[Anemia, iron and zinc deficiencies, supplements consumption and morbidity in Mexican children aged 1 to 4: analysis of Ensanut 100k.] / Anemia, deficiencias de zinc y hierro, consumo de suplementos y morbilidad en niños mexicanos de 1 a 4 años: resultados de la Ensanut 100k.

OBJECTIVE: To analyze the association between supplements and Liconsa milk intake, with anemia, zinc (ZD) and iron (ID) deficiencies, and morbidity in Mexican children resident of less than 100 000 habitants' localities. MATERIALS AND METHODS: A subsample of 1 516 children aged 1-4 participants of Ensanut 100k was analyzed, carried out in 2018. Anemia was considered if [Hb]<11 g/dL, ZD if [Zn]<65 µg/dL and ID if [ferritin]<12 µg/L. Supplements and Liconsa milk consumption were obtained from a semi-quantitative food frequency; morbidity by self-report of the mother. Multiple logistic regression models were used adjusted by confounders. RESULTS: Medium and high consumption of Liconsa milk was associated to lower odds of ID (OR=0.02, [95%CI 0.002,0.24] and OR=0.07, [95%CI 0.01,0.52]) and anemia (OR=0.13, [95%CI 0.04,0.37] and OR=0.17, [95%CI 0.03,0.87]). A high intake of Liconsa milk (OR=0.09, [95%CI 0.01,0.44]) and Vitaniño (OR=0.05 [95%CI 0.005, 0.46]) were both associated to lower diarrhea risk. CONCLUSIONS: To assure the continuity of the consumption of nutritional supplements is necessary for improving the health and the micronutrients status in vulnerable Mexican children.

OBJETIVO: Analizar la asociación entre el consumo de suplementos o leche Liconsa y anemia, deficiencias de zinc (DZ) y hierro (DH) y morbilidad en niños mexicanos residentes de localidades menores a 100 000 habitantes. MATERIAL Y MÉTODOS: Se analizó información de 1 516 niños de 1 a 4 años de la Encuesta Nacional de Salud y Nutrición en localidades con menos de 100 000 habitantes realizada en el año 2018. Se definió Anemia si [Hb]<11 g/dL, DZ: [Zn]<65 µg/dL y DH: [ferritina]<12 µg/L. El consumo de suplementos y de leche Liconsa se obtuvo del cuestionario de Frecuencia de Consumo de Alimentos y morbilidad por autorreporte de la madre. Se emplearon modelos de regresión logística múltiple para el análisis de las asociaciones, ajustados por confusores. RESULTADOS: El consumo medio y alto de leche Liconsa se asoció con menor momio de DH (RM=0.02 [IC95% 0.002,0.24] y RM=0.07 [IC95% 0.01,0.52]) y anemia (RM=0.13 [IC95% 0.04,0.37] y RM=0.17 [IC95% 0.03,0.87]). Un alto consumo de leche Liconsa (RM=0.09, [IC95% 0.01,0.44]) y de Vitaniño (RM=0.05 [IC95% 0.005, 0.46]) se asoció con menor momio de diarrea. CONCLUSIONES: Es necesario considerar la continuidad del consumo de suplementos nutricionales para mejorar la salud y el estado de micronutrimentos en población infantil mexicana vulnerable.

[High prevalence of anemia in Mexican women in poverty, Ensanut 100k]. / Alta prevalencia de anemia en mujeres mexicanas en pobreza, Ensanut 100k.

OBJECTIVE: To estimate the prevalence and distribution of anemia in Mexican women and their association with sociodemographic factors and diet diversity. MATERIALS AND METHODS: We analyzed information of women in childbearing age. The Ensanut 100k is a probabilistic survey that overrepresents households with less economic capacity. Anemia was estimated using hemoglobin concentration. We collected sociodemographic and health information, food insecurity, and dietary diversity. RESULTS: 34.3% of the women presented anemia, belong to tertile 3 of welfare status is a protective factor for anemia (OR= 0.26, 95%CI 0.16-0.61), and living in a household with food security, as well as high diversity of the diet in rural women (OR= 0.57, 95%CI 0.36-0.92). CONCLUSIONS: It is necessary to implement actions of detection and early attention of the anemia in women in childbearing age, identification of its underlying causes, strengthening and reformulation of strategies to prevent it.

OBJETIVO: Estimar la prevalencia y distribución de anemia en mujeres mexicanas y su asociación con factores sociodemográficos y la diversidad de la dieta. MATERIAL Y MÉTODOS: Se incluyeron mujeres en edad fértil de la encuesta probabilística Ensanut 100k, que representa a los hogares con menos capacidades económicas. Se estimó la prevalencia de anemia mediante concentración de hemoglobina, con información sociodemográfica, de salud, inseguridad alimentaria y diversidad de la dieta. RESULTADOS: El 34.3% de las mujeres presentó anemia; los factores protectores para anemia fueron pertenecer al tercil 3 de condición de bienestar (OR=0.26, IC95% 0.16-0.61), alta diversidad de la dieta en áreas rurales (OR=0.57, IC95%0.36-0.92), así como vivir en un hogar con seguridad alimentaria. CONCLUSIONES: Es necesario implementar acciones de detección y atención temprana de la anemia en las mujeres de edad fértil, así como identificar las causas subyacentes y fortalecer y reformular estrategias para prevenirla.

Dietary intake and adequacy of energy and nutrients in Mexican adolescents: Results from Ensanut 2012.

OBJECTIVE: To estimate energy and nutrient intakes and adequacies in Mexican adolescents. MATERIALS AND METHODS: Dietary intake was assessed in 1 961 adolescents who participated in the National Health and Nutrition Survey 2012 (Ensanut 2012), by a food frequency questionnaire. Medians of intakes and adequacies were estimated for energy, macroand micronutrients and are presented by residence area, region and household wealth index (HWI). Consumption by food groups was estimated. RESULTS: Median daily energy intake was 2 000 Kcal in males and 1 800 Kcal in females. High prevalences of inadequacy were observed for fiber, PUFAs, iron, zinc and calcium. These inadequacies were higher among individuals of low HWI. Moreover, excessive intakes of total and saturated fat were higher among adolescents of higher HWI. CONCLUSIONS: The diet of Mexican adolescents is deficient in essential nutrients for good health and high in saturated fat. Actions are needed to promote a healthy diet.

Prevalence of iron, folate, and vitamin B12 deficiencies in 20 to 49 years old women: Ensanut 2012.

OBJECTIVE: To describe the prevalence of iron, folate, and B12 deficiencies in Mexican women of reproductive age from the National Health and Nutrition Survey (Ensanut) 2012. MATERIALS AND METHODS: Data came from a national probabilistic survey, representative from rural and urban areas, and different age groups. Blood samples were obtained from 4 263, 20 to 49 years old women for serum ferritin, vitamin B12 and serum folate concentrations. The prevalence of deficiencies, was assessed using adjusted logistic regression models. RESULTS: The deficiency of folate was 1.9% (95%CI 1.3-2.8), B12 deficiency was 8.5% (95%CI 6.7-10.1) and iron deficiency was 29.4% (95%CI 26.5-32.2). No differences were found when compared with 2006, 24.8% (95%CI 22.3-27.2). CONCLUSIONS: The vitamin B12 deficiency is still a problem for women of reproductive age and their offspring in Mexico, while folate deficiency disappeared as a problem. Iron deficiency needs prevention and fortification strategies.

[Waist-to-height ratio as a predictor of blood pressure in Mexican children. Follow-up study]. / Índice cintura/estatura como un predictor de la presión arterial en niños mexicanos. Estudio de seguimiento

OBJECTIVE: To assess the effect of increased waist-to-height ratio (WHtR) on the development of high blood pressure or hypertension in Mexican children. MATERIAL AND METHODS: 313 preschoolers followed for one year. We measured height and waist circumference (WC) and calculated the WHtR (cm WC/cm height). Blood pressure was obtained with a mercury sphygmomanometer. Children were classified with high blood pressure according to the fourth report of diagnosis, evaluation and treatment of high blood pressure in children and adolescents. We assessed longitudinally the impact of body mass indicators (body mass index, WC and total fat) and WHtR on the development of high pressure in separate models. Longitudinal analysis was performed with random effects using Husman test for assessing the adequacy of the model. RESULTS: WHtR 1.75 unit increased the risk of hypertension. CONCLUSION: The WHtR is a better predictor of hypertension compared to BMI and WC in preschool children followed over time.

Short Stature Modifies the Waist-to-height Ratio cut-off Points as an Indicator of Cardiovascular Risk in Mexican Adult Women and Men.

BACKGROUND: Waist-to-height ratio (WHtR) is one of the anthropometric measures associated with cardiovascular risk (CVR). However, WHtR cut-off points may vary depending according to population characteristics, including sex and height. OBJECTIVE: To identify optimal WHtR cut-off points to predict CVR factors by sex in Mexican adults according to height. MATERIAL AND METHODS: Information from adults >20 years (n = 3550) from the 2016 National Health and Nutrition Survey were analyzed. Prevalence of high WHtR, CVR factors (glucose and insulin, lipid profile (total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides) and blood pressure were estimated by sex and height (short height <1.60 and <1.50 m in men and women, respectively). The maximum proximity procedure was used to establish the point of maximum simultaneous sensitivity and specificity using the operating characteristic curve of the receiver. The estimates were stratified by sex and height condition. RESULTS: The WHtR cut-off points identified to predict CVR were higher than those suggested for international use (≥0.5), being significantly higher (p <0.0001) for women (0.61) than for men (0.56). Also, the WHtR cut-off points were higher for short stature (men 0.58 and 0.56, women 0.63 and 0.58, with short and normal stature, respectively). CONCLUSIONS: The WHtR cut-off points for predicting CVR in the Mexican population were higher than 0.5 in both sexes and it was higher for individuals with short stature. The identified cut-off points may be an additional tool in screening the adult population in Mexico to predict CVR.

Physical activity and fat mass gain in Mexican school-age children: a cohort study.

BACKGROUND: In México, the prevalence of unhealthy weight increased from 24% at 6 y to 33% at 12 y of age, opening a window of opportunity to better understand the pathogenesis of obesity. The objective of this study was to explore the association between time spent on medium, vigorous physical activity (MVPA) and concurrent gains in BMI, fat mass (FM) and fat-free mass (FFM), alternately, in a cohort of Mexican children followed from kindergarten (baseline) to 2nd grade elementary school (endline). METHODS: The MVPA (5-d accelerometry), BMI, FM and FFM (air displacement plethysmography) were measured at baseline and endline. Associations between gains in BMI, FM and FFM and changes in MVPA were examined using lagged and dynamic regression models, controlling for energy intake and demographic variables. RESULTS: A total of 205 children were analyzed. Gender affected the effect of MVPA on FM gain. In girls, a high baseline MVPA predicted a lower FM gain (-0.96 kg, p=0.025) compared to low/medium MVPA. Increasing, decreasing or having a persistently high MVPA predicted a lower FM gain (range -1.6 to -1.03 kg, p<0.05) compared to persistently low MVPA. In boys, increases in MVPA were associated with higher gains in BMI (+0.76 kg/m2, p=0.04) and FFM (+1.1 kg, p=0.01) compared to persistently low MVPA. CONCLUSION: These results support a protective role of MVPA on FM gain in girls, suggesting that it may play a crucial role in the development of obesity. Further research on the gender effect of MVPA is warranted to better understand its role in the prevention and control of overweight and obesity.

The physical activity level of Mexican children decreases upon entry to elementary school.

OBJECTIVE: To compare the physical activity patterns of a cohort of Mexican children in kindergarten (K), first (1ES) and second grade (2ES) of elementary school. MATERIAL AND METHODS: The physical activity of 217 children (123 girls and 94 boys) aged 5-6 years was measured (five full-day triaxial accelerometry) annually.Weekday and weekend moderate/ vigorous physical activity (MVPA) and school and off-school MVPA was calculated. Comparisons between surveys were made using longitudinal multilevel generalized linear models. RESULTS: Weekday MVPA was 22 and 37 min/d lower for 1ES (p=0.06) and 2ES (p<0.01), respectively, compared to K. School MVPA for 1ES and 2ES was 37 (-5.0 min/h) and 40% (-5.5 min/h) (p<0.001) lower, respectively, compared to K. No differences were found between weekend and off-school MVPA among school stages (p>0.5). CONCLUSION: MVPA was significantly reduced from K to ES,in part because of a decline in MVPA during school activities. Interventions targeted to school environment modifications should be promoted.

Association between High Waist-to-Height Ratio and Cardiovascular Risk among Adults Sampled by the 2016 Half-Way National Health and Nutrition Survey in Mexico (ENSANUT MC 2016).

Little evidence exists regarding the association between waist-to-height ratio (WHtR) and cardiovascular risk (CVR) factors in Mexican adults. Our study pursued a twofold objective: To describe the association between a high WHtR and CVR indicators among Mexican adults canvassed by the 2016 Half-Way National Health and Nutrition Survey, and to examine the interaction of sex and age on this association. We analyzed data from the adult sample (≥20 years old) and classified in two groups using WHtRs ≥0.5 considered high and low otherwise. The following CVR factors were analyzed: High-total-cholesterol (≥200 mg/dL), low high-density-lipoprotein-cholesterol (HDL-c < 40 mg/dL), high low-density-lipoprotein-cholesterol (LDL-c ≥ 130 mg/dL), high triglycerides (≥150 mg/dL), insulin resistance (IR) (HOMA-IR) (≥2.6), and hypertension (HBP) (≥140/≥90 mmHg). We estimated prevalence ratios (PR) to analyze the association between high WHtRs and CVR indicators. Over 90% of participants had high WHtRs and were at greater risk for dyslipidemias, HBP, and IR compared to those that had low WHtRs. PR for men with high WHtRs were between 1.3 to 2.3 for dyslipidemias, 3.4 for HBP and 7.6 for IR; among women were between 1.8 to 2.4 for dyslipidemias and HBP and 5.9 for IR (p < 0.05). A high WHtR is associated with CVR factors in Mexican adults.

Alta prevalencia de anemia en mujeres mexicanas en pobreza, Ensanut 100k / High prevalence of anemia in Mexican women in poverty, Ensanut 100k

Resumen: Objetivo: Estimar la prevalencia y distribución de anemia en mujeres mexicanas y su asociación con factores sociodemográficos y la diversidad de la dieta. Material y métodos: Se incluyeron mujeres en edad fértil de la encuesta probabilística Ensanut 100k, que representa a los hogares con menos capacidades económicas. Se estimó la prevalencia de anemia mediante concentración de hemoglobina, con información sociodemográfica, de salud, inseguridad alimentaria y diversidad de la dieta. Resultados: El 34.3% de las mujeres presentó anemia; los factores protectores para anemia fueron pertenecer al tercil 3 de condición de bienestar (OR=0.26, IC95% 0.16-0.61), alta diversidad de la dieta en áreas rurales (OR=0.57, IC95%0.36-0.92), así como vivir en un hogar con seguridad alimentaria. Conclusiones: Es necesario implementar acciones de detección y atención temprana de la anemia en las mujeres de edad fértil, así como identificar las causas subyacentes y fortalecer y reformular estrategias para prevenirla.

Abstract: Objective: To estimate the prevalence and distribution of anemia in Mexican women and their association with sociodemographic factors and diet diversity. Materials and methods: We analyzed information of women in childbearing age. The Ensanut 100k is a probabilistic survey that over-represents households with less economic capacity. Anemia was estimated using hemoglobin concentration. We collected sociodemographic and health information, food insecurity, and dietary diversity. Results: 34.3% of the women presented anemia, belong to tertile 3 of welfare status is a protective factor for anemia (OR= 0.26, 95%CI 0.16-0.61), and living in a household with food security, as well as high diversity of the diet in rural women (OR= 0.57, 95%CI 0.36-0.92). Conclusions: It is necessary to implement actions of detection and early attention of the anemia in women in childbearing age, identification of its underlying causes, strengthening and reformulation of strategies to prevent it.

Anemia, deficiencias de zinc y hierro, consumo de suplementos y morbilidad en niños mexicanos de 1 a 4 años: resultados de la Ensanut 100k / Anemia, iron and zinc deficiencies, supplements consumption and morbidity in Mexican children aged 1 to 4: analysis of Ensanut 100k

Resumen: Objetivo: Analizar la asociación entre el consumo de suplementos o leche Liconsa y anemia, deficiencias de zinc (DZ) y hierro (DH) y morbilidad en niños mexicanos residentes de localidades menores a 100 000 habitantes. Material y métodos: Se analizó información de 1 516 niños de 1 a 4 años de la Encuesta Nacional de Salud y Nutrición en localidades con menos de 100 000 habitantes realizada en el año 2018. Se definió Anemia si [Hb]<11 g/dL, DZ: [Zn]<65 µg/dL y DH: [ferritina]<12 µg/L. El consumo de suplementos y de leche Liconsa se obtuvo del cuestionario de Frecuencia de Consumo de Alimentos y morbilidad por autorreporte de la madre. Se emplearon modelos de regresión logística múltiple para el análisis de las asociaciones, ajustados por confusores. Resultados: El consumo medio y alto de leche Liconsa se asoció con menor momio de DH (RM=0.02 [IC95% 0.002,0.24] y RM=0.07 [IC95% 0.01,0.52]) y anemia (RM=0.13 [IC95% 0.04,0.37] y RM=0.17 [IC95% 0.03,0.87]). Un alto consumo de leche Liconsa (RM=0.09, [IC95% 0.01,0.44]) y de Vitaniño (RM=0.05 [IC95% 0.005, 0.46]) se asoció con menor momio de diarrea. Conclusiones: Es necesario considerar la continuidad del consumo de suplementos nutricionales para mejorar la salud y el estado de micronutrimentos en población infantil mexicana vulnerable.

Abstract: Objective: To analyze the association between supplements and Liconsa milk intake, with anemia, zinc (ZD) and iron (ID) deficiencies, and morbidity in Mexican children resident of less than 100 000 habitants' localities. Materials and methods: A subsample of 1 516 children aged 1-4 participants of Ensanut 100k was analyzed, carried out in 2018. Anemia was considered if [Hb]<11 g/dL, ZD if [Zn]<65 µg/dL and ID if [ferritin]<12 µg/L. Supplements and Liconsa milk consumption were obtained from a semi-quantitative food frequency; morbidity by self-report of the mother. Multiple logistic regression models were used adjusted by confounders. Results: Medium and high consumption of Liconsa milk was associated to lower odds of ID (OR=0.02, [95%CI 0.002,0.24] and OR=0.07, [95%CI 0.01,0.52]) and anemia (OR=0.13, [95%CI 0.04,0.37] and OR=0.17, [95%CI 0.03,0.87]). A high intake of Liconsa milk (OR=0.09, [95%CI 0.01,0.44]) and Vitaniño (OR=0.05 [95%CI 0.005, 0.46]) were both associated to lower diarrhea risk. Conclusions: To assure the continuity of the consumption of nutritional supplements is necessary for improving the health and the micronutrients status in vulnerable Mexican children.

Dietary intake and adequacy of energy and nutrients in Mexican adolescents: Results from Ensanut 2012 / Ingesta dietética y adecuación de energía y nutrimentos en adolescentes mexicanos: resultados de la Ensanut 2012

Abstract Objective To estimate energy and nutrient intakes and adequacies in Mexican adolescents. Materials and methods Dietary intake was assessed in 1 961 adolescents who participated in the National Health and Nutrition Survey 2012 (Ensanut 2012), by a food frequency questionnaire. Medians of intakes and adequacies were estimated for energy, macro- and micronutrients and are presented by residence area, region and household wealth index (HWI). Consumption by food groups was estimated. Results Median daily energy intake was 2 000 Kcal in males and 1 800 Kcal in females. High prevalences of inadequacy were observed for fiber, PUFAs, iron, zinc and calcium. These inadequacies were higher among individuals of low HWI. Moreover, excessive intakes of total and saturated fat were higher among adolescents of higher HWI. Conclusion The diet of Mexican adolescents is deficient in essential nutrients for good health and high in saturated fat. Actions are needed to promote a healthy diet.

Resumen Objetivo Estimar la ingesta de energía, nutrientes e inadecuaciones en adolescentes mexicanos. Material y métodos La ingesta se evaluó en 1 961 adolescentes mexicanos participantes en la Encuesta Nacional de Salud y Nutrición 2012 (Ensanut 2012), mediante un cuestionario de frecuencia. Se calcularon las medianas de ingestas y adecuaciones para la energía, macro y micronutrientes, y el consumo por grupo de alimentos. Resultados La ingesta energética diaria fue de 2 000 kcal en varones y 1 800 kcal en las mujeres. Se observó una alta prevalencia de inadecuación de fibra, grasa poliinsaturada, hierro, zinc y calcio. Las inadecuaciones fueron mayores en el índice de bienestar bajo, mientras que el nivel alto se caracterizó por ingesta excesiva de grasas. Conclusión La dieta de los adolescentes mexicanos es deficiente en nutrientes esenciales para la buena salud y es excesiva en grasas saturadas. Es necesario promover una dieta saludable.

Prevalence of iron, folate, and vitamin B12 deficiencies in 20 to 49 years old women: Ensanut 2012 / Prevalencia de deficiencias de hierro, folato y vitamina B12 en mujeres de 20 a 49 años: Ensanut 2012

Objective. To describe the prevalence of iron, folate, and B12 deficiencies in Mexican women of reproductive age from the National Health and Nutrition Survey (Ensanut) 2012. Materials and methods. Data came from a national probabilistic survey, representative from rural and urban areas, and different age groups. Blood samples were obtained from 4 263, 20 to 49 years old women for serum ferritin, vitamin B12 and serum folate concentrations. The prevalence of deficiencies, was assessed using adjusted logistic regression models. Results. The deficiency of folate was 1.9% (95%CI 1.3-2.8), B12 deficiency was 8.5% (95%CI 6.7-10.1) and iron deficiency was 29.4% (95%CI 26.5-32.2). No differences were found when compared with 2006, 24.8% (95%CI 22.3-27.2). Conclusions. The vitamin B12 deficiency is still a problem for women of reproductive age and their offspring in Mexico, while folate deficiency disappeared as a problem. Iron deficiency needs prevention and fortification strategies.

Objetivo. Describir las prevalencias de deficiencias de hierro, folato y B12 en mujeres mexicanas en edad reproductiva de la Encuesta Nacional de Salud y Nutrición (Ensanut) 2012. Material y métodos. Datos derivados de una encuesta probabilística nacional, representativa del área rural y urbana por grupos de edad. Se obtuvo una submuestra de sangre en 4 263 mujeres de 20 a 49 años de edad para medir las concentraciones séricas de ferritina, vitamina B12 y folato. Las deficiencias fueron evaluadas mediante regresiones logísticas múltiples ajustadas. Resultados. La prevalencia de deficiencias de folatos fue de 1.9% (IC95% 1.3-2.8) y vitamina B12 de 8.5% (IC95% 6.7-10.1). La deficiencia de hierro no fue diferente a la de 2006: 29.4% (IC95% 26.5-32.2) vs 24.8% (IC95% 22.3-27.2). Conclusiones. La prevalencia de deficiencias de hierro y vitamina B12 todavía representan un problema en mujeres mexicanas (20-49), mientras que la deficiencia de folato ha dejado de ser un problema de salud pública. Aún se requieren estrategias de prevención en México.

The physical activity level of Mexican children decreases upon entry to elementary school / El nivel de actividad física disminuye en niños mexicanos al ingresar a la escuela primaria

OBJECTIVE: To compare the physical activity patterns of a cohort of Mexican children in kindergarten (K), first (1ES) and second grade (2ES) of elementary school. MATERIAL AND METHODS: The physical activity of 217 children (123 girls and 94 boys) aged 5-6 years was measured (five full-day triaxial accelerometry) annually.Weekday and weekend moderate/ vigorous physical activity (MVPA) and school and off-school MVPA was calculated. Comparisons between surveys were made using longitudinal multilevel generalized linear models. RESULTS: Weekday MVPA was 22 and 37 min/d lower for 1ES (p=0.06) and 2ES (p<0.01), respectively, compared to K. School MVPA for 1ES and 2ES was 37 (-5.0 min/h) and 40 percent (-5.5 min/h) (p<0.001) lower, respectively, compared to K. No differences were found between weekend and off-school MVPA among school stages (p>0.5). CONCLUSION: MVPA was significantly reduced from K to ES,in part because of a decline in MVPA during school activities. Interventions targeted to school environment modifications should be promoted.

OBJETIVO: Comparar los patrones de actividad física (AF) en una cohorte de niños mexicanos en el jardín de niños, primer y segundo grado de primaria. MATERIAL Y MÉTODOS: Se midió anualmente la AF (acelerometría triaxial de cinco días completos) en 217 niños (123 niñas y 94 niños) de 5 a 6 años de edad. Se calculó la AF moderada/vigorosa (AFMV) entre semana y de fin de semana, dentro y fuera del horario escolar. Se realizaron comparaciones mediante modelos lineales generalizados multinivel longitudinales. RESULTADOS: La AFMV entre semana fue 22 (p=0.06) y 37 min/d (p<0.01) menor, y la AFMV durante el horario escolar disminuyó 37 (-5.0 min/h) y 40 por cento (-5.5 min/h) (p<0.001), en 1º y 2º de primaria,respectivamente,comparado con el jardín de niños.No se encontraron diferencias en la AFMV de fin de semana o fuera del horario escolar entre los grados escolares (p>0.05). CONCLUSIONES: La AFMV disminuyó de manera significativa del jardín de niños a 2º de primaria en parte debido a una reducción de AFMV durante las actividades escolares. Es necesaria la promoción de intervenciones enfocadas a la modificación del ambiente escolar.