title: Prevalence of hypertension at high altitude: cross-sectional survey in Ladakh, Northern India 2007-2011.
abstract: OBJECTIVE
  Prevalence of hypertension was examined in a widely dispersed (45 110 km(2)) 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.
  
  
  METHODS
  2800 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.
  
  
  RESULTS
  The 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.
  
  
  CONCLUSIONS
  Socioeconomic and cultural factors play a big role with the effect of high altitude itself on high prevalence of hypertension in highlanders in Ladakh.
authors.affiliation: Ladakh Institute of Prevention, Leh-Ladakh, India.
authors.forename: Tsering
authors.initials: T
authors.lastname: Norboo
authors.affiliation: University of California, San Diego, California, USA.
authors.forename: Tsering
authors.initials: T
authors.lastname: Stobdan
authors.affiliation: Ladakh Institute of Prevention, Leh-Ladakh, India.
authors.forename: Norboo
authors.initials: N
authors.lastname: Tsering
authors.affiliation: Sonam Norboo Memorial Hospital, Leh-Ladakh, India.
authors.forename: Norboo
authors.initials: N
authors.lastname: Angchuk
authors.affiliation: Sonam Norboo Memorial Hospital, Leh-Ladakh, India.
authors.forename: Phunsog
authors.initials: P
authors.lastname: Tsering
authors.affiliation: Sonam Norboo Memorial Hospital, Leh-Ladakh, India.
authors.forename: Iqbal
authors.initials: I
authors.lastname: Ahmed
authors.affiliation: Sonam Norboo Memorial Hospital, Leh-Ladakh, India.
authors.forename: Tsewang
authors.initials: T
authors.lastname: Chorol
authors.affiliation: Defence Institute of High Altitude Research, Defence Research & Development Organization, Leh-Ladakh, India.
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumar Sharma
authors.affiliation: Defence Institute of Physiology & Allied Sciences, Defence Research & Development Organization, Delhi, India.
authors.forename: Prasanna
authors.initials: P
authors.lastname: Reddy
authors.affiliation: Defence Institute of Physiology & Allied Sciences, Defence Research & Development Organization, Delhi, India.
authors.forename: Shashi Bala
authors.initials: SB
authors.lastname: Singh
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kimura
authors.affiliation: Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Sakamoto
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Fukutomi
authors.affiliation: Department of Medicine, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan.
authors.forename: Motonao
authors.initials: M
authors.lastname: Ishikawa
authors.affiliation: Department of Medicine, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Suwa
authors.affiliation: Graduate School of Asian and African Area Studies, Kyoto University, Kyoto, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kosaka
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Nose
authors.affiliation: National Institute for Agro-Environmental Sciences, Ibaragi, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Faculty of Education and Regional Studies, University of Fukui, Fukui, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Tsukihara
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Matsubayashi
authors.affiliation: Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Otsuka
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan Research Institute for Humanity and Nature, Kyoto, Japan.
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Okumiya
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000531:Altitude; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004641:Emigration and Immigration / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D000860:Hypoxia / Q000453:epidemiology*; D007194:India / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000453:epidemiology*; D016273:Occupational Exposure / Q000706:statistics & numerical data; D009790:Occupations; D050177:Overweight / Q000453:epidemiology; D010092:Oximetry; D015995:Prevalence; D012307:Risk Factors; D057185:Sedentary Behavior; D012922:Social Change; D014171:Transients and Migrants / Q000706:statistics & numerical data*; D014505:Urban Population; D014507:Urbanization; D055815:Young Adult
keywords: ALTITUDE MEDICINE; EPIDEMIOLOGY