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Recent studies have found mixed results regarding the association between leukocyte telomere length (LTL)--thought to be a marker of cellular aging--and all-cause mortality. Some studies have reported a significant inverse relationship, but others have not, perhaps in part owing to insufficient power. We examine the relationship using data from a nationally representative sample of older Taiwanese (54+ in 2000), which is larger (n = 942) than most previous studies, and which includes comprehensive information on potential confounders including white blood cell distribution and inflammatory markers. Results from a Cox hazards model demonstrate a small, but significant, association between LTL and mortality that is independent of age, sex, and lifestyle factors. White blood cell distribution, especially the proportion of neutrophils, is an important predictor of LTL; however, the association between LTL and mortality changes little controlling for white blood cell distribution. In contrast, the association between LTL and mortality weakens considerably (by 48%) after adjustment for inflammatory markers and homocysteine. Our results suggest that the relationship between short telomeres and mortality is tied to inflammation and homocysteine. Longitudinal studies are needed to explore bidirectional influences resulting from the fact that inflammation leads to shorter leukocyte telomeres, which in turn results in senescence, which exacerbates inflammation. [ABSTRACT FROM AUTHOR]

Background. Few studies focus on "preclinical" warning signs associated with mortality. In this article, we investigate associations between all-cause mortality and two clusters of biological risk factors: (i) standard clinical measures related to cardiovascular disease and metabolic function; and (ii) nonclinical measures pertaining to hypothalamic-pituitary-adrenal axis activity, sympathetic nervous system activity, and inflammatory response. Methods. Data come from the 2000 Social Environment and Biomarkers of Aging Stud,. a national sample of Taiwanese persons aged 54 years or older; 1497 persons were interviewed in their homes, and 1023 participated in a hospital examination. The analysis is based on 927 respondents with complete information. Logistic regression models describe the association between biomarkers and the 3-year probability of dying. Results. Although both groups of biomarkers are significantly associated with mortality, the model with neuroendocrine and immune biomarkers has better explanatory and discriminatory power than the one with clinical measures. The association between these nonclinical measures and mortality remains strong after adjustment for the clinical markers, suggesting that the physiological effects of the nonclinical biomarkers are broader than those captured by the cardiovascular and metabolic system measures included here. Conclusions. Nonclinical markers are likely to provide warning signs of deteriorating health and function beyond what can be learned from conventional markers. Our findings are consistent with those of recent studies that (i) demonstrate the importance of neuroendocrine and immune system markers for survival, and (ii) indicate that standard clinical variables are less predictive of mortality in older than in younger populations. [ABSTRACT FROM AUTHOR]

We investigate how biological markers of individual responses to stressful experiences are associated with profiles of physical and mental functioning in a national sample of middle-aged and elderly Taiwanese. Data come from a population-based sample of middle-aged and elderly Taiwanese in 2000. The data combine rich biological measures with self-reported information on physical and mental health. Grade of membership methods are used to summarize functional status, and multinomial logit models provide information on the association between biological measures and function. The analysis identifies significant associations between biomarkers of stressful experience and profiles of physical and mental functioning. The estimates reveal the potential importance for health of both low and high values of biological parameters. The findings point to directions for future research regarding development of aggregate measures of cumulative dysregulation across multiple physiological systems. [ABSTRACT FROM AUTHOR]

Quantification of biological aging is of interest in gerontology as a means to surveil aging rates in the population and to evaluate the effects of interventions to increase healthy life span. Analysis of proposed methods to quantify biological aging has focused on samples of midlife or mixed-age adults in the West. Research is needed to test whether quantifications of biological aging can differentiate aging rates among older adults and if quantifications of biological aging developed in Western samples can differentiate aging rates in non-Western populations. We conducted analysis of Klemera-Doubal method (KDM) Biological Age and homeostatic dysregulation measures of biological aging developed in the U.S. NHANES and tested in a sample of older Taiwanese adults in the Social Environment and Biomarkers of Aging Study. We conducted analysis of physical and cognitive function and mortality, comparing quantifications of biological aging to a biomarker index based on norms within our analysis sample and to participants' ratings of their own health. Results showed that quantifications of biological aging (a) predicted differences in physical and cognitive function and in mortality risk among Taiwanese older adults and (b) performed as well as a traditional biomarker index and participant self-rated health for prediction of these outcomes. [ABSTRACT FROM AUTHOR]