OBJECTIVETo explore the level and effect factors of superoxide dismutase (SOD) and malondialchelyche (MDA) of the people aged 90 years old and above in longevity regions in China.

METHODSFrom Xiayi county (Henan province), Zhongxiang county (Hubei province), Mayang county (Hunan province), Foshan county Sanshui district (Guangdong province) and Yongfu county (Guangxi province), the people of hundred-year were selected and numbered. The old people aged 90 - 99 according to the age and sex were appointed by the centenarians' code and 496 people were selected in total. Questionnaire investigation was conducted on nationality, education, nutrition, smoking, alcohol drinking, tea drinking and physical activities.436 blood sampling (4 ml Per sampling) were conducted and the level of triglyceride (TG), SOD, MDA, Ca, Mg, and some microelements were determined. Non-conditional logistic regression analysis was conducted to explore the effect factors of SOD and MDA in plasma.

RESULTSAnalysis showed that the activity of plasma SOD was (31.19 +/- 5.51) U/ml, and the content of MDA was (4.68 +/- 1.98) micromol/L. The SOD level of minority people of 90 years old and over was (27.55 +/- 4.97) U/ml, lower than that of Han nationality ((31.73 +/- 5.39) U/ml; t = 5.85, P < 0.01); the MDA level of minority people of 90 years old and over was (5.58 +/- 1.95) micromol/L, higher than that of Han nationality ((4.54 +/- 1.95) micromol/L; t = -3.94, P < 0.01). logistic regression showed, comparing with the Han nationality, the minority had lower level of SOD (OR = 0.493), and higher level of MDA (OR = 5.412, P < 0.05). Beside nationality, the factors significantly affecting the activity of SOD included the intake frequency of meat, intake frequency of eggs and plasma concentration of Se (OR values were 0.388, 2.260 and 1.906, P < 0.05). The factors significantly affecting the level of MDA included the intake frequency of milk, physical activity and the level of TG (OR values were 0.435, 1.850 and 1.647, P < 0.05).

CONCLUSIONThe level of SOD of the oldest-old people aged 90 years old and over is relatively higher than the younger ones, and the level of MDA is relatively lower in longevity region, China. The effect factors of SOD are nationality, meat intake frequency, eggs intake frequency and the level of Se in plasma. The effect factors of MDA are nationality, milk intake frequency, physical activity and the level of TG in plasma.