Thesis Defence: Time course for ferritin decay at 3800m

Nina Geerts, supervised by Dr. Philip Ainslie, will defend their thesis titled “Time course for ferritin decay at 3800m: Influence of biological sex” in partial fulfillment of the requirements for the degree of Master of Science in Health and Exercise Sciences.
An abstract for Nina Geerts’ thesis is included below.
Defences are open to all members of the campus community as well as the general public. Registration is not required for in-person defences.
Abstract
Sojourn to high altitude (HA) increases iron demand through hypoxia-induced erythropoiesis. Females have higher baseline iron requirements than males and may be more prone to iron deficiency at HA, yet previous studies examining ascent and iron were limited to small female sample sizes and limited temporal measures. To expand on past findings and assess sex differences in the ∆[ferritin] over 11 days at HA with ad-lib food availability, blood samples were obtained at sea-level and on days 2-4, 5-7, and 11 at HA in 27 (13 female) healthy volunteers. Using linear mixed modelling and Pearson’s correlations, we tested the hypotheses that at altitude ferritin would a) be lower in females at all timepoints, b) decrease similarly between sexes despite adequate energy and iron intake, and c) be inversely related to elevations in hemoglobin. A day*sex interaction (p < 0.01) revealed a steeper slope of ferritin decay in males (β = −3.74 µg/L/day) than females (β = −1.44 µg/L/day). Despite this observation, [ferritin] remained consistently ∼70% lower in females across timepoints. By day 11 at HA, 6 out of 13 females were iron deficient ([ferritin] < 12µg/L), with no iron deficiency ([ferritin] < 15µg/L) occurring in males. The reductions in [ferritin] at HA were strongly related to elevations in hemoglobin in females (r = −0.79; p < 0.01) but not males (r = 0.28; p = 0.37). These data indicate that at 3800m, despite ad-lib food availability, females are at a greater risk of iron deficiency, and [ferritin] is related to elevations in hemoglobin in females. Iron supplementation should be considered for females travelling and working at high altitude.