Moderate altitude as a risk factor for isolated congenital malformations. Results from a case-control multicenter-multiregional study.

BACKGROUND: Living in high-altitude regions has been associated with a higher prevalence of some birth defects. Moderate altitudes (1500-2500 m) have been associated with some congenital heart diseases and low birth weight. However, no studies have been conducted for other isolated congenital malformations. OBJECTIVES: To estimate the prevalence at birth of isolated congenital malformations in low and moderate altitudes and to determine if moderate altitudes are a risk factor, such as high altitudes, for isolated congenital malformations adjusted for other factors. METHODS: The study consisted of a case-control multicenter-multiregional study of 13 isolated congenital malformations. Cases included live births with isolated congenital malformations and controls at low (10-1433 m) and moderate altitudes (1511-2426 m) from a Mexican registry from January 1978 to December 2019. Prevalence per 10,000 (95% CI) per altitude group was estimated. We performed unadjusted and adjusted logistic regression models (adjusted for maternal age, parity, malformed relatives, socioeconomic level, and maternal diabetes) for each isolated congenital malformation. RESULTS: Hydrocephaly and microtia had a higher at-birth prevalence, and spina bifida, preauricular tag, and gastroschisis showed a lower at-birth prevalence in moderate altitudes. Moderate altitudes were a risk factor for hydrocephaly (aOR 1.39), microtia (aOR 1.60), cleft-lip-palate (aOR 1.27), and polydactyly (aOR 1.32) and a protective effect for spina bifida (aOR 0.87) compared with low altitudes. CONCLUSIONS: Our findings provide evidence that moderate altitudes as higher altitudes are an associated risk or protective factor to some isolated congenital malformations, suggesting a possible gradient effect.

Reference values for the 6-min walking test in children and adolescents living in a moderate altitude region of Peru.

BACKGROUND: The assessment of cardiorespiratory fitness is important because it allows the identification of subgroups with poor health status and the targeting of effective intervention strategies to improve health. OBJECTIVE: To compare the cardiorespiratory capacity of children and adolescents living in a moderate altitude region of Peru with international studies and to develop reference values for the 6-min walk test (6MWT) according to age and sex. METHODOLOGY: A descriptive cross-sectional study of schoolchildren from a region of moderate altitude in Peru was carried out. A total of 704 schoolchildren (400 males and 304 females) with an age range of 6 to 17 years were studied. Weight, standing height, waist circumference (WC), body mass index (BMI) and tri-ponderal mass index (TMI) were evaluated. The 6MWT was assessed in a straight line over a distance of 30 m. Percentiles were created through the LMS method [L (skewness: lambda), M (median: mu) and S (coefficient of variation: Mu)]. RESULTS: There were discrepancies in cardiorespiratory fitness performance with international studies by age and sex. The schoolchildren in the study reached stability and the highest number of meters in the last two age ranges (14 to 15 years: 698.1 m and 16 to 17 years 686.3 m in males). While females (14 to 15 years: 698.1 m and 16 to 17 years: 686.3 m). The proposed percentile values show ascending values as age advances. The cut-off points adopted are: low cardiorespiratory fitness < p25, moderate p25 to p75 and high cardiorespiratory fitness p > 75. CONCLUSION: We verified that the cardiorespiratory fitness evaluated by means of the 6MWT is ascending with the course of age. Even the performance with other countries is heterogeneous at early and middle ages, stabilizing during adolescence. The proposed reference values can be used to evaluate and monitor cardiorespiratory fitness during physical education classes.

Impact of Moderate Altitude on Lung Diseases and Risk of High Altitude Illnesses

ABSTRACT A large world population resides at moderate altitudes. In the Valley of Mexico (2240 m above sea level) and for patients with respiratory diseases implies more hypoxemia and clinical deterioration, unless supplementary oxygen is prescribed or patients move to sea level. A group of individuals residing at 2500 or more meters above sea level may develop acute or chronic mountain disease but those conditions may develop at moderate altitudes although less frequently and in predisposed individuals. In the valley of México, at 2200 m above sea level, re-entry pulmonary edema has been reported. The frequency of other altitude-related diseases at moderate altitude, described in skiing resorts, remains to be known in visitors to Mexico City and other cities at similar or higher altitudes. Residents of moderate altitudes inhale deeply the city's air with all pollutants and require more often supplementary oxygen.

Impact of moderate altitude on lung diseases and risk of high altitude illnesses.

A large world population resides at moderate altitudes. In the Valley of Mexico (2240 m above sea level) and for patients with respiratory diseases implies more hypoxemia and clinical deterioration, unless supplementary oxygen is prescribed or patients move to sea level. A group of individuals residing at 2500 or more meters above sea level may develop acute or chronic mountain disease but those conditions may develop at moderate altitudes although less frequently and in predisposed individuals. In the valley of México, at 2200 m above sea level, re-entry pulmonary edema has been reported. The frequency of other altituderelated diseases at moderate altitude, described in skiing resorts, remains to be known in visitors to Mexico City and other cities at similar or higher altitudes. Residents of moderate altitudes inhale deeply the city's air with all pollutants and require more often supplementary oxygen.

Maximal inspiratory and expiratory flow at moderate altitude: a study of a Latin American population.

BACKGROUND: Peak inspiratory and expiratory flows (PIF, PEF) are parameters used to evaluate the mechanics of the respiratory system. These parameters can vary based on whether they are measured using mechanical devices vs. spirometry and based on the barometric pressure at which the measurements are obtained. Our objectives were (1) to report the normal values and variability of PEF and PIF of a Latin American population living at a moderate altitude (2240 m above sea level), (2) to analyze the adjustment of reference values obtained at sea level with those obtained in healthy subjects living at a moderate altitude, and (3) to assess the correlation between PEF obtained by spirometry (PEFs) and PEF obtained by mechanical devices (PEFm). METHODS: In this prospective and transversal study, men and women with good respiratory health aged between 2.8 and 68 years old were invited to participate. Randomly, they underwent spirometry (to measure PEFs and PIFs) and mechanical flowmetry (to measure PEFm). RESULTS: A total of 314 subjects participated, with an average age of 24.3 ± 16.4 years; 59% were Women. The main determinants for the reference equations were age, weight, height and sex at birth. The agreement of the PEFm, PEFs and PIFs values was inconsistent with that reported by other authors, even at the same barometric pressure. The association between PEFm and PEFs was r = 0.91 (p < 0.001), and the correlation coefficient of concordance was 0.84. CONCLUSIONS: The PEFm, PEFs, and PIFs measurements in individuals living at moderate altitudes are different from those found by other authors in cities with different barometric pressures and ethnicities.

Adaptation to Moderate Altitude Hypoxemia: The Example of the Valley of Mexico.

A large world population resides at moderate altitude. In the Valley of Mexico (2,240 m above sea level), its inhabitants, breathe approximately 29% more on average and have 10% increased hemoglobin concentrations compared to sea level residents, among other differences. These compensations reduce but not eliminate the impact of altitude hypoxemia. The objective of the manuscript is to review and describe the information available on health and disease at moderate altitudes, mainly with data in Spanish language from Latin-American countries. Young adults in Mexico City have an SaO2 between 92% and 94% versus 97% at sea level, frequently decreasing below 90% during sleep and intense exercise. It is likely that among the population living at this altitude, lung growth, and development during pregnancy and infancy are enhanced, and that after residing for several tens of thousands of years, more important adaptations in oxygen transport and utilization have developed, but we are not certain about it. For patients with respiratory diseases, residing at moderate altitudes implies increased hypoxemia and clinical deterioration, unless supplementary oxygen is prescribed or patients move to sea level. Hyperventilation increases exposure of residents to air pollutants compared to those living in cities with similar concentrations of pollutants, although at sea level. Humans evolved at sea level and lack the best-known adaptations to reside at moderate or high altitudes. Residents of moderate altitudes breathe deeply the city´s air with all its pollutants, and more often require supplementary oxygen.

Capacidad cardio-respiratoria de niños escolares que viven a moderada altitud / Cardiorespiratory capacity in children living at moderate altitude

Objetivo: Determinar la capacidad cardio-respiratoria de niños escolares que viven a moderada altitud. Pacientes y Método: Fueron seleccionados 795 niños (394 niños y 401 niñas) de escuelas públicas del área urbana de moderada altitud (2.320 msnm) de Arequipa, Perú. Se evaluaron variables antropométricas (masa corporal, estatura, porcentaje de grasa) y capacidad cardio-respiratoria a través del test indirecto de Course Navette, considerando las siguientes categorías: deficiente, malo, aceptable, bueno, muy bueno y excelente. Resultados: Los resultados muestran diferencias significativas en todas las categorías (p < 0,05). Se verificó que los valores medios de las categorías malo y deficiente en ambos sexos son inferiores a los de la categoría aceptable (p < 0,05). Se determinó que el 19 por ciento de niños y 21 por ciento de niñas mostraron bajo nivel de capacidad cardio-respiratoria, además se verificó correlación negativa baja con la categoría sobrepeso (r = -0,20 a -0,22) y moderada con la obesidad (r = -0,39 a -0,42) en ambos sexos. Conclusiones: Existen bajos niveles de capacidad cardio-respiratoria en niños de ambos sexos niños escolares que viven a moderada altitud, que se correlaciona negativamente con el exceso de peso corporal. Los resultados sugieren que uno de cada 5 niños se encuentra con posibilidades de padecer algún evento de índole cardiovascular.

Objective: To determine the cardiorespiratory capacity of school children living at moderate altitude. Patients and Method: 795 children (394 children and 401 girls) were selected from urban public schools in Arequipa, Peru at moderate altitude (2,320 m). Anthropometric variables (body mass, height, body fat percentage) and cardiorespiratory capacity were assessed using the Course Navette test, considering the following categories: deficient, poor, fair, good, very good and excellent. Results: The results showed significant differences in all categories (p < 0.05). It was described that the median values of the poor and deficient categories in both gender were lower than what is considered acceptable (p < 0.05). It was concluded that 19 percent of boys and 21 percentof girls showed low level of cardiorespiratory capacity and a low negative correlation with overweight (r = -0.20 to -0.22) and a moderate negative correlation with obesity (r = -0.39 to -0.42) were described for both genders. Conclusions: Low levels of cardiorespiratory capacity in boys and girls living at moderate altitude are observed, which is negatively correlated with excess body weight. The results suggest that 1 in 5 children are likely to suffer some type of cardiovascular event.