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  • Author: Krzysztof Strzelec x
  • Evolutionary Biology x
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Association of serum bilirubin with longevity: Evidence from a retrospective longitudinal study and cross-sectional data

Abstract

Bilirubin is a potent antioxidant and an important anti-inflammatory factor. Therefore, there has been an increasing focus on serum bilirubin as a negative risk factor of cardiovascular mortality in men and an indicator of improved survival in both sexes, but the direct mechanisms of these links and the causes of sex differences are not well understood. Moreover, the evidence from longitudinal studies on effects of bilirubin on longevity is limited. In this study, we retrospectively analyzed two groups of older adults to explore age-dependent changes in serum bilirubin levels and their associations with long-term survival in both sexes. Longitudinal data from 142 individuals (68 men and 74 women) aged 45 to 70 years were compared with cross-sectional data from 225 individuals (113 men and 112 women). The latter group was divided into four categories of survival, i.e. 53, 63, 68, and 76+ based on data on lifespan. ANOVA, t-test, and regression analysis were run. The analysis of the longitudinal data showed an increase in serum total bilirubin levels in men (0.3038e0.093x, R2 = 0.667) and women (0.1838e0.0187x, R2 = 0.950), while the analysis of cross-sectional data revealed a U-shaped pattern of age-related changes in men (0.001x2 - 0.1263x + 4.4524, R2 = 0.999) but an inverted U-shaped pattern in women (0.0006x2 + 0.072x - 1.6924, R2 = 0.195). On balance, these results suggest that elevated but normal bilirubin levels might confer a survival advantage in older men but not women. Alternatively, the positive relationship between serum total bilirubin and lifespan was not causal but coincidental. Further studies are needed to elucidate the direct mechanisms of the association between serum bilirubin levels and longevity in elderly people of both sexes.

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Association between body size and selected hematological parameters in men and women aged 45 and above from a hospitalized population of older adults: an insight from the Polish Longitudinal Study of Aging (1960–2000)

Abstract

In elderly people, anemia occurs with increasing frequency with each advancing decade and can be a harbinger of very serious health conditions, including gastrointestinal bleeding, gastric and duodenal ulcers, and cancer. Therefore, age-dependant changes in hematological parameters deserve special attention. Nonetheless, very few longitudinal studies of aging have focused on possible associations between basic anthropometric characteristics and hematological parameters in older people. Here, we present some evidence that body size can be associated with red blood cell count as well as some other selected hematological parameters in adults aged 45 to 70 years. Longitudinal data on anthropometric and hematological parameters have been obtained from physically healthy residents at the Regional Psychiatric Hospital for People with Mental Disorders in Cibórz, Lubuskie Province, Poland (142 individuals, including 68 men and 74 women). The residents who took psychoactive drugs were excluded from the study. To evaluate the studied relationships, three anthropometric traits were used and three dichotomous divisions of the study sample were made. The medians of body height, body weight, and body mass index at the age of 45 years were used to divide the sample into: shorter and taller, lighter and heavier, and slimmer and stouter individuals, respectively. Student’s t-test, Pearson’s correlation, and regression analysis were employed. The results of the present study suggest that the relationship between body size and red blood cell count is slightly more pronounced in men and its strength depends on age. However, the correlations between body size and red blood cell count proved to be weak in both sexes. With aging, the strength of the relation decreased gradually, which might have been caused by the aging-associated changes in the hematopoietic system, anemia, or was an artifact. Further studies are needed to elucidate the unclear association between body size and hematological parameters in older adults.

Open access
Contemporary views on human aging and longevity

Abstract

Aging is currently stimulating intense interest of both researchers and the general public. In developed countries, the average life expectancy has increased by roughly 30 years within the last century, and human senescence has been delayed by around a decade. Although aging is arguably the most familiar aspect of human biology, its proximate and ultimate causes have not been elucidated fully and understood yet. Nowadays there are two main approaches to the ultimate causes of aging. These are deterministic and stochastic models. The proximate theories constitute a distinct group of explanations. They focus on mechanistic causes of aging. In this view, there is no reason to believe that there is only one biological mechanism responsible for aging. The aging process is highly complex and results from an accumulation of random molecular damage. Currently, the disposable soma theory (DST), proposed by Thomas Kirkwood, is the most influential and coherent line of reasoning in biogerontology. This model does not postulate any particular mechanism underpinning somatic defense. Therefore, it is compatible with various models, including mechanistic and evolutionary explanations. Recently, however, an interesting theory of hyper-function of mTOR as a more direct cause of aging has been formulated by Mikhail Blagosklonny, offering an entirely different approach to numerous problems and paradoxes in current biogerontology. In this view, aging is quasi-programmed, which means that it is an aimless continuation of developmental growth. This mTOR-centric model allows the prediction of completely new relationships. The aim of this article is to present and compare the views of both parties in the dispute, based on the results of some recent experimental studies, and the contemporary knowledge of selected major aspects of human aging and longevity

Open access
Effects of aging on the function of the urinary system: longitudinal changes with age in selected urine parameters in a hospitalized population of older adults

Abstract

Although normal aging does not have a pernicious effect on the homeostasis of fluids, renal reserve in elderly people can be depleted. The purpose of the present study was to assess the relationship between longitudinal changes with age in basic urine parameters (specific gravity and pH) in older men and women, depending on their body height and relative body weight. Longitudinal data on these two quantitative traits of the urine were available for 142 physically healthy individuals, including 68 men and 74 women. All subjects were 45 years of age at the beginning and 70 at the end of the period under investigation. All measurements were taken in accordance with internationally accepted requirements. Specific gravity was assessed using a hydrometer, and pH was measured using a pH meter. ANOVA, t-test, and regression analysis were performed. No significant sex differences in specific gravity or urine pH were observed. In both sexes, urine specific gravity decreased with age according to exponential model of regression. In men, there was a gradual increase in the pH of the urine until age 65, and the best fitting regression model was polynomial. In women, on the other hand, there was an exiguous decrease in urine pH throughout the period under study, and the best fitting regression model proved to be exponential. As the process of renal aging commences relatively early in ontogeny and manifests itself in many structural and functional changes, urinalysis and other more sophisticated methods of diagnosis of renal diseases are essential for proper assessment of health status of adults and older individuals. The rate of age-related changes in the analyzed traits of the urine was commensurate in both sexes, thereby revealing no evidence of significant sex differences in terms of renal aging in the period between 45 and 70 years of age.

Open access