Methemoglobin Levels in Smokers and Non-Smokers

Abstract

The authors analyzed the blood of a group of 336 smokers and 336 non-smokers to determine if tobacco smoke, potentially the major source of nitrogen oxide pollution for 40% of the adult population, significantly reduces oxygen carrying capacity as a result of methemoglobin formation. Each blood sample was analyzed for carboxyhemoglobin, methemoglobin, and hemoglobin using an automated spectrophotometer. The mean value of methemoglobin in the smokers did not exceed that in the non-smokers; in fact, the level in the non-smokers was significantly greater. As expected, carboxyhemoglobin levels in smokers substantially exceeded those in non-smokers. The authors conclude that methemoglobin arising from cigarette smoke exposure does not interfere with the oxygen carrying capacity of the blood in smokers.

The Role of Methemoglobin and Carboxyhemoglobin in COVID-19: A Review

“…According to the case reports of Kuipers et al [17], Al-Aamri et al [23], Palmer et al [22], Faisal et al [20], and Naymagon et al [18], MetHb values for COVID-19 patients were above the reference range of 0.67 ± 0.33% for healthy non-smokers (Borland et al 1985) with the highest MetHb value of >30% for a patient reported by Naymagon et al [18].…”

“…Visualization of (a) methemoglobin (MetHb) and (b) carboxyhemoglobin (COHb) values of COVID-19 patients reported in the literature. The green shaded areas refer to the reference ranges for healthy individuals in case of MetHb (0.67 ± 0.33% for healthy non-smokers [15]) and COHb (0.5-1.5% for healthy non-smokers [16]). Different subjects reported in the case reports are marked with "#", and red lines with arrows indicate the development of subject-specific values during the course of the disease.…”

“…(d) Time-course of MetHb of a COVID-19 patient reported by Palmer et al [22]. The yellow bar refers to the MetHb reference range for healthy non-smokers [15]. The figures show data extracted from the original figures of the respective publications.…”

“…The resulting COHb limits the blood's O2-carrying capacity [14]. In healthy, non-smoking individuals, MetHb is in the range of 0.67 ± 0.33% [15] and COHb in the range of 0.5%-1.5% [16].…”

Evaluation of oxidative stress and whole blood viscosity for clinical laboratory testing of smoking toxicity

“…28,29 Further, oxidative damage has been implicated in various diseases and it seems that the mechanism of air pollution-induced health effects involves oxidative stress. 30 Increased malondialdehyde levels in breath after experimentally exposing adult human subjects to wood smoke in a controlled environment is an example of this effect.…”