Effects of cigarette smoking on erythrocyte sedimentation rate, platelet count, total and differential leucocyte counts in adult male smokers

Received 05 March 2019 Revised 26 March 2019 Accepted 27 March 2019 Online 28 March 2019 Print 31 March 2019 Smoking is one of the leading causes of death worldwide. Smokers have higher risk for coronary heart disease, atherosclerosis, acute myocardial infarction, hypertension, clotting disorders, inflammation, respiratory diseases, cancers, etc. A cigarette smoker is exposed to a number of harmful substances. In this study we hypothesized that smoking causes inflammatory reactions and induces hyperthrombic state in the body which may be reflected in erythrocyte sedimentation rate (ESR), total leucocyte count (TLC), differential leucocyte count (DLC) and platelet count values. The purpose of the study was to study the effects of cigarette smoking on erythrocyte sedimentation rate, total leucocyte count and platelet count in adult male smokers and to compare the results with non-smokers and to establish a relationship between the duration and quantity of smoking with the change in ESR, TLC, DLC and platelet count. A cross sectional study was conducted in the department of Pathology on 86 healthy male subjects (smokers=43 and non-smokers=43). ESR was estimated using Westergrens method. TLC, DLC and platelet counts were estimated using HORIBA Pentra ES60 auto-analyzer. TLC and basophil counts were significantly higher in smokers than in non-smokers (p<0.05). The mean value of ESR was higher among smokers than non-smokers but it was statistically insignificant. Platelets counts showed no significant difference between smokers and nonsmokers. No correlation was observed in various blood parameters and smoking (in pack years). We conclude that smoking initiates an inflammatory response as evidenced from raised TLC, monocyte and basophil counts. Keywords

Smoking is one of the leading causes of death worldwide. Smokers have higher risk for coronary heart disease, atherosclerosis, acute myocardial infarction, hypertension, clotting disorders, inflammation, respiratory diseases, cancers, etc. A cigarette smoker is exposed to a number of harmful substances. In this study we hypothesized that smoking causes inflammatory reactions and induces hyperthrombic state in the body which may be reflected in erythrocyte sedimentation rate (ESR), total leucocyte count (TLC), differential leucocyte count (DLC) and platelet count values. The purpose of the study was to study the effects of cigarette smoking on erythrocyte sedimentation rate, total leucocyte count and platelet count in adult male smokers and to compare the results with non-smokers and to establish a relationship between the duration and quantity of smoking with the change in ESR, TLC, DLC and platelet count. A cross sectional study was conducted in the department of Pathology on 86 healthy male subjects (smokers=43 and non-smokers=43). ESR was estimated using Westergrens method. TLC, DLC and platelet counts were estimated using HORIBA Pentra ES60 auto-analyzer. TLC and basophil counts were significantly higher in smokers than in non-smokers (p<0.05). The mean value of ESR was higher among smokers than non-smokers but it was statistically insignificant. Platelets counts showed no significant difference between smokers and non-smokers. No correlation was observed in various blood parameters and smoking (in pack years). We conclude that smoking initiates an inflammatory response as evidenced from raised TLC, monocyte and basophil counts.

Materials and methods
A cross-sectional study was conducted in the department of Pathology of our medical college between May and June 2016. A total of 86 male subjects (smokers: 43; non-smokers: 43) in the age group of 18-40 years were included in the study. Ethics approval was obtained from Institutional Review Board (IRB number: 2016/11/003) before the start of this study.

Selection of subjects
Inclusion criteria: Apparently healthy smokers (n=43) in the age group 18-40 years who smoke one or more cigarette per day and healthy nonsmokers (n=43) of the age group 18-40 years were included in the study.
Exclusion criteria: Male subjects suffering from coagulation disorders, hypertension, diabetes, infections, acute or chronic respiratory illness or debilitating illness have been excluded from the study. Male subjects taking non-steroidal antiinflammatory drugs (NSAIDs) or any other antiplatelet aggregation drugs were excluded from this study. Non-smokers who are subjected to passive smoking were also excluded from the study.

Methodology
The subjects were divided into 2 groups i.e. smokers (n=43) and non-smokers (n=43). Informed consent was obtained from each subject. The particulars of the subjects and required history were taken from all the subjects. Under aseptic precautions, 4ml venous blood sample was collected from the median cubital vein using a 5ml disposable syringe. 2ml of blood was mixed in K3 EDTA containing vacutainer for estimation of red blood cell (RBC) count, hemoglobin (Hb) concentration, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RCDW), total leucocyte count (TLC), differential leucocyte count (DLC) i.e. counts of neutrophils, eosiniphils, basophils, lymphocytes and monocytes; platelet count, plateletcrit, mean platelet volume (MPV), platelet distribution width (PDW) using HORIBA Pentra ES60 auto-analyzer. Additional parameters documented were atypical lymphocytes and large immature cells. 2ml of blood was mixed in 3.8% trisodium citrate (in the ratio of 1:4) containing vacutainer for estimation of erythrocyte sedimentation rate by Westergren's method. The samples were evaluated within 1 hour of sample collection.
Manual confirmation of platelet count was done in few samples by making blood smear and staining with Leishman's stain and examination under microscope. Controls were used prior to testing on auto-analyzer for quality control.

Statistical analysis
Data collected was analyzed using independent sample 't' test and partial correlation available in SPSS 17.0 statistical software (SPSS Inc., Chicago, USA).   Table 1 shows the mean values of hematological parameters. ESR was higher in smokers than nonsmokers but the difference was not statistically significant. Total leucocyte count (TLC) was significantly higher (p=0.019) in smokers than in non-smokers (Figure 1). Counts of monocytes (p=0.021) and basophils (p=0.023) were significantly higher among smokers. RBC count, hematocrit and hemoglobin concentration was not significantly different between the two groups. Among RBC indices, only MCHC was significantly different between smokers and non-smokers. Platelet counts, plateletcrit and platelet indices showed no significant difference between smokers and non-smokers.

Figure 1. Differences in TLC between smokers and non-smokers
Also there was no significant linear relationship observed between various hematological parameters and cigarette smoking (in pack years). Figure 2 shows the distribution of smokers into groups based on pack years.

Discussion
The present study was done to document any change in total leucocyte count (TLC), differential leucocyte count (DLC), platelet count and erythrocyte sedimentation rate (ESR) among smokers and non-smokers and to evaluate any relationship between hematological values and duration/intensity of smoking among smokers. As the previous studies did not delve into the effect of chronicity of smoking and the intensity of smoking on the TLC, platelet count and ESR, this is the newer dimension in this study. found that platelet counts were significantly increased in smokers when compared to nonsmokers whereas Sandhya et al [18] concluded that the platelet counts of chronic smokers were significantly lower than that of non-smokers and decreased significantly with increase in duration of smoking.

Limitations of the study
Sample size was relatively small for such type of case-control study. Since the hematological parameters are having wide range of normalcy, the differences in many parameters was not evident.

Conclusion
We found no statistically significant difference in erythrocyte sedimentation rate and platelet count of smokers and non-smokers. There was a significant increase in total leucocyte count, basophil count and monocyte count in smokers when compared to non-smokers which indicate inflammation in the body. As these changes are occurring in young healthy men with no other risk factors, smoking cessation can reduce the risk of developing cardiovascular and respiratory problems in future.