Tracking anthropometric dimensions and grip strength among children, adolescents and adults in an indigenous community of southern Mexico: 1968-1978-2000.

PURPOSE: To track body size and proportions, arm dimensions and grip strength in children, adolescents, and adults resident in an indigenous community in Oaxaca who were measured on two or three occasions across surveys in 1968, 1978, and 2000. METHODS: The three cross-sectional surveys included measures of height, weight, sitting height, arm circumference, triceps skinfold, and grip strength in surveys of schoolchildren in 1968 and of schoolchildren, adolescents and adults in 1978 and 2000. Cross-checks of surnames, forenames and ages/dates of birth of participants in the three surveys identified three samples of individuals measured on two occasions (1968-1978, two age groups in 1978-2000) and a subsample of individuals measured in the three surveys. Partial correlations controlling for age at each observation were calculated for each variable in the three sex-specific samples measured on two occasions, and for the subsamples of males and females measured on three occasions. RESULTS: Allowing for variation in age among subsamples, inter-age correlations were moderate to high for stature, moderate for sitting height and estimated leg length, and low to moderate for weight, BMI, arm and estimated arm muscle circumference, triceps skinfold, and grip strength. CONCLUSION: Allowing for the relatively broad chronological age intervals, the inter-age correlations for height, weight and BMI were at the low end, while those for grip strength and for strength per unit body weight for males (though not females) were generally in the range of correlations noted in studies of European samples. Likely associated with improved health, nutritional, and sanitation conditions, obesity and overweight were emerging among adults by 2000. Obesity and overweight in adults paralleled the introduction of mechanized agriculture that reduced routine physical work. Among children, the association of obesity and overweight is likely with increased nutritional availability, but poor choices in diet.

Do mating preferences remain the same when phenotypes change? Assortative mating for physical characteristics in an indigenous community in the valley of Oaxaca, southern Mexico.

Objective. To test the hypothesis that assortative mating for physical characteristics differs before and after major secular increases in height in an indigenous community in the Valley of Oaxaca, Mexico. Methods. Spouse pairs were identified in household and anthropometric surveys of a Zapotec-speaking community in 1978 (n = 68-70 pairs) and 2000 (n = 99-100 pairs). Height, weight, arm circumference, triceps skinfold and grip strength were measured. Assortative mating was calculated as Pearson correlations. Results. Husband-wife correlations for age were high in both years (r = 0.96, 0.95). Assortative mating for height was significant in 1978 (r = 0.35, p < 0.001) and in 2000 (r = 0.21, p < 0.01), but decreased when ages were controlled (1978, 0.21, p < 0.05; 2000, 0.11). Correlations (zero and second order, respectively) were low for the BMI (1978, 0.02, 0.02; 2000, 0.04, 0.05). Spouse correlations for grip strength were significant in both surveys (r = 0.25 to 0.45), but were reduced (p > 0.05) when ages of spouses were controlled (r = -0.02 to 0.16). Conclusion. Assortative mating for physical characteristics did not differ between surveys conducted before (1978) and after (2000) major secular increases in height in the community, and any possible genetic effect of the secular trend on assortative was likely negligible.

Thinness, overweight, and obesity in indigenous school children and youth in Mexico.

Background: The prevalence of overweight (OWT) and obesity (OB), defined by the body mass index (BMI, kg/m2) among children and youth has increased worldwide in the last 30-40 years.Aim: To evaluate the weight status, defined by the BMI, of indigenous school children and youth resident in different regions of MexicoSubjects and methods: Students 6-18 years (31,448 boys, 27,306 girls) were enrolled in bilingual schools for indigenous children and youth in Mexico in 2012. Height and weight were measured; the BMI was calculated. The BMI of each student was classified relative to International Obesity Task Force (IOTF) age- and sex-specific criteria as thin (three grades), normal, overweight (OWT) or obese (OB). The sample was divided into five geographic regions for analysis: North, Central, South-Gulf, South-Pacific, and South-Southeast. Age- and sex-specific prevalence, 95% confidence intervals, and Chi-square tests were calculated.Results: Prevalence of OWT + OB was highest in the South-Gulf, South-Pacific and South-Southeast regions and lowest in the North and Central regions, while thinness was most prevalent in the North and Central regions.Conclusion: Prevalence of severe and moderate thinness was relatively low, while the combined prevalence of OWT + OB was generally more prevalent in indigenous boys than girls. However, the prevalence of thinness, OWT + OB among indigenous children and youth was lower than in the general population of children and youth in Mexico.

Body mass index and physical fitness in Brazilian adolescents / Índice de massa corporal e aptidão física em adolescentes brasileiros

Abstract Objective: Evaluate the relationship between body mass index and physical fitness in a cross-sectional sample of Brazilian youth. Methods: Participants were 3849 adolescents (2027 girls) aged 10 -17 years. Weight and height were measured; body mass index was calculated. Physical fitness was evaluated with a multistage 20 m shuttle run (cardiovascular endurance), standing long jump (power), and push-ups (upper body strength). Participants were grouped by sex into four age groups: 10 -11, 12 -13, 14 -15, and 16 -17 years. Sex-specific ANOVA was used to evaluate differences in each physical fitness item among weight status categories by age group. Relationships between body mass index and each physical fitness item were evaluated with quadratic regression models by age group within each sex. Results: The physical fitness of thin and normal youth was, with few exceptions, significantly better than the physical fitness of overweight and obese youth in each age group by sex. On the other hand, physical fitness performances did not consistently differ, on average, between thin and normal weight and between overweight and obese youths. Results of the quadratic regressions indicated a curvilinear (parabolic) relationship between body mass index and each physical fitness item in most age groups. Better performances were attained by adolescents in the mid-range of the body mass index distribution, while performances of youth at the low and high ends of the body mass index distribution were lower. Conclusion: Relationships between the body mass index and physical fitness were generally nonlinear (parabolic) in youth 10 -17 years.

Resumo Objetivo: Avaliar a relação entre o índice de massa corporal e a aptidão física em uma amostra transversal de jovens brasileiros. Métodos: Os participantes foram 3.849 adolescentes (2.027 meninas) entre 10-17 anos. Foram medidos o peso e a estatura e foi calculado o índice de massa corporal. A aptidão física foi avaliada com: a corrida vaivém de 20 metros de vários estágios (resistência cardiovascular), impulsão horizontal (energia) e flexões (força superior do corpo). Os participantes foram agrupados por sexo em quatro faixas etárias: 10-11, 12-13, 14-15 e 16-17 anos. A Anova específica para sexo foi usada para avaliar as diferenças em cada item de aptidão física entre as categorias de status do peso por faixa etária. As relações entre o índice de massa corporal e cada item de aptidão física foram avaliadas com os modelos de regressão quadrática por faixa etária com relação ao sexo. Resultados: A aptidão física de jovens magros e normais foi, com poucas exceções, significativamente melhor do que a aptidão física de jovens com sobrepeso e obesos em cada faixa etária por sexo. Por outro lado, os desempenhos na aptidão física não diferiram de forma consistente, em média, entre jovens magros e com peso normal e entre jovens com sobrepeso e obesos. Os resultados das regressões quadráticas indicaram uma relação curvilínea (parabólica) entre o índice de massa corporal e cada item de aptidão física na maior parte das faixas etárias. Os melhores desempenhos foram obtidos pelos adolescentes na faixa intermediária da distribuição do índice de massa corporal, ao passo que os desempenhos dos jovens nas extremidades inferiores e superiores da distribuição do índice de massa corporal foram menores. Conclusão: As relações entre o índice de massa corporal e a aptidão física foram, em geral, não lineares (parabólica) nos jovens entre 10-17 anos.

Body mass index and physical fitness in Brazilian adolescents.

OBJECTIVE: Evaluate the relationship between body mass index and physical fitness in a cross-sectional sample of Brazilian youth. METHODS: Participants were 3849 adolescents (2027 girls) aged 10-17 years. Weight and height were measured; body mass index was calculated. Physical fitness was evaluated with a multistage 20m shuttle run (cardiovascular endurance), standing long jump (power), and push-ups (upper body strength). Participants were grouped by sex into four age groups: 10-11, 12-13, 14-15, and 16-17 years. Sex-specific ANOVA was used to evaluate differences in each physical fitness item among weight status categories by age group. Relationships between body mass index and each physical fitness item were evaluated with quadratic regression models by age group within each sex. RESULTS: The physical fitness of thin and normal youth was, with few exceptions, significantly better than the physical fitness of overweight and obese youth in each age group by sex. On the other hand, physical fitness performances did not consistently differ, on average, between thin and normal weight and between overweight and obese youths. Results of the quadratic regressions indicated a curvilinear (parabolic) relationship between body mass index and each physical fitness item in most age groups. Better performances were attained by adolescents in the mid-range of the body mass index distribution, while performances of youth at the low and high ends of the body mass index distribution were lower. CONCLUSION: Relationships between the body mass index and physical fitness were generally nonlinear (parabolic) in youth 10-17 years.

Skeletal maturity and oxygen uptake in youth soccer controlling for concurrent size descriptors.

Interrelationships among skeletal maturity status, body size, ventilator thresholds (VT) and peak oxygen uptake (VO2peak) were considered in 47 adolescent male soccer players aged 12.5-15.4 years. Body mass, stature, and the triceps and subscapular skinfolds were measured. The latter were used to estimate fat mass and fat-free mass. Skeletal age was assessed with the Fels method. VO2peak and VO2 at the first (VT1) and second (VT2) ventilatory thresholds were determined during an incremental maximal exercise test on a motorized treadmill. Ratio standards and allometric models were used in the analysis. Scaling exponents suggested linearity for all combinations between size descriptors and physiological variables, except between log-transformed values of VT1 and body mass (mL·kg-0.801·min, 95%CI: 0.649 to 0.952). Early maturing players attained greater values than players classified as "on-time" in skeletal maturity for the three ventilatory parameters expressed in absolute terms (d ranged from 0.65 to 0.71). The differences were attenuated after normalizing for mass descriptors using ratio standards and scaled variables (d ranged from 0.00 to 0.31). The results suggested significant variability between maturity groups when moving from VT1 to maximal metabolic conditions expressed by unit of stature (VT1: t = -2.413, p = 0.02, d = 0.60; VT2: t = -2.488, p = 0.02, d = 0.65; VO2peak: t = -2.475, p = 0.02, d = 0.65). Skeletal maturity status and associated variation in overall body size affects VT1, VT2 and VO2peak. The observed scaling of ventilatory outputs for body size may be related to the better running economy and smaller body size of average maturing athletes.

Geographic variation in the growth status of indigenous school children and youth in Mexico.

OBJECTIVE: To analyze variation in the growth status of indigenous children and youth attending bilingual schools, escuelas albergues, for the indigenous population in México. MATERIALS AND METHODS: The children and youth attended escuelas albergues in 1,009 localities in 21 Mexican states in 2012. Heights and weights of 31,448 boys and 27,306 girls 6-18 years of age were measured by trained staff at each school; the BMI was calculated. The students were divided into five geographic regions for analysis: North, Central, South-Gulf, South-Pacific, and South-Southeast. Growth status was compared to United States reference percentiles (P). RESULTS: Mean heights of children and youth from the five regions varied between P10 and P5 of the reference until about 13 years (girls) and 14 years (boys); subsequently, heights were ≤P5. Mean weights in both sexes were at P25 of the reference between 6 and 12 years, and then varied between P25 and P10 in boys and were ≥P25 in girls. Given the elevated weights relative to heights compared to the reference, mean BMIs of indigenous boys and girls were at or above the reference medians. Children and youth in the North and Central regions were, on average, taller than those in the South-Pacific and South-Southeast regions, while heights of those in the South-Gulf region were generally intermediate. In contrast, mean weights and BMIs differed negligibly among the regions. CONCLUSIONS: The geographic gradient in heights of indigenous children and youth was consistent with a north-to-south pattern noted among indigenous adults in studies spanning 1898 through 2013. Variation in height among children and youth likely reflected ethnic-specific and geographic variation interacting with economic and nutritional factors.

Multivariate Relationships among Morphology, Fitness and Motor Coordination in Prepubertal Girls.

Motor coordination and physical fitness are multidimensional concepts which cannot be reduced to a single variable. This study evaluated multivariate relationships among morphology, physical fitness and motor coordination in 74 pre-pubertal girls 8.0-8.9 years of age. Data included body dimensions, eight fitness items and four motor coordination tasks (KTK battery). Maturity status was estimated as percentage of predicted mature stature attained at the time of observation. Canonical correlation analysis was used to examine the relationships between multivariate domains. Significant pairs of linear functions between indicators of morphology and fitness (rc = 0.778, Wilks' Lambda = 0.175), and between fitness and motor coordination (rc = 0.765, Wilks' Lambda = 0.289) were identified. Girls who were lighter and had a lower waist-to-stature ratio and % fat mass attained better scores in the endurance run, sit-ups and standing long jump tests, but poorer performances in hand grip strength and 2-kg ball throw. Better fitness test scores were also associated with better motor coordination scores. Relationships between body size and estimated fatness with motor fitness suggested an inverse relationship that was particularly evident in performance items that required the displacement of the body through space, while motor coordination was more closely related with fitness than with somatic variables.

Secular trends are associated with the demographic and epidemiologic transitions in an indigenous community in Oaxaca, Southern Mexico.

OBJECTIVE: To test the hypothesis that secular changes in body size and age at menarche are related to the demographic and epidemiologic transitions in an indigenous community in Oaxaca, southern Mexico. METHODS: Data were derived from surveys of a Zapotec-speaking community conducted between 1968 and 2000. Segmented linear regressions of height, weight, BMI and recalled age at menarche on year of birth in cohorts of adults born before and after the demographic transition were used to evaluate secular changes. Corresponding comparisons of body size (MANCOVA controlling for age) and age at menarche (status quo, probit analysis) were done for samples of children and adolescents born before and after the epidemiological transition. RESULTS: Height and weight increased in adults born after the demographic transition (mid-1950s), and especially in children and adolescents born after the epidemiological transition (mid-1980s). Age at menarche also decreased significantly in women born after the demographic transition, but at a more rapid estimated rate in adolescents born after the epidemiological transition. Secular gains in body weight were proportional to those for height among children and adolescents, but adults, males more so than females, gained proportionally more weight. CONCLUSIONS: The secular trend in height in adults of both sexes was associated with the decade of the demographic transition in the mid-1950s. Significant secular gains in size attained and age at menarche occurred in children and youth born after the epidemiologic transition which likely reflected improved health and nutritional conditions since the mid-1980s.

Natural selection and type 2 diabetes-associated mortality in an isolated indigenous community in the valley of Oaxaca, southern Mexico.

OBJECTIVE: This study tests the hypothesis that natural selection is associated with type 2 diabetes (T2D)-associated mortality and fertility in a rural isolated Zapotec community in the Valley of Oaxaca, southern Mexico. PARTICIPANTS AND METHODS: Mortality data and related demographic and genealogic information were linked with data for fertility, prereproductive mortality and family history of mortality attributed to T2D. Physician verified T2D mortality (n = 27) between 1980 and 2009 and imputed T2D (n = 70) from cardiovascular mortality (68% random sample) and renal failure (44% random sample). Bootstrapping was used to obtain a robust variance estimate in survival analysis and multivariate analysis of variance. RESULTS: Estimated maximum natural selection by Crow's Index occurred circa 1930 and was relaxed after this time in the study population. Cox-regression survival analysis of T2D mortality with covariates (family history of T2D, cardiovascular disease, renal failure) indicated a significant hazard ratio (HR = 5.95, 95% CI: 1.38-25.67, p < .008) for the increase in T2D in 2000 to 2009. Survival analysis of imputed T2D resulted in a significant HR of 2.03 (95% CI: 1.08-3.85, p = .01) for the increase in T2D in the 2000 to 2009 cohort (reference group: 1980-1989). Mean number of live born offspring was lower among T2D (n = 27, 4.04 ± 3.85 SD) compared to non-T2D (n = 199, 5.30 ± 3.48) groups (p < .08). Mean number of live born offspring was lower (p = .003) among imputed T2D compared to non-T2D groups (4.10 ± 3.44 vs. 5.62 + 3.50). DISCUSSION: T2D-associated mortality increased in frequency as natural selection decreased, and favored offspring survival of non-T2D descedants. The results indicated statistically significant directional selection against T2D and imputed T2D to this population isolate.

Metabolic risk and television time in adolescent females.

OBJECTIVES: A sedentary lifestyle is increasingly implicated in a negative metabolic health profile among youth. The present study examined relationships between clustered metabolic risk factors and TV viewing in female adolescents. METHODS: The sample comprised 262 girls 14-17 years. Height, weight, fasting glucose, insulin, HDL cholesterol, triglycerides, and blood pressure were measured. Body mass index (BMI) was calculated. TV viewing time and moderate-to-vigorous physical activity (MVPA) were estimated from a 3-day diary. Outcome variables were normalized and expressed as Z scores which were summed into a metabolic risk score. Multiple linear regression analysis was used. RESULTS: TV viewing was independently associated with increased prevalence of clustered metabolic risk in girls after adjustment for several confounders (i.e., chronological age, BMI, MVPA, and parental education). The final model also indicated that lower levels of MVPA, higher BMI, and lower mother education were associated with higher metabolic risk. CONCLUSIONS: Increased TV viewing had an adverse effect on metabolic health of adolescent girls. The findings highlight the potential importance of preventive actions to ameliorate metabolic risk in youth which target both sedentary and physically active behaviors.

Relationship between metabolic syndrome and moderate-to-vigorous physical activity in youth.

BACKGROUND: Associations of metabolic syndrome (MetS) with lifestyle behaviors in youth is potentially important for identifying subgroups at risk and encourage interventions. This study evaluates the associations among the clustering of metabolic risk factors and moderate-to-vigorous physical activity (MVPA) in youth. METHODS: The sample comprised 522 girls and 402 boys (N = 924) aged 11 to 17 years. Height, weight, waist circumference (WC), fasting glucose, high-density lipoprotein cholesterol, triglycerides, and blood pressures were measured. Cardiorespiratory fitness (CRF) was assessed using the 20-m shuttle run test. MVPA was estimated with a 3-day diary. Outcome variables were statistically normalized and expressed as z scores. A clustered metabolic risk score was computed as the mean of z scores. Multiple linear regression was used to test associations between metabolic risk and MVPA by sex, adjusted for age, WC, and CRF. RESULTS: After adjustment for potential confounders, MVPA was inversely associated with the clustering of metabolic risk factors in girls, but not in boys; in addition, after adjusting for WC, the statistical model of that relationship was substantially improved in girls. CONCLUSION: MVPA was independently associated with increased risk of MetS in girls. Additional efforts are needed to encourage research with different analytical approach and standardization of criteria for MetS in youth.

Independent association of clustered metabolic risk factors with cardiorespiratory fitness in youth aged 11-17 years.

BACKGROUND: Although the prevalence of metabolic syndrome (MetS) has increased in youth, the potential independent contribution of cardiorespiratory fitness (CRF) to the clustering of metabolic risk factors has received relatively little attention. AIM: This study evaluated associations between the clustering of metabolic risk factors and CRF in a sample of youth. SUBJECTS AND METHODS: Height, weight, BMI, fasting glucose, insulin, HDL-cholesterol, triglycerides and blood pressures were measured in a cross-sectional sample of 924 youth (402 males, 522 females) of 11-17 years. CRF was assessed using the 20-metre shuttle run test. Physical activity (PA) was measured with a 3-day diary. Outcome variables were statistically normalized and expressed as Z-scores. A MetS risk score was computed as the mean of the Z-scores. Multiple linear regression was used to test associations between CRF and metabolic risk, adjusted for age, sex, BMI, PA and parental education. RESULTS: CRF was inversely associated with MetS after adjustment for potential confounders. After adjusting for BMI, the relationship between CRF and metabolic risk has substantially improved. CONCLUSION: CRF was independently associated with the clustering of metabolic risk factors in youth of 11-17 years of age.

Thinness, overweight and obesity in indigenous youth in Oaxaca, 1970 and 2007.

OBJECTIVE: To evaluate change in body mass index (BMI) and weight status of indigenous youth in Oaxaca between the 1970s and 2007. MATERIALS AND METHODS: Heights and weights were measured in cross-sectional samples of school children 6-14 years in the 1970s (2 897) and 2007 (4 305); BMI was calculated. International Obesity Task Force cutoffs for weight status were used. BMI and prevalence of severe and moderate thinness, overweight and obesity were compared by year. RESULTS: BMI increased significantly across time. Primary change in weight status occurred in overweight, 1970s, <2%; 2007, 7 to 12%. Little change occurred in thinness (<2%) and obesity (≤ 1%) in both surveys, except in children 6-9 years (obesity=4% in 2007). CONCLUSION: BMI and prevalence of overweight increased across all ages from the 1970s to 2007, but children 6-9 years appeared to be more at risk for obesity than youth 10-14 years. Prevalence of thinness was unchanged.

Altitude effects on growth of indigenous children in Oaxaca, Southern Mexico.

The effect of altitude of residence on the growth status of 11,454 indigenous school children 6-14 years of age in Oaxaca, southern Mexico, was examined. Indicators of living conditions (human development index [HDI], index of community nutritional risk [INR], index of marginalization [IM], index of relative isolation [II]) were regressed on z-scores for height, weight and BMI, and the residuals were regressed on altitude of residence (km). Independent of other environmental conditions, altitude negatively affected height by approximately -0.07 z-scores per kilometer altitude above sea level. The estimated average decrease in stature was 0.92 cm per kilometer elevation. BMI was significantly increased, 1.2 units per kilometer elevation, consistent with earlier studies of growth status and altitude. In contrast, weight was not affected by altitude of residence. Approximately 36% of the reduction in height and 54% of the increase in BMI were due to altitude effects; the remaining changes in height and BMI were associated with environmental factors reflected in the indices of community well-being considered.

Thinness, overweight and obesity in indigenous youth in Oaxaca, 1970 and 2007 / Delgadez, sobrepeso y obesidad en jóvenes indígenas en Oaxaca, 1970 y 2007

Objective. To evaluate change in body mass index (BMI) and weight status of indigenous youth in Oaxaca between the 1970s and 2007. Materials and methods. Heights and weights were measured in cross-sectional samples of school children 6-14 years in the 1970s (2 897) and 2007 (4 305); BMI was calculated. International Obesity Task Force cutoffs for weight status were used. BMI and prevalence of severe and moderate thinness, overweight and obesity were compared by year. Results. BMI increased significantly across time. Primary change in weight status occurred in overweight, 1970s, <2%; 2007, 7 to 12%. Little change occurred in thinness (<2%) and obesity (≤1%) in both surveys, except in children 6-9 years (obesity=4% in 2007). Conclusion. BMI and prevalence of overweight increased across all ages from the 1970s to 2007, but children 6-9 years appeared to be more at risk for obesity than youth 10-14 years. Prevalence of thinness was unchanged.

Objetivo. Evaluar el cambio en el índice de masa corporal (IMC) y el estatus de peso entre 1970 y 2007 en jóvenes indígenas de Oaxaca. Material y métodos. Se midieron estatura y peso de series transversales de escolares indígenas en edades de 6 a 14 años en 1970 (2 897) y en 2007 (4 305), se calculó el IMC y se emplearon los puntos de corte del International Obesity Task Force para el estatus de peso. El IMC y la prevalencia de delgadez, sobrepeso y obesidad en 1970 y 2007 fueron comparados. Resultados. El IMC aumentó de manera significativa entre 1970 y 2007. Los cambios más importantes fueron en sobrepeso, <2% en 1970 a 7-12% en 2007. Hubo poco cambio en la delgadez (<2%) y la obesidad (≤1%) en ambas investigaciones, excepto en niños de 6 a 9 años (4% en 2007). Conclusión. El IMC y la prevalencia de sobrepeso aumentaron a través de todas las edades de los años 1970 a 2007, pero los niños de 6 a 9 años parecen tener un mayor riesgo para la obesidad que los jóvenes de 10 a 14 años. La frecuencia de la delgadez fue igual.

Weight status of indigenous youth in Oaxaca, southern Mexico: concordance of IOTF and WHO criteria.

PURPOSE: To compare the prevalence of thinness, overweight and obesity with IOTF and WHO criteria among indigenous school youth from the state of Oaxaca, southern Mexico. METHODS: The sample included 11 454 indigenous youth (6216 boys, 5238 girls) 6-14 years of age. Heights and weights were measured in 2007 by trained staff. BMIs were calculated and classified as severely thin, moderately thin, normal, overweight or obese using age- and sex-specific IOTF and WHO cut-offs. Prevalence, percentage agreement between classifications, Spearman rank order correlations and Kappa coefficients were calculated. RESULTS: Prevalence of overweight and obesity was higher with WHO than IOTF criteria, while prevalence of severe and moderate thinness did not appreciably differ between criteria. Weight status with the two criteria was discordant in 839 boys (13.5%) and 383 girls (7.3%) and more often for overweight and obesity than thinness. Percentage agreement, correlations and Kappa coefficients were moderate-to-high and were higher in girls than boys. CONCLUSION: Prevalence of overweight and obesity among indigenous youth in Oaxaca was higher with WHO than IOTF criteria, whereas prevalence of severe and moderate thinness was similar. Differences in estimates for overweight and obesity have implications for surveillance.

Secular change in height and weight of indigenous school children in Oaxaca, Mexico, between the 1970s and 2007.

BACKGROUND: Information on secular change in indigenous children in Oaxaca, southern Mexico, is limited. AIM: To evaluate secular change in heights and weights of indigenous school children 6-14 years in four regions of the state of Oaxaca between the 1970s and 2007. SUBJECTS AND METHODS: Heights and weights of 2897 (1419 boys, 1478 girls) and 4305 (2368 boys, 1937 girls) school children 6-14 years of age were measured in the 1970s (1971-1978) and 2007, respectively. The sample was from 18 communities in the 1970s and from 58 communities in 2007 in four regions of Oaxaca. Sex-specific MANCOVA, with age of the child and altitude of each community as covariates, was used to compare size attained in the 1970s and 2007 in two age groups: 6-9 years and 10-14 years. RESULTS: Indigenous Oaxaca school children are taller and heavier in 2007 than the 1970s. Secular gains are larger in youth of 10-14 years than in children of 6-9 years, while sex differences are small. CONCLUSION: Improved growth status between the 1970s and 2007 presumably reflects better health and nutritional conditions in indigenous communities of Oaxaca. Mean heights in 2007, however, only approximate 5(th) percentiles of the US reference.

Correlates of physical activity and inactivity in urban Mexican youth.

OBJECTIVES: To evaluate correlates of physical activity in Mexico City school youth. METHODS: A cross-sectional survey was conducted with 1,004 school youth (490 males and 514 females), 9-18 years of age resident in Mexico City. Age, height, body mass index (BMI), socioeconomic status (SES), time viewing television and playing video games (physical inactivity), and perceived sport/physical activity status of mother and father were evaluated as potential correlates of physical activity [Physical Activity Questionnaire (PAQ)]. Multiple linear regression analyses (backward elimination) by age group and sex were used. RESULTS: Physical activity declined in older adolescents, while differences between the two younger age groups were minimal. Television time showed a similar tendency. Overall, fathers were perceived as being active in sport/physical activity more frequently than mothers. Significant predictors of activity differed by age group and sex. For the total sample, age (negative) and perceived sport/activity status of the mother (positive) were significant predictors of the PAQ in boys, and age and the BMI (negative) and height and perceived sport/activity status of both parents (positive) were significant predictors for girls. Age (negative) was the main predictor for inactivity in both males and females. CONCLUSIONS: Potential correlates of physical activity and inactivity considered in this analysis were limited and accounted for relatively little of the variance in physical activity. The role of perceived sport/activity of the parents, especially among younger boys and girls, is particularly of interest and merits more detailed study. Nevertheless, many other variables also need to be considered.

Age and secular effects on muscular strength of indigenous rural adults in Oaxaca, Southern Mexico: 1978-2000.

PURPOSE: To evaluate age and secular changes in strength of rural Zapotec adults in Oaxaca between 1978 and 2000. METHODS: Grip strength, height and weight were measured in 1978 (n = 247, 19-82 years) and 2000 (n = 407, 19-89 years); 35 males and 52 females were measured in both years. MANCOVA was used for comparisons by age and year. RESULTS: Grip strength and strength/height decline with age; the slope is greater after 40-49 years. Both are significantly greater in 2000 compared to 1978 only in males 19-29 and 30-39 years and in females 30-39 years. Strength and strength/height decline at a slightly faster rate in females than males during young adulthood, but at similar rates in both sexes during middle age. Strength/mass is greater in 1978 than 2000, but differences are not significant in most age groups. Strength/mass declines linearly with age and rates do not differ between young and older adults of both sexes. Left grip strength/left mid-arm muscle circumference shows a pattern across age similar to strength/mass in both sexes. CONCLUSION: Grip strength and strength per unit size declined with age. Strength and strength/height tended to increase between 1978 and 2000, while the opposite occurred for strength/weight. Results likely reflected in changes in habitual physical activity patterns associated with the transition from subsistence agriculture to less economic dependence upon agriculture.