The effect and correlation of smoking with platelet indices, neutrophil lymphocyte ratio and platelet lymphocyte ratio

Introduction: Smoking is associated with the occurrence and progression of cardiovascular diseases, inflammatory disorders and malignancies. Objective: To study the platelet indices, neutrophil lymphocyte ratio (NLR) and platelet lymphocyte ratio (PLR) in smokers and their correlation with smoking pack-years. Method: A total of 110 smokers and 110 non-smokers were included. The smokers were grouped into three groups: mild (<5 pack-years), moderate (5-10 pack-years) and heavy (>10 pack-years). The platelet count, plateletcrit (PCT), mean platelet volume (MPV) and platelet distribution width (PDW) were noted. The NLR and PLR were calculated and the statistical analysis was made using the Student's T-test, Analysis of Variance (ANOVA) and Spearman's correlation coefficient. Results: The platelet count, PCT and PDW were significantly higher with mean values: 218.56 +/- 121.31 vs 203.23 +/- 80.35 (p-value = 0.038), 0.27 +/- 0.10 vs 0.26 +/- 0.10 (p-value = 0.041) and 12.54 +/- 1.45 vs 11.99 +/- 1.70 (p-value = 0.001) in smokers and non-smokers, respectively. The PLR differed significantly with mean values: 119.40 +/- 84.81 in smokers and 181.99 +/- 313.09 in non-smokers, with a p-value of 0.045. A significant positive correlation was found between pack-years of smoking and platelet count and PLR with the Pearson correlation coefficient of 0.250 and 0.198 and p-values, 0.008 and 0.037, respectively. The Platelet Count, PCT, MPV and PDW varied significantly between mild, moderate and heavy smoker groups, with p-values of 0.045, 0.010, 0.015 and 0.017, respectively. Conclusion: The platelet indices and inflammatory markers NLR and PLR are derived from routine blood investigations, which are easily available and inexpensive. The monitoring of platelet indices, along with the PLR, can be used as early predictors of morbidity in smokers. (C) 2020 Associacao Brasileira de Hematologia, Hemoterapia e Terapia Celular. Published by Elsevier Editora Ltda.