Compliance compromises an interventional study on iron supplementation in female combatants.

INTRODUCTION: Low iron levels are related to overuse injuries, poor physical performance and cognitive impairments in female recruits. The aim of this study was to evaluate iron supplement compliance in female combatants during basic training, and its effect on haemoglobin (Hgb), ferritin and injuries.

METHODS: 329 female recruits to light infantry units filled induction questionnaires regarding smoking status, previous overuse injuries and iron deficiency. Blood was drawn for Hgb and ferritin. Subjects with ferritin levels below 20 ng/mL were considered iron depleted and were prescribed a ferrous fumarate supplement. After 4 months of basic training, the subjects completed a follow-up questionnaire regarding overuse injuries, reasons for failure to complete basic training and compliance with iron supplementation. Blood tests were repeated.

RESULTS: Mean ferritin levels declined during training (from 18.1±18.2 to 15.3±9.6, p=0.01). Compliance with iron supplementation was observed in 26 (26.3%) of the subjects. In compliant subjects, Hgb levels remained constant and ferritin levels increased by 2.9±5.4 (p=0.07). The main reasons for reported non-compliance were forgetfulness, 26 (35.6%), and gastrointestinal side effects, 17 (23.3%). Injuries during training were not found to be associated with iron status. Smokers had a significantly higher rate of reported injuries prior to training (p<0.01).

CONCLUSIONS: Ferritin levels decline during training. Compliance with iron supplementation is low. Iron supplementation has a significant effect on ferritin levels, even in the non-compliance group. Injuries were not related to iron status in this group. Further research is needed in order to clarify the most appropriate iron supplementation method.