@article {Barrack200, author = {Michelle T Barrack and Michael Fredericson and Adam S Tenforde and Aurelia Nattiv}, title = {Evidence of a cumulative effect for risk factors predicting low bone mass among male adolescent athletes}, volume = {51}, number = {3}, pages = {200--205}, year = {2017}, doi = {10.1136/bjsports-2016-096698}, publisher = {British Association of Sport and Excercise Medicine}, abstract = {Background Limited research has evaluated risk factors for low bone mineral density (BMD) in male adolescent athletes.Aims/objectives To evaluate predictors of low BMD (defined as BMD Z-score \<-1.0) in a sample of male adolescent distance runner and non-runner athletes.Methods Male adolescent athletes completed a survey characterising sports participation, nutrition, stress fracture history, dual energy X-ray absorptiometry (DXA)-measured BMD and body composition. Independent t-tests and analysis of covariance (ANCOVA) evaluated group differences; logistic regression evaluated low BMD risk factors.Results Runners (n=51) exhibited a lower body weight (p=0.02), body mass index (BMI) (kg/m2) (p=0.02), per cent expected weight (p=0.02) and spine BMD Z-score (p=0.002) compared with non-runners (n=18). Single risk factors of low BMD included \<85\% expected weight (OR=5.6, 95\% CI 1.4 to 22.5) and average weekly mileage \>30 in the past year (OR=6.4, 95\% CI 1.5 to 27.1). The strongest two-variable and three-variable risk factors included weekly mileage \>30+ stress fracture history (OR=17.3, 95\% CI 1.6 to 185.6) and weekly mileage \>30+\<85\% expected weight + stress fracture history (OR=17.3, 95\% CI 1.6 to 185.6), respectively. Risk factors were cumulative when predicting low BMD (including \<85\% expected weight, weekly mileage \>30, stress fracture history and \<1 serving of calcium-rich food/day): 0{\textendash}1 risk factors (11.1\%), 2 risk factors (42.9\%), or 3{\textendash}4 risk factors (80.0\%), p\<0.001).Conclusions Male adolescent runners exhibited lower body weight, BMI and spine BMD Z-score values. The risk of low BMD displayed a graded relationship with increasing risk factors, highlighting the importance of using methods to optimise bone mass in this population.}, issn = {0306-3674}, URL = {https://bjsm.bmj.com/content/51/3/200}, eprint = {https://bjsm.bmj.com/content/51/3/200.full.pdf}, journal = {British Journal of Sports Medicine} }