The paternal ancestry of Uttarakhand does not imitate the classical caste system of India

The matrilineal ancestry of Nepali populations

The Tibetan plateau and high mountain ranges of Nepal are one of the challenging geographical regions inhabited by modern humans. While much of the ethnographic and population-based genetic studies were carried out to investigate the Tibetan and Sherpa highlanders, little is known about the demographic processes that enabled the colonization of the hilly areas of Nepal. Thus, the present study aimed to investigate the past demographic events that shaped the extant Nepalese genetic diversity using mitochondrial DNA (mtDNA) variations from ethnic Nepalese groups. We have analyzed mtDNA sequences of 999 Nepalese and compared data with 38,622 published mtDNA sequences from rest of the world. Our analysis revealed that the genomic landscapes of prehistoric Himalayan settlers of Nepal were similar to that of the low-altitude extant Nepalese (LAN), especially Newar and Magar population groups, but differ from contemporary high-altitude Sherpas. LAN might have derived their East Eurasian ancestry mainly from low-altitude Tibeto-Burmans, who likely have migrated from East Asia and assimilated across the Eastern Himalayas extended from the Eastern Nepal to the North-East of India, Bhutan, Tibet and Northern Myanmar. We also identified a clear genetic sub-structure across different ethnic groups of Nepal based on mtDNA haplogroups and ectodysplasin-A receptor (EDAR) gene polymorphism. Our comprehensive high-resolution mtDNA-based genetic study of Tibeto-Burman communities reconstructs the maternal origins of prehistoric Himalayan populations and sheds light on migration events that have brought most of the East Eurasian ancestry to the present-day Nepalese population.

Signatures of high altitude adaptation in Tibeto-Burman tribes of the Darjeeling Hill Region

OBJECTIVES

The long-term isolation, endogamy practices, and environmental adaptations have shaped the enormous human diversity in India. The genetic and morphological variations in mainland Indians are well studied. However, the data on the Indian Himalayan populations are scattered. Thus, the present study attempts to understand variations in the selected parameter among four Tibeto-Burman speaking ethnic tribal populations from the Darjeeling Hill Region (DHR) in the Eastern Himalaya Biodiversity Hotspot region of India.

METHODS

A total of 178 healthy male individuals (Lepcha 98, Sherpa 31, Bhutia 27, and Tibetans 22) living at an altitudinal range of 1467-2258 m above the sea level were studied for the 10 parameters namely, weight (kg), height (cm), body mass index (BMI) (kg/m² ) systolic and diastolic pressure (mm of Hg), pulse rate (per minute), saturation of peripheral oxygen (SPO₂ ) (%), hemoglobin (g/dl), hematocrit (HCT) (%), and blood glucose (mg/dl). The data was statistically analyzed using analysis of variance and multiple linear regression methods.

RESULTS

Our analysis revealed comparatively lower hemoglobin and HCT levels, and higher systolic and diastolic blood pressure in the Sherpas followed by the Tibetans. This may be reflecting the persistence of high-altitude adaptation signatures even in lowlands. Interestingly, the Tibetans differed significantly from other populations in terms of their higher body weight, height, and BMI.

CONCLUSION

Thus, our study showed the persistence of high altitude signatures in Tibetans and Sherpa inhabited the DHR. Additionally, we also observed significant differences in the anthropometric and physiological parameters among the Tibeto-Burman populations of the DHR.

Prevalence, Awareness, Treatment, Control, and Related Factors of Hypertension among Tajik Nomads Living in Pamirs at High Altitude

Background

Hypertension is a global problem, for which high-altitude residents exhibit higher burden. Hypertension in Tajik nomads from Pamirs with an average altitude above 4000 m remains less studied. We aimed to determine the prevalence, awareness, treatment, control, and risk factors associated with hypertension among Tajik population in Pamirs.

Methods

A cross-sectional survey was conducted between August and September 2015 using stratified three-stage random sampling in Taxkorgan county, Pamirs, China. Hypertension is defined as mean systolic and/or diastolic blood pressure (SBP, DBP) ≥140/90 mmHg and/or taking antihypertensive medication within the past two weeks. The prevalence (SBP ≥130 or DBP ≥80 mmHg) was also estimated using the 2017 American College of Cardiology (ACC)/American Heart Association (AHA) High Blood Pressure Guideline. The awareness, treatment, and control of hypertension and associated factors were evaluated.

Results

Totally, 797 subjects aged ≥18 years were enrolled with 46.3% men and 88.8% nomads with the mean age of 42.3 ± 15.2 years. The prevalence of hypertension was 24.2% (140/90 mmHg), and the prevalence was as high as 40.3%, based on the 2017 ACC/AHA guideline. Overall awareness, treatment, and control of hypertension were 52.8%, 40.9%, and 9.3%, respectively. In multivariate logistic regression, BMI ≥24.0 kg/m² (OR: 2.41, 95% CI: 1.44–4.04) was a risk factor for prehypertension, and age ≥60 years (OR: 2.04, 95% CI: 1.15–3.61), BMI ≥24.0 kg/m² (OR: 2.04, 95% CI: 1.15–3.61), and abdominal obesity (OR: 1.87, 95% CI: 1.09–3.22) were risk factors for hypertension. Angiotensin-converting enzyme inhibitors/angiotensin receptor blockers were the most commonly used antihypertensive medication (45.4%) as monotherapy, and 13.6% of treated hypertensive patients used two drugs.

Conclusions

There is a considerable prevalence of hypertension with low awareness, treatment, and control rates among Tajik nomads in Pamirs, where health programs improving the hypertension status are urgently needed, with the excess weight loss as a strategy.

Comparison of Subjective Sleep Quality of Long-Term Residents at Low and High Altitudes: SARAHA Study

STUDY OBJECTIVES

To study the effect of altitude on subjective sleep quality in populations living at high and low altitudes after excluding cases of restless legs syndrome (RLS).

METHODS

This population-based study was conducted at three different altitudes (400 m, 1,900-2,000 m, and 3,200 m above sea level). All consenting subjects available from random stratified sampling in the Himalayan and sub-Himalayan regions of India were included in the study (ages 18 to 84 years). Sleep quality and RLS status were assessed using validated translations of Pittsburgh Sleep Quality Index (PSQI) and Cambridge Hopkins RLS diagnostic questionnaire. Recent medical records were screened to gather data for medical morbidities.

RESULTS

In the total sample of 1,689 participants included, 55.2% were women and average age of included subjects was 35.2 (± 10.9) years. In this sample, overall 18.4% reported poor quality of sleep (PSQI ≥ 5). Poor quality of sleep was reported more commonly at high altitude compared to low altitude (odds ratio [OR] = 2.65; 95% CI = 1.9-3.7; P < .001). It was more frequently reported among patients with RLS (29.7% versus 17.1% without RLS; P < .001). Other factors that were associated with poor quality of sleep were male sex, smoking, chronic obstructive pulmonary disease (COPD), and varicose veins. Binary logistic regression indicated that COPD (OR = 1.97; 95% CI = 1.36-2.86; P < .001), high altitude (OR = 2.22; 95% CI = 1.55-3.18; P < .001), and RLS (OR = 1.66; 95% CI = 1.12-2.46; P = .01) increased the odds for poor quality of sleep.

CONCLUSIONS

This study showed that poor quality of sleep was approximately twice as prevalent at high altitudes compared to low altitudes even after removing the potential confounders such as RLS and COPD.