Iron deficiency without anaemia: Do not wait for the haemoglobin to drop?

Fit to Teach?-Cardiorespiratory Capacity, Vitamin D3, and Ferritin in Physical Education Teachers With Specialization in Dance

ABSTRACT

Schmidt, M, Ohlendorf, D, Groneberg, DA, and Wanke, EM. Fit to teach?-Cardiorespiratory capacity, vitamin D3, and ferritin in physical education teachers with specialization in dance. J Strength Cond Res 35(4): 1156-1164, 2021-Numerous studies have shown that good cardiorespiratory capacity is of great importance for a healthy and long-term professional career as a dancer. Although the cardiorespiratory demands during teaching can reach into the submaximal intensity range, current data on the objective physical fitness of this occupational group are still missing. The aim of this pilot project was to determine selected cardiorespiratory parameters. In addition, measurements of the vitamin D3 (25(OH)D3) and iron balance as well as a subjective assessment of dance teachers' (DTs) fitness were performed. Twenty-one DTs (f: n = 18, m: n = 3) aged 48.2 ± 9.3 years were examined for cardiorespiratory performance within the framework of maximum bicycle spiroergometry. In addition, the self-perception of DTs' fitness was examined as well as the serum vit D3 levels and ferritin concentration in the blood. The cardiorespiratory fitness of DTs can be assessed as average (maximal oxygen consumption, V̇o2max = 29.5 ± 7.1 ml·k-1·min-1; physical working capacity, PWCmax = 165.0 ± 44.4). The DTs seemed to underestimate or overestimate their own capacity. Laboratory diagnostics showed that the 25(OH)D3 levels (21.8 ± 8.5 ng·ml-1) and serum ferritin values (102.4 ± 35.0 g·dl-1) were not optimal for almost the entire sample. In view of the physical occupational requirements, an increase in aerobic cardiorespiratory fitness by endurance-oriented basic training for DTs seems advisable. In addition, the substitution of vit D3 is worth being discussed.

Reticulocyte hemoglobin content (MCHr) in the detection of iron deficiency

BACKGROUND

Blood hemoglobin (Hb) concentration within the reference interval does not exclude iron deficiency (ID): individuals with normal stores lose iron during a long period before their Hb falls below of the level that is defined as anemia. The process entails a decrease of storage iron, shown by serum ferritin below reference range, followed by iron depletion, eventually leading to iron restricted erythropoiesis; consequence of an imbalance between erythropoietic iron requirements and too low supply is a reduction of Hb synthesis in reticulocytes.

OBJECTIVE

We study the potential utility of mean reticulocyte hemoglobin content (MCHr), reported by CELL-DYN Sapphire (Abbott Diagnostics) analyzer, in the detection of ID in non-anemic adults.

METHODS

207 patients with Hb within the reference range were enrolled. ID was defined as Hb>120g/L (women), >130g/L (men) and serum ferritin <30μg/L. Student's t-test was applied to detect deviations between groups, statistical significance P<0.05. The performance of MCHr in detecting ID was evaluated applying Receiver Operating Characteristic (ROC) curve analysis. Kappa test was applied to verify concordance between ferritin and MCHr.

RESULTS

68 patients (33%) suffered ID, median MCHr in this group was 26.9 pg, statistically different from the normal group, MCHr 30.9pg (P<0.0001). ROC ANALYSIS (GOLD STANDARD FERRITIN <30μG/L): Area under curve AUC 0.851 (95% CI 0.770-0.912) at cut off 30.0 pg, with sensitivity 84.1% and specificity 71.1%. Kappa 0.667 (95% CI 0.527-0.858).

CONCLUSION

Due to their short lifespan reticulocytes and derived parameters reflect current erythropoiesis status, before Hb and erythrocyte indices drop. MCHr had the best AUC and diagnostic value compared to erythrocyte indices. MCHr is a reliable test for the investigation of ID and could improve the detection of iron deficient adults.

Clinical Value of Hypochromia Markers in the Detection of Latent Iron Deficiency in Nonanemic Premenopausal Women

BACKGROUND

Iron deficiency (ID) is the most common cause of anemia in fertile women and hemoglobin (Hb) within the reference interval does not exclude ID. The consequence of an imbalance between the iron requirements and supply is a reduction of red-cell Hb content, which causes hypochromic cells. The aim of this study was to assess the reliability of new parameters low Hb density (LHD%), reticulocyte Hb equivalent (RetHe), and percentage of hypochromic erythrocytes (%HypoHe) in the detection of latent ID (LID), defined as depletion of iron stores without anemia.

METHODS

Two hundred fifty consecutive nonanemic women in fertile age (18-40 years, mean 33.5 years), whose analyses had been requested by general practitioners, were included. Independent samples t-test, receiver operating characteristic (ROC) curve analysis (gold standard for detecting LID ferritin <30 μg/l), and Cohen's kappa index were applied.

RESULTS

One hundred fifty-three women had ferritin within the reference range and Hb >120 g/L; 97 (38.8%) had LID. The results were as follows: %HypoHe-AUC 0.934, cutoff 1.6%, sensitivity 85.7%, specificity 92.1%; RetHe-AUC 0.914, cutoff 29.9 pg, sensitivity 86.8%, specificity 85.7%; LHD%-AUC 0.898, cutoff 5.0%, sensitivity 85.9%, specificity 84.1%. Applying those cutoffs, agreement between ferritin and %HypoHe was κ 0.61 and 0.56 for RetHe and LHD%.

CONCLUSIONS

LHD%, %HypoHe, and RetHe emerge as reliable tests for the investigation of LID and could improve the ability to detect ID before anemia is present.

Four weeks of IV iron supplementation reduces perceived fatigue and mood disturbance in distance runners

Purpose

To determine the effect of intravenous iron supplementation on performance, fatigue and overall mood in runners without clinical iron deficiency.

Methods

Fourteen distance runners with serum ferritin 30–100 µg·L⁻¹ were randomly assigned to receive three blinded injections of intravenous ferric-carboxymaltose (2 ml, 100 mg, IRON) or normal saline (PLACEBO) over four weeks (weeks 0, 2, 4). Athletes performed a 3,000 m time trial and 10×400 m monitored training session on consecutive days at week 0 and again following each injection. Hemoglobin mass (Hbmass) was assessed via carbon monoxide rebreathing at weeks 0 and 6. Fatigue and mood were determined bi-weekly until week 6 via Total Fatigue Score (TFS) and Total Mood Disturbance (TMD) using the Brief Fatigue Inventory and Brunel Mood Scale. Data were analyzed using magnitude-based inferences, based on the unequal variances t-statistic and Cohen's Effect sizes (ES).

Results

Serum ferritin increased in IRON only (Week 0: 62.8±21.9, Week 4: 128.1±46.6 µg·L⁻¹; p = 0.002) and remained elevated two weeks after the final injection (127.0±66.3 µg·L⁻¹, p = 0.01), without significant changes in Hbmass. Supplementation had a moderate effect on TMD of IRON (ES -0.77) with scores at week 6 lower than PLACEBO (ES -1.58, p = 0.02). Similarly, at week 6, TFS was significantly improved in IRON vs. PLACEBO (ES –1.54, p = 0.05). There were no significant improvements in 3,000 m time in either group (Week 0 vs. Week 4; Iron: 625.6±55.5 s vs. 625.4±52.7 s; PLACEBO: 624.8±47.2 s vs. 639.1±59.7 s); but IRON reduced their average time for the 10×400 m training session at week 2 (Week 0: 78.0±6.6 s, Week 2: 77.2±6.3; ES–0.20, p = 0.004).

Conclusion

During 6 weeks of training, intravenous iron supplementation improved perceived fatigue and mood of trained athletes with no clinical iron deficiency, without concurrent improvements in oxygen transport capacity or performance.

Lower hemoglobin with lower ferritin: It is not just a question of anemia

AIM

To study the association between blood hemoglobin concentration (b-hemoglobin) and serum ferritin concentration (s-ferritin) in an ambulant patient population without inflammation and with normal kidney function.

METHODS

In ambulant, adult patients with normal values of s-CRP and s-creatinine, median b-hemoglobin and the fraction with anemia was compared in groups with lower s-ferritin from a level of 100 μg/L. The 10, 50 and 90 percentiles of b-hemoglobin were modelled as functions of s-ferritin using quantile regression.

RESULTS

Among 3206 women the entire b-hemoglobin distribution was shifted downwards in patients with s-ferritin less than 20 μg/L. Accordingly, the median b-hemoglobin was statistically significantly lower and the fraction with anemia was higher. In 1246 men the findings were similar, except that the turning point toward lower b-hemoglobin was at a s-ferritin level of 30 μg/L.

CONCLUSIONS

Low s-ferritin is associated with decreased b-hemoglobin in many more subjects than those labelled anemic.