Comprehensive geriatric assessment of elderly highlanders in Qinghai, China, III: oxidative stress and aging in Tibetan and Han elderly highlanders.

BACKGROUND

Although there are several factors which may contribute to oxidative stress at high altitude, little is known about the association between oxidative stress and aging in the community-dwelling elderly in the Tibetan Plateau.

METHODS

Reactive oxygen species (ROS) and comprehensive geriatric functions were examined among 235 community-dwelling elderly subjects aged 60 years or more (146 Hans and 89 Tibetans). As a marker of ROS, the levels of reactive oxygen metabolites (ROM) were measured using the d-ROM test.

RESULTS

The rate of dependence of basic activities of daily living (basic ADL) among Tibetan elderly highlanders was significantly higher than that among Han elderly highlanders. The d-ROM level was higher among the Tibetan elderly than those among the Han elderly (Tibetan 465.6 +/- 97.9 Carr U, Han 415.3 +/- 72.0 Carr U, P = 0.003). The ROM level was higher among women than those among men. Stepwise multiple regression analysis showed that being Tibetan, female, and oxygen saturation were independent predictors of increasing d-ROM level (Tibetan beta, 0.241; female beta, 0.206; oxygen saturation beta, 0.218). The high levels of ROM (d-ROM >500 Carr U) were significantly associated with dependence of basic ADL after adjustment for age, sex and ethnicity (odds ratio = 2.51, P = 0.028).

CONCLUSION

The findings of this study imply the possibility that ROS is higher among Tibetan elderly highlanders than that of Han, which related to the geriatric items. Further studies are needed to show the impact of oxidative stress on the aging of highlanders.