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Health effects of the London bicycle sharing system: health impact modelling study

BMJ 2014; 348 doi: (Published 13 February 2014) Cite this as: BMJ 2014;348:g425

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Re: Health effects of the London bicycle sharing system: health impact modelling study

Dear Editors,

This study did not take into account important morbidity associated with cycling.

As potential health risks, only road traffic incidents and exposure to air pollution were included.

Genitourinary tract injuries, pudendal nerve entrapment, erectile dysfunction, infertility in both men and women(!), priapism, penile thrombosis, hematuria, torsion of spermatic cord, prostatitis, perineal nodular indurations, elevated serum PSA levels, were not even mentioned.
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]

Studies have demonstrated that a high percentage of cyclists are affected by all these pelvic symptoms.

Failing to include all this cycling-associated morbidity has compromised Authors' final conclusions, regarding the amount of health risks associated to cycling, in my opinion.


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Biomechanics Laboratory, Utah State University, Logan, UT 84322, USA.

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[5] Curr Urol Rep. 2007 Nov;8(6):491-7.
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San Diego Sexual Medicine, Alvarado Hospital, 6655 Alvarado Road, San Diego, CA 92120, USA.

[6] BJU Int. 2007 Jan;99(1):135-40.
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Gemery JM, Nangia AK, Mamourian AC, Reid SK.
Department of Radiology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA.

[7] J Sex Med. 2005 Sep;2(5):612-9.
Only the nose knows: penile hemodynamic study of the perineum-saddle interface in men with erectile dysfunction utilizingbicycle saddles and seats with and without nose extensions.
Munarriz R, Huang V, Uberoi J, Maitland S, Payton T, Goldstein I.
Institute for Sexual Medicine, Department of Urology, Boston University School of Medicine, 720 Harrison Avenue, Suite 600, Boston, MA 02118, USA.

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Institute for Sexual Medicine, Department of Urology, Boston University School of Medicine, 720 Harrison Avenue, Boston, MA 02118, USA.

[9] J Urol. 2004 Aug;172(2):637-41.
Erectile dysfunction after a long-distance cycling event: associations with bicycle characteristics.
Dettori JR, Koepsell TD, Cummings P, Corman JM.
Department of Epidemiology, School of Public Health and Community Medicine, University of Washington and Department of Urology, Virginia Mason Medical Center, Seattle, USA.

[10] Eur Urol. 2005 Mar;47(3):277-86; discussion 286-7. Epub 2004 Dec 30.
The vicious cycling: bicycling related urogenital disorders.
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Department of Urology, Meir Medical Center, Affiliated to Sackler School of Medicine, Tel Aviv University, 59 Tchernichovski st., Kfar Saba, Israel.

[11] J Appl Physiol. 1984 Jun;56(6):1453-63.
Endurance training effects on plasma hormonal responsiveness and sex hormone excretion.
Bullen BA, Skrinar GS, Beitins IZ, Carr DB, Reppert SM, Dotson CO, Fencl MD, Gervino EV, McArthur JW.

Competing interests: No competing interests

10 March 2014
Stavros Saripanidis
Consultant in Obstetrics and Gynaecology
Private Surgery
Thessaloniki, Greece