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.

Secular change in height, sitting height and leg length in rural Oaxaca, southern Mexico: 1968–2000

OBJECTIVE

To evaluate secular changes in height, sitting height and estimated leg length between 1968 and 2000 in residents in a rural Zapotec-speaking community in Oaxaca, southern Mexico.

MATERIALS AND METHODS

Height and sitting height were measured in school children 6-13 years (1968; 1978, 2000), in adolescents 13-17 years (1978, 2002) and adults 19-29 years (1978, 2000). Leg length was estimated as height minus sitting height. The sitting height/ height ratio was calculated. Subjects were grouped by sex into four age categories: 6-9, 10-13, 13-17 and 19-29 years for analysis. The Preece-Baines Model I growth curve was fitted to cross-sectional means for 1978 and 2000.

RESULTS

There were no differences between children 6-9 and 10-13 years in 1968 and 1978 with the exception of the sitting height ratio in girls 6-9 years. Children of both sexes 6-13 years and adolescent boys 13-17 years were significantly larger in the three dimensions in 2000 compared to 1978; adolescent girls differed only in height and sitting height. Adult males in 2000 were significantly taller with longer legs than those in 1978, but the samples did not differ in sitting height and the ratio. Adult females in 1978 and 2000 did not differ significantly in the three dimensions. Rates of secular change in height and sitting height between 1978 and 2000 were reasonably similar in the three age groups of male children and adolescents, but the rate for estimated leg length was highest in 10-13-year-old boys. Secular gains were smaller in adult males, but were proportionally greater in estimated leg length. Girls 6-9 and 10-13 years experienced greater secular gains in height, sitting height and estimated leg length than adolescent and young adult females, while secular gains and rates decreased from adolescent girls to young adult women. Ages of peak velocity for height, sitting height and estimated leg length declined in boys, while only ages of peak velocity for height and estimated leg length declined in girls.

CONCLUSIONS

There are major secular increases in height, sitting height and estimated leg length of children and adolescents of both sexes since 1978. Secular gains in height are of similar magnitude in boys and girls 6-13 years, but are greater in adolescent and young adult males than females. The secular increase in height of young adults of both sexes is smaller than that among adolescents. Estimated leg length accounts for about 60% of the secular increase in height in children of both sexes. Estimated leg length and sitting height contribute equally to the secular increase in height in adolescent boys, whereas estimated leg length accounts for about 70% of the secular increase in height in young adult males. Sitting height contributes about two-thirds of the secular increase in height in adolescent and young adult females.

Blood lead level and physical fitness of schoolchildren in the copper basin of south-western Poland: Indirect effects through growth stunting

OBJECTIVE

The present study was set in the context of two questions. First, does blood lead level exert a direct effect on measures of physical fitness? And second, might blood lead influence physical fitness indirectly through growth stunting?

BACKGROUND

Blood lead level is negatively associated with performances on a variety of fine motor tasks. Corresponding information on associations with measures of physical fitness and gross motor coordination are limited.

MATERIALS AND METHODS

Schoolchildren 7-15 years of age (463 males, 436 females) living in the vicinity of copper smelters and refineries were tested for blood lead. In addition to body size and blood lead, physical fitness was measured: right and left grip strength, timed sit-ups, flexed arm hang, plate tapping, shuttle run, standing long jump and medicine ball throw. Simple reaction time was also measured.

RESULTS

The effect of blood lead level on physical fitness was indirect and small, and operated through anthropometric dimensions that more directly influenced the measures of fitness.

CONCLUSIONS

Direct effects of blood lead level on indicators of physical fitness in school age youth are not evident. Blood lead level adversely affects physical fitness indirectly through growth stunting.

Physical activity in youth from a subsistence agriculture community in the Valley of Oaxaca, southern Mexico

Observations of activities of contemporary subsistence agricultural communities may provide insights into the lifestyle of youth of 2 to 3 generations ago. The purpose of this study was to document age- and sex-associated variation in household activities and daily steps walking to school of youth 9-17 years in an indigenous subsistence agricultural community in Oaxaca, southern Mexico. Activities during leisure were also considered. A cross-sectional survey of a rural Zapotec-speaking community was undertaken, and respondents included 118 boys and 152 girls, aged 8.7-17.9 years. Household and leisure activities were documented by questionnaire and subsequent interview. Household activities were classified by estimated intensity for before and after school and on the weekend, and an estimate of METS per day accumulated while doing chores was derived. Number of steps from home to school was estimated. Contingency table analysis and MANCOVA controlling for age was used to evaluate results. Household activities tended to cluster at light and moderate intensities in girls and at moderate to moderate-to-vigorous intensities in boys. Estimated METS per day in approximately 2 h of chores differed significantly by sex. Secondary school girls expended significantly more METS per day in chores than primary school girls, but there was no difference by school level in boys. The daily round trip from home to school was approximately 2400 steps for primary students and approximately 2700 and approximately 3100 steps for secondary boys and girls, respectively. Television viewing and participation in sports were major leisure activities for boys and girls. Daily household chores, walking, and leisure activities suggest moderately active and moderately-to-vigorously active lifestyles in girls and boys, respectively, in this indigenous subsistence agricultural community.

Physical activity: the present in the context of the past

In the broad sense, modern humans have lived in an environment in which physical activity and associated movement skills were central, especially in the context of physical competition with other animals. The physically active lifestyle of earlier human populations has been emphasized, especially the cardiovascular endurance component and energy expenditure, but less attention has been devoted to the gross and fine motor skills that are essential components of this lifestyle. Motor skills developed through practice are important determinants of success and survival in preindustrial societies. In industrial and postindustrial societies, on the other hand, the role of physical activity is different, with prowess in certain areas of physical expertise (e.g., accuracy with projectiles, muscular strength, among others) and prolonged exertion (i.e., cardiovascular endurance) less important for survival. The combined effects of the transition to a sedentary lifestyle and attendant dietary changes have resulted first an epidemic of coronary heart disease and more recently an epidemic of overweight/obesity in postindustrial societies. Although mortality associated with coronary heart disease has declined, due largely to biomedical advances, overweight and obesity have increased concomitantly with population reduction in physical activity (energy expenditure) and increased calorie (energy) consumption. The current scenario begs several questions which have implications for contemporary human biology related to sustaining the pace of cultural change on a biological base that is increasingly being compromised by physical inactivity, overweight, and obesity.

Comparison of the impact of short (<1 year) and long-term (> or =1 year) clopidogrel use following percutaneous coronary intervention on mortality

The optimal duration of clopidogrel administration after percutaneous coronary intervention (PCI) remains unknown. Clopidogrel is currently recommended for minimums of 1 and 12 months after bare-metal stent and drug-eluting stent implantation, respectively. To determine the impact of clopidogrel discontinuation 1 year after PCI, the outcomes of 530 consecutive patients who underwent PCI from January 2004 to July 2006, were free of cardiovascular events for 6 months after PCI, and had follow-up available for >12 months were examined. The outcomes of patients who received clopidogrel for > or =1 year were compared with those of patients who received it for <1 year. The mean age was 65 +/- 9 years. Patients often presented with acute coronary syndromes (57%), and 85% received drug-eluting stents. Clopidogrel was used for > or =1 year and for <1 year in 341 and 189 patients, respectively. During a mean follow-up period of 2.4 +/- 0.8 years, 40 patients (8%) died, 21 (4%) had acute myocardial infarctions, and 89 (17%) underwent repeat coronary revascularization. Compared with patients with clopidogrel administration for <1 year after PCI, those who received clopidogrel for > or =1 year had lower mortality (14.8% vs 3.5%, p <0.001). On multivariate analysis, clopidogrel use for > or =1 year was associated with lower mortality (hazard ratio 0.28, 95% confidence interval 0.14 to 0.59), independent of traditional cardiovascular risk factors, clinical presentation, and the use of drug-eluting stents. In conclusion, the use of clopidogrel for > or =1 year after PCI was associated with lower mortality.

Epidemiologic transition in an isolated indigenous community in the Valley of Oaxaca, Mexico

The objective of the present study is to analyze age-specific mortality in a rural indigenous community in the throes of a secular increase in size in the Valley of Oaxaca, southern Mexico, over 30 years, 1970-1999. Variation in mortality by age group was analyzed over time for evidence of an epidemiological transition. The seasonal rain pattern in the Valley of Oaxaca (83% from May through September) was evaluated for its relationship with mortality in wet and dry months. Mortality and causes of death changed markedly over the 30-year interval. Infant and preschool mortality, overall mortality, and causes of death changed from the 1970s through the 1990s. Prereproductive deaths (<15 years) predominated in the 1970s and were largely due to gastrointestinal and respiratory diseases, with periodic outbreaks of measles. Deaths of adults 65+ years predominated in the 1990s and were largely due to degenerative diseases usually associated with aging. The marked changes in age and causes of death over the three decades (epidemiologic transition from Stage I to Stage II) occurred concurrently with significant secular increases in body size in children, adolescents, and young adults, highlighting improved health and nutritional conditions in the community which is in early Stage II of the demographic transition. The demographic transition to Stage II is a leading indicator (15-25 years lag) for the onset of the secular trend, while the epidemiologic transition to Stage II is a predictor that the secular increase is in process in the study community.

The Risk of Acute Myocardial Infarction with Etodolac Is not Increased Compared to Naproxen: A Historical Cohort Analysis of a Generic COX-2 Selective Inhibitor

Background: This study compares the risk of acute myocardial infarction among patients exposed to etodolac, naproxen, celecoxib, and rofecoxib.

Methods: A retrospective cohort study in 38 258 veteran patients (26 376 patient-years) measured the adjusted odds ratios of acute myocardial infarction during exposure to etodolac, naproxen, celecoxib, or rofecoxib.

Results: Diagnosis of acute myocardial infarction was confirmed in 100 patients who were exposed to a study nonsteroidal anti-inflammatory drug. Compared to naproxen, the increased risk of acute myocardial infarction was not significant for etodolac (OR = 1.32, P = .27), whereas celecoxib (OR = 2.18, 95% CI 1.09-4.35, P = .03) and rofecoxib (OR = 2.16, 95 CI 1.04-4.46, P = .04) were significant. A post hoc analysis indicates that patients with a prior history of acute myocardial infarction had a significant, 4.26-fold risk for another acute myocardial infarction if taking celecoxib or rofecoxib.

Conclusion: Etodolac is not associated with a statistically increased risk of acute myocardial infarction compared to naproxen.

Natural selection and demographic transition in a Zapotec-speaking genetic isolate in the Valley of Oaxaca, southern Mexico

OBJECTIVE

The study analyzed the potential for natural selection and the demographic transition in an isolated Amerindian population in the process of secular change in body size.

SETTING

A genetically isolated, Zapotec-speaking community located in the Valley of Oaxaca, southern Mexico, has been studied regularly from the mid-1960s to 2000. Children, adolescents and young adults have experienced a recent secular increase in body size since 1978 after a major period of no change.

METHODS

Potential for natural selection and the demographic transition were analyzed over a 100-year period, ca 1900-2000. National census data, results from anthropological surveys and community archives and reports were used.

RESULTS

Opportunity for natural selection changed markedly over the last century. Demographic transition to Stage II occurred ca 1955 and preceded a secular increase in body size. The crossover between curves for mortality (I(m)) and fertility (I(f)) occurred at approximately the time of onset of the secular trend among children, adolescents and young adults, i.e. those born since the early 1970s.

CONCLUSIONS

The 'classic' demographic transition occurred in the mid-1950s and preceded the secular increase in body size. A 'critical mass' of environmental improvement appears to be necessary to activate secular improvements in growth status, possibly turning on a gene complex that interacts with the improved environmental conditions. The lead time from the onset of demographic transition phase II to beginning of the secular trend is approximately 25 years (one generation) in this community.

Overweight and obesity in a rural Amerindian population in Oaxaca, Southern Mexico, 1968-2000

The purpose of this study was to evaluate secular change in the prevalence of overweight and obesity in a rural Zapotec Indian community in southern Mexico between 1968 and 2000. Cross-sectional surveys of children 6-13 years, adolescents 13-17 years, and adults 19 years of age and older resident in a rural community in Oaxaca were conducted in 1968/1971, 1978, and 2000. Individuals present in the 1968, 1978, and 2000 surveys provided a small longitudinal component. Height and weight were measured; the BMI was calculated. International criteria for overweight and obesity were used. Overweight and obesity were virtually absent in school children 6-13 years in 1968 and 1978 and in adolescents in 1978. Small proportions of children (boys, 5%; girls, 8%) and adolescents (boys, 3%; girls, 15%) were overweight in 2000; two children (1%) and no adolescents were obese. Among adults, 7% of males and 19% of females were overweight and <1% of males and 4% of females were obese in 1971/1978, but 46% of males and 47% of females were overweight; and 5% of males and 14% of females were obese in 2000. The trends for children, adolescents, and adults were confirmed in the longitudinal subsamples. In conclusion, overweight and obesity are not presently a major problem in children and adolescents in this rural Zapotec community. Overweight, in particular, and to a lesser extent obesity have increased in prevalence among adults since the late 1970s. The results suggest adulthood as a critical period for onset of overweight and obesity in this sample.

Overweight and obesity among youth participants in American football

OBJECTIVE

To estimate the prevalence of overweight and obesity among participants in youth American football 9 to 14 years of age.

STUDY DESIGN

Cross-sectional, 653 boys, 8.7 to 14.6 years. Height and weight were measured; body mass index (BMI) was calculated. Overweight and obesity were defined by international (International Obesity Task Force [IOTF]) and United States (Centers for Disease Control [CDC]) criteria. Prevalence and 95% confidence interval were calculated. Player age, height, and weight and midparent height were used to predict mature height; current height was expressed as a percentage of predicted mature height as an estimate of maturity status.

RESULTS

Overall 45.0% (41.2% to 48.9%) and 42.6% (38.8% to 46.5%) of players were overweight or obese by CDC and IOTF criteria, respectively. Prevalence was highest in early maturing boys. Based on position-activity at time of injury (n = 180), overweight and obesity were more common among offensive and defensive linemen.

CONCLUSION

Overweight and obesity were more prevalent in youth football players than in national samples of American boys. Allowing for limitations of the BMI and the relative stability of the BMI from adolescence into adulthood, a relatively large number of football participants may be at risk for later overweight or obesity, and the risk appears to be greater for offensive and defensive line positions.

Gene-environment interaction in skeletal maturity and body dimensions of urban Oaxaca Mestizo schoolchildren

OBJECTIVE

The study analyzed the relationship between skeletal age (SA) and the difference between skeletal and chronological ages (SA-CA) and body size among growth-stunted and well-nourished children.

METHODS AND MATERIALS

Tanner-Whitehouse 2 (TW2) 20 bone, radius-ulna-short (RUS) bone, and carpal SAs were analyzed in three cross-sectional samples of school children aged 6-13 years: Mestizo children (n = 396) from the city of Oaxaca, southern Mexico, and American Black (n = 570) and White (n = 432) from Philadelphia. The Oaxaca children were mild-to-moderately undernourished while the Philadelphia children were well nourished. The total sample included 1398 radiographs assessed with the Tanner-Whitehouse protocol by a single, experienced rater. Maturity scores were converted to TW2 20 bone, RUS and carpal SAs.

RESULTS

Correlations of SA and SA-CA differences with body dimensions (height, sitting height, leg length, weight, triceps skinfold, arm and estimated midarm muscle circumferences) were consistent and approximately equal in magnitude for the well-nourished samples but were different among Oaxaca children. SAs of Philadelphia children were significantly more highly correlated with body dimensions than were SA-CA differences compared to Oaxaca Mestizo children. Patterns of RUS and carpal SA correlations with body size (height, sitting height, and leg length) in Oaxaca children were different from the Philadelphia samples. Oaxaca children tended to have advanced RUS SA and delayed carpal SA.

CONCLUSION

Long bone complexes mature earlier than round bone complexes in Oaxaca children compared to Philadelphia Black and White children, resulting in short stature in Oaxaca children. Results suggest a gene-environment interaction effect on the program for skeletal growth and maturation in undernourished Oaxaca children compared to well-nourished Black and White children from Philadelphia.

Lead and growth status of school children living in the copper basin of south-western Poland: differential effects on bone growth

OBJECTIVE

The study analyzed the relationship between blood lead (BPb) levels and growth status of upper and lower body segments among schoolchildren living in the copper basin of south-western Poland.

MATERIALS AND METHODS

Schoolchildren 7-15 years of age (463 males, 436 females) living in the vicinity of copper smelters and refineries were tested for blood lead. Weight, height, symphyseal height (leg, lower segment length), and arm length were measured. Trunk (upper segment including head and neck) length was estimated as height minus symphyseal height. The BMI was calculated using weight/height2 (kg m-2).

RESULTS

Mean blood lead in the total sample was 7.7 +/- 3.5 micro g dL-1 (2.0-33.9 micro g dL-1). Blood lead level was significantly and linearly related to reduced weight, height, trunk, leg, and arm lengths. The estimated reduction in height was 5 mm per 1 micro g dL-1 increase in blood lead (5.0 cm per 10 micro g dL-1). The reduction occurred in leg length (males, 64%; females 72%) compared to trunk length (males, 36%; females, 28%). Estimated reductions in arm length were 2.0 cm (males) and 2.5 cm (females) per 10 micro g dL-1 increase in blood lead. Hence, limb (leg and arm) lengths were markedly reduced.

CONCLUSIONS

Linear skeletal growth was reduced with increased blood lead, even at levels below that considered for action by US CDC standards. The reduction in height occurred primarily in leg length. Arm length was also reduced, suggesting limb lengths in general were affected by blood lead. Results are consistent with lead-associated interruption of (1) major epiphyseal growth plate chondrocyte hyperplasia, hypertrophy, and interrupted matrix calcification as a primary cause of stunted long bone growth, and reduced stature; and (2) attenuated osteoblast activity (proliferation and migration) as a secondary cause of stunted growth in the study population.

Familial similarity in body size in an isolated Zapotec-speaking community in the valley of Oaxaca, southern Mexico: estimated genetic and environmental effects

OBJECTIVE

The study used path analysis to estimate genetic and environmental determinants of familial similarity in anthropometric characteristics among children from a rural subsistence agrarian community in the Valley of Oaxaca in southern Mexico.

METHODS

Anthropometric dimensions included height, weight, arm circumference and triceps skinfold; the BMI was calculated. Parent-offspring pairs (n = 34) were constructed from pedigrees and prior studies using listwise case deletion for parent-male child and parent-female child, respectively. Path coefficients for genetic and environmental effects were computed using linear regression. Age effects were held constant by computing residuals after parameter regression on age and age2. Environmental effects were analysed using a previously published factor analysis of village ecology.

RESULTS

By path analysis, the paternal effect was low-to-moderately strong on males (0.21-0.57) but low on females (0.13-0.23). Maternal effects were low, inconsistent and negligible on males (-0.16-0.09), but high on females (0.57-0.81), except for height (0.19). Estimated environmental effects on sibling similarity were low (0.12-0.27).

CONCLUSION

The environment exerts a relatively consistent effect on growth status, and probably accounts for the low path coefficients (i.e. sibling correlations, parent-offspring regressions). Sex-specific effects are apparent in a strong paternal influence on male offspring height and moderate influences on weight, triceps skinfold, and arm circumference. Maternal influences are small on the anthropometric characteristics of males, but are exceptionally large on female weight, triceps skinfold and arm circumference. Estimated environmental effects on sibling similarity are low-to-moderately high.

Opportunity for Natural Selection and Gene Flow in an Isolated Zapotec-Speaking Community in Southern Mexico in the Throes of a Secular Increase in Size

Our object in this paper is to analyze the opportunity for natural selection and gene flow in an isolated Zapotec-speaking community in the valley of Oaxaca, southern Mexico, that is undergoing a secular increase in body size. Surveys were conducted in the community in 1968, 1978, and 2000, including anthropometric and census data. No secular change was found in the growth status of schoolchildren and adult height between 1968 and 1978; subsequently, major secular gains in height occurred among children and adolescents between 1978 and 2000. The 1978 household data were used to compute gene flow (3.3%) and opportunity for selection intensity (I = 1.312). Migration and other demographic information was obtained from household census data for 1978 and 2000, and mortality information was extracted from community records and archives. These data were used to compute gene flow and opportunity for natural selection. Gene flow increased from 3.3% to 4.7% and intensity of natural selection decreased from 1.312 to 0.272 from 1978 to 2000. Variance in fertility increased slightly over time (12.25 to 13.69). Opportunity for selection was dominant during the prereproductive period in 1978, but approached 0 for the mortality component in 2000, resulting in a marked decrease in the mortality component (Im) of selection (0.626 and 0.019, respectively) and total opportunity for selection (I = 1.312 and 0.272, respectively). Secular increase in height and markedly decreased opportunity for natural selection (1) were associated with better health and nutritional conditions. Genotype-environment interaction and environmental influences are apparently the predominant causes of the secular trend. If natural selection plays a role in causing the secular trend, it is a small one.

Craniofacial dimensions in children in rural Oaxaca, Southern Mexico: Secular change, 1968–2000

The objective of this investigation was to analyze the underlying cause(s) of secular changes in craniofacial dimensions among indigenous children in an isolated community in Oaxaca, southern Mexico, between 1968-2000. Subjects were schoolchildren resident in a rural, agrarian, Zapotec-speaking community in the Valley of Oaxaca, previously characterized as mildly-to-moderately undernourished with growth-stunting in 1968 and 1978. In 2000, children had experienced a secular increase in height compared with two prior growth surveys. Four craniofacial dimensions (head length, head breadth, and bizygomatic and bigonial breadths) were measured during anthropometric surveys of schoolchildren aged 6-13 years in 1968, 1978, and 2000. Cephalic and zygomandibular indices were calculated. Samples by survey were: 1968, 151 males and 157 females; 1978, 179 males and 184 females; and 2000, 180 males and 186 females. The analysis was based on a total of 1,037 children. Multivariate analysis of covariance was used to assess secular trend effects, with height, age, and age2 as covariates by sex. Over the interval of 32 years, significant secular changes occurred in craniofacial dimensions and one index: 1) head length was shorter in boys and girls; 2) bizygomatic breadth was narrower in boys and girls; 3) head breadth increased over time only among girls; 4) brachycephalization increased significantly in a linear manner among both sexes; and 5) the zygomandibular index decreased significantly only in boys. Thus, the cranial complex remodeled to a shorter head length, both relatively (brachycephalization) and absolutely. Remodeling over time also resulted in a narrower face, with the midface changing at about the same rate as the lower face (i.e., mandible). Secular changes are generally recognized as multifactorial. Changes in the cephalic index and cranium over time in schoolchildren in an isolated rural agrarian Zapotec-speaking community in the Valley of Oaxaca suggest that the underlying forces for the secular change are associated: 1) decreased food (maize) coarseness or grit content (masticatory stress), and 2) relaxed natural selection, resulting in 3) a greater role for developmental plasticity.

Childhood obesity in United Arab Emirates schoolchildren: a national study

OBJECTIVE

The study assessed the national prevalence of obesity among schoolchildren in the United Arab Emirates (UAE).

SUBJECTS

A stratified 10% random sample of 16,391 children was drawn from 145,492 pupils in the UAE.

METHODS

Height and weight were measured by physicians and trained nurses, and the body mass index (BMI; weight (kg)/height (m)2) was computed. BMIs for UAE were compared to recently published international standards.

RESULTS

Comparison of BMIs to international reference data revealed that UAE children are at increased risk for overweight (>25 kg m-2 and =30 kg m-2) and obesity (=30 kg m-2). For example, 10-year-old male UAE children had 1.7 times the rate of overweight compared to international standards and 1.9 times at 18 years. Similarly, female UAE children have 1.8 times the rate of overweight compared to international standards at 10 and 18 years of age. Obesity was 2.3-fold higher among UAE males at 14 years compared to international standards, and increased to 3.6 times at 18 years of age. Among UAE female children, obesity was same as males at 14 years, 2.3 times than the international standards. At 18 years of age, UAE female obesity was 1.9-fold higher than the international standard, nearly one-half the rate of obesity among UAE males at the same age.

CONCLUSION

The frequency of obesity among UAE youth is two to three times greater than the recently published international standard. Profound public health implications of childhood obesity for UAE children and young adults are seriously increased because of adult chronic disease processes (e.g. cardiovascular disease, diabetes) normally attendant to increased obesity rates.

Secular change in age at menarche in rural Oaxaca, southern Mexico: 1968--2000

OBJECTIVE

To evaluate secular change in the age at menarche between 1978 and 2000 in residents of a rural Zapotec-speaking community in Oaxaca, southern Mexico, using status quo and retrospective methods.

MATERIALS AND METHODS

Status quo menarcheal status of girls 9-18 years of age in 1978 (n= 101) and 2000 (n=238) and retrospective ages at menarche of adult women 19+ years of age in 1978 (n = 228) and 2000 (n = 246) were obtained via interview. Probit analysis was used to estimate median ages at menarche and 95% confidence intervals (CI) for the status quo data. Analysis of variance and linear regression was used to compare the retrospective data across surveys.

RESULTS

The median ages at menarche of adolescents are 14.8+/-1.2 years (0.24 year, 95% CI 14.2-15.4 years) in 1978 and 13.0+/-1.0 years (0.10 year, 95% CI 12.7-13.3 years) in 2000. Age at menarche has declined by 1.8 years over about 23 years, 0.78 year/decade (95% CI = 0.65-0.91 year/decade). Recalled ages at menarche do not differ by age group in the 1978 survey, but differ significantly by age group in the 2000 survey (p <0.001). Within the 2000 survey, the two youngest age groups (< 29, 30-39 years) do not differ, but attain menarche earlier than women in the four older age groups (p < 0.05), who do not differ from each other in age at menarche. The estimated rates of secular decline in age at menarche in adult women vary between 0.38 and 0.42 years/decade (0.26-0.56 year/decade).

CONCLUSIONS

There is a major secular decline in the age at menarche of adolescent girls and young adult women between 1978 and 2000. The estimated rate of decline in adult women is about one-half of that in adolescent girls. The secular decline in age at menarche is consistent with corresponding secular gains height, sitting height and estimated leg length of children and adolescents in the community; corresponding secular gains are smaller in young adults 19-29 years.

Inbreeding avoidance in an isolated indigenous Zapotec community in the valley of Oaxaca, southern Mexico

We analyzed inbreeding using surname isonymy in an indigenous genetic isolate. The subjects were residents of a rural Zapotec-speaking community in the valley of Oaxaca, southern Mexico. The community can be classified as a genetic isolate with an average gene flow of < or = 3% per generation. Surnames were collected for individuals in each household in pedigree form using the culturally traditional patronym-matronym naming. Estimation of inbreeding from surname isonymy is facilitated by the traditional patronym-matronym name assignment among indigenous Mexican populations. A total of 2,149 individuals had valid surname patronym-matronym pairings, including 484 deceased ancestors. Surname isonymy analysis methods were used to estimate total inbreeding and to segregate it into random and nonrandom components. The surname isonymy coefficient computed from 119 isonymous surname pairings (119/2,149) was 0.0554. The estimated inbreeding coefficient from surname isonymy was 0.0138 (0.0554/4). The random and nonrandom components of inbreeding were F(r) = 0.0221 and F(n) = -0.0091, respectively. The results suggest that consanguinity is culturally avoided. Nonrandom inbreeding decreased total inbreeding by about 41%. Total estimated inbreeding by surname isonymy was 0.0138, which is similar to inbreeding estimated from a sample of pedigrees, 0.01. Socially prescribed inbreeding avoidance substantially lowered total F through negative nonrandom inbreeding. Even in the situation of genetic isolation and small effective population size (N(e)), estimated inbreeding is lower than may have otherwise occurred if inbreeding were only random. However, among the poorest individuals, socially prescribed jural rules for inbreeding avoidance failed to operate. Thus the preponderance of inbreeding appears to occur among the poor, economically disadvantaged in the community.