Logistics of using the Actiheart physical activity monitors in urban Mexico among 7- to 9-year-old children

Logistics of using new measurement devices are important to understand when developing protocols. This paper discusses the logistics of using Actiheart physical activity monitors on children in an urban, tropical environment in a developing country. Actiheart monitoring of 36 children aged 7-9 years old was undertaken for 7 days in the city of Mérida, Yucatán, Mexico. The Actiheart proved fragile for children and difficult to mend in the field. The excessive sweating due to the tropical climate caused poor adherence of the electrode pads, requiring a pad change midway through and extra pads to be provided. Also extra time was needed to be allotted for increased instructions to participants and their mothers and for individual calibration. When collecting objectively measured physical activity data under harsh conditions, the protocol must accommodate local conditions and device limitations and allow increased time with participants to obtain good quality data. © 2011 Wiley-Liss, Inc

Fat free mass explains the relationship between stunting and energy expenditure in urban Mexican Maya children

Background: Childhood stunting has been associated with an increased risk of obesity in adulthood, but the causes are unclear. This study hypothesizes that stunting significantly reduces both resting and activity energy expenditure. Aim: To assess and describe energy expenditure of low socio-economic Maya children and to determine whether stunting is independently related to energy expenditure after controlling for lean mass. Subjects and methods: Thirty-three urban Maya children, 17 boys, aged 7–9 years, living in Merida, Mexico, were measured for height, weight and bioelectrical impedance analysis (BIA). Body composition was estimated from BIA. Energy expenditure was measured for one week using the Actiheart (combined heart rate and accelerometer). Results: Stunting (height-for-age below the 5th percentile of NHANES III based references) affected 35% of these physically active children. Using multiple linear regression analysis, greater lean body mass predicted higher resting and activity energy expenditure. Stature was not a significant predictor of resting energy expenditure. A lower height-for-age z-score, but not stunting as a categorical variable, significantly predicted lower activity energy expenditure. Conclusion: The hypothesis that stunting reduces total energy expenditure (resting + active) in children is not supported. Rather, children with shorter stature and less lean body mass have lower total energy expenditure. Complex interactions between body size, body composition, and metabolic activity appear to elevate the risk for later life obesity in these Maya children

Globalization and children’s diets: the case of Maya of Mexico and Central America

Globalization is, in part, an economic force to bring about a closer integration of national economies. Globalization is also a biological, social and ideological process of change. Globalization results in powerful multinational corporations imposing their products on new markets. Food globalization brings about nutritional transitions, the most common being a shift from a locally-grown diet with minimally refined foods, to the modern diet of highly processed foods, high in saturated fat, animal products and sugar, and low in fiber. This paper will examine the influences of food globalization using the Maya of Mexico as a case study. The Maya people of Mexico are a poignant case. Maya health and culture has deteriorated as a result, with highly processed foods affecting physical growth and health of Maya children and their families. The case of the Maya is not isolated and we must come to terms with food globalization if we are to translate research into better child health and well-being

Health indicators in double burdened urban Maya children and mothers

Background Middle-income countries are currently undergoing nutrition transition more rapidly than did high income countries. These populations are therefore at high risk of over-nutrition (obesity) and nutrition-related, non-communicable diseases before the elimination of under-nutrition and infectious diseases. Such nutritional double burden is most common in low SES groups of middle-income countries, such as the Maya of Mexico. Long-term poor environmental conditions during early life results in a population with high levels of chronic under-nutrition (stunting), and a consequent predisposition toward overweight/ obesity, and associated health risks later in life. It is important to be able to identify individuals at an increased risk of diseases related to double burden and to determine whether stunting impacts the ability to identify at risk individuals. Aims The overall purpose of this doctoral research was to examine double burden in the urban Maya, a low SES section of the Mexican population which is a current example of a population undergoing significant transition. The specific aims of this thesis were fourfold: 1) To describe the living conditions and population characteristics of the urban Maya of southern Merida in the spring and summer of 2010; 2) to determine whether body mass index (BMI) predicts adiposity indicators in a sample of women and children with a high prevalence of stunting, 3) to determine whether measures of linear growth in women can be predicted by their recalled childhood environment and 4) To determine whether the relationship between objectively estimated free-living energy expenditure and body composition is altered by stunting. Methods Data from interviews, anthropometric measurements and bioelectrical impedance analysis were collected on 58 Maya schoolchildren aged 7-9 years-old and their mothers living in the south of Merida, Mexico. Objective, free-living physical activity monitoring using combined accelerometry and heart rate monitoring of the children was also performed for one week. The interview data was used to describe the living conditions of the south of Merida. Whether stunting status or body proportions influenced the power of BMI to predict adiposity indicators was assessed for the mothers and the children. The mothers recalled early life SES was compared to their current measures of linear growth. The children s objectively estimated energy expenditure was compared to their body composition and measurements of body size. Results The Maya of southern Merida overall had access to clean drinking water and basic health care and have apparently eliminated acute under-nutrition. Yet they remained double burdened with simultaneous stunting and overweight/ obesity. Individual double burden levels were high, with 70% of the mothers were simultaneously stunted and overweight. Family level double burden was also high, with 28% of the families having an overweight mother and a stunted child. The rates of childhood malnutrition varied widely when using different cut-offs. Child stunting rates were between 15.5% and 37.9% when using -2 z-scores of Frisancho s Comprehensive (created using NHANES data) reference versus the 5th percentile of the WHO reference, respectively. Child overweight/ obesity rates were less than 10% when using weight-for-age on both the Comprehensive and WHO reference charts. Child overweight/ obesity as classified using BMI z-scores was between 27.5 to 34.5% using the Comprehensive and WHO reference, respectively, while child overfat was over 80% when using body fat percentage for age reference curves. BMI predicted adiposity indicators in these Maya children, explaining between 33 and 84% of the variance in arm fat index and waist circumference z-score, respectively. BMI was less strongly related to the mothers adiposity indicators, explaining between 19 and 70% of the variance in arm fat area and waist circumference. The relationship between BMI and adiposity indicators was unchanged by stunting or body proportions in either mothers or children. Mothers recalled early life SES was significantly related to but explained little of the variance in her measures of linear growth. Birth decade explained 5% of the variance in stature and the Modernisation index (urban/ rural birth, sugar sweetened beverage consumption, packaged food consumption) explained 5% of the variance in mothers leg length. Birth order, sibling number and consumer durable ownership were also significantly related to linear growth of the mothers. These Maya children had high levels of physical activity, as all exceeded the recommended 60 minutes of moderate-to-vigorous physical activity per day. After controlling for fat free mass, short stature did not predict lower resting energy expenditures in the children. However shorter stature did predict lower levels of activity energy expenditure, particularly in girls. Stunted girls had the lowest activity energy expenditures. Conclusions These urban Maya tend to have access to basic sanitation and services and are at a very high risk for NR-NCDs with the co-existence of chronic under-nutrition (stunting) and overweight/ obesity. The high rates of stunting do not impact the usefulness of BMI to estimate adiposity nor does stunting appear to impact children s energy expenditure. While BMI is useful to predict adiposity in these urban Maya children, it is not recommended for use in the mothers. Interventions to reduce childhood adiposity need to begin very early in life to most effectively reduce adiposity. Research into the low SES groups of middle-income countries, offers insight to what may occur in low-income countries as they advance in the nutrition transition

Maternal short stature does not predict their children's fatness indicators in a nutritional dual-burden sample of urban Mexican Maya

The co-existence of very short stature due to poor chronic environment in early life and obesity is becoming a public health concern in rapidly transitioning populations with high levels of poverty. Individuals who have very short stature seem to be at an increased risk of obesity in times of relative caloric abundance. Increasing evidence shows that an individual is influenced by exposures in previous generations. This study assesses whether maternal poor early life environment predicts her child's adiposity using cross sectional design on Maya schoolchildren aged 7–9 and their mothers (n = 57 pairs). We compared maternal chronic early life environment (stature) with her child's adiposity (body mass index [BMI] z-score, waist circumference z-score, and percentage body fat) using multiple linear regression, controlling for the child's own environmental exposures (household sanitation and maternal parity). The research was performed in the south of Merida, Yucatan, Mexico, a low socioeconomic urban area in an upper middle income country. The Maya mothers were very short, with a mean stature of 147 cm. The children had fairly high adiposity levels, with BMI and waist circumference z-scores above the reference median. Maternal stature did not significantly predict any child adiposity indicator. There does not appear to be an intergenerational component of maternal early life chronic under-nutrition on her child's obesity risk within this free living population living in poverty. These results suggest that the co-existence of very short stature and obesity appears to be primarily due to exposures and experiences within a generation rather than across generations

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. Am. J. Hum. Biol., 2011. © 2011Wiley-Liss, Inc

Dietetic characteristics of a sample of Mayan dual burden households in Merida, Yucatan, Mexico

The Maya are the most populous and shortest in stature Native American ethnic group. The Maya provide us a good opportunity to study the dietetic characteristics of a group who experience nutritional dual burden (the combination of under and overnutrition) at the individual, mother-child dyad and population level. The aim of this study is to describe general dietetic patterns of a sample of Maya mothers and children who experienced nutritional dual burden and were living in the city of Merida, Yucatan, Mexico. From February to July 2010 we applied food frequency questionnaires (FFQ) to 58 dyads of Maya mothers and their children (7-9 years old). The FFQ was developed by the staff of the Human Ecology Group at Cinvestav and included 78 foods, grouped in: cereals and tubers, foods of animal origin, leguminous vegetables, fats, fruits, vegetables, sugars, and daily products. The frequencies of consumption were classified in four levels: 1) no consumption, 2) low (1-2 days/week), 3) medium (3-4 days/week), high (5-7 days/week). The observed pattern suggests a low consumption of fruits and vegetables, a medium consumption of pork, eggs, oil and lard, and a high consumption of soda and whole milk. From these frequencies we extrapolated that the dietetic pattern is characterized by a low intake of fibre and micronutrients and high intake of fat and sugars, findings supported by previous National and regional studies. Our observations suggest that the studied group have a dietetic pattern that has moved away from a traditional Maya diet. Key words: The Maya are the most populous and shortest in stature Native American ethnic group.; The Maya provide us a good opportunity to study the dietetic characteristics of a group who experience nutritional dual burden (the combination of under and overnutrition) at the individual, mother-child dyad and population level. The aim of this study is to describe general dietetic patterns of a sample of Maya mothers and children who experienced nutritional dual burden and were living in the city of Merida, Yucatan, Mexico. From February to July 2010 we applied food frequency questionnaires (FFQ) to 58 dyads of Maya mothers and their children (7-9 years old). The FFQ was developed by the staff of the Human Ecology Group at Cinvestav and included 78 foods, grouped in: cereals and tubers, foods of animal origin, leguminous vegetables, fats, fruits, vegetables, sugars, and daily products. The frequencies of consumption were classified in four levels: 1) no consumption, 2) low (1-2 days/week), 3) medium (3-4 days/week), high (5-7 days/week). The observed pattern suggests a low consumption of fruits and vegetables, a medium consumption of pork, eggs, oil and lard, and a high consumption of soda and whole milk. From these frequencies we extrapolated that the dietetic pattern is characterized by a low intake of fibre and micronutrients and high intake of fat and sugars, findings supported by previous National and regional studies. Our observations suggest that the studied group have a dietetic pattern that has moved away from a traditional Maya diet