In this study, adult male smokers with heart disease had significantly decreased serum concentrations of retinol, alpha-tocopherol, and selenium, and increased concentrations of copper, compared to non-smokers. Depression of trace elements in blood was more with increasing doses of smoking.
In a study in Turkey, plasma selenium, copper, zinc and iron concentrations, and the activities of related erythrocyte antioxidative enzymes copper-zinc superoxide dismutase (Cu-Zn SOD), catalase, and glutathione peroxidase (GSH-Px) were measured in tobacco smokers and compared with those of nonsmokers . Plasma thiocyanate levels were measured as an index of smoking status. While plasma copper concentration and erythrocyte Cu-Zn SOD activity were significantly higher, plasma selenium concentration and erythrocyte GSH-Px activities were significantly lower in tobacco smokers than in nonsmokers. We did not measure antioxidative enzyme levels in blood; however, our study had consistency with earlier findings of decreased serum concentrations of selenium and increased concentrations of copper among smokers. Kocyigit et al.  did not observe any significant effect of smoking on zinc or iron status. Our observation of a significantly depressed zinc status only among heavy smokers (those who smoked 21 or more sticks per day) compared to non-smokers was consistent with findings of Uz et al. in Turkey .
Several studies documented that smoking may increase oxidative stress and impair oxidant defense system . Serum selenium glutathione peroxidase, glutathione reductase, and extracellular superoxide dismutase activities were found lower in smokers than in non-smokers. Serum ascorbic acid and folate concentrations were lower in smokers than in non-smokers, whereas serum thiobarbituric acid-reactive substances (TBARS) were higher. However, Kim et al. (2003) did not observe any effect of smoking on serum copper, iron, and magnesium concentrations .
In a later study, Kim et al. (2004) further evaluated the influence of short– and long-term cigarette smoking on blood antioxidant status among Korean teenage girls (aged 14 to 18 y) and adult males (aged 36 to 51 y) . Extracellular superoxide dismutase activities and concentrations of serum vitamin C and folate were lower in both short-term and long-term smokers. Serum copper concentrations were higher only among long-term smokers compared to non-smokers. In our study, we observed increased serum concentrations of copper among grade II and grade III smokers (those who smoked 16 or more sticks per day) but not among grade I smokers (those who smoked 10–15 sticks per day), as compared to non-smokers. Both the studies suggest that probably an increasing dose of smoking modify serum copper status more compared to those who smoke less or do not smoke at all. However, cigarette smoking, irrespective of dose or duration, had negative effects on antioxidant status in the Korean study .
Increasing evidence suggests that smoking is a causal factor for coronary heart disease and stroke. In a prospective study in Japan , 19,782 men and 21,500 women aged 40 to 59 years who were free of prior diagnosis of stroke, coronary heart disease, or cancer and reported their smoking status were followed. During a 461,761 person-year follow-up, relative risks (95% CIs) for current smokers compared with never-smokers were 1.27 (1.05 to 1.54) for total stroke, 0.72 (0.49 to 1.07) for intraparenchymal hemorrhage, 3.60 (1.62 to 8.01) for subarachnoid hemorrhage, and 1.66 (1.25 to 2.20) for ischemic stroke.
One of the limitations of our study is that it is difficult to establish any causal association of heart disease and deficiency of trace elements or increased isolation of Streptococcus β-hemolyticus among our study subjects, because it is a cross-sectional study. However, epidemiologic evidence has suggested a modifying role for antioxidant micronutrients, including tocopherols and carotenoids, in atherosclerosis and heart disease. In an experimental study, Handelman et al. (1996) exposed freshly obtained human plasma to the gas phase of cigarette smoke to assess its effects on tocopherols, carotenoids, and retinol. Exposure to cigarette smoke led to the depletion of most of the lipophilic antioxidants in human plasma .
In addition to the impact on health, tobacco smoking represents a major economic burden for impoverished Bangladeshis. Average male cigarette smokers spend more than twice as much on cigarettes as per capita expenditure on clothing, housing, health and education combined. The typical poor smoker could easily add over 500 calories to the diet of one or two children with the daily tobacco expenditure . It may be noted that most of the study subjects were undernourished, as indicated by an average BMI of 23. Strong tobacco control measures are needed in the context of Bangladesh to decrease tobacco expenditures and thus significantly increase resources and improve health and nutrition of the people.