The Maximum Expiratory Flow-Volume Loop in Natives of Ladakh and Acclimatized Lowlanders

Apte, Chandrashekhar V.; Rao, K. S.

doi:10.1089/ham.2005.6.209

Cited by 8 publications

(7 citation statements)

References 23 publications

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“…Tibetans compared to lowlanders have larger chest circumference, larger total lung capacity, and larger vital capacity (Sun et al, 1990;Droma et al, 1991;Apte and Rao, 2005). This difference is already apparent at adolescence (Cheng et al, 1997), corroborating the contention that being born and raised at high altitude leads to increased lung volumes, as reported earlier in Andeans (Brody et al, 1977).…”

Section: Staticssupporting

confidence: 83%

“…In Ladakhis, maximum expiratory flow-volume loops show greater forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1) compared to acclimatized lowlanders. Flow rates were especially higher at low lung volumes (Apte and Rao, 2005). Altitude-born and -living residents of Tibetan ethnicity thus have greater lung recoil or greater total cross-sectional area of airways (or both) compared to acclimatized lowlanders.…”

Section: Dynamicsmentioning

confidence: 88%

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High Altitude Adaptation in Tibetans

Wu¹,

Kayser

2006

High Altitude Medicine & Biology

203

181

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Since the beginning of the Himalayan climbing era, the anecdotal extraordinary physical performance at high altitude of Sherpas and Tibetans has intrigued scientists interested in altitude adaptation. These ethnic groups may have been living at high altitude for longer than any other population, and the hypothesis of a possible evolutionary genetic adaptation to altitude makes sense. Reviewed here is the evidence as to whether Tibetans are indeed better adapted for life and work at high altitude as compared to other populations and, if so, whether this better adaptation might be inborn. Tibetans, compared to lowlanders, maintain higher arterial oxygen saturation at rest and during exercise and show less loss of aerobic performance with increasing altitude. Tibetans have greater hypoxic and hypercapnic ventilatory responsiveness, larger lungs, better lung function, and greater lung diffusing capacity than lowlanders. Blood hemoglobin concentration is lower in Tibetans than in lowlanders or Andeans living at similar altitudes. Tibetans develop only minimal hypoxic pulmonary hypertension and have higher levels of exhaled nitric oxide than lowlanders or Andeans. Tibetans' sleep quality at altitude is better and they desaturate less at night. Several of these findings are also found in Tibetans born at low altitude when exposed for the first time to high altitude once adult. In conclusion, Tibetans indeed seem better adapted to life and work at high altitude, and this superior adaptation may very well be inborn, even though its exact genetic basis remains to be elucidated.

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Section: Staticssupporting

confidence: 83%

Section: Dynamicsmentioning

confidence: 88%

High Altitude Adaptation in Tibetans

Wu¹,

Kayser

2006

High Altitude Medicine & Biology

203

181

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“…Our findings of greater than predicted lung function are similar to thse reported previously for Lahdaki highlanders. 47, 48 Wood et al47 suggested that the augmented lung mechanics of this high-altitude population is adaptive to reduce the work of breathing. Apte and Rao48 further suggested an inherited adaptive mechanism resulting in greater lung elastic recoil and larger cross section of the small airways.…”

Section: Discussionmentioning

confidence: 99%

Respiratory Health and Indoor Air Pollution at High Elevation

Rosati

Yoneda²,

Wood³

et al. 2005

Archives of Environmental & Occupational Health

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In this research, the authors sought to provide experimental data on indoor air quality, and the resulting respiratory impact, for a high-elevation (4550 m), rural community in Ladakh, India. This community is of interest because the primarily nomadic residents burn biomass inside the home for heating and cooking. The concentrations of particulate matter (PM), endotoxin, and carbon monoxide were determined for 6 homes. Lung function data and induced sputum samples were collected for 9 female test-home subjects. In addition, lung function data were collected for 84 additional Ladakhi highlanders at this location. Sputum from 3 visiting scientists (sojourners) was collected and analyzed as well. The average PM concentration ranged from 2 mg/m 3 to 7 mg/m 3 , with 85% of the sampled PM sized as respirable. The average endotoxin concentration ranged from 2.4 ng/m 3 to 19 ng/m 3 , and average carbon monoxide levels ranged from 50 ppm to 120 ppm. Lung function values for the highlander population and the test-home subjects were equal to or greater than predicted, despite the highlanders' significant exposure to indoor pollutants. An induced sputum analysis revealed a significantly greater total inflammatory cell count (M ± SD, 10 5 cell/mg) in the Ladakhi natives than in the sojourners (107.5 ± 75.2 vs 7.1 ± 8.1, p .01). Although the high levels of indoor pollutants did not correlate with significant decrements in lung function, the induced sputum analysis revealed marked airway inflammation dominated by macrophages and neutrophils. It appears that augmented lung mechanics of this high-altitude population are adaptive to reduce the work of breathing; thus, decrements in lung function go undetected because the true predicted values are greater than expected.Keywords biomass combustion; high-altitude population; indoor air quality; lung functionThe World Health Organization estimates that 20% to 30% of all respiratory diseases are caused by ambient and indoor air pollution.1 Globally, indoor air contaminants are of Request for reprints should be sent to Jacky Ann Rosati, PhD, USEPA, Office of Research and Development, National Homeland Security Research Center, E-343−06, 109 TW Alexander Drive, Research Triangle Park, NC 27711. E-mail: rosati.jacky@epa.gov. HHS Public Access Author ManuscriptAuthor Manuscript Author ManuscriptAuthor Manuscript concern because nearly 50% of the world's population burns biomass for domestic purposes such as cooking and heating.1,2 In developing nations, indoor exposure to biomass combustion byproducts has been associated with an increased incidence of respiratory disease as well as an increased rate of mortality.3-12 The World Bank has estimated that indoor air pollution is responsible for almost half the burden of disease in developing countries.2,13 In India alone, it is estimated that 400,000 to 550,000 premature deaths can be contributed to the use of biomass fuels.14 In Ladakh, Indian Himalaya, research has shown a prevalence of chronic cough, chronic phlegm, nonoccupational...

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“…Lung volumes and capacities are known to exhibit strong ethnic differences. [11][12][13] We had the opportunity to study the changes in pulmonary function on acute ascent and during a 4-week stay at an altitude of 3200 m in human male volunteers from 2 different populations: Indians and Kyrgyzis.…”

Section: Introductionmentioning

confidence: 99%