Predicting Alzheimer's disease in the Baltimore longitudinal study of aging

Association between testosterone and cognitive performance in postmenopausal women: a systematic review of observational studies

This review was conducted to explore the association between endogenous testosterone blood concentrations and cognitive performance among community dwelling postmenopausal women. We searched Ovid MEDLINE, EMBASE, PsycINFO and Web of Science databases for observational studies with at least 100 postmenopausal participants. The results were categorized by study design, reporting of total or free testosterone and risk of bias assessments, narratively. Ten of the 26 articles retrieved for full-text review met the inclusion criteria, six provided cross-sectional data, seven provided longitudinal data and one provided case-control data. Cognitive performance tests differed between studies. Eight studies measured testosterone by immunoassay, one by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and one did not specify their methodology. Eleven different cognitive domains were tested by 37 different instruments. Irrespective of the study design, the findings were inconsistent and inconclusive. Both positive and inverse associations were reported for each of global cognition and immediate and delayed verbal recall. The majority of studies reported no association between total or free testosterone and cognitive performance. Although this review did not demonstrate an association between testosterone and cognitive performance in postmenopausal women, the findings should be considered inconclusive due to the imprecision of testosterone measurement and the methodological heterogeneity of the included studies.

Therapeutics of Alzheimer's Disease: Recent Developments

With increasing aging, dementia is a growing public health concern globally. Patients with dementia have multiple psychological and behavioral changes, including depression, anxiety, inappropriate behavior, paranoia, agitation, and hallucinations. The major types of dementia are Alzheimer's disease (AD), vascular dementia (VCID), Lewy body dementia (LBD), frontotemporal dementia (FTD), and mixed dementia (MiAD). Among these, AD is the most common form of dementia in the elderly population. In the last three decades, tremendous progress has been made in understanding AD's biology and disease progression, particularly its molecular basis, biomarker development, and drug discovery. Multiple cellular changes have been implicated in the progression of AD, including amyloid beta, phosphorylated tau, synaptic damage, mitochondrial dysfunction, deregulated microRNAs, inflammatory changes, hormonal deregulation, and others; based on these changes, therapeutic strategies have been developed, which are currently being tested in animal models and human clinical trials. The purpose of our article is to highlight recent therapeutic strategies' developments, critically discuss current strategies' failures, and propose new strategies to combat this devasting mental illness.

Hormone therapy and the decreased risk of dementia in women with depression: a population-based cohort study

Background

The literature has shown depression to be associated with an increased risk of dementia. In addition, hormone therapy can be a responsive treatment option for a certain type of depression. In this study, we examined the association between hormone therapy, including lifetime oral contraceptive (OC) use, and hormone replacement therapy (HRT) after menopause with the occurrence of dementia among female patients with depression.

Methods

The South Korean national claims data from January 1, 2005, to December 31, 2018, was used. Female subjects aged 40 years or older with depression were included in the analyses. Information on hormone therapy was identified from health examination data and followed up for the occurrence of dementia during the average follow-up period of 7.72 years.

Results

Among 209,588 subjects, 23,555 were diagnosed with Alzheimer’s disease (AD) and 3023 with vascular dementia (VD). Lifetime OC usage was associated with a decreased risk of AD (OC use for < 1 year: HR, 0.92 [95% CI, 0.88–0.97]; OC use for ≥ 1 year: HR, 0.89 [95% CI, 0.84–0.94]), and HRT after menopause was associated with a decreased risk of AD (HRT for < 2 years: HR, 0.84 [95% CI, 0.79–0.89]; HRT for 2–5 years: HR, 0.80 [95% CI, 0.74–0.88]; and HRT for ≥ 5 years : HR, 0.78 [95% CI, 0.71–0.85]) and VD (HRT < 2 years: HR, 0.82 [95% CI, 0.71–0.96]; HRT for 2–5 years: HR, 0.81 [95% CI, 0.64–1.02]; and HRT for ≥ 5 years: HR, 0.61 [95% CI, 0.47–0.79]).

Conclusions

In this nationwide cohort study, lifetime OC use was associated with a decreased risk of AD, and HRT after menopause was associated with a decreased risk of AD and VD among female patients with depression. However, further studies are needed to establish causality.

Thyroid hormone: sex-dependent role in nervous system regulation and disease

Thyroid hormone (TH) regulates many functions including metabolism, cell differentiation, and nervous system development. Alteration of thyroid hormone level in the body can lead to nervous system-related problems linked to cognition, visual attention, visual processing, motor skills, language, and memory skills. TH has also been associated with neuropsychiatric disorders including schizophrenia, bipolar disorder, anxiety, and depression. Males and females display sex-specific differences in neuronal signaling. Steroid hormones including testosterone and estrogen are considered to be the prime regulators for programing the neuronal signaling in a male- and female-specific manner. However, other than steroid hormones, TH could also be one of the key signaling molecules to regulate different brain signaling in a male- and female-specific manner. Thyroid-related diseases and neurological diseases show sex-specific incidence; however, the molecular mechanisms behind this are not clear. Hence, it will be very beneficial to understand how TH acts in male and female brains and what are the critical genes and signaling networks. In this review, we have highlighted the role of TH in nervous system regulation and disease outcome and given special emphasis on its sex-specific role in male and female brains. A network model is also presented that provides critical information on TH-regulated genes, signaling, and disease.

Androgen-deprivation therapy, dementia, and cognitive dysfunction in men with prostate cancer: How much smoke and how much fire?

Androgen-deprivation therapy (ADT) remains the cornerstone of management for patients with metastatic prostate cancer. Although the toxicities of ADT are well established, there is increasing controversy surrounding the association between cognitive dysfunction and the receipt of ADT, with some evidence suggesting an increased risk of dementia. The authors conducted a literature search to identify pertinent clinical studies in this field. This general review outlines the key findings and discusses the relative strengths and weaknesses when drawing conclusions about the risk of cognitive dysfunction or dementia with ADT use. Cancer 2018;124:1326-34. © 2018 American Cancer Society.

Aging and sex hormones in males

Several large cohort studies have disclosed the trajectories of sex steroids changes overtime in men and their clinical significance. In men the slow, physiological decline of serum testosterone (T) with advancing age overlaps with the clinical condition of overt, pathological hypogonadism. In addition, the increasing number of comorbidities, together with the high prevalence of chronic diseases, all further contribute to the decrease of serum T concentrations in the aging male. For all these reasons both the diagnosis of late-onset hypogonadism (LOH) in men and the decision about starting or not T replacement treatment remain challenging. At present, the biochemical finding of T deficiency alone is not sufficient for diagnosing hypogonadism in older men. Coupling hypogonadal symptoms with documented low serum T represents the best strategy to refine the diagnosis of hypogonadism in older men and to avoid unnecessary treatments.

Metabolic dysfunction in Alzheimer's disease and related neurodegenerative disorders

Alzheimer's disease and other related neurodegenerative diseases are highly debilitating disorders that affect millions of people worldwide. Efforts towards developing effective treatments for these disorders have shown limited efficacy at best, with no true cure to this day being present. Recent work, both clinical and experimental, indicates that many neurodegenerative disorders often display a coexisting metabolic dysfunction which may exacerbate neurological symptoms. It stands to reason therefore that metabolic pathways may themselves contain promising therapeutic targets for major neurodegenerative diseases. In this review, we provide an overview of some of the most recent evidence for metabolic dysregulation in Alzheimer's disease, Huntington's disease, and Parkinson's disease, and discuss several potential mechanisms that may underlie the potential relationships between metabolic dysfunction and etiology of nervous system degeneration. We also highlight some prominent signaling pathways involved in the link between peripheral metabolism and the central nervous system that are potential targets for future therapies, and we will review some of the clinical progress in this field. It is likely that in the near future, therapeutics with combinatorial neuroprotective and 'eumetabolic' activities may possess superior efficacies compared to less pluripotent remedies.

Assessing statistical applications in publications on Alzheimer's disease

BACKGROUND/AIMS

To evaluate statistical applications in publications on Alzheimer's disease (AD).

METHODS

Three instruments/checklists were developed: Assessment of Statistical Reporting (ASR; 44 items), Survey of Statistical Designs (SSD; 10 items), and Survey of Statistical Methods (SSM; 7 items). After a pilot testing on 5 AD publications, the instruments/checklists were revised and tested for reliability with a sample of 30 AD articles and for validity with another sample of 10 AD articles from MEDLINE.

RESULTS

Item-specific test-retest and interrater reliability for ASR ranged from 0.29 to 1.0 with the associated standard errors (SEs) ranging from 0.01 to 0.31. The test-retest reliability (intraclass correlation coefficient = 0.94, 95% CI: 0.88-0.97) and the interrater reliability (intraclass correlation coefficient = 0.84, 95% CI: 0.69-0.92) for the overall score of ASR were high. The correlational validity of the ASR with a published checklist was also high (r = 0.74, SE = 0.24). The item-specific test-retest reliability in SSD and SSM ranged from 0.58 to 1.00 with the associated SEs ranging from 0.01 to 0.32. The item-specific interrater reliability in SSD and SSM ranged from 0.17 to 1.00 with the associated SEs ranging from 0.01 to 0.22.

CONCLUSIONS

This study suggested that it was feasible to assess statistical applications in AD publications.