The association of time of day and serum testosterone concentration in a large screening population

@article{Crawford2007TheAO,
  title={The association of time of day and serum testosterone concentration in a large screening population},
  author={E. David Crawford and Al Baha Barqawi and Colin I. O’Donnell and Abraham Morgentaler},
  journal={BJU International},
  year={2007},
  volume={100}
}
Authors from the USA reviewed semen samples for their National Prostate Cancer Awareness screening programme. They evaluated semen testosterone levels at various times during the day, depending on when the person attended for screening. In this study, they found that testosterone levels in older men remain stable throughout the morning and early afternoon, and declined only moderately after that. Further case control studies have been suggested to confirm this finding. 
Seasonal fluctuations in testosterone-estrogen ratio in men from the Southwest United States.
Although controversial, seasonal variations in testosterone have been observed in several populations of men throughout the world. This finding might have an impact on screening and treatment ofExpand
Recommendations on the diagnosis, treatment and monitoring of testosterone deficiency in men.
The relative proportional increase of the elderly population within many countries will become one of the most significant social transformations of the twenty-first century and, for the first timeExpand
The evidence for seasonal variations of testosterone in men.
TLDR
Current research suggests that while some evidence exists to support the notion of seasonal testosterone variations, the discussed inconsistencies preclude the incorporation of this concept into current clinical standards. Expand
Association of low testosterone with changes in non-cardiovascular biomarkers in adult men
TLDR
The hypothesis that testosterone deficiency is associated with a broad range of systemic changes demonstrable in hormonal and non-hormonal serum assays in men over 40 years old being tested for possible hypogonadism is confirmed. Expand
Absent Diurnal Variation in Serum Testosterone in Young Men With Testosterone Deficiency.
TLDR
It is speculated that similar central mechanisms may be involved in the pathophysiology leading to secondary T deficiency as well as the loss of circadian rhythmicity in young men with T deficiency. Expand
The Evaluation and Management of Testosterone Deficiency: the New Frontier in Urology and Men’s Health
TLDR
Overall, TTh is relatively safe but the risks, such as erythrocytosis, makes long-term monitoring mandatory, and the evidence does not support concerns regarding cardiovascular and prostate cancer risks. Expand
Influence of baseline serum testosterone on changes in body composition in response to testosterone therapy.
TLDR
Baseline severity of symptomatic TD influences body composition and similar changes in LM and FM were seen with TTh regardless of baseline severity in TD, providing support for the value of FT in the assessment of men with symptoms suggestive of TD. Expand
Are we testing appropriately for low testosterone?: Characterization of tested men and compliance with current guidelines.
TLDR
The rate of testosterone testing is increasing with most testing practices directed toward a subset of men with comorbidities that are associated with hypogonadism. Expand
Late-onset Hypogonadism and Testosterone Therapy - A Summary of Guidelines from the American Urological Association and the European Association of Urology.
TLDR
The benefits and risks of testosterone therapy are controversial, as reflected in the European Association of Urology and American Urological Association guidelines that differ on several points of management. Expand
Pharmacokinetics of testosterone therapies in relation to diurnal variation of serum testosterone levels as men age.
TLDR
To compare pharmacokinetic (PK) profiles of serum T from approved T formulations with endogenous diurnal T variations in young and older men, and to consider whether there may be value in mimicking thediurnal T rhythmicity with exogenous TTh as men age. Expand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 25 REFERENCES
Are published normal ranges of serum testosterone too high? Results of a cross‐sectional survey of serum testosterone and luteinizing hormone in healthy men
To derive normal ranges of serum testosterone and luteinizing hormone (LH) concentrations in healthy men, and thus evaluate whether testosterone replacement therapy is prescribed inappropriately.
Risks of testosterone-replacement therapy and recommendations for monitoring.
TLDR
What is known (and not known) about the risks of testosterone-replacement therapy and recommendations for monitoring men who are receiving testosterone are discussed. Expand
Diurnal rhythms of serum total, free and bioavailable testosterone and of SHBG in middle‐aged men compared with those in young men
TLDR
This work has measured total, free and bioavailable testosterone along with SHBG in samples taken every 30 min throughout a 24‐h period in 10 young and eight middle‐aged men. Expand
Circadian variation in serum free and non‐SHBG‐bound testosterone in normal men: measurements, and simulation using a mass action model
OBJECTIVE We measured the changes in testosterone fractions in serum of normal men over a 24‐hour period, and determined whether they could be simulated on the basis of current understanding of theExpand
Loss of circadian rhythmicity in blood testosterone levels with aging in normal men.
TLDR
A clear decrease in serum testosterone levels in healthy old men compared to those in young men is demonstrated and this results provide an explanation for the inability to demonstrate an age-related decline inosterone levels in earlier studies using serum samples obtained in the afternoon. Expand
Endogenous sex hormones and the development of type 2 diabetes in older men and women: the Rancho Bernardo study.
TLDR
Low testosterone levels in men and highosterone levels in women predict insulin resistance and incident type 2 diabetes in older adults. Expand
Low sex hormone-binding globulin, total testosterone, and symptomatic androgen deficiency are associated with development of the metabolic syndrome in nonobese men.
TLDR
Low serum SHBG, low total testosterone, and clinical AD are associated with increased risk of developing MetS over time, particularly in nonoverweight, middle-aged men (BMI, <25). Expand
Neuroendocrine-gonadal axis in men: frequent sampling of LH, FSH, and testosterone.
TLDR
A previously unappreciated spectrum of gonadotropin and T secretory patterns was observed in normal men, and results suggested a relative refractory period at the level of the hypothalamus or pituitary. Expand
Low SHBG, Total Testosterone, and Symptomatic Androgen Deficiency are Associated with Development of the Metabolic Syndrome in Non-Obese Men
This is an un-copyedited author manuscript copyrighted by The Endocrine Society. This may not be duplicated or reproduced, other than for personal use or within the rule of “Fair Use of CopyrightedExpand
Circadian rhythm of serum immunoreactive inhibin in young and elderly men.
TLDR
It is demonstrated that immunoreactive inhibin, like T, displays a circadian rhythm in the serum of adult men and the inhibin biorhythm is maintained in elderly men. Expand
...
1
2
3
...