Cognitive dietary restraint is associated with stress fractures in women runners.

High levels of cognitive dietary restraint (CDR) have been associated with subclinical menstrual cycle irregularities and increased cortisol levels, both of which can affect bone mineral density (BMD). Low BMD has been implicated in stress fracture risk. We assessed CDR in female runners (> or = 20 km/wk) with a recent stress fracture (SF) and with no stress fracture history (NSF). A sample of 79 runners (n = 38 SF, 29 +/- 5 y; n = 41 NSF, 29 +/- 6 y) completed a 3-d food record and questionnaire assessing physical activity, menstrual cycle history, and perceived stress. SF and NSF runners had similar body mass index (21.2 +/- 1.8 vs. 22.0 +/- 2.5 kg/m2), physical activity (35.7 +/- 13.5 vs. 33.4 +/- 1.34 km/wk), perceived stress, and dietary intakes. CDR, however, was higher in SF runners (11.0 +/- 5.4 vs. 8.4 +/- 4.3, P < 0.05). Subclinical menstrual cycle disturbances and increased cortisol levels that are associated with high CDR, might in turn contribute to lowered BMD and increased stress fracture risk.