Iron Deficiency: Causes, Anemia, and Health Implications

Do you know what it is?

Iron deficiency is a public health problem and the leading cause of anemia worldwide, as well as the most prevalent nutritional deficiency. The high prevalence of this nutritional deficiency in Portugal is well recognized, as is its underdiagnosis in laboratory settings, underscoring the need for strategies to prevent, diagnose, and treat this condition.

Iron is an essential nutrient and plays a central role in many metabolic processes. Iron deficiency manifests through many nonspecific signs and symptoms (fatigue, pallor, hair loss, difficulty concentrating, intolerance to cold, …) and, in most cases, is only diagnosed when its final manifestation—anemia (hemoglobin <13 g/dL in men and <12 g/dL in women)—is investigated.

In known at-risk groups, such as pregnant women, patients with chronic kidney disease, patients with inflammatory bowel disease, or those with heart failure, iron deficiency is associated with a poorer prognosis, including increased hospitalizations and reduced quality of life and life expectancy.

Iron deficiency statistics in Portugal^¹

31.9% of Portuguese people have IRON DEFICIENCY (ferritin <30 ng/mL)

53.3% have a functional iron deficiency (ferritin <50 ng/mL)

It is more common in women

40.7% of pregnant women have iron deficiency

19.9% have anemia (84% of whom are undiagnosed)

1 Fonseca C, Marques F, Robalo Nunes A, Belo A, Brilhante D, Cortez J. “Prevalence of anemia and iron deficiency in Portugal: the EMPIRE study.” Intern Med J. 2016;46:470–8.

Laboratory Diagnosis

2If iron deficiency is suspected, it should be confirmed through laboratory testing with:

Complete blood count

Reticulocytes

Iron metabolism parameters

Transferrin saturation (TS) = iron/CTFF

Ferritin

2 NOC No. 30/2015 DGS – Approach, Diagnosis, and Treatment of Iron Deficiency in Adults. Available at: https://www.dgs.pt/?cr=25229

Clinical and Laboratory Interpretation

Reference Values for Iron Deficiency in Adults
Absolute iron deficiency	<30 ng/mL
Functional Iron Deficiency	30–50 ng/mL
Pregnancy	<70 ng/mL
Heart failure	<100 ng/mL
Heart failure	100–300 ng/mL with ST <20%
Active inflammatory bowel disease	<100 ng/mL with ST <20%