Symptomatic late-onset hypogonadism but normal total testosterone: the importance of testosterone annual decrease velocity

Understanding human aging and the fundamental cell signaling link in age-related diseases: the middle-aging hypovascularity hypoxia hypothesis

Aging-related hypoxia, oxidative stress, and inflammation pathophysiology are closely associated with human age-related carcinogenesis and chronic diseases. However, the connection between hypoxia and hormonal cell signaling pathways is unclear, but such human age-related comorbid diseases do coincide with the middle-aging period of declining sex hormonal signaling. This scoping review evaluates the relevant interdisciplinary evidence to assess the systems biology of function, regulation, and homeostasis in order to discern and decipher the etiology of the connection between hypoxia and hormonal signaling in human age-related comorbid diseases. The hypothesis charts the accumulating evidence to support the development of a hypoxic milieu and oxidative stress-inflammation pathophysiology in middle-aged individuals, as well as the induction of amyloidosis, autophagy, and epithelial-to-mesenchymal transition in aging-related degeneration. Taken together, this new approach and strategy can provide the clarity of concepts and patterns to determine the causes of declining vascularity hemodynamics (blood flow) and physiological oxygenation perfusion (oxygen bioavailability) in relation to oxygen homeostasis and vascularity that cause hypoxia (hypovascularity hypoxia). The middle-aging hypovascularity hypoxia hypothesis could provide the mechanistic interface connecting the endocrine, nitric oxide, and oxygen homeostasis signaling that is closely linked to the progressive conditions of degenerative hypertrophy, atrophy, fibrosis, and neoplasm. An in-depth understanding of these intrinsic biological processes of the developing middle-aged hypoxia could provide potential new strategies for time-dependent therapies in maintaining healthspan for healthy lifestyle aging, medical cost savings, and health system sustainability.

Associations between smoking, sex hormone levels and late-onset hypogonadism in men differ depending on age

Few studies have investigated whether associations between smoking, sex hormone levels, and symptoms of late-onset hypogonadism (LOH) in men are affected by age. This multi-center, cross-sectional study involving 6,296 men aged 40-79 years was conducted between June 1, 2013 and August 31, 2016 in 6 provinces of China. Total testosterone, free testosterone, and Aging Males’ Symptoms scale (AMS) scores were compared depending on smoking status and the number of cigarettes smoked. Total testosterone was higher in smokers than in non-smokers in all except the 70-79 year old subgroup. Free testosterone was higher in smokers than non-smokers for the 40-49 and 50-59 year old subgroups, but not the 60-69 and 70-79 year old subgroups. Total testosterone was positively associated with number of cigarettes consumed in smokers aged 40-49 and 50-59 years. Sexual and somatic AMS scores were higher in current and ex-smokers than in non-smokers in all age subgroups from 40 to 79 years and were negatively associated with cigarette consumption in smokers aged 40-49 years. These results indicate that, as men age, the positive association between smoking and testosterone weakens, while the positive association between smoking and LOH symptoms becomes stronger.