The following is a summary of “Prevalence of Iron Deficiency in Endurance Runners: A Cross-Sectional Study of the Detroit Free Press Marathon and Half-Marathon Athletes” published in the November 2022 issue of Blood by Kohler et al.

It’s possible that endurance athletes have higher rates of iron shortage than the general population, whether or not they also have anemia. Through a variety of causes, including increased demand, foot-strike hemolysis, perspiration, and others, marathon and half-marathon runners, a subgroup of these endurance athletes, are susceptible to the iron shortage. There hasn’t been any research on the prevalence of iron insufficiency among marathon and half-marathon runners in the US.

For a study, researchers sought to determine the prevalence of iron insufficiency among runners taking part in the Detroit Free Press Marathon or Half-Marathon on October 17, 2021, so they conducted cross-sectional research. The pre-race expo served as the screening location where eligible competitors filled out questionnaires and had blood samples drawn. The surveys asked about things like demographic data, food and exercise habits, past bleeding episodes, and symptoms. Hemoglobin, hematocrit, ferritin, serum iron, total iron binding capacity (TIBC), and iron saturation were all analyzed on the blood samples on the same day. Participants received an email with their test results and a $30 Amazon gift card as a thank-you for taking part.

For the purposes of the investigation, severe iron deficiency was defined as ferritin levels below <15 ng/mL or ferritin levels <35 ng/mL and iron saturation levels<16%. It was similar to earlier criteria used in research looking at other endurance athletes and was probably associated with a lack of iron storage. Clinical iron deficiency was defined by us as clinicians as ferritin <30 ng/mL, ferritin <100 ng/mL, and iron saturation <20%. There was a good chance that this was related to low iron reserves, at-risk iron stores, or iron deficiency in some populations. Additionally, the definition was probably going to lead to care and/or research. Using SPSS version 28.0, the data were analyzed using chi-squared analysis, Student’s t-test, ANOVA, and logistic regression.

The average age of the 277 participants was 40.6±13.6 years, and 107 men, or 38.6%, were male. (n=219, 79.1%) of our participants primarily identified as white. All participants were citizens of the United States, and 213 of them were from Michigan (80.1%). The bulk of our participants—185 (66.8%) half marathoners, 87 (31.4%) marathoners, and 3 (1.1%) unknowns—registered for the half marathon. Females were substantially more likely than men to have clinical iron deficiency, at 47.6% versus 15%, respectively (P<0.001). For severe iron insufficiency, the trend was the same, with 14.7% of females and 2.8% of men (P=0.001). The anemia status had no bearing on these outcomes. Younger age, race entry, history of anemia, heavy monthly bleeding, blood thinner usage, 15 hours of activity per week, restricted eating habits, lightheadedness, and unsteadiness were variables linked with iron deficiency (clinical and/or severe). They performed various models for multivariable analysis according to sex.

Iron deficiency was common in marathon and half-marathon runners and was linked to a number of risk factors, some of which are gender-specific. Patients who engaged in endurance training and/or sports should undergo the appropriate screening.