Socioeconomic variation in the growth status of urban school children 6-13 years in Oaxaca, Mexico, in 1972 and 2000

Height growth of Mexican boys by geographic region: an evaluation based on nationally representative data of ENSANUT 2012 and 2018

Existing research on human growth in Mexico is regionally focused, creating a gap in the understanding of growth patterns of children and adolescents at national level and regional variation. The objective of the present study was to characterize the height growth curve of the Mexican population by geographic area and to cluster the states of the Mexican Republic according to their somatic maturation characteristics, based on a national representative sample of boys. Data on age, height, socioeconomic level, and geographic area of 18,219 boys were obtained from the National Health and Nutrition Survey 2012 (ENSANUT) and ENSANUT 2018, carried out in 32 Mexican states. Both surveys had representative samples. Preece-Baines 1 model was applied to fit height growth curves. Biological parameters were estimated; principal component analysis and cluster analysis were performed to group Mexican states based on these biological parameters. The estimated age at peak height velocity (PHV) was 12.3 years in the sample. Significant regional differences in the timing and tempo of PHV among Mexican boys were observed. Boys in the northern region experienced PHV at an earlier age and had a shorter duration of growth compared with boys in the central and southern regions. Boys in the central region had a longer duration of growth and a later age of PHV compared with the boys in the southern region. The cluster that included the southern states of the country showed estimated lower adult height and earlier somatic maturation. A lower height was found in the low and low-middle socioeconomic levels compared with the medium-high and high socioeconomic levels. Future research in Mexico should focus on longitudinal studies to analyse the timing and tempo of growth and maturation, considering the impacts of environmental and genetic factors. Public health strategies should account for geographic variations.

Comparing Spirometric Reference Values From Childhood to Old Age Estimated by LMS and Linear Regression Models

BACKGROUND

Proper reference values for lung function testing are essential for achieving adequate interpretations. The LMS procedure (lambda, mu, sigma) permits continuous analyses of entire populations avoiding gaps in the transition between childhood and adulthood. It also allows more precise calculations of average values, dispersion, and 5th percentiles, which are usually considered the lower limit of normality. The objective of this study was to compare our results fitted with the LMS method with standard multiple linear regression, and with those from international Global Lung Function Initiative (GLI) equations.

METHODS

Data from 9835 healthy residents of the metropolitan area of Mexico City aged 8-80 years were compiled from several studies: EMPECE, PLATINO, adult Mexican workers and two unpublished studies. The LMS procedure and multiple linear regression models were fit to obtain reference equations using R software.

RESULTS

Residuals from the LMS models had a median closer to zero, and smaller dispersion than those from the linear model, but differences although statistically significant were very small and of questionable practical relevance. For example, for females and ln(FEV₁), median residual was -0.001 with p25 of -0.08 and p75 of 0.08 for LMS, compared with 0.004 (-0.08, 0.09) [p<0.05] for the linear model. Average spirometric values for a given height for our population, were higher than those predicted by the GLI study.

CONCLUSION

Continuous reference equations for the Mexican population calculated using the LMS technique showed slightly better fit than linear regression models.

An intervention to promote physical activity in Mexican elementary school students: building public policy to prevent noncommunicable diseases

Physical activity is an important component of strategies for health promotion and prevention of noncommunicable diseases. It is also associated with decreased risk for cardiovascular disease in overweight and obese adults and children. This article addresses the initial description of a physical activity intervention for children attending public elementary schools in Mexico. The objective was to develop a replicable model based on a strategic public, private, academic, and social partnership that would have a short-term impact on the metabolic health of children and be useful for building effective public policy. Forty-nine schools (20 000 students) participated, and 5 schools were selected for evaluation. The intervention included a 30-minute supervised middle-effort interchangeable routine, 5 days a week for a complete school year, adapted for different school conditions and students of different ages. Evaluation included anthropometric measurements and biochemical markers. Actual prevalence of combined overweight and obesity in these children was 31.9%. The intervention was successfully implemented in all schools. No change in body mass index, waist circumference, or other anthropometric indicators was found. However, changes in biochemical markers showed a significant decrease in blood glucose, total cholesterol, and cholesterol-low-density lipoproteins, reflecting a positive effect on cardiovascular health indicators.

Socioeconomic Status and Longitudinal Lung Function of Healthy Mexican Children

Introduction

Our aim was to estimate the longitudinal effect of Socioeconomic status (SES) on lung function growth of Mexican children and adolescents.

Materials and Methods

A cohort of Mexican children in third grade of primary school was followed with spirometry twice a year for 6 years through secondary school. Multilevel mixed-effects lineal models were fitted for the spirometric variables of 2,641 respiratory-healthy Mexican children. Monthly family income (in 2002 U.S. dollars [USD]) and parents’ years completed at school were used as proxies of SES.

Results

Individuals with higher SES tended to have greater height for age, and smaller sitting height/standing height and crude lung function. For each 1-year increase of parents’ schooling, Forced expiratory volume in 1 sec (FEV₁) and Forced vital capacity (FVC) increased 8.5 (0.4%) and 10.6 mL (0.4%), respectively (p <0.05) when models were adjusted for gender. Impact of education on lung function was reduced drastically or abolished on adjusting by anthropometric variables and ozone.

Conclusions

Higher parental schooling and higher monthly family income were associated with higher lung function in healthy Mexican children, with the majority of the effect likely due to the increase in height-for-age.

Body fatness in relation to physical activity and selected socioeconomic parameters of adolescents aged 15-17 years in Merida, Yucatan

BACKGROUND

Increasing rates of overweight and obesity in adolescents are major concerns in many countries, including Mexico.

OBJECTIVES

To study anthropometric and body composition characteristics (BCC) and their relations with socioeconomic status (SES), biological history and physical activity (PA) of school-going adolescent boys and girls in the city of Merida, Yucatan, Mexico.

SUBJECTS AND METHODS

In this cross-sectional study, a sample of 321 adolescents (156 boys and 165 girls) aged 15-17 years from public and private schools in Merida, was taken from a study carried out in 2008-2009.

RESULTS

Body mass index had significant correlations to BCC (fat mass and fat-free mass). The rate of stunting was higher in girls (18.20%) than in boys (7.69%). Stunted adolescents had higher body fat (%) than normally growing peers. High rates of overweight (boys 26.28%, girls 24.24%) and obesity (boys 10.26%, girls 6.06%) were recorded. SES (parents' age, education and occupation; crowding index in the family; household food expenditure), participants' biological history and PA are related with height and BCC by age and sex.

CONCLUSION

Adolescents with excess weight (overweight + obesity) reported being less physically active. SES and PA were strongly related to growth and body fatness in the studied adolescents.

Longitudinal lung function growth of Mexican children compared with international studies

Introduction

Our aim was to compare the longitudinal lung function growth of Mexican children and adolescents with the collated spirometric reference proposed for international use and with that of Mexican-Americans from the National Health State Examination Survey III (NHANES) III study.

Materials and Methods

A cohort of Mexican children in third year of primary school was followed with spirometry twice a year through secondary school. Multilevel mixed-effects lineal models separated by gender were fit for the spirometric variables of 2,641 respiratory-healthy Mexican children expressed as Z-scores of tested reference equations. Impact of adjustment by sitting height on differences with Mexican-American children was observed in a subsample of 1,987 children.

Results

At same gender, age, and height, Mexican children had increasingly higher forced expiratory volume in 1 s (FEV₁) and Forced vital capacity (FVC) than the children from the collated reference study (mean Z-score, 0.68 for FEV₁ and 0.51 for FVC) and than Mexican-American children (Z-score, 0.23 for FEV₁ and 0.21 for FVC) respectively. Differences with Mexican-Americans were not reduced by adjusting by sitting height.

Conclusions

For reasons that remain unclear, the gender-, age-, and height-adjusted lung function of children from Mexico City is higher than that reported by several international studies.

Equação preditora de idade óssea na iniciação esportiva através de variáveis antropométricas

INTRODUÇÃO: Atualmente o desempenho esportivo tem se desenvolvido de forma rápida e concreta, exigindo, dessa forma, uma eficiente evolução das diferentes áreas das ciências do esporte, oferecendo o suporte cientifico necessário à continuidade desse fenômeno. OBJETIVO: O estudo em questão teve como objetivo desenvolver uma equação matemática preditora de idade óssea de jovens atletas, com base em variáveis antropométricas. MÉTODOS: Para se alcançar o resultado final foram medidas dobras cutâneas, perímetros corporais e diâmetros ósseos, idade cronológica e idade óssea. O tratamento estatístico utilizou a correlação entre as variáveis, a regressão linear múltipla com modelagem backward. RESULTADO: Se obteve como resultado final um modelo de equação que explica 75,4% da variação da idade óssea com r = 0,868 e R² = 0,754, utilizando idade cronológica, estatura, dobra tricipital, perímetro corrigido de braço e diâmetros de fêmur e úmero. CONCLUSÃO: Concluiu-se a partir dos resultados, que esse tipo de modelo revela valores aproximados aos observados através da radiografia de mão e punho, tornando-se importante na observação do estágio maturacional através de testes de fácil aplicabilidade por profissionais da área esportiva.

VARIATION IN HEIGHT AND KNEE HEIGHT IN ADOLESCENTS IN MERIDA, MEXICO, BY HEAD OF HOUSEHOLD EMPLOYMENT LEVEL AND FAMILY INCOME

Variation in height among young adults has been linked to the living conditions of different social groups. The aim of this study was to measure variation in the height and knee height of young adults by head of household employment level and family income. The sample comprised 180 individuals (90 girls) aged 16 and 17 years living in the city of Merida, Mexico. Height and knee height were measured by anthropometry, and individuals' family social and economic data collected from their mothers. Variation in these measurements was analysed by three categories of employment and family income terciles. One-way ANOVAs were done by sex to compare mean height and knee height by employment and family income. Coefficients of variation were calculated and a Bartlett test applied. Significant differences in height and knee height were observed only between family income terciles. Both sexes were taller at the highest levels of family income (p<0.05) and men had the highest (p<0.05) knee height. Highest family income individuals exhibited the least variation in height and knee height. Similarity in socioeconomic conditions for families in the lowest family income tercile and with employee heads of household was not associated with lower variation of height and knee height.

How useful is BMI in predicting adiposity indicators in a sample of Maya children and women with high levels of stunting?

OBJECTIVES

Body mass index (BMI) is used frequently to estimate adiposity levels in children and adults. However, the applicability of BMI to populations with high levels of stunting has been questioned. Stunted people can have disproportionately short legs, which may increase BMI without increasing body fat because of the relatively larger trunk compared with the legs.

METHODS

A sample of 57 urban Maya schoolchildren, aged 7-9 years (31 boys), and 53 adult women underwent anthropometric assessments and bioelectrical impedance analysis. Multiple linear regression was performed to determine whether the ability of BMI to predict adiposity indicators is altered by stunting and sitting height ratio (SHR). The adiposity indicators were waist circumference, sum of skinfolds, upper arm muscle area, upper arm fat area, and arm fat index.

RESULTS

BMI was the strongest predictor of all adiposity indicators and in most cases, explained more of the variance in adiposity of Maya children than Maya women. Abdominal adiposity was better predicted by BMI than peripheral adiposity in Maya women and Maya children. Stunting was significant in predicting adiposity in some models but never substantially changed the variance explained. SHR was never a significant predictor.

CONCLUSIONS

The relationship between BMI and adiposity indicators is not changed by stunting status or body proportions in this short population of urban Maya children and women. BMI can be used as an indicator of adiposity for these children but not the women. It is recommended that BMI is used in conjunction with other estimates of body composition.

Physical fitness of normal, stunted and overweight children 6-13 years in Oaxaca, Mexico

BACKGROUND/OBJECTIVE

The objective of this study is to compare the growth and physical fitness of normal, stunted and overweight/obese (owt/ob) Oaxaca children 6-13 years.

SUBJECTS/METHODS

This study was a cross-sectional, included 688 school children (grades 1-3, 4-6), aged 6-13 years, from an indigenous rural community (n=361) and colonia popular (n=327) in Oaxaca, southern Mexico.

MEASUREMENTS

Anthropometry-weight, height, sitting height, limb circumferences, skinfolds. Derived-body mass index, sitting height/height ratio, leg and step lengths, limb muscle areas, sum of skinfolds. Physical fitness-sit and reach, sit-ups, distance run, grip strength, standing long jump, 35 yard dash. Physical activity-steps to and from school, household chores, sports participation.

ANALYSIS

Normal-not stunted, not owt/ob; stunted-not owt/ob; and owt/ob-not stunted were compared with multivariate analysis of covariance controlling for age. Two children were stunted and owt/ob, and were excluded.

RESULTS

Age-adjusted means for body size, muscularity, adiposity and grip strength showed a gradient, owt/ob>normal>stunted in both sexes and grade levels (P<0.001). Relative position of stunted and owt/ob children was reversed for strength per unit mass. Stunted and normal children ran a greater distance than owt/ob children (P<0.05). Normal, stunted and owt/ob children did not differ consistently in other fitness items and indicators of activity and inactivity.

CONCLUSION

Size, muscularity, fatness and strength differed significantly, owt/ob>normal>stunted, but owt/ob children had less strength per unit mass and poorer endurance. Normal and stunted children did not differ consistently in fitness. Physical activity and television time did not differ among the three groups.

Stunting associated with poor socioeconomic and maternal nutrition status and respiratory morbidity in Colombian schoolchildren

BACKGROUND

There are few recent reports on the prevalence and risk factors of stunting and thinness among schoolchildren in Latin America.

OBJECTIVE

To determine the prevalence and sociodemographic correlates of stunting and thinness among school-age children in Bogotá, Colombia, and to examine whether these nutritional indices are associated with the risk of respiratory and diarrheal morbidity symptoms, visits to the doctor, and school absenteeism during the school year in a prospective study.

METHODS

We obtained information on anthropometric and maternal sociodemographic characteristics of 3100 children 5 to 12 years of age who attended public primary schools in 2006 and who came from low- and middle-income households. Data on the incidence of common gastrointestinal and respiratory symptoms were collected prospectively on morbidity diaries throughout the year.

RESULTS

The prevalence rates of stunting and thinness were 9.9% and 8.7%, respectively. There were inverse, statistically significant trends in the prevalence of stunting by categories of child's birth and current weight; maternal education level, height, and body mass index (BMI); and household socioeconomic stratum. A strong positive association was found with maternal parity (p for trend < .0001). Thinness was positively associated with the child's and the mother's age and inversely associated with birthweight and maternal BMI. Stunting was associated with a 44% increase in the incidence of cough with fever during the school year (p = .04).

CONCLUSIONS

Child stunting in Bogotá is associated with poor socioeconomic and maternal nutritional status and predicts symptoms of respiratory infection.

Community well-being and growth status of indigenous school children in rural Oaxaca, southern Mexico

OBJECTIVE

To evaluate the relationship between community well-being based on an index of marginalization and growth status of indigenous rural school children in Oaxaca.

METHODS

Heights and weights of a cross-sectional sample of 11,454 children, 6-14 years, from schools for indigenous rural children (escuelas albergue) in 158 municipios in Oaxaca were measured in 2007. Tertiles of an index of marginalization were used to classify the 158 municipios into three categories of community well-being: lowest (highest marginalization), low, and moderate (lowest marginalization). Multivariate analysis of covariance, controlling for age, relative isolation and population size, was used to compare body size of children by category of community well-being. Contributions of marginalization, isolation and population size to variation in body size were estimated with sex-specific linear regression.

RESULTS

Children from municipios lowest in well-being were shorter and lighter than children from municipios low and moderate in well-being. Marginalization and relative isolation accounted for 23% (boys) and 21% (girls) of the variance in height and for 21% of the variance in weight of girls. Marginalization was the predictor of weight in boys (23%).

CONCLUSION

Community well-being was reflected in the growth status of rural indigenous school children. Compromised growth status was consistent with poor health and nutritional conditions that were and are characteristic of rural areas in the state of Oaxaca.