Heights and Weights of Mexican Children

1. Heights and Weights of Mexican ChildrenPaul R EarlFacultad de Ciencias BiológicasUniversidad Autónoma de Nuevo LeónSan Nicolás de los Garza, NL 66451Mexico

2. ReviewThe anthropometrics of Mexican schoolchildren, university students and soldiers are reviewed. Obesity is a concern of affluent countries, whereas malnutrition concerns the poor. Rural malnutrition in Mexico is marked in Guerrero, Oaxaca and Chiapas. Clinical growth charts for Mexico are still unavailable by social class. HT is used for height in cm and WT in kg for weight. Young middle-class adults have linear growth equations of HT = 68.3 + 1.6446 WT for men and HT = 61.2 + 1.7919 WT for women. The main purpose of this ledcture is to collect the relevant bibliography for future research.

3. Desertic and mountainous, Mexico with almost 2 million km2 of territory has a population of about 105 million persons. The number of children per woman is dropping with increasing industrialization, but the population has a young structure so that many more families with fewer children each are now produced. Lack of rainfall (<700 mm/yr) is the main reason why food must be imported mainly from the US then Canada. Migration from the country to the cities and to the US is an indefinite process over a century behind the Industrial Revolution that it weakly imitates. Latin westcoast migration reaches from Peru to California.

4. Educational levels must rise if the rural poor of the southern Mexican states are to successfully enter the international industrialized community that is calling for higher skills. The impoverished states suffering malnutrition most are a) Guerrero, b) Oaxaca and c) Chiapas in that order. See also Bogin et al. (1989) on Guatemala. These farmers and those of all of Central America have many health problems like simple iron deficiency anemia and many parasitoses related to rural poverty. In strong contrast, industrial centers are magnets that reduce the birth rate that was fostered in antieconomic agriculture.

5. Many countries do not adequately monitor human growth. Regardless, the purpose of this note is to record and discuss the somatometrics of Mexican schoolchildren and adults as available to date. Pioneer works in Mexico are by Ramos-Galván (1975) and Faulhaber (1976). Without doubt, sufficient practical introduction to health-oriented anthropometry is given by Casillas & Vargas (1989), Earl & Villareal (1980), Earl (1991) and Avila-Curiel et al. (1998). Other presentations that give the general picture well are Malacara & Ramírez-Estrada (1981) and Prado-León (2001).

6. Malnutrition and iron deficiency anemiaSimple iron deficiency anemia (Argote et al., 1975) is highly prevalent in Mexico due to the cost of meat, much imported. Nonetheless, many communities do not have high anemia levels (Earl & Villareal, 1980). Extremely easy to use, the microhematocrit alone efficiently evaluates nutrition related to iron deficiency. Regardless, size and hematocrit are well categorized by their poverty levels. A pulse oximeter that of course is quick and noninvasive once or before and after excercice like jumping a minute would give most welcome information.

7. Mexico City and air pollutionPérez-Padilla et al. (2003) studied simulated not actual pulmonary functions in over 4,000 Mexico City schoolchildren. This city of over 20 million people has desperately severe air pollution due to car traffic. The equations for boys and girls now derived from their Tables 1 & 2 are not entirely satisfactory because the means not individuals are used. HT = (a + cAGE + eAGE2)/(1 + bAGE + dAGE2) for boys and HT has a sigmoid curve for girls. The adolescent growth spurt stops at 16 for boys and at 15 years for girls, although cessation of growth in girls is gradual.

8. ReanalysisData in Tables 1-4 of Casillas & Vargas (1980, 1984) are reanalyzed, including some data by Romero (1959) and Ramos-Galván (1975). The Casillas & Vargas (CV) data has charts based on 5,621 male and 3,632 female students of Universidad Nacional Autónoma de Mexico in 1975-78. Data for equations is from Earl & Villareal (1980). Unpublished data is given on 56 middle-class men and 75 women from Monterrey, NL, Mexico in Table 1. Sabinas (2380 children) and Monterrey (Earl, 1991, 366 children) were further examined.The relations of HT to WT for the Casillas & Vargas (1980) data are given in Equations 1 & 2. HT = 68.3 + 1.6446 WT for men (Eq 1) HT = 61.2 + 1.7919 WT for women (Eq 2)

9. Using the same data for height and age, a simple quadratic equation will serve for Sabinas boys: H = 10.5 + 0.02587 (AGE)2. For girls, H = 8.9 + ((0.0780 (AGE)2)(–0.0034 (AGE)3)) serves. Although these equations are imminently successful in predicting one variable from another having DF (degrees of freedom) adjusted coefficients of determination like r2 = 0.9946, different equations close to the ones given may do just as well.Average middle-class northern Mexican adults are presented in Table 1. They are considerably heavier than soldiers, mainly due to eating habits with ageing. Obesity is a equal problem in both sexes with women tending to fatten at 20-30 years.

10. Table 1. Height (HT), Weight (WT) and age of 56 men and 75 northern, urban Mexican women are given with lower and upper bounds of the 95 % confidence intervals. For Sex, 1 is male, 2 female.Variable Sex Mean SD 95% CI Lower Upper HT 1 167.66 7.22 165.73 169.59 2 156.87 6.61 155.35 158.39 Total 161.48 8.70 159.98 162.98 WT 1 73.26 15.52 69.10 77.42 2 71.71 19.11 67.31 76.10 Total 72.37 17.62 69.33 75.42 AGE 1 46.61 14.81 42.64 50.57 2 45.33 13.08 42.32 48.34 Total 45.88 13.80 43.49 48.26

12. Table 2. Correlation Matrix. Abbreviations are AGEB age of Sabinas boys, WB = WT of boys, HB = HT of boys, AGEG age of the girls, WG 3 WT of the girls, HG HT of the girls and WM WT of Monterrey boys and girls. AGEB WB HB AGEG WG HGAGEB 1.0000WB 0.9773 1.0000HB 0.9946 0.9914 1.0000AGEG 0.9998 0.9777 0.9946 1.0000WG 0.9922 0.9875 0.9942 0.9913 1.0000 HG 0.9906 0.9533 0.9758 0.9897 0.9760 1.0000WM 0.9778 0.9995 0.9926 0.9781 0.9879 0.9514

13. DiscussionA considerable body of information can be gathered from original works, but new standardizations and innovations are encouraged. Equations involving the square of x or the square root of x, log x or even cube x can occur as alternate choices. HT:WT for boys vs girls might be linear, log or log-log and close to intercept zero and angle 45. Read also Hennenberg et al. (1989), Martins & Menezes (1997) and Pan & Goldstein (1997). A larger number of variables would raise the quality of the investigation.

14. Many lawlike correlations arise during calculations when means rather than raw data are used. Several different equations often can be substituted for each other, and it may be an error to look for a single solution for some correlation. Does rural mean poor therefore hungry? No doubt it sometimes does. Industrial solutions for rural southern Mexico, all of Central America and the Caribbean involve cheap labor. Solutions have yet to arrive and may never, except for emmigration.

15. Suggested reading