Background: Metabolic syndrome (MetS) is a cluster of risk factors for CVD and DM2 that includes abdominal obesity, hypertension, hyperglycemia, and dyslipidemia. While cigarette smoking has been associated with MetS risk factors in adults, young adulthood is an under-studied, susceptible period for developing long-term morbidity and mortality related to MetS.
Objective: This study aims to examine the association between cigarette smoking and MetS in Chilean young adults. We hypothesized that cigarette smoking, even at low levels of exposure (< 30 per week), is associated with an increased risk of developing MetS in young adults.
Methods: We studied 243 Chilean young adults who were part of infancy studies related to iron deficiency and recruited for a study of cardiovascular risk at age 16. Participant BMI, waist circumference, blood pressure, fasting serum glucose, cholesterol, triglycerides, and HDL were measured. MetS was defined using IDF and AHA/NHLBI criteria, and MetS risk z-scores were calculated using published equations. Participants self-reported smoking and drinking habits using standardized questionnaires. Logistic regressions examined associations between smoking and each MetS risk factor. All models were adjusted for sex, MetS at adolescence, and frequency of alcohol consumption.
Results: Participants were mean 22.5 years old and 49.8% male (121 of 243). The prevalence of obesity and MetS was 24.3% (59 of 243) and 15.3% (37 of 243) respectively. Among smokers (125 of 243), mean age of smoking initiation was 14.6 years and mean consumption was smoking 28 cigarettes per week. Smokers had significantly higher fasting serum glucose levels, lower HDL, and higher MetS risk scores compared to non-smokers. Smoking was significantly associated with greater odds of fasting hyperglycemia (OR 2.41, CI 1.04 - 5.59) and low HDL (OR 1.87, CI 1.05 - 3.31).
Conclusion: Cigarette smoking was associated with MetS risk factors, specifically fasting hyperglycemia and low HDL cholesterol levels, in a population-based sample of Chilean young adults. Since our sample had low levels of smoking exposure (< 30 cigarettes per week), these risk factors may herald the onset of MetS associated with light cigarette smoking. Increased emphasis should be placed on preventing the initiation of smoking or promoting cessation during this crucial risk period.