Residents who lost land and houses due to disasterous heavy rainfall-related events on July 13, 2004 and the Chuetsu Earthquake on October 23, 2004 were moved to emergency temporary housing. The change in life style due to living under such conditions is assumed to increase oxidative stress level. In this study, we investigated the oxidative stress level in elderly residents of emergency temporary housing, and analyzed its association with lifestyle and body composition following these disasters.

A noninvasive oxidative stress marker, urinary 8-hydroxydeoxyguanosine ( 8-OHdG ), and body composition were measured in 73 elderly residents of emergency temporary housing.

In the elderly female residents, the urinary 8-OHdG level tended to decrease with time after the disasters. 8-OHdG levels were slightly higher in females than males and significantly higher among those who exercised regularly compared to those who did not, particularly in females. A weak correlation was noted between the urinary 8-OHdG level and muscle ratio in females.

The in vivo oxidative stress level in our study cohort of elderly residents of emergency temporary housing changed following the change in life style, but remained within the normal range. The increase in oxidative stress levels of elderly females was related to menopause. A decrease in estrogen levels due to menopause inhibits its antioxidant effects, which increases 8-OHdG levels. Although it is difficult to determine, a decrease in daily stressors over time following the disaster could be a cause of the decrease in oxidative stress levels. We suggest that the close evaluation of the stress level of disaster victims is desirable, in combination with evidence of antioxidative substances and the psychosocial influence of suffering as a consequence of the disaster.