Do the short die young? Evidence from a large sample of deceased Polish adults

Body height is associated with various socioeconomic and health-related outcomes. Despite numerous studies, the relationship between stature and longevity remains uncertain. This study explores the association between self-reported height and lifespan. Data from 848,860 adults who died between 2004 and 2008 in Poland were collected. After excluding a small proportion of records due to missing data or errors, we examined records for 848,387 individuals (483,281 men, age range: 20–110 years; 365,106 women, age range: 20–112 years). Height was expressed as standardized residual variance derived from linear regression in order to eliminate the variance of year of birth on height. After the elimination of the cohort effect, five height classes were designated using centiles: very short, short, medium, tall and very tall. The differences between sexes and among classes were evaluated with two-way ANOVA and post hoc Tukey’s test. The effect size was assessed using partial eta squared (η2). Pearson’s r coefficients of correlation were calculated. The effect of sex on lifespan was nearly 17 times stronger than the effect of height. No correlation between height and lifespan was found. In conclusion, these findings do not support the hypothesis that taller people have a longevity advantage. We offer tentative explanations for the obtained results.

From gerontology to geroscience: a synopsis on ageing

Biological ageing can be tentatively defined as an intrinsic and inevitable degradation of biological function that accumulates over time at every level of biological organisation from molecules to populations. Senescence is characterised by a progressive loss of physiological integrity, leading to impaired function and increased vulnerability to death. With advancing age, all components of the human body undergo these cumulative, universal, progressive, intrinsic and deleterious (CUPID) changes. Although ageing is not a disease per se, age is the main risk factor for the development of a panoply of age-related diseases. From a mechanistic perspective, a myriad of molecular processes and components of ageing can be studied. Some of them seem especially important and they are referred to as the hallmarks of ageing. There is compelling evidence that senescence has evolved as an emergent metaphenomenon that originates in the difficulty in maintaining homeodynamics in biological systems. From an evolutionary perspective, senescence is the inevitable outcome of an evolutionarily derived equilibrium between the amount of resources devoted to somatic maintenance and the amount of resources devoted to sexual reproduction. Single-target, single-molecule and disease-oriented approaches to ageing are severely limited because they neglect the dynamic, interactive and networking nature of life. These limitations notwithstanding, many authors promote single-target and disease-oriented approaches to senescence, e.g. repurposed drugs, claiming that these methods can enhance human health and longevity. Senescence is neither a disease nor a monolithic process. In this review, the limitations of these methods are discussed. The current state of biogerontology is also summarised.

Leukocyte count, systemic inflammation, and health status in older adults: a narrative review

Epidemiological and clinical studies suggest that elevated leukocyte count within the normal range can predict cardiovascular and total mortality in older adults. These findings are remarkable because this simple and common laboratory test is included in routine medical check-ups. It is well known that chronic systemic inflammation (inflammaging) is one of the hallmarks of aging and an important component of obesity-associated insulin resistance that can lead to type 2 diabetes and other health problems in both overweight individuals and elderly people. To understand the molecular mechanisms linking increased systemic inflammation with aging-associated diseases and elevated leukocyte counts in the elderly is to unravel the multiplicity of molecular factors and mechanisms involved in chronic low-grade systemic inflammation, the gradual accumulation of random molecular damage, age-related diseases, and the process of leukopoiesis. There are several possible mechanisms through which chronic low-grade systemic inflammation is associated with both higher leukocyte count and a greater risk of aging-associated conditions in older adults. For example, the IL-6 centric model predicts that this biomediator is involved in chronic systemic inflammation and leukopoiesis, thereby suggesting that elevated leukocyte count is a signal of poor health in older adults. Alternatively, an increase in neutrophil and monocyte counts can be a direct cause of cardiovascular events in the elderly. Interestingly, some authors assert that the predictive ability of elevated leukocyte counts with regard to cardiovascular and allcause mortality among older adults surpass the predictive value of total cholesterol. This review reports the recent findings on the links between elevated but normal leukocyte counts and the increased risks of all-cause, cardiovascular, and cancer mortality. The possible molecular mechanisms linking higher but normal leukocyte counts with increased risk of aging-associated diseases in the elderly are discussed here.

Association of serum bilirubin with longevity: Evidence from a retrospective longitudinal study and cross-sectional data

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.

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)

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.

Understanding the links between month of birth, body height, and longevity: why some studies reveal that shorter people live longer – further evidence of seasonal programming from the Polish population

There is a lack of agreement in the literature as to whether adult height depends on month of birth and whether height affects lifespan. Additionally, the relationship between stature and longevity involves conflicting findings and the results remain mixed due to several confounders, such as: year of birth, somatotype, relative body weight, genetic inheritance, diet, diseases, etc. Here, we hypothesize that the season of birth effect can also be involved in shaping the mysterious link between body height and longevity. To assess the links between month of birth, adult height, and longevity in the Polish population, data on 848,860 individuals, of whom 483,512 were men (57%) and 365,348 were women (43%), born in the years 1896-1988 and died in the years 2004-2008, were collected from the ‘PESEL’ database and signalments in the censuses obtained from identity card offices throughout Poland. ANOVA and the LSD test were performed. A significant relationship between month of birth and lifespan was found. Individuals born in autumn and winter months lived significantly longer than those who were born in the middle of the year (May). The amplitudes of lifespan were 16 months in men and 14 months in women. As expected, subjects of both sexes born in autumn and winter months were significantly shorter than their peers born around the middle of the year. In conclusion, the results of the study not only corroborate the theory of seasonal programming of longevity and support the idea that some undetermined factors from early stages of ontogeny and associated with season of birth have long-term effects on phenotype in later life in terms of adult height and longevity, but also bear out the hypothesis that month of birth can be another important confounding factor with respect to the relationship between adult height and longevity.

The relationship between adult stature and longevity: tall men are unlikely to outlive their short peers – evidence from a study of all adult deaths in Poland in the years 2004–2008

Early epidemiological studies demonstrated that short stature is associated with cardiovascular disease (CVD), diabetes, lower energy intake or food deprivation during growth, poor health, and increased all-cause mortality. Nevertheless, the links between adult height and longevity become tenuous if certain confounders (e.g. BMI, SES, educational attainment, etc.) are allowed for. Furthermore, numerous studies have found that like excess weight, tallness is costly in terms of longevity in late ontogeny, and shorter people tend to outlive their taller peers, especially if they are slim and maintain a healthy diet and lifestyle. Therefore, there is currently a lack of agreement in the literature as to whether and how body height and lifespan are linked. The objective of this study was to explore the relationship between adult stature and longevity on the basis of a large sample from a population-based cohort study. Data on declared height and exact dates of birth and death were available from 480,493 men and 364,666 women who died in the years 2004-2008 in Poland. To control for secular changes, the sample was divided into fifteen birth cohorts and each group was subsequently split into five height categories using pentiles, separately for both sexes. The analysis has revealed an inverse relationship between height and lifespan in men and women. However, after controlling for secular changes in height, the relationship turned out to be very weak and linear in men, and inverted U-shaped in women. In general, taller individuals had lower age at death compared to shorter ones, and this relationship was more pronounced and consistent in men. To sum up, these findings do not comport with the traditional belief that taller individuals live longer. The role of several possible biological mechanisms pertinent to enhanced longevity in smaller individuals was emphasized, and these biological factors were discussed.

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

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.

Contemporary views on human aging and longevity

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