4Iron deficiency and iron deficiency anaemia in women
Introduction
Iron deficiency (ID) is the commonest micronutrient deficiency worldwide and is defined as a reduction of total body iron ∗[1], ∗[2] As a result, there may be impairment of oxygen transportation and enzyme reactions involved in nearly all major metabolic pathways. ID may occur with or without anaemia defined as a decreased quantity of erythrocytes or level of haemoglobin associated with morphological changes in erythrocytes ∗[3], ∗[4]. Anaemia has been wrongly considered as an indicator of ID. However, it is only with progressive iron depletion and its associated functional impairment that anaemia finally develops [5]. Furthermore, haemoglobin concentration has a low sensitivity and specificity for ID [6].
Iron-restricted erythropoiesis and functional ID occur in those with chronic inflammation, cancer or renal disease. This is because inflammatory processes impair the delivery of iron to red cell precursors, irrespective of iron stores, with mobilisation of iron from stores insufficient to meet metabolic demands. This can also be observed following treatment with erythropoiesis-stimulating agents [1].
Section snippets
Incidence and prevalence of ID/IDA
Anaemia is a global health problem affecting both low- and high-income countries with social and economic consequences for all [7]. Anaemia impairs the health and well-being of women and increases the risk of adverse maternal and neonatal outcomes [8]. Worldwide anaemia accounted for 68.4 million years of life lived with a disability in 2010, an increase from 65.5 million years of life in 1990 [3]. However, during this time frame, the prevalence of anaemia decreased from 40.2% to 32.9% [3]. The
Iron metabolism and its role in the body's physiological processes
Iron is crucial for cellular functions including respiration, oxygen transport, DNA synthesis, energy production and cell proliferation [1]. It mediates electron transfer with iron acting as an electron donor in the ferrous state and an acceptor in the ferric state. However, excess iron is toxic. To ensure iron requirements are met but toxicity is prevented, a tightly regulated homeostatic system operates to maintain levels within normal ranges. The controller of this system is the peptide
Clinical presentation
ID/IDA are chronic conditions that may be asymptomatic. Symptoms can include weakness, fatigue, irritability, hair loss, poor concentration and poor work performance, resulting from reduced enzyme activity and oxygen delivery to tissues [1]. Many of these symptoms are also associated with HMB [13].
There is a higher prevalence of constant tiredness in young and middle-aged women with ID (67% and 63%, respectively) compared with those without ID (45% and 48%, respectively) [14]. In a recent
Aetiology of ID/IDA
RDI of iron for women of reproductive age is 18 mg, although the median is 12 mg to combat loss due to menstruation. ID/IDA occurs when loss or requirements exceed absorption. The causes of ID/IDA are often multifactorial [12]. In general, there are four broad causative categories: increased loss of iron, decreased intake of iron in the diet, decreased absorption of iron from the gut and an increased iron requirement [15] (see Table 2). Blood loss is an important cause of ID/IDA, as there is
Diagnosis, assessment and investigation of ID and IDA
The WHO defines anaemia as a haemoglobin concentration of <130 g/L in men, 120 g/L in non-pregnant women and 110 g/L in pregnant women [10] (see Table 3). Pavord et al. (2012) recommended that in pregnancy, anaemia is diagnosed when haemoglobin is <110 g/L in the first trimester, <105 g/L in the second and third trimesters and <100 g/L during the postpartum period [2] (Table 3).
As the normal range for haemoglobin varies in different populations, a pragmatic approach is to define anaemia as a
Management of ID/IDA
The presence ID/IDA requires further investigation in all individuals to ensure that pathology is not missed. A comprehensive history should be taken and additional investigations ordered, depending on the key findings [17]. It is recommended that urinalysis is also undertaken for all patients diagnosed with ID as 1% of these patients will have an underlying renal tract malignancy [17].
Simply increasing dietary iron intake is insufficient to treat IDA. Replacement therapy is intended to correct
Conclusion
Iron plays a pivotal role in the metabolic pathways of the body. Worldwide ID and IDA are highly prevalent with the increased iron need associated with normal menstrual loss largely unmet. Women with HMB are at a higher risk of ID and IDA; therefore, we need to carefully evaluate and investigate our patients for the possibility of these conditions and where appropriate commence iron therapy. Furthermore, it is important that both the underlying cause and anaemia are managed effectively. Simply
Disclosure of interest
Dr Percy has received financial support to undertake training from Bayer.
Dr Mansour has received financial support to attend pharmaceutical advisory board meetings, undertake research studies and speak in educational meetings and conferences together with travel grants from Aspen, Astellas, Bayer, Consilient Healthcare, HRA Pharma, Mithra, Merck, Pfizer and Vifor Pharma.
Professor Fraser has received financial support to attend pharmaceutical advisory board meetings, undertake research studies
Author contribution
Laura Percy conducted the research and wrote the first draft. Diana Mansour revised the initial plan and edited the article. Ian Fraser instigated the article, wrote the initial plan and undertook the final edit. All authors have approved the final version.
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