Anecdotally, it has been estimated that between 10% and 15% of men and adolescent boys in the general population have varicocele.[3]Evers JL, Collins JA. Assessment of efficacy of varicocele repair for male subfertility: a systematic review. Lancet. 2003 May 31;361(9372):1849-52.
http://www.ncbi.nlm.nih.gov/pubmed/12788571?tool=bestpractice.com
In the US, the overall incidence of adolescent varicocele is 15%, which is similar to that of the adult population.[4]Steeno O, Knops J, Declerck L, et al. Prevention of fertility disorders by detection and treatment of varicocele at school and college age. Andrologia. 1976;8(1):47-53.
http://www.ncbi.nlm.nih.gov/pubmed/986121?tool=bestpractice.com
Globally, incidences may vary; a slightly lower incidence was reported in a prospective study from Bulgaria.[5]Kumanov P, Robeva RN, Tomova A. Adolescent varicocele: who is at risk? Pediatrics. 2008 Jan;121(1):e53-7.
http://www.ncbi.nlm.nih.gov/pubmed/18166544?tool=bestpractice.com
However, the true incidence of adolescent varicoceles may be under-reported, as most teens are not routinely examined in the upright position.
The majority (>80%) of adult varicoceles are not associated with infertility.[6]Sylora JA, Pryor JL. Varicocele. Curr Ther Endocrinol Metab. 1994;5:309-14.
http://www.ncbi.nlm.nih.gov/pubmed/7704742?tool=bestpractice.com
[7]Green KF, Turner TT, Howards SS. Varicocele: reversal of the testicular bloodflow and temperature effects by varicocele repair. J Urol. 1984 Jun;131(6):1208-11.
http://www.ncbi.nlm.nih.gov/pubmed/6726930?tool=bestpractice.com
However, the prevalence of varicocele is greater in patients with subfertility. Approximately 1 of 4 men with abnormal semen parameters will have a varicocele, and 40% of men presenting with infertility have a varicocele.[8]World Health Organization. The influence of varicocele on parameters of fertility in a large group of men presenting to infertility clinics. Fertil Steril. 1992 Jun;57(6):1289-93.
http://www.ncbi.nlm.nih.gov/pubmed/1601152?tool=bestpractice.com
Furthermore, up to 80% of men with secondary infertility have a varicocele.[9]Gorelick JI, Goldstein M. Loss of fertility in men with varicocele. Fertil Steril. 1993 Mar;59(3):613-6.
http://www.ncbi.nlm.nih.gov/pubmed/8458466?tool=bestpractice.com
Pre-pubertal varicoceles are very rare, suggesting that puberty may be one initiating factor.[10]Vasavada S, Ross J, Nasrallah P, et al. Prepubertal varicoceles. Urology. 1997 Nov;50(5):774-7.
http://www.ncbi.nlm.nih.gov/pubmed/9372891?tool=bestpractice.com
Ninety percent of varicoceles are on the left side, while approximately 10% are bilateral. An isolated right-sided varicocele is rare.
Varicoceles appear to be more common in males who are tall and lean, with a lower BMI than age-matched controls.[11]Prabakaran S, Kumanov P, Tomova A, et al. Adolescent varicocele: association with somatometric parameters. Urol Int. 2006;77(2):114-7.
http://www.ncbi.nlm.nih.gov/pubmed/16888413?tool=bestpractice.com
[12]Delaney DP, Carr MC, Kolon TF, et al. The physical characteristics of young males with varicocele. BJU Int. 2004 Sep;94(4):624-6.
http://www.ncbi.nlm.nih.gov/pubmed/15329126?tool=bestpractice.com
[13]May M, Taymoorian K, Beutner S, et al. Body size and weight as predisposing factors in varicocele. Scand J Urol Nephrol. 2006;40(1):45-8.
http://www.ncbi.nlm.nih.gov/pubmed/16452055?tool=bestpractice.com
One meta-analysis reported that underweight patients had a higher risk of varicocele, while patients with a BMI greater than or equal to 25 had a lower risk.[14]Xiao-Bin G, Fang-Lei W, Hui X, et al. The association between body mass index and varicocele: a meta-analysis. Int Braz J Urol. 2021 Jan-Feb;47(1):8-19.
https://www.doi.org/10.1590/S1677-5538.IBJU.2019.0210
http://www.ncbi.nlm.nih.gov/pubmed/32271509?tool=bestpractice.com
There is an increased incidence of varicocele in first-degree relatives, particularly brothers of affected males, suggesting a potential genetic basis, and also a role for screening.[15]Raman JD, Walmsley K, Goldstein M. Inheritance of varicoceles. Urology. 2005 Jun;65(6):1186-9.
http://www.ncbi.nlm.nih.gov/pubmed/15913726?tool=bestpractice.com
[16]Mohammadali Beigi F, Mehrabi S, Javaherforooshzadeh A. Varicocele in brothers of patients with varicocele. Urol J. 2007 Winter;4(1):33-5.
http://www.ncbi.nlm.nih.gov/pubmed/17514609?tool=bestpractice.com
[17]Mokhtari G, Pourreza F, Falahatkar S, et al. Comparison of prevalence of varicocele in first-degree relatives of patients with varicocele and male kidney donors. Urology. 2008 Apr;71(4):666-8.
http://www.ncbi.nlm.nih.gov/pubmed/18279919?tool=bestpractice.com