1999). MATERIAL AND METHODS: Overweight and obesity (defined as an excess of adipose tissue in the body) were evaluated through the Body Mass Index (BMI) in 10,901 children, using the standard proposed by the International Obesity Task Force. Sociodemographic variables were obtained using a questionnaire administered to the children's mothers. RESULTS: The national prevalence of overweight and obesity was reported to be 19.5%. The highest prevalence figures were found in Mexico City (26.6%) and the North region (25.6%). When adjusting by region, rural or urban area, sex, maternal schooling, socioeconomic status, indigenous ethnicity and age, the highest prevalences of overweight and obesity were found among girls. The risks of overweight and obesity were positively associated with maternal schooling, children's age and socioeconomic status. CONCLUSIONS: Overweight and obesity are prevalent health problems in Mexican school-age children, particularly among girls, and positively associated with socioeconomic status, age, and maternal schooling. This is a major public health problem requiring preventive interventions to avoid future health consequences. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Prevalence of anemia in children 1 to 12 years of age: results from a nationwide probabilistic survey in Mexico

OBJETIVO: Describir la epidemiología y analizar los determinantes de la anemia en una muestra probabilística de la Encuesta Nacional de Nutrición 1999 (ENN-99). MATERIAL Y MÉTODOS: La muestra del estudio, hecho en 1999, incluyó 8 111 menores de entre 1 a 12 años de edad, representativa a escala nacional, de estratos rural y urbano y de cuatro regiones geográficas de México. La hemoglobina capilar fue medida mediante un fotómetro portátil (HemoCue). El análisis de los determinantes de anemia se hizo mediante razón de momios obtenidas con un modelo de regresión logística y modelos de regresión múltiple. RESULTADOS: La prevalencia de anemia fue más alta (50 por ciento) en menores de dos años de edad, sin diferencias entre urbanos y rurales en las cuatro regiones geográficas. La prevalencia general de anemia varió entre 14 y 22 por ciento en niños y niñas de 6 a 12 años de edad, y fue más alta en la región sur y en los niños indígenas. La ingestión de hierro fue muy baja en menores de dos años de edad (50 por ciento de la ingesta diaria recomendada), pero no en los mayores; la ingestión de fitatos (¼500-800 mg/d) y taninos (¼19 mg/d) fue muy alta en niños >7 años de edad. El nivel de hemoglobina se asoció positivamente con el estado nutricio de los niños (p=0.01) y el nivel socioeconómico (intervalo p 0.05-0.001); en menores de dos años de edad, se asoció con la duración del amamantamiento (p=0.1), la ingestión de hierro y de calcio (p=0.02), pero no con la ingestión de ácido fólico ni de vitamina B12. El nivel de hemoglobina se asoció negativamente con la educación materna (p=0.01) en niños mayores, pero no en menores de dos años de edad. CONCLUSIONES: Se presenta evidencia de una alarmante epidemia nacional de anemia en niños, especialmente preocupante en los menores de 24 meses de edad. La anemia debe considerarse como una emergencia nacional, debido a las graves consecuencias que tiene sobre el desarrollo físico y mental de niños y niñas y sobre su salud durante la vida adulta.

Vitamins A, and C and folate status in Mexican children under 12 years and women 12-49 years: a probabilistic national survey

OBJETIVO: Describir la epidemiología de las deficiencias de las vitaminas A y C y del ácido fólico, y analizar su asociación con factores sociodemográficos y dietéticos en una muestra probabilística nacional de mujeres y niños mexicanos. Informar acerca del estado nutricio de estas vitaminas en una muestra probabilística nacional en México. MATERIAL Y MÉTODOS: Esta muestra probabilística de la Encuesta Nacional de Nutrición 1999 incluyó 1 966 niños y 920 mujeres. Las concentraciones séricas de las vitaminas A y C fueron medidas por cromatografía líquida de alta resolución HPLC (por sus siglas en inglés) y las de ácido fólico en sangre total por un método microbiológico. Se exploraron los posibles determinantes de la deficiencia de tales nutrimentos mediante modelos de regresión logística. RESULTADOS: La deficiencia de vitamina A (retinol <10 µg/dl) fue rara, tanto en niños como en mujeres. El 25 por ciento de los niños de 1 a 8 años de edad tuvieron deficiencia subclínica (retinol >10 <20 µg/dl). El riesgo de tener deficiencia subclínica de vitamina A fue menor en los niños de mayor edad (OR=0.98, p=0.01) y en mujeres con mayor índice de masa corporal (OR=0.93, p=0.01). El 30 por ciento de los niños <2 años de edad y 40 por ciento de las mujeres tuvieron deficiencia de vitamina C. El riesgo de esta deficiencia fue menor en niños y mujeres de nivel socioeconómico alto (OR=0.69, p=0.03, y OR=0.80, p=0.04), y mayor en mujeres de mayor edad (OR=1.02, p=0.05). En los niños la prevalencia de deficiencia de ácido fólico varió entre 2.3 y 11.2 por ciento, en las mujeres de 5 por ciento. El riesgo de tener deficiencia de folatos fue menor en niños con nivel socioeconómico alto (OR=0.66, p=0.04), y menor en aquellos que consumían más vegetales (OR= 0.22, p=0.01). CONCLUSIONES: La alta prevalencia en México de deficiencia subclínica de vitamina A en niños y de vitamina C tanto en niños como en mujeres reclama acciones programáticas para reducirlas.

Iron, zinc and iodide status in Mexican children under 12 years and women 12-49 years of age: a probabilistic national survey

OBJETIVO: Describir la epidemiología de las deficiencias de hierro, zinc y yodo en una muestra probabilística de mujeres y niños mexicanos y analizar algunas asociaciones con factores dietéticos y sociodemográficos. MATERIAL Y MÉTODOS: Descripción epidemiológica de las deficiencias de hierro (Porcentaje de saturación de transferrina <16 por ciento), zinc (<65ug/dl) y yodo (<50ug/l orina) en una muestra probabilística de 1363 niños y 731 mujeres. Las concentraciones séricas de hierro, y la capacidad total de saturación de hierro y zinc se midieron por espectrometría de absorción atómica, y el yodo por un método colorimétrico. Los determinantes de tales deficiencias se estudiaron mediante modelos de regresión logística. RESULTADOS: La deficiencia de hierro fue mayor (67 por ciento) en niños <2 años de edad. La prevalencia disminuyó en los escolares (34-39 por ciento). La prevalencia de deficiencia de hierro en mujeres fue de 40 por ciento. La deficiencia de zinc fue mayor en niños <2 años de edad (34 por ciento) que en escolares (19-24 por ciento). La prevalencia en mujeres fue de 30 por ciento, sin diferencia rural/urbana. La probabilidad de tener deficiencia de hierro en mujeres disminuyó con el nivel socio-económico (p=0.04) y aumentó con la ingestión de cereales (p=0.01). La probabilidad de tener concentraciones bajas de zinc sérico fueron mayores en mujeres de nivel socioeconómico (SES) bajo (p=0.02 y p=0.001). La prevalencia de deficiencia de yodo fue casi inexistente tanto en niños como en mujeres. CONCLUSIONES: Los datos demuestran una alta prevalencia de deficiencia de hierro, especialmente en niños de 12 a 24 meses de edad. Se sugiere que en niños mayores y en mujeres de 12 49 años existe una baja biodisponibilidad de hierro. La deficiencia de zinc fue tambien muy alta.

Factors associated with overweight and obesity in Mexican school-age children: results from the National Nutrition Survey 1999

OBJETIVO: Documentar las prevalencias de sobrepeso y obesidad en niños mexicanos en edad escolar (5 a 11 años de edad) obtenidas de la Encuesta Nacional de Nutrición en 1999 (ENN-1999).MATERIAL Y MÉTODOS: El sobrepeso y la obesidad (definida como un exceso de tejido adiposo en el organismo) se evaluaron a través del Indice de Masa Corporal (IMC) en 10 901 niños, tomando como patrón de referencia el propuesto por el International Obesity Task Force. Las variables sociodemográficas se obtuvieron a partir de un cuestionario aplicado a la madre del niño. RESULTADOS: La prevalencia nacional de sobrepeso y obesidad fue de 19.5 por ciento. Las prevalencias más altas se encontraron en la Ciudad de México (26.6 por ciento) y en la región norte (25.6 por ciento). Al ajustar por región, zona rural o urbana, sexo, escolaridad de la madre, nivel socioeconómico, edad e indigenismo, los mayores riesgos de sobrepeso y obesidad se encontraron en niñas; el riesgo de obesidad y sobrepeso se asoció positivamente con la escolaridad de la madre, con el nivel socioeconómico y con la edad de los escolares. CONCLUSIONES: El sobrepeso y obesidad son problemas de salud de alta prevalencia en niños en edad escolar en México, especialmente en niñas, y se asocia positivamente con el nivel socioeconómico, la edad de los escolares y la escolaridad de las madres. Este es un problema de salud pública que requiere acciones de prevención para evitar riesgos en la salud en un futuro.