Birth size and the serum level of biological age markers in men.

Previous studies showed that intrauterine growth restrictions, resulting in smaller body size at birth, are associated with altered development and the risk of age-related diseases in adult life. Thus, prenatal development may predict aging trajectories in humans. The study aimed to verify if body size at birth is related to biological age in adult men. The study sample consisted of 159 healthy, non-smoking men with a mean age of 35.24 (SD 3.44) years. Birth weight and length were taken from medical records. The ponderal index at birth was calculated. Biological age was evaluated based on serum levels of s-Klotho, hsCRP, DHEA/S, and oxidative stress markers. Pregnancy age at birth, lifestyle, weight, cortisol, and testosterone levels were controlled. The results showed no relationship between birth size and s-Klotho, DHEA/S level, inflammation, or oxidative stress. Also, men born as small-for-gestational-age (N = 49) and men born as appropriate-for-gestational-age (N = 110) did not differ in terms of biological age markers levels. The results were similar when controlled for pregnancy week at birth, chronological age, BMI, testosterone, or cortisol level. The results suggest that there is no relationship between intrauterine growth and biomarkers of aging in men aged 30-45 years from the affluent population.

Effects of Dominance and Sprint Interval Exercise on Testosterone and Cortisol Levels in Strength-, Endurance-, and Non-Training Men.

The aim of the study was to investigate the response of testosterone and cortisol to sprint interval exercises (SIEs) and to determine the role of dominance. The experiment was conducted in a group of 96 men, divided into endurance-training, strength-training, and non-training groups. Participants performed SIEs consisting of 5 × 10-s all-out bouts with a 50-s active recovery. Using the passive drool method, testosterone and cortisol concentrations were measured in saliva samples at rest at 10 min pre and 12 min post exercise. Participants' heart rate (HR) was measured during the whole exercise. Dominance was assessed by the participants before the study; the rating of perceived exertion (RPE) was measured immediately after each bout. The study showed that those who trained in endurance and strength sports had significantly lower mean HRs after five acute 10-s interval bouts than those in the non-training group (p = 0.006 and p = 0.041, respectively). Dominance has an inverse relation to changes in HR; however, it has no relation to hormone response. No significant differences were observed in testosterone and cortisol changes in the endurance-training, strength-training, and non-training groups after SIE (p > 0.05), which may indicate that the exercise volume was too low.

Perceived facial age and biochemical indicators of glycemia in adult men and women.

Glycemia is linked with one of the key mechanisms underlying the aging process and inter-individual differences in biological age. Previous research showed that glucose level is linked with perceived age in elder individuals. This study aimed to verify if glycemia is related to perceived facial age in healthy adult individuals as interventions in younger and healthy cohorts are crucial for preventing the onset of age-related diseases. The study sample consisted of 116 healthy men of mean age 35.53 ± 3.54 years (29.95-44.29) and 163 healthy women of mean age 28.38 ± 2.40 (24.25-34.17) years. Glycemia was evaluated by fasting glucose, insulin, HOMA-IR, and glycated hemoglobin level. BMI, facial sexual dimorphism, estradiol, testosterone, and hsCRP levels were controlled. Perceived age was evaluated based on standardized facial photos in an online survey. Additionally perceived facial aging was calculated as a difference between perceived age and chronological age. No relationship between the levels of biochemical indicators of glycemia and perceived facial age or aging was found both in men and women, also when controlled for possible confounders. This study shows that perceived facial age in adult individuals is rather linked with body adiposity of sexual dimorphism but not with glycemic markers.

S-Klotho level and physiological markers of cardiometabolic risk in healthy adult men.

S-Klotho is perceived as a biomarker of healthy aging that has been shown to be inversely associated with cardiometabolic risk in elderly individuals. The aim of this study was to test if s-Klotho level is associated with cardiometabolic risk markers in younger healthy men in order to verify the possible role of s-Klotho level as an early marker of cardiometabolic risk. A cross-sectional study was conducted among 186 healthy men (Mage=35.33, SDage=3.47) from a Western urban population. Serum basal levels of s-Klotho, lipid profile, homocysteine, glycemia markers, C-reactive protein, liver transaminases and creatinine were evaluated. Also, blood pressure was measured and cardiometabolic risk score and homeostatic model assessment for insulin resistance (HOMA-IR) were calculated. Testosterone and cortisol levels, self-reported psychological stress, physical activity, smoking in the past, alcohol use and body adiposity were controlled for. We found no relationship between levels of s-Klotho and physiological markers of cardiometabolic risk in the studied population. The results were similar when controlled for adiposity, testosterone level, physical activity, alcohol use and smoking in the past. We suggest that s-Klotho level is not an early marker of cardiometabolic risk in younger middle-aged healthy men.

No evidence for association between human body odor quality and immune system functioning.

Previous studies have shown that women perceive male faces with a more reactive immune system as more attractive, but whether body odor might likewise provide cues to immune function has not been investigated yet. These two studies tested a possible relationship between body odor quality and immunoreactivity (Study 1) and immune system function (Study 2). In Study 1, we collected body odor samples from 21 men just before and two weeks after vaccination against hepatitis A/B and meningococcus. We determined the levels of specific antibodies (selected as markers of immune system's reactivity), testosterone, and cortisol. Subsequently, 88 female raters assessed the odor samples for their attractiveness, intensity, and healthiness. In Study 2, we collected body odor and blood samples from 35 men and women. We assessed key parameters of their innate and adaptive immunity, such as complement activity or total lymphocyte T and B counts and asked 95 raters to assess the odor samples for their attractiveness, intensity, and healthiness. In Study 1, we found no significant association between antibody levels induced by vaccination and perceived body odor attractiveness, intensity, and healthiness. We also found no significant relationship between antibody levels and steroid hormones (testosterone and cortisol). In Study 2, we likewise found no association between basal key parameters (innate and adaptive) of the immune system and body odor quality. Our results indicate that body odor may not serve as a cue to the reactivity of the immune system.

Predicted reproductive longevity and women's facial attractiveness.

Physical attractiveness has been shown to reflect women's current fecundity level, allowing a man to choose a potentially more fertile partner in mate choice context. However, women vary not only in terms of fecundity level at reproductive age but also in reproductive longevity, both influencing a couple's long-term reproductive success. Thus, men should choose their potential partner not only based on cues of current fecundity but also on cues of reproductive longevity, and both may be reflected in women's appearance. In this study, we investigated if a woman's facial attractiveness at reproductive age reflects anti-Müllerian hormone (AMH) level, a hormone predictor of age at menopause, similarly as it reflects current fecundity level, estimated with estradiol level (E2). Face photographs of 183 healthy women (Mage = 28.49, SDage = 2.38), recruited between 2nd - 4th day of the menstrual cycle, were assessed by men in terms of attractiveness. Women's health status was evaluated based on C-reactive protein level and biochemical blood test. Serum AMH and E2 were measured. The results showed that facial attractiveness was negatively correlated with AMH level, a hormone indicator of expected age at menopause, and positively with E2, indicator of current fecundity level, also when controlled for potential covariates (testosterone, BMI, age). This might result from biological trade-off between high fecundity and the length of reproductive lifespan in women and greater adaptive importance of high fecundity at reproductive age compared to the length of reproductive lifespan.

Masculinity and immune system efficacy in men.

Masculinity-related morphological traits are supposed to be honest indicators of a man's biological quality. While some studies showed that sexually dimorphic traits are related to various aspects of biological condition such as general health, immunity or fertility, still little is known about the relationship between masculine traits and the effectiveness of innate and adaptive immunity in humans. The aim of this study was to see if masculine traits, which are dependent on androgen levels in foetal and pubertal stages of development, are related to the immune quality in healthy men. The immune quality was evaluated for 91 healthy men aged 19-36 years. Immunity measurements included innate and adaptive parameters. General health status, age, testosterone level, BMI, physical activity, and smoking were controlled. The shoulder-to-hip ratio (SHR), 2D:4D digit ratio and hand-grip strength (HGS) were used as markers of masculinization. The regressions showed that when controlling for confounds, masculinity-related traits were in general not related to innate and adaptive immunity. Only a weak association was observed for right 2D:4D ratio and T-lymphocyte counts (but it becomes non-significant after adjustment for multiple comparisons). Our results do not support the premise that masculinity is a cue for immunological quality in men. However, the positive association between right 2D:4D and T lymphocytes might suggest that further studies are needed to verify if androgen stimulation in prenatal development might be related to immunity in adulthood.

Pharyngeal Detection of Staphylococcus aureus as a Possible Factor Related to Disgust Sensitivity in Humans.

Disgust triggers behavioral avoidance of pathogen-carrying and fitness-reducing agents. However, because of the cost involved, disgust sensitivity should be flexible, varying as a function of an individual's immunity. Asymptomatic colonization with Staphylococcus aureus often results from weakened immunity and is a potential source of subsequent infections. In this study, we tested if pharyngeal colonization with S. aureus, evaluated based on a single swab collection, is related to an individual's disgust sensitivity, measured with the Three Domain Disgust Scale. Levels of immunomodulating hormones (cortisol and testosterone), general health, and body adiposity were controlled. Women (N = 95), compared to men (N = 137), displayed higher sexual disgust sensitivity, but the difference between individuals with S. aureus and without S. aureus was significant only in men, providing support for prophylactic hypothesis, explaining inter-individual differences in disgust sensitivity. Men (but not women) burdened with asymptomatic S. aureus presence in pharynx exhibit higher pathogen disgust (p = 0.04) compared to individuals in which S. aureus was not detected. The positive relationship between the presence of the pathogen and sexual disgust was close to the statistical significance level (p = 0.06), and S. aureus colonization was not related with moral disgust domain.