Judyta Nowak

Human body morphology, prevalence of nasopharyngeal potential bacterial pathogens, and immunocompetence handicap principal.

Body height, body mass index (BMI) and waist‐to‐hip ratio (WHR) are the main traits characterizing human body morphology. Studies show that these traits are related to attractiveness and, therefore, according to an evolutionary point of view, are supposed to be honest signals of biological quality. If the immunocompetence handicap principal (IHP) is true, people with more attractive values of these traits should be more immunologically competent. To test this, we analyzed whether nasal and throat colonization with potentially pathogenic bacteria is related to body height and BMI in both sexes and to WHR in females.

Leukocyte changes across menstruation, ovulation, and mid-luteal phase and association with sex hormone variation

Total leukocyte count (white blood cells—WBC) and the count of each subpopulation vary across the menstrual cycle, but results of studies examining the time and direction of these changes are inconsistent and methodologically flawed. Besides, no previous study focused on leukocyte count on the day of ovulation.

Individual differences in cortisol stress response predict increases in voice pitch during exam stress

Despite a long history of empirical research, the potential vocal markers of stress remain unclear. Previous studies examining speech under stress most consistently report an increase in voice pitch (the acoustic correlate of fundamental frequency, F0), however numerous studies have failed to replicate this finding. In the present study we tested the prediction that these inconsistencies are tied to variation in the severity of the stress response, wherein voice changes may be observed predominantly among individuals who show a cortisol stress response (i.e., an increase in free cortisol levels) above a critical threshold. Voice recordings and saliva samples were collected from university psychology students at baseline and again immediately prior to an oral examination. Voice recordings included both read and spontaneous speech, from which we measured mean, minimum, maximum, and the standard deviation in F0. We observed an increase in mean and minimum F0 under stress in both read and spontaneous speech, whereas maximum F0 and its standard deviation showed no systematic changes under stress. Our results confirmed that free cortisol levels increased by an average of 74% (ranging from 0 to 270%) under stress. Critically, increases in cortisol concentrations significantly predicted increases in mean F0 under stress for both speech types, but did not predict variation in F0 at baseline. On average, stress-induced increases in voice pitch occurred only when free cortisol levels more than doubled their baseline concentrations. Our results suggest that researchers examining speech under stress should control for individual differences in the magnitude of the stress response.

Woman's body symmetry and oxidative stress in the first trimester of pregnancy

High level of oxidative stress (OS) during the first weeks of pregnancy is related to many serious pregnancy complications. Previous studies showed that body fluctuating asymmetry (FA) is related to OS level in men, suggesting that FA is a marker of oxidative balance in an individual. The aim of this study was to analyze if body FA was related to the level of biomarkers of OS in the first trimester of pregnancy.

No evidence for the immunocompetence handicap hypothesis in male humans

The observations that testosterone might be immunosuppressive, form the basis for the immunocompetence handicap hypothesis (ICHH). According to ICHH only high-quality individuals can maintain high levels of testosterone and afford the physiological cost of hormone-derived immunosuppression. The animal and human studies that attempted to support the ICHH by precisely defined impairment of immunity associated with high testosterone levels are inconclusive. Furthermore, human studies have used only selected immune functions and varying testosterone fractions. This is the first study examining the relationship between multiple innate and adaptive immunity and serum levels of free testosterone, total testosterone, DHT and DHEA in ninety-seven healthy men. Free testosterone and marginally DHT levels were positively correlated with the strength of the influenza post-vaccination response. Total testosterone and DHEA showed no immunomodulatory properties. Our findings did not support ICHH assumptions about immunosuppressive function of androgens. In the affluent society studied here, men with higher levels of free testosterone could afford to invest more in adaptive immunity. Since the hormone-immune relationship is complex and may depend on multiple factors, including access to food resources, androgens should be treated as immunomodulators rather than implicit immunosuppressants.

Body symmetry and reproductive hormone levels in women

ABSTRACT Fluctuating asymmetry (FA), a morphological marker of developmental stability, may be related to an individual’s biological condition, e.g., health or fertility. The aim of this study was to test if the level of a woman’s FA was related to her fertility and reproductive potential as measured by reproductive hormone levels. Fifty-three healthy, non-pregnant, naturally cycling women (mean age = 23.42, SD = 1.85 years), participated in the study, conducted in Wrocław (Poland) in May 2015. Early-follicular phase serum levels of anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were measured. FA was calculated based on anthropometric measures of six bilateral body traits, and the composite FA index was used in statistical analyses. No relationship was observed between FA and the levels of FSH, LH, and AMH (p > .05), controlled for potential confounders. However, the level of E2 was positively correlated with FA (p < .05). Thus, in young women, FA was not related to hormones levels related to ovarian reserve, but more symmetrical women had lower E2 levels. As FA is an index of developmental stability, environmental, and genetic stress, the results of the study confirm previous research suggesting that developmental conditions may be related to women’s endogenous estrogen levels.

Multimodal stress detection: Testing for covariation in vocal, hormonal and physiological responses to Trier Social Stress Test

Abstract Examining the effects of acute stress across multiple modalities (behavioral, physiological, and endocrinological) can increase our understanding of the interplay among stress systems, and may improve the efficacy of stress detection. A multimodal approach also allows for verification of the biological stress response, which can vary between individuals due to myriad internal and external factors, thus allowing for reliable interpretation of behavioral markers of stress. Here, controlling for variables known to affect the magnitude of the stress response, we utilized the Trier Social Stress Test (TSST) to elicit an acute stress response in 80 healthy adult men and women. The TSST involves an interview‐style oral presentation and critical social evaluation, and is highly effective in inducing psychosocial stress. Participants completed the study in individual 2 h sessions, during which we collected voice, polygraph and salivary hormone measures in baseline, stress, and relaxation phases. Our results show sizeable systematic increases in voice pitch (mean, minimum and variation in fundamental frequency, F0), hormone levels (cortisol) and decreases in skin temperature and hand movement during psychosocial stress, with striking similarities between men and women. However, cortisol and skin temperature only weakly predicted changes in voice pitch during stress, in either women or men, respectively. Thus, while our results provide compelling evidence that psychosocial stress manifests itself behaviorally by increasing voice pitch and its variability alongside simultaneous activation of physiological and endocrinological stress systems, our results also highlight a relatively weak degree of intra‐individual ‘response coherence’ across these stress systems, with dissociations among different stress measures related most strongly to sex. HighlightsMultimodal measurement of acute stress may improve stress detection.Voice, hormone and polygraph measures were collected before, during, and after stress.Psychosocial stress affected voice pitch, cortisol, skin temp and hand movement.Cortisol and skin temp predicted changes in womens and mens voice pitch, respectively.Behavioral, physiological and endocrine measures showed weak ‘response coherence’.

Human body symmetry and immune efficacy in healthy adults: PAWLOWSKI et al.

OBJECTIVES More symmetric organisms are perceived as more attractive. Fluctuating asymmetry (FA) i.e. small, random deviations from perfect bilateral symmetry, is supposed to inform about developmental instability. According to the good genes hypothesis, a low level of FA is a putative cue to an organisms biological quality. An important aspect of this quality is the immune system functioning. The aim of this study was to evaluate the relationship between immune system functioning and body symmetry in healthy people. MATERIALS AND METHODS The composite body FA (cFA) was assessed on the basis of six bilateral traits (on hands and feet). The ISF was determined by many innate (total complement and lysozyme activity, neutrophils function) and adaptive immune parameters (T CD3 and B CD19 lymphocytes, total IgA and IgG and response to flu vaccine). A total of 98 men and 92 women were subjected to flu (among them 37 men and 30 women also to tetanus) vaccination. The blood samples were collected before and 4 weeks after the antigens exposure. Immunomodulatory factors: participants age, body fat, and free testosterone level, were controlled. RESULTS Apart from the weak positive association between CD3 or CD19 and cFA in men, we found no association between the level of body symmetry and the rest of the analyzed immune parameters for both sexes. DISCUSSION Our results are the opposite of the good genes hypothesis prediction and suggest that in western, healthy populations, human mate preferences for more symmetric bodies are not related to immune competence.

Body height and immune efficacy: testing body stature as a signal of biological quality

According to the good genes hypothesis and energy allocation theory, human adult body height may reflect biological quality. An important aspect of this quality is immune system functioning (ISF). The aim of this study was to evaluate the relationship between ISF and body height in healthy people. The ISF was determined by several important innate (total complement and lysozyme activity, neutrophil function) and adaptive immune parameters (lymphocytes, IgA and IgG, and response to the flu vaccine). Overall, 96 males and 97 females were subjected to flu vaccination, and of these, 35 males and 34 females were subjected to tetanus. Blood samples were collected before and four weeks after vaccination. Immunomodulatory factors, participants age, body fat, and free testosterone levels, were controlled. There was no association between body height and all analysed immune parameters for both sexes. That might suggest that in Western society, a womens preference for taller men is not related to ‘good genes for immune competence’. We propose the novel Immunity Priority Hypothesis that explains the lack of relationship between adult body stature and ISF. This hypothesis, however, does not contradict the signalling role of a mans body height as a morphological marker of biological quality.

Sex differences in the risk factors for Staphylococcus aureus throat carriage

HighlightsRisk factors for S. aureus throat carriage are sex‐specific.High body fat amount is a risk factor for S. aureus colonization in healthy men.High free testosterone level is a risk factor for colonization in healthy women. Background Male gender and adiposity are considered to be risk factors for Staphylococcus aureus carriage. We tested whether colonization is related to free testosterone (fT) level and adiposity, measured with body mass index (BMI) and body fat percentage (BFP), in healthy adults. Methods Blood sample and throat swabs were taken twice (at 4‐week intervals) from healthy men and women aged 18‐36 years. fT level, height, weight, and BFP were measured. Participants were classified as persistent carriers, intermittent carriers (excluded from the analyses), and noncarriers. The final sample was 152 participants: 85 men and 67 women. Results BFP, but not BMI, correlated positively with S aureus colonization (P = .02) in men. BMI became a significant predictor of carriage only when comparing groups within and above norms (P = .04). There was no relationship for BMI nor BFP in women. Higher fT level was related to persistent carriage (P = .02) in women, there was no relationship for fT level in men. Conclusion Risk factors for S aureus carriage are sex dependent. Within‐sex variation in colonization is related to fT level in women, whereas in men it is related to the amount of body fat.