The relationship between metabolic syndrome and smoking: A case-control study

Objective: This study aimed to evaluate the association between smoking and metabolic syndrome among individuals aged 18–70 who applied to the Smoking Cessation Clinic of Afyonkarahisar Health Sciences University, Department of Family Medicine. Materials and Methods: This retrospective case-control study included data from 229 smokers and 295 non-smokers. Sociodemographic characteristics, clinical measurements, biochemical parameters, and smoking-related information were collected. Statistical analyses were conducted using IBM SPSS Statistics for Windows, version 26.0, with a significance level set at p<0.05. Results: The overall prevalence of metabolic syndrome was 26.71% (n=140), and it was significantly higher in smokers (34.5%) compared to non-smokers (20.7%) (p<0.001). Systolic blood pressure, height, and waist circumference were significantly higher in the smoking group (p<0.05). While HDL levels were higher in non-smokers, triglyceride levels were higher in smokers (p<0.05). Smokers also showed higher MetsCalc Z-scores (based on BMI and waist circumference) and atherogenic index of plasma (AIP) values (p<0.001). The proportion of individuals with high AIP risk was greater in smokers (32.3%) than in non-smokers (14.9%) (p<0.001). Among smokers, males had higher total cholesterol, waist circumference, and AIP values, whereas females had higher HDL levels (p<0.05). Heavy smokers exhibited significantly higher systolic/diastolic blood pressure, waist circumference, BMI, fasting glucose, LDL, total cholesterol, triglycerides, AIP, MetsCalc Z-scores, and FTND scores, while their HDL and oxygen saturation were lower (p<0.05). Both metabolic syndrome prevalence and high AIP risk were significantly increased in heavy smokers (p=0.022; p=0.003). Conclusion: In this study, smokers had higher levels of metabolic syndrome, AIP, waist circumference, and triglycerides, along with lower HDL levels. Additionally, heavy smoking was associated with a marked increase in metabolic risk. These findings suggest that smoking poses a significant burden on metabolic health and highlight the importance of early metabolic risk assessment in this population. Keywords: Smoking, Metabolic Syndrome, Atherogenic Index of Plasma, MetSCalc, Z-Score, Fagerström