SHORT COMMUNICATION High bone turnover in Irish professional jockeys F. Waldron-Lynch & B. F. Murray & J. J. Brady & M. J. McKenna & A. McGoldrick & G. Warrington & G. O’Loughlin & J. M. Barragry Received: 29 October 2008 / Accepted: 3 February 2009 / Published online: 7 March 2009 # International Osteoporosis Foundation and National Osteoporosis Foundation 2009 Abstract Summary Professional jockeys are routinely exposed to high impact trauma and sustain fractures frequently. We found that jockeys restrict their caloric intake in order to maintain regulation weights, and that bone turnover is high. There are significant health and safety implications for the racing industry. Introduction Professional jockeys routinely sustain frac- tures from high impact falls. Jockeys maintain a low percentage body fat and a low body mass index (BMI) to achieve low weight targets in order to race. We evaluated dietary habits and bone metabolism in jockeys. Methods Bone mineral density (BMD) was measured in 27 male jockeys of the 144 jockeys licensed in Ireland. Fourteen (52%) had BMD T score below -1.0, of whom 12 consented to clinical review, nutritional survey, endo- crine studies, and bone turnover markers (BTM). BTM were compared to age- and sex-matched controls (n =16). Results BMI was 20.6±1.7 kg/m 2 ; previous fracture fre- quency was 3.2±2.0 per rider. All had normal endocrine axes. The jockeys' diet as determined by a 7-day dietary recall was deficient in energy, calcium, and vitamin D intake. Compared with the control group, the jockey group had evidence of increased bone turnover. Conclusions A substantial proportion of the professional jockeys in Ireland have low–normal BMD, low BMI, and high bone turnover that may result from weight and dietary restrictions. These factors seem to have a deleterious effect on their bone health and predispose the jockeys to a high fracture risk that should be remediated. Keywords Bone mineral density . Bone turnover . Diet . Jockeys . Osteopenia . Osteoporosis Introduction Professional racing, which is divided into flat racing and jump racing (national hunt racing), is regulated in Ireland by The Turf Club. In Ireland during 2007, 67 flat jockeys, 12 jump jockeys, and 65 apprentice jockeys held full registra- tion as professionals with the Turf Club [1]. Professional jockeys are exposed to unique occupational risks by having to ride racehorses weighing approximately 450 to 550 kg capable of traveling at speeds of over 60 km/h while at a height of over 2 m from the ground [2]. Recent reports from different countries have cataloged the high rate of injuries in jockeys [2–5]. Racehorses are handicapped through weight penalties, with jockeys required to achieve a low percentage body fat and a low body mass index (BMI) to make weights of 52.7 Osteoporos Int (2010) 21:521–525 DOI 10.1007/s00198-009-0887-0 F. Waldron-Lynch : J. M. Barragry Adelaide and Meath Hospital, Dublin, Ireland B. F. Murray : J. J. Brady : M. J. McKenna St Vincent’ s University Hospital, Dublin, Ireland A. McGoldrick : G. O’Loughlin Curragh Racecourse, Co., Kildare, Ireland G. Warrington Dublin City University, Dublin, Ireland F. Waldron-Lynch (*) Department of Medicine, Section of Endocrinology and Metabolism, Yale University School of Medicine, 333 Cedar Street, P. O. Box 208020, New Haven, CT 06520-8020, USA e-mail: frank.waldron-lynch@yale.edu