Tag Archives: The Maya

The health of the Maya people in Mesoamerica: what do we know?

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“The Maya people descend from the indigenous inhabitants of southeastern Mexico, Guatemala, Belize, San Salvador, and Honduras. They are the largest Native American group (6-7 million people) and show the shortest average height of any non-pygmy human population” (1: 679).

The Maya carry a long legacy of political, educational, and socioeconomic deprivation that feeds racism and perpetuates a livelihood of poverty. These socio-political aspects negatively impact on the health of the Maya and bring about further cycles of adverse outcomes. I use a biocultural approach (2) on my research and include inputs from the Maya communities when defining research designs. This post summarises most of the research conducted by my research team. It is not a systematic review of the literature on the health of the Maya, but I hope it becomes a useful resource as a starting point for further research. This is a live post, I welcome comments and suggestions for improvement, and I will be adding information when relevant.


Physical growth

The measurement of physical growth and the accurate measurement of stature and other long bones – such as limb length – are powerful reflexions of the social, political, and moral conditions of a society. James Tanner (b1920-d2010) coined the expression “growth as a mirror of the human condition” and stated that:

“ the growth of children (…) is a wonderfully good gauge of living conditions and the relative prosperity of different groups in a population” (3:96)

Height has been used extensively as an economic variable that reflects health and human capital, especially when other economic indicators are not available.

I started this post with a quote from our most recent paper (1), stating that the Maya are, on average, the shortest non-pigmy people in the world. Being “non-pygmy”, in this context, is an important factor because it means that there are not any known genomic and/or hormonal factors that code for the Maya short stature. However, for a long time, they were considered the “pygmies” of Latin America” (4) . This was damaging because it assumed that being so short was “genetic” and “adaptive”, that everything was fine with this group of people, and nothing needed to change. However, our research showed that, when the Maya started migrating to the US, and benefited from clean drinking water, basic health care, much lower rates of infection load, extended education, enough food, and a peaceful environment, the average stature of the school children increased almost 11cm, in less than one decade. From these, 7cm were due to the increase in the relative length of the legs, in proportion to total stature (5). Genetic/genomic expressions do not change in such a brief period of time, therefore, all evidence suggest that the short stature of the Maya is due to a combination of environmental and epigenetic factors.

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I must emphasize, here and now, that no human group “adapts” to poverty, segregation, racism, deprivation, infection, heavy workloads, and shortage of nutrients. They all suffer and many die. The ones who survive to adulthood, do so at the expense of their health and productivity, in some way or other. These are trade-offs that may maximize survival but come at a cost that, sooner or later, will be painfully paid with interest (6).

Very short stature-for-age, or stunting, is an indicator of chronic undernutrition and has long lasting health implications (7). Stunting is usually defined as the individual’s height-for-age being below the 5th percentile of the references, although slightly different cut-off points can be used (8). This makes stunting a sort of moving target. Depending what references and what cut-off points are used, a stunted child may or may not be classified as such. Stunting affects all body systems and, if not curbed early in life, will leave permanent and damaging physical, cognitive, and developmental traits.

In his paper “Nutritional status and physical work capacity”, Spurr (9) summarizes the effects of stunting on physical work capacity, maximal oxygen consumption, aerobic power, heart rate response to exercise, and endurance at submaximal work loads. Other studies have shown that no body system is spared of the nefarious consequences of stunting and that the longer it lingers, the worse the outcomes will be (10-12).

High levels of stunting have been consistently reported, for more than two decades, among the Maya in Belize (13-15), Guatemala (16-19), and Mexico (20-21). Fast and steep increases in height and leg-length, among the Maya migrants to the US, have been mentioned already in this post (5) but this positive outcome needs to be addressed in the context of the whole physical and health changes that characterize this group. Increments in height were accompanied by even steeper increments in weight, and body-mass-index (BMI) (22). The height of the Maya-American children averaged at the 25th percentile of the height of the US children, but their weight and BMI averaged at the 85th percentile. In summary, although the average height of these Maya-American children increased, and the percentage of stunted children decreased, they were still significantly shorter, but much heavier, than the references.


The nutritional dual-burden paradox

The nutritional dual-burden is defined as the coexistence of stunting and overweight/obesity in the same person (individual dual-burden), in the same household (stunted child, overweight/obese mother), or within the same population (8,23,24).

Nutritional dual-burden at the individual level is not common among Maya children, but is frequent among Maya adults, who tend to be very short and very fat. This means that they were stunted children who grew up to become stunted, overweight/obese adults, and accumulate in their bodies the negative effects of both of these conditions (25). Nutritional dual-burdened adult individuals, and specially women, are at higher risk of producing offspring who will also be stunted and, therefore, will perpetuate the short-and-fat legacy throughout generations. This is a non-genomic mechanism that may lead to low birth weight and elevated cardiovascular risk in the subsequent generations (26).


Intergenerational effects of stunting on health and disease

The intergenerational influences hypothesis (IIH) was proposed by Irving Emanuel (27:35) as, ‘‘… those factors, conditions, exposures and environments experienced by one generation that relate to the health, growth and development of the next generation.’’ The IIH has been further discussed elsewhere (26, 28–30), and put in perspective with related concepts such as “foetal programming”, “life history trade-offs”, and developmental origins of health and disease (DOHaD) (6,31–36). We have tested the IIH with the Maya communities and found out that Maya-Mexican children with a stunted mother were more likely to be stunted by 4-6 years of age (30). Also, in another Maya-Mexican three-generational sample, stunting in children was directly associated with the short stature of the mothers; and the children’s levels of fatness were also directly associated with the short stature of the mothers and the maternal grandmothers (20,37).


Stunting, muscle mass, and energy expenditure

Associations between stunting, body composition, and energy expenditure (or work capacity) have been studied for decades, showing that stunted individuals have less muscle, and much less energy for voluntary physical activity (9,11,12,38,39). In the last 10 years, this area of research has benefited considerably due to the commercialisation of accurate portable technology that allows free-living assessment of all components of energy expenditure, metabolism, and respiratory and cardiac function. Usually, the sample sizes are small and the studies tend to focus on only one or two parameters, making it difficult to establish more complex associations.

We conducted a study with a sample of 37 Maya-Mexican children and found that a lower height-for-age z-score, as a continuous variable (but not stunting as a categorical variable) significantly predicted lower activity energy expenditure (40). This study was innovative because the children wore a combined heart-rate and uni-axial accelerometer for 7 days (The Actiheart), but it was challenging because the device, when used in the field, performed differently than under laboratorial conditions (41), and required a much greater deal of maintenance than initially predicted. The continuous advance of portable, wearable technology, for the estimation of energy expenditure and other physiological parameters, is promising. This line of research must be pursued to further disentangle the associations between stunting, energy expenditure, body composition, and other health outcomes. The state of Yucatan has one of the highest rates of childhood stunting and, at the same time, the highest mortality rates for diabetes, cardiovascular diseases and stroke in Mexico as a whole. Among these, the Maya – being the poorest of the poor – tend to suffer more than the rest of the population (42).


Nutrition and globalization

The nutritional patterns of the Maya, in the last 20 years, have moved away from a diet high in fibre, vegetables, and pulses to a globalised diet with a very high content of salt, sugar, fat, processed foods, and carbonated beverages. In a study conducted in 2013 (43) the most common diet among the Maya in Mexico was characterized by 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. The Maya health and culture has deteriorated as a result of this nutritional transition which is affecting the physical growth and health of the Maya families. The summary illustrates clearly the shifts in food consumption, and emphasises the role of globalization in the exacerbation of negative health outcomes among the Maya (44).


A photo that summarizes it all

The photo below was taken in 2010, in the Colonia San Jose Tecoh, Merida, Yucatan, Mexico. I am with a Maya grandmother and her 8 year old granddaughter. In this photo, I am the tallest person which is very unusual for me, because I am only 159cm (5ft 1inches). This photo illustrates the height gap of the Maya much better than any written description. Therefore, I will say no more!

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References:

  1. Varela-Silva MI, Bogin B, Sobral JAG, Dickinson F, Monserrat-Revillo S, the Healthy Birth and Development – Knowledge Integration (HBGDki) Initiative. Deep data science to prevent and treat growth faltering in Maya children. Eur J Clin Nutr [Internet]. Macmillan Publishers Limited; 2016 Apr 20;70:679–80. Available from: 10.1038/ejcn.2016.63
  2. Dufour DL. Biocultural approaches in human biology. American journal of human biology : the official journal of the Human Biology Council. United States; 2006. p. 1–9.
  3. Tanner JM. Growth as a Mirror of the Condition of Society: Secular Trends and Class Distinctions. Pediatr Int [Internet]. Blackwell Publishing Ltd; 1987 Feb 1 [cited 2016 Nov 24];29(1):96–103. Available from: http://onlinelibrary.wiley.com/doi/10.1111/j.1442-200X.1987.tb00015.x/abstract
  4. Diamond J. A Question of Size. Bigger is better, right? So why in the world have Pygmies opted for smallness? Discovery. Discover Magazine; 1992. p. 3.
  5. Bogin B, Smith P, Orden AB, Varela Silva MI, Loucky J. Rapid change in height and body proportions of Maya American children. Am J Hum Biol [Internet]. 2002;14(6):753–61. Available from: http://www.ncbi.nlm.nih.gov/pubmed/12400036
  6. Bogin B, Varela-Silva MI, Rios L, Varela-Silva MI, Rios L, Silva MIV, et al. Life history trade-offs in human growth: Adaptation or pathology? Am J Hum Biol [Internet]. Wiley Subscription Services, Inc., A Wiley Company; 2007;19(5):631–42. Available from: http://www3.interscience.wiley.com/cgi-bin/abstract/114293374/ABSTRACT
  7. de Onis M, Branca F. Childhood stunting: a global perspective. Matern Child Nutr [Internet]. 2016 May 1 [cited 2016 May 23];12 Suppl 1(S1):12–26. Available from: http://onlinelibrary.wiley.com/doi/10.1111/mcn.12231/full
  8. Varela-Silva MI, Dickinson F, Wilson H, Azcorra H, Griffiths PL, Bogin B. The Nutritional Dual-Burden in Developing Countries – How is it Assessed and What Are the Health Implications? Coll Anthropol [Internet]. Collegium Antropologicum; 2012 Mar;36(1):39–45. Available from: http://www.ncbi.nlm.nih.gov/pubmed/22816196
  9. Spurr GB. Nutritional status and physical work capacity. Yearb Phys Anthropol [Internet]. 1983;26:1–35. Available from: http://onlinelibrary.wiley.com/doi/10.1002/ajpa.1330260503/abstract
  10. Aguayo VM, Nair R, Badgaiyan N, Krishna V. Determinants of stunting and poor linear growth in children under 2 years of age in India: an in-depth analysis of Maharashtra’s comprehensive nutrition survey. Matern Child Nutr [Internet]. 2016 May 1 [cited 2016 Jun 17];12 Suppl 1(S1):121–40. Available from: http://onlinelibrary.wiley.com/doi/10.1111/mcn.12259/full
  11. Spurr GB, Reina JC. Influence of dietary intervention on artificially increased activity in marginally undernourished Colombian boys. Eur J Clin Nutr. 1988;42(10):835–46.
  12. Spurr GB, Reina JC, Barac-Nieto M. Marginal malnutrition in school-aged Colombian Boys – anthropometry and maturation. Am J Clin Nutr. 1983;37(1):119–32.
  13. Jenkins CL. Patterns of growth and malnutrition among preschoolers in Belize. Am J Phys Anthropol [Internet]. 1981 Oct [cited 2013 Jan 16];56(2):169–78. Available from: ISRF
  14. Crooks DL. Growth status of school-age Mayan children in Belize, Central America. Am J Phys Anthropol [Internet]. Department of Anthropology, University of Kentucky, Lexington 40506-0024.; 1994;93(2):217–27. Available from: http://www.ncbi.nlm.nih.gov/pubmed/8147437
  15. Crooks DL. Relationship between environment and growth for Mopan children in Belize. Am J Hum Biol [Internet]. 1994;6(5):571–84. Available from: http://doi.wiley.com/10.1002/ajhb.1310060505
  16. Bogin B, MacVean RB. Body composition and nutritional status of urban Guatemalan children of high and low socioeconomic class. Am J Phys Anthropol [Internet]. 1981 Aug;55(4):543–51. Available from: http://www.ncbi.nlm.nih.gov/pubmed/7337142
  17. Bogin B, Wall M, MacVean RB. Longitudinal analysis of adolescent growth of ladino and Mayan school children in Guatemala: effects of environment and sex. Am J Phys Anthropol. 1992;89:447–57.
  18. Bogin B, Loucky J. Plasticity, political economy, and physical growth status of Guatemala Maya children living in the United States. Am J Phys Anthropol [Internet]. 1997 Jan;102(1):17–32. Available from: http://www.ncbi.nlm.nih.gov/pubmed/9034036
  19. Johnston FE, Borden M, MacVein R (1973). Height, weight and their growth velocities in Guatemalan private school children of high socioeconomic class. Hum Biol., 45 (4): 627-641.
  20. Azcorra H, Varela-Silva MI, Rodriguez L, Bogin B, Dickinson F. Nutritional status of Maya children, their mothers, and their grandmothers residing in the City of Merida, Mexico: Revisiting the leg-length hypothesis. Am J Hum Biol [Internet]. 2013 Sep 1 [cited 2013 Aug 5];25(5):659–65. Available from: http://www.ncbi.nlm.nih.gov/pubmed/23907793
  21. Wolañski N, Dickinson F, Siniarska A. Biological traits and living conditions of Maya Indian and non Maya girls from Merida, Mexico. Int J Anthropol [Internet]. 1993 Oct [cited 2015 Nov 11];8(4):233–46. Available from: http://link.springer.com/10.1007/BF02442158
  22. Smith PK, Bogin B, Varela-Silva MI, Orden B, Loucky J. Does immigration help or harm childrens health? The Mayan case. Soc Sci Q [Internet]. 2002;83(4):994–1002. Available from: http://search.ebscohost.com/login.aspx?direct=true&db=ecn&AN=0664513&site=ehost-live
  23. Doak CM, Adair LS, Monteiro C, Popkin BM. Overweight and underweight coexist within households in Brazil, China and Russia. J Nutr. 2000;130(12):2965–71.
  24. Doak CM, Adair LS, Bentley M, Monteiro C, Popkin BM. The dual burden household and the nutrition transition paradox. Int J Obes (Lond). 2005;29(1):129–36.
  25. Wilson HJ, Dickinson F, Griffiths PL, Azcorra H, Bogin B, Varela-Silva MI, et al. How useful is BMI in predicting adiposity indicators in a sample of Maya children and women with high levels of stunting? Am J Hum Biol [Internet]. Wiley Subscription Services, Inc., A Wiley Company; 2011 Jan [cited 2012 Jul 5];23(6):780–9. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21936013
  26. Drake AJ, Walker BR. The intergenerational effects of fetal programming: non-genomic mechanisms for the inheritance of low birth weight and cardiovascular risk. J Endocrinol. 2004;180(1):1–16.
  27. Emanuel I. Maternal health during childhood and later reproductive performance. Ann N Y Acad Sci. 1986;477:27–39.
  28. Emanuel I, Filakti H, Alberman E, Evans SJ. Intergenerational studies of human birthweight from the 1958 birth cohort. 1. Evidence for a multigenerational effect. Br J Obstet Gynaecol [Internet]. 1992 Jan [cited 2013 May 7];99(1):67–74. Available from: http://www.ncbi.nlm.nih.gov/pubmed/1547177
  29. Emanuel I, Kimpo C, Moceri V. The association of grandmaternal and maternal factors with maternal adult stature. Int J Epidemiol. 2004;33(6):1243–8.
  30. Varela-Silva MIM, Azcorra H, Dickinson F, Bogin B, Frisancho AR, Varela-silva S. Influence of maternal stature, pregnancy age, and infant birth weight on growth during childhood in Yucatan, Mexico: a test of the intergenerational effects hypothesis. Am J Hum Biol [Internet]. Wiley Subscription Services, Inc., A Wiley Company; 2009 [cited 2012 Jul 6];21(5):657–63. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19214997
  31. Barker DJ. The fetal and infant origins of adult disease. BMJ. 1990;301(6761):1111–7.
  32. Barker DJ. Fetal origins of coronary heart disease. BMJ. 1995;311(6998):171–4.
  33. Gluckman PD, Hanson MA. Living with the past: evolution, development, and patterns of disease. Science (80- ). 2004;305(5691):1733–6.
  34. Gluckman PD, Hanson MA. Developmental and epigenetic pathways to obesity: an evolutionary-developmental perspective. Int J Obes. 2008;32:S62.
  35. Kuzawa CW, Pike IL. Introduction. Fetal origins of developmental plasticity. Am J Hum Biol. 2005;17(1):1–4.
  36. Kuzawa CW. Developmental Origins of Life History : Growth, Productivity, and Reproduction. Am J Hum Biol. 2007;661(February):654–61.
  37. Azcorra H, Dickinson F, Datta Banik S. Maternal height and its relationship to offspring birth weight and adiposity in 6- to 10-year-old Maya children from poor neighborhoods in Merida, Yucatan. Am J Phys Anthropol [Internet]. 2016 Dec [cited 2016 Nov 26];161(4):571–9. Available from: http://www.ncbi.nlm.nih.gov/pubmed/27465976
  38. Barac-Nieto M, Spurr GB, Lotero H, Maksud MG, Dahners HW. Body composition during nutritional repletion of severely undernourished men. Am J Clin Nutr. 1979;32(5):981–91.
  39. Spurr GB. Physical activity and energy expenditure in undernutrition. Prog food nut sci. 1990;14:139–92.
  40. Wilson HJ, Dickinson F, Hoffman DJ, Griffiths PL, Bogin B, Varela-Silva MI. Fat free mass explains the relationship between stunting and energy expenditure in urban Mexican Maya children. Ann Hum Biol [Internet]. Informa Healthcare London; 2012 Sep 4 [cited 2012 Oct 5];39(5):432–9. Available from: http://www.ncbi.nlm.nih.gov/pubmed/23035655
  41. Wilson H, Dickinson F, Griffiths P, Bogin B, Varela-Silva MI. Logistics of using the Actiheart physical activity monitors in urban Mexico among 7- to 9-year old children. Am J Hum Biol. 2011;23:426–8.
  42. Azcorra, Hugo; Valentin, Graciela; Vazquez-Vazquez AP; Dickinson F. Growth status in children and adolescents in Yucatan, Mexico: A Human Ecology Perspective. In: Studies in Human Ecology. 2010. p. 121–38.
  43. Azcorra H, Wilson H, Bogin B, Varela-silva MI, Vázquez-vázquez A, Dickinson F. Dietetic characteristics of a sample of Mayan dual burden households in Merida , Yucatan , Mexico. Arch Lat Am Nutr. 2013;63(2):209–17.
  44. Bogin B, Azcorra H, Wilson HJ, Vázquez-Vázquez A, Avila-Escalante ML, Castillo-Burguete MT, et al. Globalization and children’s diets: The case of Maya of Mexico and Central. Anthropol Rev. 2014;77(1):11–32.

Climate change and negative effects on human growth

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On the 25th November 2014, a research paper by Danysh et al (2014) was published in the journal Climate Change Responses (Open Access). The  paper  El Niño adversely affected childhood stature and lean mass in northern Peru associates extreme weather variability, heavy rainfall and flooding – caused by the 1997/98 El Niño phenomenon –  with decreases in stature and lean body mass among Peruvian rural children. Children  born during and immediately after 1997/98 were, on average, shorter and with less lean body mass than expected. These children were measured in 2008/09 – 10 years after the El Niño episode – showing that its negative effects linger for a long time. This study also shows that the poorest children were the most affected by the phenomenon. The authors concluded by pointing out the need “…to design prevention strategies and target aid and relief during future El Niño episodes (pp.9). They emphasise that when so many young children are affected the whole country will be affected –  and this can only be a very bad thing.

I strongly recommend the reading of this paper, its inclusion on lectures, and the promotion of further debate about climate change and health outcomes. I also welcome collaborations to engage in further discussions on how to include climate change variables on studies focusing on child growth and health.

I work with The Maya from Guatemala, Mexico and Belize. They too are poor, marginalised and disproportionately affected by climate change events. The Yucatan Peninsula in Mexico is on the Atlantic hurricane pathway and every year many Maya families lose their homes, their crops and they all suffer.

I have no knowledge of any studies that associate health outcomes, among the Maya, with climate change but I have photos that show how devastating it is. These photos are part of The Maya Project collection that I direct  – and they speak louder than my words.

Photo by Francisco Martin (2005)
After hurricane Wilma | Photo by Francisco Martin (2005)
Photo by Cuauhtemoc Moreno (2012)
Photo by Cuauhtemoc Moreno (2012)
Photo by Cuauhtemoc Moreno (2013)
Photo by Cuauhtemoc Moreno (2013)