Higher free testosterone level is associated with faster visual processing and more flanker interference in older men

Gender Differences in the Epidemiological Characteristics and Long-Term Trends of Injuries in Taiwan from 1998 to 2015: A Cross-Sectional Study

Objective: This study used a long-term trend analysis to investigate whether gender differences were related to the risk of injury and epidemiological characteristics in Taiwan from 1998 to 2015. Materials and methods: Data on 4,647,259 hospitalized patients that were injured from 1 January 1998, to 31 December 2015 were collected from the National Health Insurance Research Database (NHIRD). Among the injured patients, 2,721,612 males and 1,925,446 females were identified. Patients were age-, gender-, and index date-matched. Multiple logistic regression was used to analyze the risks of injury via gender differences. A p-value < 0.05 was considered significant. Results: The injury risk of the male patients was 1.4 times higher than that of female patients (AOR = 1.427, 95% CI = 1.40−1.44). The rising trend of male injured hospitalized patients was also greater than that of female injured hospitalized patients. Conclusion: Males were more at risk of injury than females. Gender differences were related to the increased risk of epidemiological characteristics of injury.

Lower Plasma Total Testosterone Levels Were Associated With Steeper Decline in Brain Glucose Metabolism in Non-demented Older Men

OBJECTIVE

There is growing evidence that testosterone may be implicated in the pathogenesis of Alzheimer's disease (AD). We aimed to examine the relationship between plasma total testosterone levels and change in brain glucose metabolism over time among non-demented older people.

METHODS

The association of plasma total testosterone levels with change in brain glucose metabolism among non-demented older people was investigated cross-sectionally and longitudinally. Given a significant difference in levels of plasma total testosterone between gender, we performed our analysis in a sex-stratified way. At baseline, 228 non-demented older people were included: 152 males and 76 females.

RESULTS

In the cross-sectional analysis, no significant relationship between plasma total testosterone levels and brain glucose metabolism was found in males or females. In the longitudinal analysis, we found a significant association of plasma total testosterone levels with change in brain glucose metabolism over time in males, but not in females. More specifically, in males, higher levels of total testosterone in plasma at baseline were associated with slower decline in brain glucose metabolism.

CONCLUSION

We found that higher levels of total testosterone in plasma at baseline were associated with slower decline in brain glucose metabolism in males without dementia, indicating that testosterone may have beneficial effects on brain function.

The Relationships Among Testosterone, Cortisol, and Cognitive Control of Emotion as Underlying Mechanisms of Emotional Intelligence of 10- to 11-Year-Old Children

Emotional intelligence is an important factor contributing to social adaptation. The current study investigated how salivary testosterone (T) and cortisol (C) levels, cognitive control of emotional conflict processing were associated with children's emotional intelligence (EI). Thirty-four 10- to 11-year-old children were enrolled and instructed to complete questionnaires on emotional intelligence as well as empirical tasks of emotional flanker and Stroop with event-related potential (ERP) recordings. Saliva collection took place on another day without ERP tasks. Results showed that lower T and C levels were associated with higher accuracy in emotional conflict tasks, as well as better emotional intelligence (managing self emotions). In the Stroop task, higher T/C ratios were associated with greater congruency effects of N2 latencies, and lower cortisol levels correlated with stronger slow potential activities (SP). For girls, the correlation between cortisol and emotional utilization was mediated by the SP amplitudes on fearful conflicts in the flanker task (95% CI: -8.64, -0.54, p < 0.050). In conclusion, the current study found the relationship between cortisol and an emotional intelligence ability, emotional utilization, might be mediated by brain activities during emotional conflict resolution processing (SP responses) in preadolescent girls. Future studies could further investigate testosterone-cortisol interaction and its relation with cognitive control of emotion as underlying mechanisms of emotional intelligence.

Debate position: cognition and mood are not improved in men administered exogenous testosterone therapy

PURPOSE OF REVIEW

The purpose of this article is to provide an overview of the increasing evidence suggesting that exogenous testosterone therapy is not associated with improvements in cognition or mood. This article is part of a series, in this issue, in which authors are assigned opinion pieces on controversial topics pertaining to testosterone replacement.

RECENT FINDINGS

Testosterone is increasingly being prescribed. Particularly in the setting of recent data suggestive of possible cardiovascular risk associated with its use; a clear understanding of the domains of health that improve with exogenous testosterone use is important. Data on endogenous and exogenous testosterone with cognition and mood are mixed, likely partly related to methodological differences of type of testosterone, patient population, and dosing.

SUMMARY

Overall, available data are not suggestive of a clear benefit of testosterone supplementation in multiple domains of cognition and in mood. Supraphysiologic testosterone has been associated with adverse psychological outcomes, albeit not uniformly in studies.

The Correlation among Neural Dynamic Processing of Conflict Control, Testosterone and Cortisol Levels in 10-Year-Old Children

Cognitive control is related to goal-directed self-regulation abilities, which is fundamental for human development. Conflict control includes the neural processes of conflict monitoring and conflict resolution. Testosterone and cortisol are essential hormones for the development of cognitive functions. However, there are no studies that have investigated the correlation of these two hormones with conflict control in preadolescents. In this study, we aimed to explore whether testosterone, cortisol, and testosterone/cortisol ratio worked differently for preadolescent's conflict control processes in varied conflict control tasks. Thirty-two 10-year-old children (16 boys and 16 girls) were enrolled. They were instructed to accomplish three conflict control tasks with different conflict dimensions, including the Flanker, Simon, and Stroop tasks, and electrophysiological signals were recorded. Salivary samples were collected from each child. The testosterone and cortisol levels were determined by enzyme-linked immunosorbent assay. The electrophysiological results showed that the incongruent trials induced greater N2/N450 and P3/SP responses than the congruent trials during neural processes of conflict monitoring and conflict resolution in the Flanker and Stroop tasks. The hormonal findings showed that (1) the testosterone/cortisol ratio was correlated with conflict control accuracy and conflict resolution in the Flanker task; (2) the testosterone level was associated with conflict control performance and neural processing of conflict resolution in the Stroop task; (3) the cortisol level was correlated with conflict control performance and neural processing of conflict monitoring in the Simon task. In conclusion, in 10-year-old children, the fewer processes a task needs, the more likely there is an association between the T/C ratios and the behavioral and brain response, and the dual-hormone effects on conflict resolution may be testosterone-driven in the Stroop and Flanker tasks.

Effects of Testosterone Therapy on Cognitive Function in Aging: A Systematic Review

Endogenous testosterone in the aging man has been scrutinized extensively in regard to its effects on performance in many cognitive domains, especially verbal fluency, visuospatial and visuoperceptual abilities, memory, and executive function. Studies of testosterone supplementation have sought to identify potential cognitive improvements in men with and without baseline cognitive impairment, and have had a wide range of results. The variability in outcomes is likely related, in part, to the lack of consensus on methods for testosterone measurement and supplementation and, in part, to the disparate measures of cognitive function used in randomized controlled studies. Despite the limitations imposed by such inconsistent methods, promising associations have been found between cognition and testosterone supplementation in both eugonadal men and men with low testosterone levels, with and without baseline cognitive dysfunction. This systematic review highlights the cognitive measures used in and the outcomes of existing studies of testosterone and cognition in aging men. The review suggests that larger studies and a more standardized approach to assessment will be needed before we can fully understand and realize sustained benefits from testosterone supplementation in the elderly male population, particularly given the substantial increase in testosterone supplementation in clinical practice.

Effects of gonadal hormones on cognitive behaviour in elderly men and women

Over the last four decades, animal and cell culture studies have shown that sex steroids can have protective effects on the ageing brain. Limited short-term positive effects (2-4 months) of oestrogen treatment were found in women without (as well as with) dementia. By contrast to these initial promising findings, several large treatment studies showed that longer-term oestrogen treatment, particularly when given in combination with progesterone, could exert negative effects on cognitive function in women aged over 65 years. Several observational studies of older women and men also suggest that longer exposure to higher endogenous oestrogen levels at an older age might confer risk for accelerated cognitive decline and dementia. However, health of participants may modify this association and, in women closer to the age at the onset of menopause, positive associations of oestrogens with cognition were also found. The 'healthy cell bias' theory suggests that oestrogens have protective effects in healthy neurones, although cells undergoing pathological change show acceleration in their demise when exposed to oestrogens. In older men, most studies reported higher bioavailable testosterone levels to be associated with better cognitive function. Other studies have reported optimal testosterone levels for better global cognitive function and a reduced risk of cognitive decline. Variation in health status over time and the use of (in)sensitive cognitive tests and hormone assays may explain why this was not always found. In older women, this association (of testosterone with cognition) is less clear. Small studies reported some benefits of testosterone treatment in combination with oestrogen on cognition, although these were of short duration. Several observational studies, on the other hand, found negative associations between high testosterone levels and worse cognitive function in older women. Age, health status, duration of treatment and sex may thus modify effects of longer-term elevated sex steroid levels on brain function.

The influence of steroid sex hormones on the cognitive and emotional processing of visual stimuli in humans

Steroid sex hormones are responsible for some of the differences between men and women. In this article, I review evidence that steroid sex hormones impact on visual processing. Given prominent sex-differences, I focus on three topics for sex hormone effects for which there is most research available: 1. Preference and mate choice, 2. Emotion and recognition, and 3. Cerebral/perceptual asymmetries and visual-spatial abilities. For each topic, researchers have examined sex hormones and visual processing using various methods. I review indirect evidence addressing variation according to: menstrual cycle phase, pregnancy, puberty, and menopause. I further address studies of variation in testosterone and a measure of prenatal testosterone, 2D:4D, on visual processing. The most conclusive evidence, however, comes from experiments. Studies in which hormones are administrated are discussed. Overall, many studies demonstrate that sex steroids are associated with visual processing. However, findings are sometimes inconsistent, differences in methodology make strong comparisons between studies difficult, and we generally know more about activational than organizational effects.

Endogenous Sex Hormones and Cognitive Function in Older Adults

Estrogen and testosterone may influence cognition in older adults, but the relationship between sex hormones and cognitive function is complex. The aim of this systematic review is to examine the role of sex hormones in cognitive function among older adults. A comprehensive, electronic review of literature was performed. Inclusion criteria were original quantitative research, written in English, used human subjects with a mean age of ≥60 years, and published from January 1997 through May 2012. Findings were mixed, although potential patterns were identified. Estradiol levels were potentially associated with benefits to episodic memory, semantic memory, verbal memory, and verbal learning in females only. The association between testosterone and cognitive function was mixed in both genders. Mixed findings may have been influenced by methodological differences and future studies should include research designs with ample rigor, sufficiently powered samples, consistent cognitive measurements, and clear descriptions of handling and storage of biological specimens.

A review on the relationship between testosterone and life-course persistent antisocial behavior

Life-course persistent antisocial behavior is 10 to 14 times more prevalent in males and it has been suggested that testosterone levels could account for this gender bias. Preliminary studies with measures of fetal testosterone find inconsistent associations with antisocial behavior, especially studies that use the 2D:4D ratio as a proxy for fetal testosterone. However, circulating testosterone consistently shows positive associations with antisocial behaviors throughout childhood, adolescence, and adulthood, particularly in males. It is suggested that high fetal/circulating testosterone interactively influence the maturation and functionality of mesolimbic dopaminergic circuitry, right orbitofrontal cortex, and cortico-subcortical connectivity, resulting in a strong reward motivation, low social sensitivity, and dampened regulation of strong motivational/emotional processes. The link between these testosterone induced endophenotypes and actual display of antisocial behavior is strongly modulated by different social (e.g., social rejection, low SES) and genetic (e.g., MAOA, 5HTT) risk factors that can disturb socio-, psycho-, and biological development and interact with testosterone in shaping behavior. When these additional risk factors are present, the testosterone induced endophenotypes may increase the risk for a chronic antisocial lifestyle. However, behavioral endophenotypes induced by testosterone can also predispose towards socially adaptive traits such as a strong achievement motivation, leadership, fair bargaining behaviors, and social assertiveness. These adaptive traits are more likely to emerge when the high testosterone individual has positive social experiences that promote prosocial behaviors such as strong and secure attachments with his caregivers, affiliation with prosocial peers, and sufficient socioeconomic resources. A theoretical model is presented, various hypotheses are examined, and future venues for research are discussed.

Age-related changes in matching novel objects across viewpoints

Object recognition is an important visual process. We are not only required to recognize objects across a variety of lighting conditions and variations in size, but also across changes in viewpoint. It has been shown that reaction times in object matching increase as a function of increasing angular disparity between two views of the same object, and it is thought that this is related to the time it takes to mentally rotate an object. Recent studies have shown that object rotations for familiar objects affect older subjects differently than younger subjects. To investigate the general normalization effects for recognizing objects across different viewpoints regardless of visual experience with an object, in the current study we used novel 3D stimuli. Older and younger subjects matched objects across a variety of viewpoints along both in-depth and picture-plane rotations. Response times (RTs) for in-depth rotations were generally slower than for picture plane rotations and older subjects, overall, responded slower than younger subjects. However, a male RT advantage was only found for objects that differed by large, in-depth rotations. Compared to younger subjects, older subjects were not only slower but also less accurate at matching objects across both rotation axes. The age effect was primarily due to older male subjects performing worse than younger male subjects, whereas there was no significant age difference for female subjects. In addition, older males performed even worse than older females, which argues against a general male advantage in mental rotations tasks.

Testosterone levels and cognition in elderly men: a review

Average testosterone levels and many cognitive functions show a decline with age. There is evidence to suggest that this association is not just age related. Results from cell culture and animal studies provide convincing evidence that testosterone could have protective effects on brain function. Alzheimer's disease (AD) is characterised by brain pathology affecting cognitive function and AD prevalence increases with age. Testosterone levels are lower in AD cases compared to controls, and some studies have suggested that low free testosterone (FT) may precede AD onset. Men with AD may show accelerated endocrinological ageing, characterised by an earlier lowering of thyroid stimulating hormone, an earlier increase in sex hormone binding globulin (SHBG), a subsequent earlier decrease in FT and an earlier increase in gonadotropin levels in response to this. Positive associations have been found between testosterone levels and global cognition, memory, executive functions and spatial performance in observational studies. However, non-significant associations were also reported. It may be that an optimal level of testosterone exists at which some cognitive functions are improved. This may be modified with an older age, with a shifting of the optimal testosterone curve to maintain cognition to the left and a lower optimal level thus needed to be beneficial for the brain. Genetic factors, such as APOE and CAG polymorphisms may further interact with testosterone levels in their effects on cognition. The roles of SHBG, gonadotropins, thyroid hormones and estrogens in maintaining cognitive function and preventing dementia in men are also not completely understood and should be investigated further. Hypogonadal men do not seem to benefit from testosterone supplementation but small scale, short term intervention studies in eugonadal men with and without cognitive impairments have shown promising results. Larger randomised, controlled trials are needed to further investigate testosterone treatment in protecting against cognitive decline and/or dementia.

Sex steroid hormones and cognitive functioning in healthy, older men

The precise impact of age-related changes in hormone levels on cognition in men is still unclear due to differing study designs and contradictory findings. This study was undertaken to examine the relationship between endogenous sex hormone levels and cognitive functioning in healthy older men using a comprehensive battery of neuropsychological tests and measurement of serum sex hormone levels. Verbal learning and memory, visual-motor processing, spatial abilities, working memory and attention, and levels of testosterone and estradiol were evaluated in 54 healthy older men. Regression analyses revealed significant curvilinear associations between working memory function and both free and bioavailable testosterone levels, suggesting that an optimal hormone level may exist for maximal performance on tasks of executive/frontal lobe functioning. However, no other relationships were evident between either estradiol or testosterone levels and any of the other cognitive functions evaluated. Hormone assays performed at the end of the study revealed that a considerable portion of the healthy elderly men in our sample met criteria for hypogonadism and suggests that their low hormone levels may have mitigated against discovering other significant hormone-cognition relationships.

Cognitive functionality of older men in St. Catherine, Jamaica

BACKGROUND

The scientific literature is replete with factors that influence the cognitive functionality of older men but no such study has been done in Jamaica.

AIMS

In this study we report our findings on the cognitive functionality of three cohorts of older men in a rural area. This is the first data published on the cognitive functionality of older men from Jamaica.

MATERIAL AND METHOD

The investigation was carried out with the administration of a 132-item questionnaire. The measure includes items on demographics, retirement and health status, the seeking and avoidance of medical care, health treatment, medication use, childhood illness, happiness and the mini-mental status examination. The measure was given to 2,000 men 55 years and older who were randomly selected from St. Catherine.

RESULTS

THE MULTIVARIATE ANALYSIS OF THE MODEL REVEALED THREE SIGNIFICANT DETERMINANTS OF COGNITIVE FUNCTIONALITY: Age (OR = 0.346, 95% CI = 0.206, 0.582), social support (OR = 0.683, 95% CI = 0.443, 1.053) and having children (OR = 2.42, 95% CI = 1.130, 5.183). There is a negative relationship between age and cognitive functionality and a positive relationship between having children and cognitive functionality.

CONCLUSIONS

Our main conclusions are that the two significant determinants of cognitive functionality of older men (age and having children) in Jamaica are unique given the many determinants of cognitive functioning cited in the scientific literature. The plethora of factors points to the need for further research to understand the range of factors that influence the cognitive functionality of older Jamaicans.