Prevalence of hypertension at high altitude: cross-sectional survey in Ladakh, Northern India 2007–2011

Abstract

ObjectivePrevalence of hypertension was examined in a widely dispersed (45 110 km2) representative group of Ladakhi in Northern India. The influence of hypoxic environment of wide-ranged altitude (2600–4900 m) and lifestyle change on hypertension was studied.Methods2800 participants (age 20–94 years) were enrolled. Systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure of ≥90 mm Hg and/or taking current anti-hypertensive medicine was defined as hypertension. Height and weight for body mass index and SpO2 were examined. The rural population comprised six subdivisions with a distinct altitude, dietary and occupational pattern. Participants in the urban area of Leh consist of two groups, that is, migrants settled in Leh from the Changthang nomadic area, and dwellers born in Leh. The prevalence of hypertension in the two groups was compared with that in the farmers and nomads in rural areas. The effects of ageing, hypoxia, dwelling at high altitude, obesity, modernised occupation, dwelling in an urban area, and rural-to-urban migration to hypertension were analysed by multiple logistic regression.ResultsThe prevalence of hypertension was 37.0% in all participants and highest in migrants settled in Leh (48.3%), followed by dwellers born in Leh town (41.1%) compared with those in rural areas (33.5). The prevalence of hypertension in nomads (all: 27.7%, Tibetan/Ladakhi: 19.7/31.9%)) living at higher altitude (4000–4900 m) was relatively low. The associated factors with hypertension were ageing, overweight, dwelling at higher altitude, engagement in modernised sedentary occupations, dwelling in urban areas, and rural-to-urban migration. The effects of lifestyle change and dwelling at high altitude were independently associated with hypertension by multivariate analysis adjusted with confounding factors.ConclusionsSocioeconomic and cultural factors play a big role with the effect of high altitude itself on high prevalence of hypertension in highlanders in Ladakh.

Living at a Geographically Higher Elevation Is Associated with Lower Risk of Metabolic Syndrome: Prospective Analysis of the SUN Cohort

“…These outcomes are consistent with our results, although they enrolled participants living at considerably higher altitudes than those in our cohort (up to 3500 m vs. <2000 m in our study). Higher hypertension prevalence was associated to highest altitudes (more than 2000 m) in highlanders of India (Norboo et al, 2015), which is opposed to our results concerning hypertension, possibly because their study was carried out with very high altitudes. As previously discussed, to date there are no longitudinal studies analyzing the association between living at geographical high altitude and the incidence of MetS.…”

“…Concerning modifiable factors, the environment has been suggested to potentially influence the development of metabolic diseases (Friel et al, 2011; Dhurandhar and Keith, 2014; Valdes et al, 2014). Moreover, some studies on subjects living at high altitudes have reported lower incidence rates of conditions linked to MetS such as obesity (Voss et al, 2013; Woolcott et al, 2014; Diaz-Gutierrez et al, 2016), heart disease (Ezzati et al, 2012; Faeh et al, 2016), hypertension (Norboo et al, 2015) or type 2 diabetes (Woolcott et al, 2014). …”

High‐altitude adaptations mitigate risk for hypertension and diabetes‐associated anemia

“…It is unlikely that this observation could be attributed to better care for hypertension among the Mosuo (e.g., via medication), for whom access to medical care remains limited. This pattern of lower risk for hypertension was obscured in previous research among Tibetans (Aryal et al, ; Mingji et al, ; Norboo et al, ; Sun, ), which was conducted at generally higher elevations and could not adequately control for differences in lifestyle between Tibetans and comparison groups. Our work suggests that lower risk for hypertension may be an additional feature of Tibetan Plateau adaptations to high altitude.…”

“…Blood pressures generally increase with altitude due to hypoxic stress; this has been observed among sojourners (Calbet, ; Luks, ), those raised at altitude (Aryal, Weatherall, Bhatta, & Mann, ; Norboo et al, ), and Tibetans (Aryal, Weatherall, Bhatta, & Mann, ; Mingji, Onakpoya, Perera, Ward, & Heneghan, ). Both lower rates of hypertension (Norboo et al, ) and higher rates of hypertension (Sun, ) have been reported among Tibetans, compared to Han or other ethnic groups at similar altitudes—this likely reflects differences in subsistence, diet, and lifestyle that confound direct comparisons between Tibetan Plateau and lowland populations residing at altitude. We resolve this by comparing Mosuo risk for hypertension to that predicted from models fit to Han with similar overall lifestyle characteristics.…”

New insights into mechanisms regulating pulmonary adventitial fibroblast proliferation

“…), the prevalence of hypoxia‐induced PH has been found to be as high as 37% among high‐altitude dwellers (>2500 m) (Norboo et al . ). Accordingly, hypoxia‐induced cell proliferation and PH in vitro and in vivo models are often used as models for PH pathogenesis.…”