## 3 Results
### Effect of the duration and frequency of smoking on the mean values of the studied parameters.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter** & **Non-Smokers (35)** & **Smokers (19)** & \(p\)**-Value** \\ \hline TC mg/dL & 154. 9 \(\pm\) 37.9 & 160.1 \(\pm\) 39.7 & 0.65 \\ \hline TG mg/dL & 222.4 \(\pm\) 193.9 & 243.2 \(\pm\) 174.9 & 0.82 \\ \hline HDL-C mg/dL & 44.2 \(\pm\) 15.9 & 41.5 \(\pm\) 10.6 & 0.5 \\ \hline LDL-C mg/dL & 72.5 \(\pm\) 28.8 & 65 \(\pm\) 21.8 & 0.48 \\ \hline TC/HDL ratio & 3.8 \(\pm\) 1.3 & 4.04 \(\pm\) 1.4 & 0.55 \\ \hline RCA (mm) & 0.58 \(\pm\) 0.22 & 0.72 \(\pm\) 0.14 & 0.005 \\ \hline LCA (mm) & 0.62 \(\pm\) 0.13 & 0.70 \(\pm\) 0.14 & 0.04 \\ \hline \end{tabular}  
Smoking was found to increase both RCA and LCA IMTs significantly.  
\end{table}
Table 2: Mean values of the investigated parameters in the study groups.  
Figure 1: Increase in the thickness of the RCA and LCA.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Parameter** & \multicolumn{4}{c}{**Duration (Years)**} & \multicolumn{4}{c}{**Frequency (Cigarettes Per Day)**} \\ \cline{2-7}  & \(\leq\)**5 no: (8)** & **6–10 (4)** & **11–15 (3)** & **16–20 (4)** & \(\leq\)**5 (9)** & **6–10 (6)** & **11–15 (4)** \\ \hline TC mg/dL & 168.2 \(\pm\) 38.1 & 125.8 \(\pm\) 14.4 & 148.1 \(\pm\) 82.2 & 171.7 \(\pm\) 31.9 & 167.1 \(\pm\) 31.3 & 160.9 \(\pm\) 49.5 & 125.5 \(\pm\) 21.9 \\ \hline TG mg/dL & 223.6 \(\pm\) 117.6 & 164.8 \(\pm\) 36.3 & 442.6 \(\pm\) 557.6 & 251.4 \(\pm\) 59.9 & 221 \(\pm\) 58.3 & 294.4 \(\pm\) 260.2 & 138.4 \(\pm\) 47.6 \\ \hline HDL-C mg/dL & 39.6 \(\pm\) 8.9 & 37.8 \(\pm\) 11.1 & 50.9 \(\pm\) 25 & 44.1 \(\pm\) 7.3 & 42.5 \(\pm\) 5.5 & 37.9 \(\pm\) 14.5 & 51 \(\pm\) 4.2 \\ \hline LDL-C mg/dL & 56.0 \(\pm\) 18.25 & 53.0 \(\pm\) 11.30 & 38.5 + 12.02 & 88.0 \(\pm\) 16.70 & 67.8 \(\pm\) 18.89 & 61.8 \(\pm\) 27.23 & 40.0 \(\pm\) 7.07 \\ \hline TC/HDL ratio & 4.5 \(\pm\) 1.7 & 3.4 \(\pm\) 0.7 & 2.9 \(\pm\) 0.22 & 3.9 \(\pm\) 0.86 & 3.9 \(\pm\) 0.79 & 4.5 \(\pm\) 1.8 & 2.5 \(\pm\) 0.64 \\ \hline RCA (mm) & 0.71 \(\pm\) 0.13 & 0.74 \(\pm\) 0.16 & 0.6 \(\pm\) 0.1 * & 0.83 \(\pm\) 0.1 * & 0.76 \(\pm\) 0.13 & 0.67 \(\pm\) 0.14 & 0.7 \(\pm\) 0.28 \\ \hline LCA (mm) & 0.68 \(\pm\) 0.14 & 0.75 \(\pm\) 0.13 & 0.6 \(\pm\) 0.1 & 0.8 \(\pm\) 0.14 & 0.76 \(\pm\) 0.12 & 0.64 \(\pm\) 0.12 & 0.60 \(\pm\) 0.28 \\ \hline \end{tabular}  
* There was a significant variation between the mean IMTs of the right carotid artery for smokers aged 11 to 15 and for those aged 16 to 20 years (\(p\)-value = 0.035).  
\end{table}
Table 3: The effect of the duration and frequency of smoking on the mean values of the studied parameters.  
The duration of smoking had an insignificant increase effect on all of the parameters studied except for the TC/HDL-C ratio, which decreased, whereas the frequency of smoking decreased all the studied parameters insignificantly, except for the HDL-C concentration, which increased.  
The frequency of smoking decreased all the studied parameters insignificantly, except for the HDL, which experienced an insignificant increase (Table 3). The frequency of smoking was correlated inversely with total cholesterol ([PERSON]'s correlation = \(-0.271\)), triglycerides ([PERSON]'s correlation = \(-0.005\)), the HDL-C ([PERSON]'s correlation = \(-0.005\)), LDL-C ([PERSON]'s correlation = \(-0.64\)), the cholesterol/HDL ratio ([PERSON]'s correlation = \(-0.139\)), the IMT of the RCA ([PERSON]'s correlation = \(-0.226\)) and the IMT of the LCA ([PERSON]'s correlation = \(-0.454\)). The inverse correlation of the frequency of smoking and the LDL-C and the IMT of the left carotid artery was significant (\(p\)-value = 0.034 and \(p\)-value = 0.045, respectively).