From the Guidelines
Smoking exacerbates anemia by reducing iron stores at birth and increasing fetal iron utilization for erythropoiesis in response to chronic fetal hypoxia.
- Impaired placental function due to smoking during pregnancy results in placental vascular insufficiency, reducing iron stores at birth 1.
- This reduction in iron stores can lead to a higher risk of anemia in infants, particularly in low-birth-weight infants or those born to mothers with impaired placental function 1.
- Furthermore, smoking can lead to chronic fetal hypoxia, which increases fetal iron utilization for erythropoiesis, further reducing iron stores 1.
- In patients with underlying anemia, smoking cessation is recommended, and in some cases, supplementation with iron and vitamin B12 may be necessary to manage the condition.
- The American and European guidelines advise to start iron supplements between 2 and 6 weeks of age in preterm infants born <32 weeks, in low-birth-weight infants weighing less than 2000 g, and in marginally-low-birth weight infants weighing 2000–2500 g at least up to 6 months, as they are at higher risk of ID(A) because of their lower iron endowment at birth 1.
From the Research
Effect of Smoking on Anemia
- Cigarette smoking can cause numerous diseases associated with anemia, but it may also increase red blood cell production due to chronic exposure to carbon monoxide, counterbalancing the low hemoglobin levels 2.
- Chronic cigarette smokers often have elevated carboxyhemoglobin (COHb) concentrations, which can lead to polycythemia, a condition characterized by an increased number of red blood cells 3.
- The relationships among cigarette smoking, hemoglobin concentration, and carboxyhemoglobin concentration were examined, and it was found that smokers had higher mean hemoglobin levels than never-smokers, which reduces the utility of hemoglobin level to detect anemia 4.
Mechanisms Involved
- Cigarette smoke can augment the production of pro-inflammatory cytokines and decrease the levels of anti-inflammatory cytokines, leading to elevated IgE concentrations and the development of atopic diseases and asthma 5.
- The increased COHb levels in smokers can lead to a generalized upward shift of the hemoglobin distribution curve, making it more difficult to detect anemia using traditional hemoglobin cutoff values 4.
Prevalence of Anemia in Smokers
- The prevalence of anemia was found to be lower among smokers compared to never-smokers, likely due to the masking effect of smoking on the detection of anemia 4.
- The study suggests that minimum hemoglobin cutoff values should be adjusted for smokers to compensate for the masking effect of smoking on the detection of anemia 4.