[Estimation of individual biological aging and individualized evaluation of biomarkers of aging in healthy people].

OBJECTIVE:To estimate the degree of biological aging for healthy people by the biological age score equation and observe the differences of various aging biomarkers so as to provide targets for clinical anti-aging intervention. METHODS:A total of 2876 subjects aged 30 - 98 years old were recruited from 3 Chinese cities in 2003. After screening, 852 healthy subjects were finally selected and assigned into 4 groups according to ages: young group (< 45 yr), middle-aged group (45 - 59 yr), young-elder group (60 - 74 yr) and elder group (≥ 75 yr). They received a total of 108 physical, morphological, physiologic and biochemical examinations. The biological age score equation was employed to compute the individual biological age scores for all subjects. Then the biological age score was taken as a dependent variable and the chronological age as an independent variable for linear regression. Based on the confidence interval with ± 1 standard deviation of regression line, they were divided into 3 groups (delayed aging, normal aging and early aging). According to the chronological ages and degrees of aging, two-way analysis of variance was conducted for the following 7 biomarkers: end diastolic velocity (EDV), intima-media thickness (IMT), ratio of peak velocity of early filling to atrial filling (E/A), mitral valve annulus lateral wall of peak velocity of early filling (MVEL), arterial pulse pressure (PP), fibrinogen (FIB) and cystatin C (CYSC). At the same time, the differences of 7 biomarkers were observed in different aging groups in 4 age groups. RESULTS:(1) A comparison of biological age score: there were no significant differences in chronological age among 3 biological aging groups in same chronological age groups. However, there were some significant differences in biological age score (young group: F = 91.8, P < 0.01; middle-aged group: F = 134.5, P < 0.01; young-elder group: F = 199.5, P < 0.01; elder group: F = 82.1, P < 0.01). (2) Two-way analysis of variance (aging groups and chronological age groups for biomarkers): there were significant differences of 7 biomarkers in different chronological age groups and different aging groups. (3) A comparison of biomarkers among aging groups: there were significant differences in PP among 3 aging groups in 4 age groups. PP increased significantly in early aging group to normal aging group and delayed aging group (young group: 49.0 ± 6.9, 37.6 ± 6.4, 30.8 ± 7.6 mm Hg, F = 93.2, P < 0.01; middle-aged group: 52.9 ± 7.3, 44.3 ± 5.9, 32.7 ± 8.4 mm Hg, F = 125.7, P < 0.01; young-elder group: 61.9 ± 7.6, 51.6 ± 6.6, 37.1 ± 8.7 mm Hg, F = 196.5, P < 0.01; elder group: 72.2 ± 13.7, 61.1 ± 6.8, 43.8 ± 10.8 mm Hg, F = 60.2, P < 0.01). There were significant differences in EDV among 3 aging groups in 4 age groups. EDV increased significantly in early aging group to normal aging group and delayed aging group. There were significant changes in IMT, MVEL, E/A, CYSC and FIB among aging groups in different age groups. CONCLUSION:(1) Biological age score plays an essential role in the evaluation of aging. Based on individual evaluation of biological age score, the degrees of aging can be categorized by grouping so that a clinician may provide clinical anti-aging interventions within the target groups. (2) The above 7 biomarkers are competent for the evaluation of aging. They can not only be used to construct biological age score equation, but also provide clinical targeted interventions for aging.