Overview of Systematic Reviews of Health Interventions for the Prevention and Treatment of Overweight and Obesity in Children.

(1) Background: The importance of studying the health interventions used to prevent and treat overweight and obesity in school-aged children is imperative. This overview aimed to summarize systematic reviews that assess the effects of school-based, family, and mixed health interventions for preventing and treating overweight and obesity in school-aged children. (2) Methods: The Cochrane Collaboration methodology and PRISMA statement were followed. A search was conducted using terms adapted to 12 databases. Systematic reviews reporting interventions in children from six to 12 years old with an outcome related to preventing or treating obesity and overweight were included. Studies with pharmacological or surgical interventions and adolescents were excluded. (3) Results: A total of 15,226 registers were identified from databases and citation searching. Of those, ten systematic reviews published between 2013 and 2022 were included. After the overlap, 331 interventions for children between 6 and 12 years old were identified, and 61.6% involved physical activity and nutrition/diet intervention. Multicomponent intervention, combining physical activity with nutrition and behavioral change, school-based plus community-based interventions may be more effective in reducing overweight and obesity in children. (4) Conclusions: Plenty of interventions for childhood overweight and obesity aimed at prevention and treatment were identified, but there is a gap in the methodological quality preventing the establishment of a certain recommendation.

Overview of systematic reviews of health interventions that aim to prevent and treat overweight and obesity among children.

BACKGROUND: Childhood overweight and obesity is a global public health issue. Although there is evidence of a reduced prevalence in some countries, there is still much controversy about the efficacy of health interventions that aim to prevent and treat obesity in this specific population. The objective of the present study is to develop an overview of systematic reviews (OSRs) that assesses the effects of school-based, family, and multi-component health interventions for the prevention and treatment of obesity, change in physical activity, dietary, and/or hydration behaviors, and change in metabolic risk factors in school-aged children. METHODS: This protocol was developed using the methodology proposed by Cochrane. It outlines a comprehensive search in 12 electronic databases to identify systematic reviews of health interventions, including studies that evaluate and how to prevent and/or treat overweight and/or obesity in children aged 6 to 12 years. The risk of bias of the included Systematic Reviews will be assessed with the ROBIS tool. DISCUSSION: Since the OSRs methodology's purpose is only to harmonize evidence from open access publications, ethical consent is not necessary for the present protocol. In terms of diffusion, a paper will be submitted for publication in a scientific journal to describe the main results obtained through the OSRs. TRIAL REGISTRATION: The present overview of the systematic review protocol has been registered in PROSPERO (ID number 218296).

Physical inactivity and sitting time prevalence and trends in Mexican adults. Results from three national surveys.

BACKGROUND: Physical inactivity and high sitting time are directly related to mortality and morbidity of non-communicable diseases (NCDs). Thus, improved understanding of the prevalence and trends of these behaviors could support the design of policies and interventions for NCDs prevention. OBJECTIVE: To determine the current prevalence of physical inactivity and high sitting time, to analyze the trends, and to estimate the association of meeting/not meeting physical activity recommendations and low/high sitting time with sociodemographic characteristics and body mass index categories. METHODOLOGY: Data from the 2018 National Health and Nutrition Survey were used. Moderate-to-vigorous physical activity (MVPA) and sitting minutes per week were calculated using the International Physical Activity Questionnaire short form (IPAQ). In total, 38,033 questionnaires of adults aged 20 to 69-year-old were analyzed. Adults were classified as physically inactive if they achieved less than 150 minutes per week of MVPA and as with high sitting time if they accumulated more than 420 minutes of sitting per day. Health and Nutrition National Surveys (ENSANUT) 2006, 2012 and 2018 were used to estimate the trends. RESULTS: In total, 16.5% were classified as physically inactive and 11.3% within the high sitting time category. Both prevalences increased more than 40% during the 12-y period (2006-2018). In 2018, men, younger adults, those living in urban areas, and people within the highest socioeconomical status and educational levels were more likely to not achieve physical activity recommendations and to be classified in the highest sitting time category. CONCLUSION: To stop current increased trends and achieve global targets, stronger and more concerted efforts to promote physical activity and reduce sitting time are required. Thus, continued surveillance of these behaviors is necessary.

Nutrient composition of mealtimes and its association with the energy intake of subsequent meals among Mexican adults.

The composition of the diet influences energy intake by affecting satiety. Macronutrients have a hierarchical effect on satiety, where proteins have the greatest influence, followed by carbohydrates and fats. Alcohol consumption has also shown an effect on increasing energy intake in subsequent meals. Most of this evidence comes from studies under controlled conditions but, it is not clear if effects of diet composition are maintained or counteracted by other determinants of EI in real life. In this paper, we described the diet composition by mealtime in a sample of free-living Mexican adults, as well as evaluated its association with the energy intake in subsequent meals between- and within-subjects. We used information from a national cross-sectional survey of the urban Mexican population. Dietary information was collected by an automated multiple-pass 24-h recall and all participants had information from three non-consecutive days (two weekdays and one weekend). We analyzed information from adults from 20 years and older and used mixed-effects hybrid models that isolate the intra-subject, from the between-subject associations using a substitution approach. We found that alcohol and added sugars were associated with an increased EI between- and within-subjects, while fiber was associated with a decreased EI in subsequent meals within-subjects. Between-subjects, the higher intake of proteins was associated with a decrease in EI, whereas carbohydrates were associated with an increased EI in subsequent meals. We concluded that the composition of the diet at one mealtime predicted EI in subsequent meals of free-living subjects. Understanding the effects of diet composition could guide strategies to reduce EI and obesity prevention.

[Methodological bases of the measurement of earlychildhood development in the Ensanut 100k survey]. / Bases metodológicas de lamedición de desarrollo infantiltemprano en la Ensanut 100k.

OBJECTIVE: The methods that were carried out for the inclusion of the early childhood development module in the Ensanut 100k are presented. MATERIALS AND METHODS: With this module and the questionnaire for children under five years-old, indicators of the state of health, development and well-being of children in the first five years of life are obtained. From November to December 2017, the sample design, instruments and manuals were defined and a test was carried out. Field staff were trained and standardized. The information was collected between January and June 2018. RESULTS: 3 892 children from 0 to 59 months of age were studied in the DIT Module of the Survey. CONCLUSIONS: Training and standardization of field personnel, by trained and standardized personnel, minimizes information biases.

OBJETIVO: Presentar los métodos realizados para la inclu-sión del módulo de Desarrollo Infantil Temprano (DIT) en la Ensanut 100k. MATERIAL Y MÉTODOS: Con dicho módulo y el cuestionario de menores de cinco años, se obtuvieron indicadores del estado de salud, desarrollo y bienestar de niñas/os en los primeros cinco años de vida.De noviembre a diciembre de 2017, se definió el diseño de la muestra, instrumentos y manuales, y se realizó una prueba piloto. Se capacitó y estandarizó al personal de campo. El levantamiento de información se realizó entre enero y junio de 2018. RESULTADOS: Se estudió en el módulo DIT de la encuesta a 3 892 niños/as de 0 a 59 meses de edad. CONCLUSIONES: La capacitación y estandarización del personal de campo, por parte de personal capacitado y estandarizado, minimiza los sesgos de información.

Bases metodológicas de la medición de desarrollo infantil temprano en la Ensanut 100k / Methodological bases of the measurement of early childhood development in the Ensanut 100k survey

Resumen Objetivo: Presentar los métodos realizados para la inclusión del módulo de Desarrollo Infantil Temprano (DIT) en la Ensanut 100k. Material y métodos: Con dicho módulo y el cuestionario de menores de cinco años, se obtuvieron indicadores del estado de salud, desarrollo y bienestar de niñas/os en los primeros cinco años de vida. De noviembre a diciembre de 2017, se definió el diseño de la muestra, instrumentos y manuales, y se realizó una prueba piloto. Se capacitó y estandarizó al personal de campo. El levantamiento de información se realizó entre enero y junio de 2018. Resultados: Se estudió en el módulo DIT de la encuesta a 3 892 niños/as de 0 a 59 meses de edad. Conclusiones: La capacitación y estandarización del personal de campo, por parte de personal capacitado y estandarizado, minimiza los sesgos de información.

Abstract Objective: The methods that were carried out for the inclusion of the early childhood development module in the Ensanut 100k are presented. Materials and methods: With this module and the questionnaire for children under five years-old, indicators of the state of health, development and well-being of children in the first five years of life are obtained. From November to December 2017, the sample design, instruments and manuals were defined and a test was carried out. Field staff were trained and standardized. The information was collected between January and June 2018. Results: 3 892 children from 0 to 59 months of age were studied in the DIT Module of the Survey. Conclusions: Training and standardization of field personnel, by trained and standardized personnel, minimizes information biases.

[Obesity in Mexico, prevalence andtrends in adults. Ensanut 2018-19.] / Obesidad en México, prevalencia y tendencias en adultos. Ensanut 2018-19.

OBJECTIVE: To describe the prevalence of obesity in Mexican adults stratifying by physical and sociodemographic conditions and to analyze trends. MATERIALS AND METHODS: The data of 16 256 adults who participated in Ensanut 2018-19 was analyzed. Obesity (WHO), abdominal adiposity (IFD) and short stature (NOM-008-SSA3-2017) were classified. Logistic regression models were performed to analyze the association between obesity and risk factors. ENSA-2000 and Ensanut (2006, 2012, 2018-19) were used to assess trends. RESULTS: The prevalence of overweight was 39.1%, obesity 36.1%, and abdominal adiposity 81.6%. Adults >40-50y and women had the highest prevalence. There was no difference by socio-economic level. Between 2000-2018, the prevalence of obesity increased 42.2% and morbid obesity 96.5%. Women with short stature had a higher risk (RM=1.84) of being obese than women without this condition, while in men the risk was lower (RM=0.79). CONCLUSIONS: In Mexico the prevalence of obesity continues to increase regardless of socio-economic level, region or locality.

OBJETIVO: Describir la prevalencia de obesidad en adultos mexicanos estratificando por condiciones físicas y sociode-mográficas, y analizar tendencias. MATERIAL Y MÉTODOS: Análisis de 16 256 adultos de la Encuesta Nacional de Salud y Nutrición (Ensanut) 2018-19. Se clasificó obesidad (OMS), adi-posidad abdominal (IDF) y talla baja (NOM-008-SSA3-2017). Se realizaron modelos de regresión logística para asociar obesidad y factores de riesgo. Para evaluar tendencias se analizaron Encuesta Nacional de Salud 2000 y Ensanut (2006, 2012, 2018-19). RESULTADOS: La prevalencia de sobrepeso fue 39.1%, obesidad 36.1% y adiposidad abdominal 81.6%. Se presentaron las prevalencias más altas en >40-50 años y en las mujeres. No hubo diferencia por nivel socioeconómico. En el periodo 2000-2018 aumentó la prevalencia de obesidad 42.2% y de obesidad mórbida 96.5%. Las mujeres con talla baja tuvieron mayor riesgo (RM=1.84) de tener obesidad que las mujeres sin esta condición, mientras que en hombres el riesgo fue menor (RM=0.79). CONCLUSIONES: En México, la prevalencia de obesidad sigue aumentando sin importar nivel socioeconómico, región o localidad.

Obesidad en México, prevalencia y tendencias en adultos. Ensanut 2018-19 / Obesity in Mexico, prevalence and trends in adults. Ensanut 2018-19

Resumen: Objetivo: Describir la prevalencia de obesidad en adultos mexicanos estratificando por condiciones físicas y sociodemográficas, y analizar tendencias. Material y métodos: Análisis de 16 256 adultos de la Encuesta Nacional de Salud y Nutrición (Ensanut) 2018-19. Se clasificó obesidad (OMS), adiposidad abdominal (IDF) y talla baja (NOM-008-SSA3-2017). Se realizaron modelos de regresión logística para asociar obesidad y factores de riesgo. Para evaluar tendencias se analizaron Encuesta Nacional de Salud 2000 y Ensanut (2006, 2012, 2018-19). Resultados: La prevalencia de sobrepeso fue 39.1%, obesidad 36.1% y adiposidad abdominal 81.6%. Se presentaron las prevalencias más altas en >40-50 años y en las mujeres. No hubo diferencia por nivel socioeconómico. En el periodo 2000-2018 aumentó la prevalencia de obesidad 42.2% y de obesidad mórbida 96.5%. Las mujeres con talla baja tuvieron mayor riesgo (RM=1.84) de tener obesidad que las mujeres sin esta condición, mientras que en hombres el riesgo fue menor (RM=0.79). Conclusiones: En México, la prevalencia de obesidad sigue aumentando sin importar nivel socioeconómico, región o localidad.

Abstract: Objective: To describe the prevalence of obesity in Mexican adults stratifying by physical and sociodemographic conditions and to analyze trends. Materials and methods: The data of 16 256 adults who participated in Ensanut 2018-19 was analyzed. Obesity (WHO), abdominal adiposity (IFD) and short stature (NOM-008-SSA3-2017) were classified. Logistic regression models were performed to analyze the association between obesity and risk factors. ENSA-2000 and Ensanut (2006, 2012, 2018-19) were used to assess trends. Results: The prevalence of overweight was 39.1%, obesity 36.1%, and abdominal adiposity 81.6%. Adults >40-50y and women had the highest prevalence. There was no difference by socio-economic level. Between 2000-2018, the prevalence of obesity increased 42.2% and morbid obesity 96.5%. Women with short stature had a higher risk (RM=1.84) of being obese than women without this condition, while in men the risk was lower (RM=0.79). Conclusions: In Mexico the prevalence of obesity continues to increase regardless of socio-economic level, region or locality.

Dietary quality indices vary with sociodemographic variables and anthropometric status among Mexican adults: a cross-sectional study. Results from the 2006 National Health and Nutrition Survey.

OBJECTIVE: To evaluate the dietary quality of Mexican adults' diet, we constructed three dietary quality indices: a cardioprotective index (CPI), a micronutrient adequacy index (MAI) and a dietary diversity index (DDI). DESIGN: Data were derived from the 2006 National Health and Nutrition Survey, which is a national survey representative of the Mexican population with a stratified, multistage, probabilistic sample design. Dietary intake was assessed from an FFQ with 101 different foods and daily nutrient intakes were computed. The CPI evaluated compliance with seven WHO recommendations for the prevention of CVD, the MAI evaluated the intake of six micronutrients based on the estimated average requirements from the US Institute of Medicine and the DDI was constructed based on the consumption of thirty different food groups. SETTINGS: Mexico. SUBJECTS: Mexican adults aged 19-59 years old. RESULTS: We evaluated the diet of 15 675 males and females. Adjusted means and adjusted proportions by age and sex were computed to predict adherence to dietary recommendations. Rural inhabitants, those living in the South and those from the lowest socio-economic status reported a significantly higher CPI (4·5 (se 0·08), 4·3 (se 0·08) and 4·2 (se 0·09), respectively; P < 0·05), but a significantly lower MAI and DDI, compared with urban inhabitants, those from the North and those of upper socio-economic status (P < 0·05). CONCLUSIONS: The constructed diet quality indices identify nutrients and foods whose recommended intakes are not adequately consumed by the population. Given the epidemiological and nutritional transition that Mexico is experiencing, the CPI is the most relevant index and its components should be considered in Mexican dietary guidelines as well as in any food and nutrition programmes developed.

Effectiveness of a large-scale iron-fortified milk distribution program on anemia and iron deficiency in low-income young children in Mexico.

BACKGROUND: Anemia during infancy impairs neurodevelopment. Little information has been published about the effectiveness of large-scale programs on anemia and iron-deficiency prevention. OBJECTIVE: The objective was to assess the effectiveness of a large-scale program that distributes subsidized iron-fortified milk in Mexico on anemia and iron deficiency in children aged 12-30 mo. DESIGN: A double-blinded, group-randomized effectiveness trial was conducted in 12 milk distribution clusters assigned to consume iron-fortified (FM; n = 7) or nonfortified (NFM; n = 5) milk. A daily portion of FM contained 5.28 mg Fe (ferrous gluconate) and 48 mg sodium ascorbate. RESULTS: Overall treatment effects were documented at 6 and 12 mo for anemia and for iron deficiency assessed by both serum ferritin (SF) and serum soluble transferrin receptor (sTfR) (interaction: P < 0.10). Differential effects at 6 mo (P = 0.004) and 12 mo (P = 0.664) were documented only for sTfR. Estimated prevalences (EPs) of anemia (hemoglobin < 110 g/L) from baseline to 6 and 12 mo decreased from 42.6% to 19.7% and 9.4%, respectively, in the NFM group (n = 210) and from 44.5% to 12.7% and 4.0%, respectively, in the FM group (n = 357). EPs of SF < 12 mug/L from baseline to 6 and 12 mo changed from 36.0% to 41.8% and 17.1%, respectively, in the NFM group (n = 43) and from 29.8% to 18.6% and 5.7%, respectively, in the FM group (n = 144). EPs of sTfR > 3.3 mg/L from baseline to 6 and 12 mo decreased from 16.2% to 8.3% and 2.0%, respectively, in the NFM group (n = 114) and from 15.5% to 0.7% and 1.1%, respectively, in the FM group. CONCLUSION: A large-scale iron-fortified subsidized-milk program was effective at reducing the rates of anemia and iron deficiency in Mexican children during 12 mo of implementation. This trial was registered at clinicaltrials.gov as NCT00508131.

Prevalence of abnormal eating behaviors in adolescents in Mexico: Mexican National Health and Nutrition Survey 2006.

OBJECTIVE: To describe the prevalence of abnormal eating behaviors in a population-based nationwide survey. MATERIAL AND METHODS: A stratified, probabilistic, multistage design sampling process was used. The Brief Questionnaire for Risky Eating Behaviors was included in the Mexican Health and Nutrition Survey 2006 (ENSANUT 2006) and administered to participants 10-19 years old (n= 25 166). The study had the power to describe nationwide characteristics by age, regions and urban/rural settings. RESULTS: A high risk for having an eating disorder was found in 0.8% of the total participants (0.4% male adolescents and 1.0% female). Inhabitants in large cities showed higher risk for having an abnormal eating behavior compared to subjects living in other settings. The highest prevalences were found in males > 15 years old and females > 13 years old for all evaluated behaviors. CONCLUSIONS: Results show less prevalence of risky eating behaviors among adolescents in comparison to other populations. The female/male ratio was 3:1, far different from the 9:1 shown in a previous study in Mexico City, but similar to results from the US national eating disorders screening.

Prevalence of abnormal eating behaviors in adolescents in Mexico: Mexican National Health and Nutrition Survey 2006 / Prevalencia de conductas alimentarias anormales de adolescentes en México: Encuesta Nacional de Salud y Nutrición ENSANUT 2006

OBJECTIVE: To describe the prevalence of abnormal eating behaviors in a population-based nationwide survey. MATERIAL AND METHODS: A stratified, probabilistic, multistage design sampling process was used. The Brief Questionnaire for Risky Eating Behaviors was included in the Mexican Health and Nutrition Survey 2006 (ENSANUT 2006) and administered to participants 10-19 years old (n= 25 166). The study had the power to describe nationwide characteristics by age, regions and urban/rural settings. RESULTS: A high risk for having an eating disorder was found in 0.8 percent of the total participants (0.4 percent male adolescents and 1.0 percent female). Inhabitants in large cities showed higher risk for having an abnormal eating behavior compared to subjects living in other settings. The highest prevalences were found in males > 15 years old and females > 13 years old for all evaluated behaviors. CONCLUSIONS: Results show less prevalence of risky eating behaviors among adolescents in comparison to other populations. The female/male ratio was 3:1, far different from the 9:1 shown in a previous study in Mexico City, but similar to results from the US national eating disorders screening.

OBJETIVOS: Describir la prevalencia de conductas alimentarias anormales en una encuesta nacional de base poblacional. MATERIAL Y MÉTODOS: Diseño muestral probabilístico, polietápico, por conglomerados y estratificado. Se utilizó el Cuestionario Breve de de Conductas Alimentarias de Riesgo de la ENSANUT 2006, en adolescentes entre 10 y 19 años de edad (n= 25 166) de ambos sexos, con resultado nacional, por región y tipo de localidad. RESULTADOS: En 0.8 por ciento de los participantes se encontró alto riesgo de desarrollar un trastorno de conducta alimentaria (0.4 por ciento hombres y 1.0 por ciento mujeres). La edad de mayor riesgo fue > 15 años en hombres y > 13 en mujeres. Los habitantes de áreas metropolitanas presentan un riesgo mayor que la población rural y urbana. CONCLUSIONES: La prevalencia de conductas alimentarias de riesgo en adolescentes es menor en comparación con otras poblaciones. La relación mujer/hombre resultó de 3:1, muy diferente del 9:1 encontrado en población estudiantil de la Ciudad de México, pero similar a lo reportado en la encuesta nacional de trastornos alimentarios en EUA.

Fortifying milk with ferrous gluconate and zinc oxide in a public nutrition program reduced the prevalence of anemia in toddlers.

We aimed to assess the efficacy of whole cow's milk fortified with ferrous gluconate and zinc oxide, along with ascorbic acid, in reducing the prevalence of anemia and improving iron status of low income children 10-30 mo of age. Healthy children were randomly assigned to drink 400 mL/d of cow's whole milk, either fortified milk (FM) with 5.8 mg/400 mL of iron as ferrous gluconate, 5.28 mg/400 mL of zinc as zinc oxide, and 48 mg/400 mL of ascorbic acid, or nonfortified milk (NFM) with 0.2 mg iron/400 mL, 1.9 mg zinc/400 mL, and 6.8 mg ascorbic acid/400 mL. Hemoglobin, serum ferritin, soluble transferrin receptors (TfR), and C-reactive protein concentrations were measured at baseline and 6 mo after intervention. The prevalence of anemia declined from 41.4 to 12.1% (P < 0.001), or 29 percentage points, in the FM group; there was no change in the NFM group. Hemoglobin (coefficient = 0.22, P < 0.01) was positively and TfR (coefficient = -0.29, P < 0.001) negatively associated with treatment, controlling for their respective baseline values, age, and gender. Treatment with FM was negatively associated with the likelihood of being anemic (pseudo R(2) = 0.085, P < 0.03) after 6 mo of intervention. Ferrous gluconate added to whole cow's milk as a fortificant along with ascorbic acid is efficacious in reducing the prevalence of anemia and in improving iron status of Mexican toddlers. The results of this study lead to broadening a subsidized FM distribution program to 4.2 million beneficiary children 1-11 y of age in Mexico.

The role of enriched foods in infant and child nutrition.

Since the last century, fortified and enriched foods are products whose original composition has been modified-through addition of essential nutrients-to satisfy specific population needs. For the fortification of foods to have a positive impact on nutritional status, the micronutrients added must be well absorbed and utilized by the organism (bioavailability). Diverse factors affect bioavailability, such as the nutritional status of individuals, the presence in the diet of substances which facilitate or inhibit its absorption, interactions among micronutrients, illnesses, and chemical characteristics of the compound used for fortification. In countries such as Chile, Venezuela and Mexico, important effects have been demonstrated in reducing iron deficiency anaemia in children under 5 years of age. In less than a decade, the salt iodization programme has also proven its effectiveness. Other programmes have fortified foods with Zn, vitamin A and folic acid, which are deficient in infants and children of many populations. In summary, food fortification is a low-cost, relatively simple strategy that may reach a wide range of people, and contribute to reducing the high prevalence of micronutrient deficiencies affecting children, especially in poor countries. The costs due to losses of human capital and their repercussions on health and future development are very high. Building links among academic researchers, politicians, food manufacturers and consumers is essential in order for food fortification to be efficacious and effective, and therefore should be considered as part of an integral strategy to combat micronutrient deficiencies.

Impact of the Mexican program for education, health, and nutrition (Progresa) on rates of growth and anemia in infants and young children: a randomized effectiveness study.

CONTEXT: Malnutrition causes death and impaired health in millions of children. Existing interventions are effective under controlled conditions; however, little information is available on their effectiveness in large-scale programs. OBJECTIVE: To document the short-term nutritional impact of a large-scale, incentive-based development program in Mexico (Progresa), which included a nutritional component. DESIGN, SETTING, AND PARTICIPANTS: A randomized effectiveness study of 347 communities randomly assigned to immediate incorporation to the program in 1998 (intervention group; n = 205) or to incorporation in 1999 (crossover intervention group; n = 142). A random sample of children in those communities was surveyed at baseline and at 1 and 2 years afterward. Participants were from low-income households in poor rural communities in 6 central Mexican states. Children (N = 650) 12 months of age or younger (n = 373 intervention group; n = 277 crossover intervention group) were included in the analyses. INTERVENTION: Children and pregnant and lactating women in participating households received fortified nutrition supplements, and the families received nutrition education, health care, and cash transfers. MAIN OUTCOME MEASURES: Two-year height increments and anemia rates as measured by blood hemoglobin levels in participating children. RESULTS: Progresa was associated with better growth in height among the poorest and younger infants. Age- and length-adjusted height was greater by 1.1 cm (26.4 cm in the intervention group vs 25.3 cm in the crossover intervention group) among infants younger than 6 months at baseline and who lived in the poorest households. After 1 year, mean hemoglobin values were higher in the intervention group (11.12 g/dL; 95% confidence interval [CI], 10.9-11.3 g/dL) than in the crossover intervention group (10.75 g/dL; 95% CI, 10.5-11.0 g/dL) who had not yet received the benefits of the intervention (P =.01). There were no differences in hemoglobin levels between the 2 groups at year 2 after both groups were receiving the intervention. The age-adjusted rate of anemia (hemoglobin level <11 g/dL) in 1999 was higher in the crossover intervention group than in the intervention group (54.9% vs 44.3%; P =.03), whereas in 2000 the difference was not significant (23.0% vs 25.8%, respectively; P =.40). CONCLUSION: Progresa, a large-scale, incentive-based development program with a nutritional intervention, is associated with better growth and lower rates of anemia in low-income, rural infants and children in Mexico.

[Factors associated with physical activity among Mexican women of childbearing age]. / Factores asociados con la actividad fisica en mujeres mexicanas en edad reproductiva.

OBJECTIVE: To document the practice of light and heavy physical activities, especially sports and exercise, among women from 12 to 49 years old in Mexico, and to evaluate the association that that has with some sociodemographic characteristics. METHODS: A sample of 2 367 women 12 to 49 years old living in Mexico in 1999 was studied through secondary analysis of data from Mexico's 1999 National Nutrition Survey (Encuesta Nacional de Nutrición). The Survey used a clustered stratified multistage sampling scheme, with a final sample of 21 000 homes in the entire country. A questionnaire was used to evaluate the time that the women spent on various forms of physical activity, with the activity measured on a scoring scale in terms of metabolic equivalents (METs). The dependent variables in the study were the time spent on heavy physical activities (those that require an energy expenditure of at least 5 METs/hour) and the time devoted to light or sedentary activities (such as sitting while on the job or elsewhere; watching television, a video, a movie, or a theater presentation; or sleeping). The independent variables were age, schooling, parity, region of the country, area of residence (urban or rural), socioeconomic level (measured through an index prepared based on housing conditions and household possessions), and marital status. The association between the independent variables and practicing sports was evaluated, and gross odds ratios (ORs) were calculated, with 95% confidence intervals (CIs). In order to identify the association between practicing sports and the independent variables a logistic regression model was used, adjusted for the effects of possible confounding variables. Adjustments were also made in the probability of a woman's being selected for the sample, using a weighting factor. In addition, adjustments were made to control for the design effect produced by the grouping of the observations in the sample, using the "svy" complex-samples routine of the Stata version 7.0 statistical analysis computer software. RESULTS: The 2 367 women whose information was analyzed spent an average of 0.08 hours per day practicing sports and 1.25 hours per day on heavy physical activities. Only 16% of the women reported that they regularly practiced some sport. After adjusting for all the independent variables, the women older than 30 years had a lower OR of practicing sports in comparison to women who were 20 years of age or less (OR = 0.53; 95% CI: 0.33 to 0.84), as was also true for women 21-30 years old (OR = 0.35; 95% CI: 0.23 to 0.54). Having the highest level of schooling and not having had children were both directly associated with practicing a sport. While the area of residence (urban or rural), marital status, and socioeconomic level showed differences among the groups, such differences were not significant after adjusting for the other study variables. In terms of physical activity measured in METs, the time spent on sports made up 10% of the total for heavy activity and 0.7% of the overall total. In terms of the possibility of being among the 10% of the women who expended the fewest METs per day, that was more likely for women under 21 years of age than it was for women 31 or older, and it was also more likely for women who had a primary level of schooling than for women with a secondary education. CONCLUSIONS: This study showed that practicing sports is not a frequent form of physical activity among women of childbearing age in Mexico, especially those who are over 20 years of age and those with a low level of schooling. This situation could contribute to increases in the prevalence of obesity and chronic diseases.

Factores asociados con la actividad física en mujeres mexicanas en edad reproductiva / Factors associated with physical activity among Mexican women of childbearing age

OBJETIVO: Documentar la práctica de actividades físicas ligeras y pesadas, particularmente de deportes y ejercicios, en mujeres de 12 a 49 años en México, y evaluar su asociación con algunas características sociodemográficas. MÉTODOS: Se estudió una muestra de 2 367 mujeres de 12 a 49 años de edad residentes en México en 1999 mediante el análisis secundario de los datos de la Encuesta Nacional de Nutrición de México, 1999 (ENN-99). En esta encuesta se utilizó un esquema de muestreo polietápico, estratificado, por conglomerados que conformó una muestra final de 21 000 hogares de todo el país. Mediante un cuestionario se evaluó el tiempo dedicado a las distintas formas de actividad física y se midió la actividad en equivalentes metabólicos (MET) según una escala puntual. Las variables dependientes del estudio fueron el tiempo dedicado a actividades físicas pesadas (las que exigen un gasto de energía equivalente a 5 MET/hora) y el dedicado a actividades ligeras o sedentarias (tales como estar sentada en el trabajo o fuera de él, ver televisión, video, cine o teatro y dormir). Las variables independientes fueron la edad, escolaridad, paridad, región del país y área de residencia (urbana o rural), nivel socioeconómico (medido mediante un índice elaborado a partir de las condiciones de la vivienda y la posesión de enseres domésticos) y estado marital. Se evaluó la asociación entre las variables independientes y la práctica de deportes y se calcularon las razones de posibilidades brutas con intervalos de confianza de 95 por ciento. Para identificar la asociación entre la práctica de deportes y las variables independientes se utilizó un modelo de regresión logística ajustado según el efecto de posibles variables de confusión. Se ajustó también mediante un factor de ponderación la probabilidad de que una mujer fuese seleccionada para la muestra, y para controlar el efecto de diseño producido por la agrupación de observaciones en esta muestra se utilizó la rutina de análisis de muestras complejas svy de Stata, versión 7.0. RESULTADOS: Se analizó la información obtenida de 2 367 mujeres. Las mujeres encuestadas dedicaron 0,08 horas diarias, en promedio, a practicar deportes y 1,25 horas diarias a actividades físicas pesadas...