Protection by Physical Activity Against Deleterious Effect of Smoking on Carotid Intima-media Thickness in Young Japanese

BackgroundThe hazardous effects of smoking and the favorable influence of physical activity on the progression of atherosclerosis have been well studied, but little is known about the interactions of these 2 factors.MethodsA total of 1090 subjects who were screened for brain disease (at annual medical checkups) between April 2007 and March 2008 were studied to clarify the effects of smoking on maximum carotid intima-media thickness (IMT) in patients with different grades of physical activity. Univariate and multivariate analyses were performed to investigate relationships between maximum IMT and independent variables, such as smoking status, age, gender, coexisting disease, physical activity, alcohol drinking, family history, subjective symptoms, body mass index, systolic blood pressure, diastolic blood pressure, blood sugar, total cholesterol, high-density lipoprotein cholesterol, and triglycerides.ResultsUnivariate analysis revealed only the low physical activity group to have a significant relationship between smoking and maximum IMT. When the subjects were divided into 3 age groups (≤49, 50-59, and ≤60 years of age, respectively), the same association was noted for high and moderate physical activity groups ≤49 years of age. Multivariate analysis further revealed smoking status to be a significant predictor of maximum IMT in the young low and moderate activity groups.ConclusionsIn physically inactive young people, smoking might have detrimental effects on maximum IMT, while high physical activity may be protective.