Introduction:
Several studies have examined the association between adipose tissue distribution and atherosclerosis. However, the effect of smoking on this association has not been evaluated yet.
Hypothesis:
We assessed the hypothesis that there is positive association between the ratio of visceral and subcutaneous adipose tissue areas and carotid intima media thickness (CIMT), and the association can be modified according to gender and smoking status in South Korea.
Methods:
A total of 1,606 middle-aged participants without cardiovascular disease were enrolled in this cross-sectional study from 2013 to 2015 in South Korea (568 men; 1,038 women). The CIMT of study participants was measured using B-mode ultrasonography at distal right common carotid artery, based on a predetermined protocol. We measured the abdominal adipose tissue distribution of study participants using computerized tomography. The area of adipose tissue at L4 vertebrae level was calculated, and the area of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were separated by abdominal wall. Then, we calculated the ratio of VAT and SAT (VAT/SAT) area. Other major cardiovascular risk factors were measured by standardized questionnaire, physical exam and fasting blood analysis. Smoking status of study participants was classified into three groups: current, former and never smokers. For evaluating the association between adipose tissue area and CIMT, we used multiple linear regressions. Separated analyses based on gender and smoking status were also performed.
Results:
Mean CIMT of study participants was 0.62 mm (SD, 0.12 mm), and mean VAF/SAF ratio of study participants was 0.62 (SD, 0.29). The prevalence of current smoker was 36.8% (209 of 568) for men, and 4.1% (42 of 1038) for women. In our multiple linear regression models, the VAT/SAT ratio showed statistically significant positive β-coefficient for total participants (β =8.62, p=0.008): showing significant for men (β =15.95, p=0.001) and not for women (β =3.15, p=0.377). When considering men only with respect to smoking status, the association between VAT/SAT ratio and CIMT was significant for current smokers (β=30.37, p<0.001), while it was not for never smokers (β=0.62, p=0.958) and former smokers (β=12.84, p=0.119). There was no significant interaction for gender and also for smoking status for men (p for interaction>0.05).
Conclusions:
In conclusion, the VAT/SAT ratio was positively associated with CIMT, and more preeminent positive association was observed for current men smokers than for never and former men smokers. The results of this study supported the need of smoking cessation to prevent atherosclerosis by adipose tissue distribution, especially for men.
Automated analysis of liver fat, muscle and adipose tissue distribution from CT suitable for large-scale studies
