Do varicoceles increase sex hormone-binding globulin (SHBG) levels?

Varicoceles and Sex Hormone-Binding Globulin (SHBG) Levels

Varicoceles can increase sex hormone-binding globulin (SHBG) levels, which may contribute to hormonal imbalances and reproductive dysfunction in affected men. This relationship is part of the broader endocrine disruption associated with varicocele pathophysiology.

Varicocele and Hormonal Effects

• Varicoceles are present in approximately 15% of the general male population, 25% of men with abnormal semen analysis, and 35-40% of men presenting with infertility 1
• The pathophysiological mechanisms through which varicoceles affect testicular function include higher scrotal temperature, hypoxia, and reflux of toxic metabolites, leading to increased oxidative stress and DNA damage 1

Impact on Sex Hormones and SHBG

• Men with varicoceles demonstrate abnormal free sex steroid levels and higher SHBG levels compared to men without varicoceles 2
• SHBG production increases in response to various conditions including hepatic disease, aging, smoking, and HIV/AIDS 1
• Increased SHBG levels bind more testosterone, reducing the amount of free (bioavailable) testosterone available for biological functions 2
• Studies have shown that men with varicoceles have significantly lower total testosterone levels (mean 416 ng/dL) compared to men without varicoceles (mean 469 ng/dL) 3

Clinical Significance of Elevated SHBG in Varicocele Patients

• Elevated SHBG leads to decreased free testosterone levels despite potentially normal total testosterone measurements 2
• Men with varicoceles and excessive gonadotropin responses to GnRH testing show higher than normal levels of SHBG and free estradiol, with lower than normal free testosterone 2
• This hormonal imbalance may contribute to:
  • Impaired spermatogenesis and reduced fertility 1, 4
  • Sexual dysfunction in some patients 5
  • Potential risk for hypogonadism 6, 3

Effects of Varicocele Repair on Hormonal Parameters

• Microsurgical varicocelectomy can normalize sex hormone levels in men with preoperative hormonal abnormalities 2, 5
• Approximately 70% of men experience improvement in testosterone levels following varicocele repair, with a mean increase of 178 ng/dL 3
• Surgical correction of varicoceles can also improve SHBG levels and restore proper hormone balance 2
• Varicocelectomy can reverse sperm DNA damage and improve oxidative stress levels 1

Clinical Approach to Varicocele and Hormonal Assessment

• Men with clinically palpable varicoceles who present with symptoms of hypogonadism should have at least two serum testosterone measurements 6
• Evaluation should include both total testosterone and SHBG levels to accurately assess bioavailable testosterone 1, 2
• Microsurgical varicocelectomy should be considered for men with:
  • Clinically palpable varicoceles
  • Documented hypogonadism or abnormal hormonal profiles
  • Fertility concerns 6, 3

Potential Pitfalls and Considerations

• Not all men with varicoceles will have hormonal abnormalities; those with normal gonadotropin responses typically have normal free sex steroid and SHBG levels 2
• The impact of varicocele on hormonal parameters tends to worsen with age, as evidenced by the significant inverse correlation between age and plasma testosterone in varicocele patients 5
• Treatment decisions should prioritize patients with abnormal preoperative hormonal profiles, as they are more likely to benefit from surgical intervention 2, 3

In conclusion, varicoceles can increase SHBG levels, contributing to hormonal imbalances that may affect reproductive function and testosterone bioavailability. Surgical correction can improve these parameters in most affected men, particularly those with preoperative hormonal abnormalities.