Developmental, genetic, and environmental components of lung volumes at high altitude

Frisancho, A. Roberto; Frisancho, Hedy G.; Albalak, Rachel; Villain, Mercedes; Vargas, Enrique; Soria, Rudy

doi:10.1002/(sici)1520-6300(1997)9:2<191::aid-ajhb5>3.0.co;2-3

Cited by 78 publications

(96 citation statements)

References 11 publications

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“…For example, people born at high altitudes have a greater lung volume that those born at lower elevations. 33 Therefore, if hypoxia does contribute to the higher suicide rate at altitude, the ratio of those who were born at a lower altitude and moved to a higher elevation to those who were born at a high altitude and remained there should be higher among suicide completers than among those in the same community who do not commit suicide.…”

Section: Suggestions For Future Researchsupporting

confidence: 47%

Elevated incidence of suicide in people living at altitude, smokers and patients with chronic obstructive pulmonary disease and asthma: possible role of hypoxia causing decreased serotonin synthesis

Young

2013

J Psychiatry Neurosci

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Section: Suggestions For Future Researchsupporting

confidence: 47%

Elevated incidence of suicide in people living at altitude, smokers and patients with chronic obstructive pulmonary disease and asthma: possible role of hypoxia causing decreased serotonin synthesis

Young

2013

J Psychiatry Neurosci

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“…However, there has been no investigation of whether the larger chest-circumference-tostature ratios observed among stunted children (Malina et al, 1975;Ounsted et al, 1986;Post and Victoria, 2001) might produce additional deviations from predicted values. At high altitude, where populations already exhibit enhanced thorax dimensions (Frisancho et al, 1997;Brutsaert et al, 1999;Wu and Kaiser, 2006), differences in chest-circumference-tostature ratios associated with stunting could further alter the relationship between stature and lung volumes. In this sample of high altitude Tibetan children, sitting height shows the same allometric relationship with stature between the ages of 6 and 20 years among all children, regardless of HAZ status.…”

Section: Discussionmentioning

confidence: 99%

“…have been attributed to developmental and/or genetic effects on thorax growth in a hypoxic environment (Frisancho et al, 1997;Brutsaert et al, 1999), and sitting-height-to-stature ratios may also have a genetic component (Stinson, 2009). However, the extent to which stunting may cause differences in body proportions among high altitude children, and whether such differences are associated with differences in lung volumes has not been studied.…”

Section: Introductionmentioning

confidence: 99%

Stunting and the Prediction of Lung Volumes Among Tibetan Children and Adolescents at High Altitude

Weitz

Garruto

2015

High Altitude Medicine & Biology

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Weitz, Charles A., and Ralph M. Garruto. Stunting and the prediction of lung volumes among Tibetan children and adolescents at high altitude. High Alt Biol Med 16: [306][307][308][309][310][311][312][313][314][315][316][317] 2015.-This study examines the extent to which stunting (height-for-age Z-scores £ -2) compromises the use of low altitude prediction equations to gauge the general increase in lung volumes during growth among high altitude populations. The forced vital capacity (FVC) and forced expiratory volume (FEV 1 ) of 208 stunted and 365 non-stunted high-altitude Tibetan children and adolescents between the ages of 6 and 20 years are predicted using the Third National Health and Nutrition Examination Survey (NHANESIII) and the Global Lung Function Initiative (GLF) equations, and compared to observed lung volumes. Stunted Tibetan children show smaller positive deviations from both NHANESIII and GLF prediction equations at most ages than non-stunted children. Deviations from predictions do not correspond to differences in body proportions (sitting heights and chest circumferences relative to stature) between stunted and non-stunted children; but appear compatible with the effects of retarded growth and lung maturation that are likely to exist among stunted children. These results indicate that, before low altitude standards can be used to evaluate the effects of hypoxia, or before high altitude populations can be compared to any other group, it is necessary to assess the relative proportion of stunted children in the samples. If the proportion of stunted children in a high altitude population differs significantly from the proportion in the comparison group, lung function comparisons are unlikely to yield an accurate assessment of the hypoxia effect. The best solution to this problem is to (1) use stature and lung function standards based on the same low altitude population; and (2) assess the hypoxic effect by comparing observed and predicted values among high altitude children whose statures are most like those of children on whom the low altitude spirometric standard is based-preferably high altitude children with HAZ-scores ‡ -1.

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“…This is supported by multivariable models, which failed to detect a mediating effect of HVR-S on the strong negative relationship between NAAP and the exercise VE. In addition, a large number of studies directly or indirectly support the hypothesis that Andeans have superior pulmonary gas-exchange at altitude, including studies showing larger pulmonary volumes (8,18,24), greater carbon monoxide diffusion capacities (51,65), smaller alveolar-arterial partial pressure differences (33), and larger lung O 2 diffusion capacities during exercise at altitude (66). Interestingly, we did not detect an association between NAAP and FVC adjusting for body size within our sample.…”

Section: Discussionmentioning

confidence: 99%

Ancestry explains the blunted ventilatory response to sustained hypoxia and lower exercise ventilation of Quechua altitude natives

Brutsaert

Parra

Shriver

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

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-Andean highaltitude (HA) natives have a low (blunted) hypoxic ventilatory response (HVR), lower effective alveolar ventilation, and lower ventilation (VE) at rest and during exercise compared with acclimatized newcomers to HA. Despite blunted chemosensitivity and hypoventilation, Andeans maintain comparable arterial O 2 saturation (SaO 2 ). This study was designed to evaluate the influence of ancestry on these trait differences. At sea level, we measured the HVR in both acute (HVR-A) and sustained (HVR-S) hypoxia in a sample of 32 male Peruvians of mainly Quechua and Spanish origins who were born and raised at sea level. We also measured resting and exercise VE after 10 -12 h of exposure to altitude at 4,338 m. Native American ancestry proportion (NAAP) was assessed for each individual using a panel of 80 ancestry-informative molecular markers (AIMs). NAAP was inversely related to HVR-S after 10 min of isocapnic hypoxia (r ϭ Ϫ0.36, P ϭ 0.04) but was not associated with HVR-A. In addition, NAAP was inversely related to exercise VE (r ϭ Ϫ0.50, P ϭ 0.005) and ventilatory equivalent (VE/V O2, r ϭ Ϫ0.51, P ϭ 0.004) measured at 4,338 m. Thus Quechua ancestry may partly explain the wellknown blunted HVR (10,35,36,57,62) at least to sustained hypoxia, and the relative exercise hypoventilation at altitude of Andeans compared with European controls. Lower HVR-S and exercise VE could reflect improved gas exchange and/or attenuated chemoreflex sensitivity with increasing NAAP. On the basis of these ancestry associations and on the fact that developmental effects were completely controlled by study design, we suggest both a genetic basis and an evolutionary origin for these traits in Quechua. genetic markers; admixture; arterial saturation; Andes THE HYPOXIC VENTILATORY RESPONSE (HVR) is the increase in ventilation (VE) that occurs when arterial blood oxygen partial pressure PO 2 decreases (60). Typically, on acute exposure to hypoxia, VE increases to a peak in the first few minutes and thereafter declines somewhat to a level higher than control depending on the level of hypoxia (13,49). This attenuation of VE has been termed the hypoxic ventilatory decline (HVD), and it is usually assessed by protocols that give a sustained hypoxic exposure greater than ϳ10 min. The sustained vs. acute response has not been systematically evaluated in Andean highland natives, but groups from this region appear to have a lower or "blunted" acute HVR and a lower effective alveolar ventilation compared with high altitude (HA)-acclimatized control groups from the lowlands (10,35,36,43,57,61,62). Andeans also have lower VE during exercise at HA compared with acclimatized lowland controls (7,32,55,66). These traits may be unique to Andeans, as many studies show normal HVR and higher VE in natives of the Himalayan plateau (2,21,25,29,75). However, little is known about the underlying genetic and/or environmental basis for ventilatory trait differences between populations. One possibility is that there are genes at which allele frequencies differ ...

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Developmental, genetic, and environmental components of lung volumes at high altitude

Abstract: Vital capacity and residual lung volume (in terms of 1/min or ml/m 2 of body surface area) of 357 subjects (205 males, 152 females) was evaluated in La Paz, Bolivia, situated at 3,750 m. The sample included: (1) 37 high altitude rural natives (all male), (2) 125 high altitude urban natives

Cited by 78 publications

References 11 publications

Elevated incidence of suicide in people living at altitude, smokers and patients with chronic obstructive pulmonary disease and asthma: possible role of hypoxia causing decreased serotonin synthesis

Elevated incidence of suicide in people living at altitude, smokers and patients with chronic obstructive pulmonary disease and asthma: possible role of hypoxia causing decreased serotonin synthesis

Stunting and the Prediction of Lung Volumes Among Tibetan Children and Adolescents at High Altitude

Ancestry explains the blunted ventilatory response to sustained hypoxia and lower exercise ventilation of Quechua altitude natives

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