Frequency of Polycythemia and Other Abnormalities in a Tibetan Herdsmen Population Residing in the Kham Area of Sichuan Province, China.

INTRODUCTION: The Kham Tibetans are one of several Tibetan ethnic subgroups living in the Kham area of China. Because studies on the high-altitude adaptation of the Kham people are scant, the main aim of this study is to investigate whether the response to hypoxia, especially polycythemia status, in the Kham Tibetans is different from other Tibetan ethnic subgroups.

METHODS: The primary investigation was conducted on 346 native Kham Tibetan adults (268 men and 78 women) from 3 herdsmen villages located in Hongyuan County situated at an altitude of greater than 3600 m. The participants were aged 46.2±14.1 (21-82; mean±SD with range) years. Anthropometric measurements such as weight, height, waist circumference, body mass index, and blood pressure, as well as laboratory blood tests such as glycosylated hemoglobin, hemoglobin, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and uric acid were analyzed.

RESULTS: The concentrations of hemoglobin were 171.3±12.9 (66-229) mg·L-1 and 151.4±16.4 (86-190) mg·L-1 in men and women, respectively. The frequency of polycythemia was found to be 25.5 and 21.8% in men and women, respectively. Polycythemia was found to be significantly associated with glycosylated hemoglobin concentrations, hypertension, and hyperuricemia (P=0.002, 0.023, and 0.009, respectively).

CONCLUSIONS: There is a higher frequency of polycythemia in the Kham Tibetans when compared with reported studies from other Tibetan ethnic subgroups living on the Qinghai-Tibet plateau.