Increased methaemoglobin formation caused by smoking habits in Calabar, Nigeria

ABSTRACT

One hundred subjects were recruited for this study, sixty were cigarette smokers while 40 were non-cigarette smokers and were treated as controls. Smokers were classified into heavy smokers, [individuals that consume more than 10 sticks per day] and moderate smokers, [individuals that consume 10 sticks of cigarette or less per day]. Samples were collected into EDTA bottles using standard venopuncture method. Methaemoglobin [MetHb] levels were determined using the method of Evelyn and Malloy. The mean MetHb value in cigarette smokers [4.7 +/- 1.3%] was higher than that of the non-smokers [1.6 +/- 0.2%]. The difference was statistically significant [P<0.05]. Heavy cigarette smokers had markedly increased MetHb level than moderate cigarette smokers [4.2 +/- 0.4%] and control subjects [1.6 +/- 0.2%]. The difference was statistically significant [P<0.05]. This work has indicated a raised level of MetHb in cigarette smokers and markedly higher in heavy smokers than in moderate smokers. MetHb is an inert haemoglobin [Hb] with no functional properties and its presence is associated with reduction in oxygen carrying capacity of the cell and raised oxidation state, which may culminate into generation of superoxide and oxygen free radicals. A condition which could accelerate oxidative damage with subsequent oxidation of haemoglobin. Cigarette smokers are exposed to high risk of developing major physiological, biochemical and haematological changes. These changes may contribute significantly to the haematological and biochemical complications in cigarette smokers. It is concluded that cigarette smoking enhances increased MetHb formation. The findings in this study may form one of the base line data available for the provision of sufficient warning to smokers on the medical consequence of smoking