title: Glucose intolerance associated with hypoxia in people living at high altitudes in the Tibetan highland.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  Cross-sectional epidemiological study on Tibetan highlanders.
  
  
  METHODS
  We enrolled 1258 participants aged 40-87 years. The rural population comprised farmers in Domkhar (altitude 2900-3800 m) and nomads in Haiyan (3000-3100 m), Ryuho (4400 m) and Changthang (4300-4800 m). Urban area participants were from Leh (3300 m) and Jiegu (3700 m).
  
  
  METHODS
  Participants were classified into six glucose tolerance-based groups: DM, intermediate hyperglycaemia (IHG), normoglycaemia (NG), fasting DM, fasting IHG and fasting NG. Prevalence of glucose intolerance was compared in farmers, nomads and urban dwellers. Effects of dwelling at high altitude or hypoxia on glucose intolerance were analysed with the confounding factors of age, sex, obesity, lipids, haemoglobin, hypertension and lifestyle, using multiple logistic regression.
  
  
  RESULTS
  The prevalence of DM (fasting DM)/IHG (fasting IHG) was 8.9% (6.5%)/25.1% (12.7%), respectively, in all participants. This prevalence was higher in urban dwellers (9.5% (7.1%)/28.5% (11.7%)) and in farmers (8.5% (6.1%)/28.5% (18.3%)) compared with nomads (8.2% (5.7%)/15.7% (9.7%)) (p=0.0140/0.0001). Dwelling at high altitude was significantly associated with fasting IHG+fasting DM/fasting DM (ORs for >4500 and 3500-4499 m were 3.59/4.36 and 2.07/1.76 vs <3500 m, respectively). After adjusting for lifestyle change, hypoxaemia and polycythaemia were closely associated with glucose intolerance.
  
  
  CONCLUSIONS
  Socioeconomic factors, hypoxaemia and the effects of altitudes >3500 m play a major role in the high prevalence of glucose intolerance in highlanders. Tibetan highlanders may be vulnerable to glucose intolerance, with polycythaemia as a sign of poor hypoxic adaptation, accelerated by lifestyle change and ageing.
authors.affiliation: Research Department, Research Institute for Humanity and Nature, Kyoto, Japan Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Okumiya
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Sakamoto
authors.affiliation: Faculty of Medicine, Public Health Nursing, School of Nursing, Mie University, Tsu, Mie, Japan.
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Ishimoto
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kimura
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: Health Promotion and Human Behavior, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Hissei
authors.initials: H
authors.lastname: Imai
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Wenling
authors.initials: W
authors.lastname: Chen
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Kato
authors.affiliation: Sakakibara Hakuho Hospital, Tsu, Mie, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakatsuka
authors.affiliation: College of Nursing, Kanto Gakuin University, Yokohama, Japan.
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Kasahara
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Michiko
authors.initials: M
authors.lastname: Fujisawa
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Taizo
authors.initials: T
authors.lastname: Wada
authors.affiliation: Affiliated Hospital of Qinghai University, Xining, Qinghai, China.
authors.forename: Hongxin
authors.initials: H
authors.lastname: Wang
authors.affiliation: Affiliated Hospital of Qinghai University, Xining, Qinghai, China.
authors.forename: Qingxiang
authors.initials: Q
authors.lastname: Dai
authors.affiliation: Affiliated Hospital of Qinghai University, Xining, Qinghai, China.
authors.forename: Huining
authors.initials: H
authors.lastname: Xu
authors.affiliation: Qinghai Academy of Animal and Veterinary Sciences, Xining, Qinghai, China.
authors.forename: Haisheng
authors.initials: H
authors.lastname: Qiao
authors.affiliation: Research Center for High Altitude Medicine, Qinghai University, Xining, Qinghai, China.
authors.forename: Ri-Li
authors.initials: RL
authors.lastname: Ge
authors.affiliation: Ladakh Institute of Prevention, Ladakh, India.
authors.forename: Tsering
authors.initials: T
authors.lastname: Norboo
authors.affiliation: Ladakh Institute of Prevention, Ladakh, India.
authors.forename: Norboo
authors.initials: N
authors.lastname: Tsering
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: Kazuo
authors.initials: K
authors.lastname: Ando
authors.affiliation: The Open University of Japan, Chiba, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Inamura
authors.affiliation: Graduate School of Asian and African Area Studies, Kyoto University, Kyoto, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Takeda
authors.affiliation: Yasugi Clinic, Shimane, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Ishine
authors.affiliation: Department of Medicine, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan Chronomics & Gerontology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Otsuka
authors.affiliation: Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Matsubayashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000531:Altitude; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000453:epidemiology*; D005260:Female; D018149:Glucose Intolerance / Q000453:epidemiology*; D006801:Humans; D000860:Hypoxia / Q000453:epidemiology*; D008019:Life Style; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012424:Rural Population / Q000706:statistics & numerical data; D012959:Socioeconomic Factors; D018609:Tibet / Q000453:epidemiology; D014171:Transients and Migrants / Q000706:statistics & numerical data; D014505:Urban Population / Q000706:statistics & numerical data
keywords: ALTITUDE MEDICINE; EPIDEMIOLOGY