Heterogeneity in Hematological Parameters of High and Low Altitude Tibetan Populations.

Introduction: High altitude hypoxia is believed to be experienced at elevations of more than 2500 meters above sea level. Several studies have shed light on the biochemical aspects of high altitude acclimatization, where participants were sojourners to the high altitude from low altitude areas. However, information regarding the difference between the high altitude adapted Tibetans living at high altitude and their counterparts who reside at low altitude are lacking.

High altitude with monotonous environment has significant impact on mood and cognitive performance of acclimatized lowlanders: Possible role of altered serum BDNF and plasma homocysteine level.

Background: Monotony resulting due to the wilderness, sparse population and isolation from society could adversely affect human physiology and cause mood alterations. Thus, observations need to be conducted in order to elucidate the possible role of circulating biomarkers in inducing altered mood and cognitive performance following prolonged exposure to high altitude (HA) with persistent monotonous environment.

Objective: The present study aimed towards investigating the impact of monotonous environment in remote HA on mood and cognitive performance of human volunteers and its correlation with serum brain derived neurotrophic factor (BDNF) and plasma homocysteine level.

Prevalence and risk factors of hypertension in acclimatized lowlanders staying at high altitude for different durations.

Hypoxic exposure at high-altitude (HA) modulates blood pressure (BP). High prevalence of hypertension among native highlanders (NH) has been reported. However, information on prevalence and determinants of hypertension in acclimatized young lowlanders (ALL) staying at HA for different durations is sparse.

Sleep quality among elderly high-altitude dwellers in Ladakh.

It has been already known that people who temporarily stay at high altitude may develop insomnia as a symptom of acute mountain sickness. However, much less is known about people living at high altitude. The aim of this study was to determine the effect of high altitude environment on sleep quality for the elderly who have been living at high altitude for their whole lives.

Health and happiness among community-dwelling older adults in Domkhar valley, Ladakh, India.

Aim: The aim of the present study was to show the status of objective geriatric functions and subjective quality of life in Ladakh, India, compared with Japanese controls.

Methods: We analyzed data of 117 people aged 60 years or older in Domkhar, and age- and sex-specific Japanese controls. Variables measured included blood pressure, hemoglobin, timed up & go test, basic activities of daily living, Geriatric Depression Scale and the Visual Analog Scale for subjective quality of life.

Glucose intolerance associated with hypoxia in people living at high altitudes in the Tibetan highland.

Objectives: To clarify the association between glucose intolerance and high altitudes (2900-4800 m) in a hypoxic environment in Tibetan highlanders and to verify the hypothesis that high altitude dwelling increases vulnerability to diabetes mellitus (DM) accelerated by lifestyle change or ageing.

Design: Cross-sectional epidemiological study on Tibetan highlanders.

Participants: We enrolled 1258 participants aged 40-87 years.

Lungs at high-altitude: genomic insights into hypoxic responses.

Hypobaric hypoxia at high altitude (HA) results in reduced blood arterial oxygen saturation, perfusion of organs with hypoxemic blood, and direct hypoxia of lung tissues. The pulmonary complications in the cells of the pulmonary arterioles due to hypobaric hypoxia are the basis of the pathophysiological mechanisms of high-altitude pulmonary edema (HAPE). Some populations that have dwelled at HA for thousands of years have evolutionarily adapted to this environmental stress; unadapted populations may react with excessive physiological responses that impair health.

Domain specific changes in cognition at high altitude and its correlation with hyperhomocysteinemia.

Though acute exposure to hypobaric hypoxia is reported to impair cognitive performance, the effects of prolonged exposure on different cognitive domains have been less studied. The present study aimed at investigating the time dependent changes in cognitive performance on prolonged stay at high altitude and its correlation with electroencephalogram (EEG) and plasma homocysteine. The study was conducted on 761 male volunteers of 25-35 years age who had never been to high altitude and baseline data pertaining to domain specific cognitive performance, EEG and homocysteine was acquired at altitude ≤240 m mean sea level (MSL).

Disaster-related psychiatric disorders among survivors of flooding in Ladakh, India.

Background: Heavy rainfall in northern India in August 2010 caused flash floods, seriously damaging homes and infrastructure. There have been no major disasters in the history of Ladakh, and no surveys on post-disaster psychiatric disorders have been conducted in this area.

Aims And Methods: To examine the impact of this disaster in Ladakh one month post-disaster, we visited Choglamsar, located near the town of Leh, where the flood had the most severe impact.

Polymorphisms of renin--angiotensin system genes as a risk factor for high-altitude pulmonary oedema.

The genes of the renin--angiotensin system (RAS) play an important role in the regulation of pulmonary vascular tone. Although studies on individual genes polymorphisms have reported association with high-altitude pulmonary oedema (HAPE), studies on multiple genes or epistasis are lacking. We therefore investigated the association of the RAS polymorphisms with HAPE.

Population based study to assess prevalence and risk factors of gastroesophageal reflux disease in a high altitude area.

Aim: We did a population-based cross-sectional study to investigate the prevalence and risk factors of gastroesophageal reflux disease (GERD) in a high altitude area.

Methods: An observational study using a validated questionnaire consisting of demographic, lifestyle and dietary characteristics was administered in an interview based format by two clinicians on a sample of adult population residing in urban area and rural high altitude areas of Ladakh. Presence of GERD was defined as a score of ≥4 using a previously validated symptom score based on the severity and frequency of heartburn and regurgitation.

Probable role of beta2-adrenergic receptor gene haplotype in high-altitude pulmonary oedema.

Background And Objective: The role of beta2-adrenergic receptor (ADRB2) in pulmonary oxygenation has been ascertained during altitude acclimatization, physical performance and lung fluid clearance, but little is known about its association with high-altitude pulmonary oedema (HAPE), a non-cardiogenic pulmonary oedema.

Methods: In a case-control study, 110 unrelated HAPE patients (HAPE-p) and 143 unrelated HAPE-resistant (HAPE-r) controls matched on age and ethnicity were used to examine the association between eight single nucleotide polymorphisms (SNP) and disease. The eight SNP including three tag-SNP were genotyped from promoter and exonic regions of ADRB2.

Differences in the control of breathing between Himalayan and sea-level residents.

We compared the control of breathing of 12 male Himalayan highlanders with that of 21 male sea-level Caucasian lowlanders using isoxic hyperoxic ( = 150 mmHg) and hypoxic ( = 50 mmHg) Duffin's rebreathing tests. Highlanders had lower mean +/- s.e.

Adaptation and mal-adaptation to ambient hypoxia; Andean, Ethiopian and Himalayan patterns.

The study of the biology of evolution has been confined to laboratories and model organisms. However, controlled laboratory conditions are unlikely to model variations in environments that influence selection in wild populations. Thus, the study of "fitness" for survival and the genetics that influence this are best carried out in the field and in matching environments.

Heterozygotes of NOS3 polymorphisms contribute to reduced nitrogen oxides in high-altitude pulmonary edema.

Study Objectives: High-altitude pulmonary edema (HAPE), which develops on exertion under hypoxic conditions, aggravates due to endothelial dysfunction. Repeat events of the disorder suggests of genetic susceptibility. Endothelial nitric oxide synthase gene (NOS3), a regulator of vasodilation, has emerged as a strong candidate marker.

Predominance of interaction among wild-type alleles of CYP11B2 in Himalayan natives associates with high-altitude adaptation.

Sojourners visiting high-altitude (HA) (>2500 m) are susceptible to HA disorders; on the contrary, HA natives are well adapted to the extreme hypoxic environment. High aldosterone levels are believed to be involved in HA disorders, we, therefore, envisaged role of CYP11B2 gene variants in HA adaptation and therefore investigated the -344T/C, intron-2 conversion (Iw/Ic), K173R, and A5160C polymorphisms. In addition, polymorphisms in AGT, AT1R, ATP1A1, ADRB2, and GSTP1 genes were also investigated.

Endothelin-1 gene variants and levels associate with adaptation to hypobaric hypoxia in high-altitude natives.

High-altitude natives are adapted to hypobaric hypoxia, suggestive of genetic basis of adaptation. Since endothelin-1 (ET-1) is of prime importance in high-altitude disorders in sojourners, we envisaged the role of allelic variants of ET-1 in high-altitude adaptation. Four ET-1 polymorphisms, viz.

Chronoecological health watch of arterial stiffness and neuro-cardio-pulmonary function in elderly community at high altitude (3524 m), compared with Japanese town.

Effects of high altitude on arterial stiffness and neuro-cardio-pulmonary function were studied. Blood pressure (BP) and heart rate (HR) were measured in a sitting position on resting Ladakhis, living at an altitude of 3250-4647 m (Phey village, 3250 m: 17 men and 55 women; Chumathang village, 4193 m: 29 men and 47 women; Sumdo village, 4540 m: 38 men and 57 women; and Korzok village, 4647 m: 84 men and 70 women). The neuro-cardio-pulmonary function, including the Kohs block design test, the Up and Go, the Functional Reach and the Button tests, was examined in 40 elderly subjects (19 men and 21 women, mean age: 74.

Effect of aging on blood pressure in Leh, Ladakh, a high-altitude (3524 m) community, by comparison with a Japanese town.

The effect of aging on blood pressure (BP) and heart rate (HR) was investigated in a cross-sectional study in the high-altitude community of Leh, Ladakh (altitude: 3524 m) and a Japanese community in U town, Hokkaido (altitude: 25 m). BP and HR were obtained in a sitting position from 332 subjects 13-81 years of age in Ladakh, and from 216 Japanese citizens, 24-79 years of age. Measurements were taken after a 2-min rest, using a semi-automated BP device (UA-767 PC, A and D Co.

Simultaneous selection of the wild-type genotypes of the G894T and 4B/ 4A polymorphisms of NOS3 associate with high-altitude adaptation.

The routine performance of high-altitude (HA) natives in the hypoxic environment of HA exemplifies the process of adaptation mainly through natural selection. The recent therapeutic application of nitric oxide (NO) in HA disorders, for the improvement of oxygenation and vasodilation, ushered us to investigate the endothelial nitric oxide synthase gene (NOS3) with respect to HA adaptation. The study subjects, 131 HA monks (HAM), 136 HA controls (HAC), and 170 lowlanders (LLs) were screened for NOS3 G894T (Glu298Asp) and 4B/4A polymorphisms.