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Saudi Journal of Kidney Diseases and Transplantation
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Year : 2009  |  Volume : 20  |  Issue : 5  |  Page : 862-866
Prevalence of cigarette smoking and khat chewing among Aden university medical students and their relationship to BP and body mass index

1 Director General of Health Affairs, Aden, Associate Professor of Surgery, Aden, Yemen
2 Medical Student, Aden University, Aden, Yemen

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Date of Web Publication2-Sep-2009


To evaluate the smoking and khat chewing habits in male Aden University medical students and correlate them with blood pressure (BP), body mass index (BMI), and year of training, we randomly selected 100 students of different levels of training and measured their BP, height, and weight, and evaluated their cigarette smoking and khat chewing habits. The mean age of the whole group was 31.8 years. The mean BMI was 23.24 with a range from 22.6 in the in first year medical students to 24.7 (4.4) in 5 th year medical students (P= 0.127). The mean SBP, DBP, and MBP were 120.35, 70.47 and 87.1 mmHg, respectively, and did not change over the years of training. Preva­lence of smoking increased from 20% to 40% and khat chewing from 35% to 90% over the 5 years of training (P= 0.0003). There was a tendency for positive correlation between age and weight, BMI and frequency of khat chewing, and BMI and MBP. We found high prevalence of smoking and khat chewing among the medical students at Aden University and their prevalence increases with student seniority with no significant changes in BMI, SBP, DBP or MBP. There was a weak positive correlation between BMI with SBP, MBP and frequency of Khat chewing.

How to cite this article:
Laswar AN, Darwish H. Prevalence of cigarette smoking and khat chewing among Aden university medical students and their relationship to BP and body mass index. Saudi J Kidney Dis Transpl 2009;20:862-6

How to cite this URL:
Laswar AN, Darwish H. Prevalence of cigarette smoking and khat chewing among Aden university medical students and their relationship to BP and body mass index. Saudi J Kidney Dis Transpl [serial online] 2009 [cited 2022 Sep 29];20:862-6. Available from: https://www.sjkdt.org/text.asp?2009/20/5/862/55381

   Introduction Top

A large proportion of the Yemeni and East African population chews khat leaves on daily basis. A khat sitting usually lasts from 4 to 6 hours. Chewed khat come in the form of leaves of catha edulis Forsk leaves (khat). Its active ingredient is cathinone, which has a mild stimu­lant effect. [1] Cathinone is structurally and phar­macologically similar to amphetamine. [1],[2],[3] Khat produces a modest degree of euphoria and slight hypomania. [4] It results in insomnia and appears to improve the users' alertness and concentration. That is why some students use it and believe that it enhances their memorization and prepa­rations before examinations. [4] However, it may result in a number of significant health and medical adverse effects and has major socioeco­nomic negative consequences

A few studies showed that khat chewing causes an increase in pulse rate, systolic and diastolic blood pressures (BP) [5] observed maximally at 3 hour from starting chewing khat and decline one hour after the end of the chewing session. These changes in BP and pulse coincide with the blood levels of cathinone. [6]

There are no available precise figures on the exact prevalence of khat usage among Yemenis but most observers agree that most male adults use it. In one large study in Yemen, 82 % of men and 43% of women reported at least one life­time use of khat. [7] Smoking is unfortunately widely spread among Yemenis whose cigarette consumption is one of the highest in the Arab world. In fact Bawazeer et al in 1999 found that 19.6% of Aden secondary school students smoke. [8]

In this study, we evaluate the smoking and khat chewing habits in male Aden University medical students and correlate them with BP, body mass index (BMI), and year of training.

   Subjects and Methods Top

This cross-sectional study involved 100 male medical students, 20 from each of the 5 years of training, was performed in 2004. The students were randomly selected, and they were asked about their smoking and khat chewing habits, then their parameters were studied and included: age, weight, systolic blood pressure (SBP) and diastolic blood pressure (DBP). The blood pres­sure was measured in the sitting position, after a 5 minutes rest, using a sphygmomanometer. The BP measurement was performed between 10 AM and 12 Noon at latest 14 hours after khat che­wing in those who indulge in this habit. The mean of two BP readings at 5 minute interval was re­corded. The SBP was measured at the 1st Korot­koff phase and the DBP at the 5 th Korotkoff phase. The mean blood pressure (MBP) and the body mass index (BMI) were calculated.

   Statistical Analysis Top

Statistical analysis was performed using SPSS 12.0 software. We investigated whether any of these parameters change with the years spent in the medical school by comparing the findings in the 5 yearly groups using the two-tailed inde­pendent t test for parametric variables and chi square for non-parametric variables. Scores were given corresponding to the frequency of khat chewing as follows: 0 =non-chewers, 1= once/week, 2= twice/week, 3= thrice/week, 4= > thrice/week. Using logistic regression analysis we investigated the correlation between BP and BMI, BP and age, and BP and stage of training and to the smoking and khat chewing habits. P< 0.05 was considered as statistically significant level.

   Results Top

The mean BMI was 23.24 (rising from 22.6 (4.3) in the in first year medical students to 24.7 (4.4) in 5 th year medical students (P=0.127) [Table 1]. The overall mean SBP, DBP, and MBP were 120.35, 70.47 and 87.1 mmHg, res­pectively. These parameters did not change sig­nificantly from the 1 st and 5 th years of medical school [Table 2],[Figure 1].

Twenty-seven percent of the medical students were smokers and 54% chewed khat. The pre­valence of smoking increased from 20% in first year medical students to 40% in 5 th year medi­cal students and that of khat chewing from 35% to 90% (P= 0.0003). The mean score for fre­quency of khat showing rose from 18.9 (13) in first year medical students to 68 (26) in 5 th year medical students (P= 0.001) with a mean overall score of 35.7 (16.8) [Table 1] and [Table 2].

There was a weak positive correlation between age with weight, BMI and frequency of Khat chewing (r= 0.23, P 0.02, r= 0.2, P 0.04 and r= 0.3, P 0.002 respectively).

There was also a weak positive correlation bet­ween BMI with SBP and MBP (r=0.31, P= 0.002 and r= 0.26 and P= 0028 respectively) [Table 3]. There was, however, no correlation between age and BP, or between khat chewing and BP.

   Discussion Top

We found that the resting diastolic, systolic and mean blood pressure levels among young Yemeni medical student to be comparable to those found by others in this age group (mean age 21.8 years range 18-28 years). Using the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treat­ment of High Blood Pressure (JNC 7) guidelines, [9] there was only one student who could be cate­gorized as hypertensive. In addition, there was a positive correlation between the BMI and SBP and MBP. [10] However, there was no correlation between khat chewing and BP. The previously observed rise in BP observed in khat chewers occurs after 3 hours of chewing khat and returns to normal after one hour of cessation of che­wing. [5],[6] .

The prevalence of khat use among medical students as a whole and in each subgroup was lower than that seen in comparable age and sex group in the general population. [7] However, we saw a disturbing increased trend of khat use as the medical students progressed in their training. Possible explanations include the social view that with increasing age there is increasing social acceptance of khat chewing; [7] and that khat is considered by many Yemenis as having an effect of concentrating the mind and keeping one awake for long periods. [11]

The positive correlation between BMI and frequency of Khat chewing would argue against khat chewing as causing anorexia, [4] but may be related to prolonged khat chewing sessions and the general lack of exercise that accompanies this habit.

The prevalence of smoking among medical students as a whole and in each subgroup was lower than that observed in matched age and sex general population. [8] Nonetheless, it is dis­turbing to note a doubling of the prevalence of smoking when comparing 1 st and 5 th year me­dical students. It is interesting that we found no relationship between cigarette smoking and khat chewing. Our findings contrast widely with a study carried out in USA medical students, which found that in male medical students of comparable age (24 years), the prevalence of smoking was only 3.3%. [12] Even more interes­tingly, this rate remained constant throughout the medical training years with no students starting smoking during his training. [12] Even more surprisingly, in a study in Shanghai Me­dical University, where there is a very high prevalence of smoking among the Chinese public, the overall smoking rate among male medical students was found to be 21.4%, [13] which is lower than the prevalence of 27% in our study .

Finally, the prevalence of obesity (defined as BMI > 30) varies from country to country with USA having a prevalence of 30.6% and Japan 3.2% in 2003. [14] Our findings are in keeping with the few available reports which suggest low prevalence of obesity in Yemen. [15]

In conclusion, there is a high prevalence of khat chewing and cigarette smoking among medical students at Aden University, and increases among the senior students. however, there is no evidence of an increase in systolic or diastolic blood pressure in khat chewers and the preva­lence of obesity is very low.

   References Top

1.Kalix P. Pharmacological properties of the stimulant khat. Pharmacol Therap 1990;48: 397-416.  Back to cited text no. 1    
2.Szendrei K. The chemistry of khat. Bull Narcot 1980;32:5-35.  Back to cited text no. 2    
3.Kalix P. Cathinone, alkaloid from khat leaves with an amphetamine-like releasing effect. Psychopharmacology 1981;74:269-70.  Back to cited text no. 3  [PUBMED]  
4.Halbach H. Medical aspects of the chewing of khat leaves. Bull World Health Organ 1972;47:21-9.  Back to cited text no. 4  [PUBMED]  [FULLTEXT]
5.Hassan NA, Gunaid AA, El-Khally FM, Al­Noami MY, Murray-Lyon. Khat chewing and arterial blood pressure. A randomized controlled clinical trial of alpha-1 and selective beta-1 adrenoceptor blockade. Saudi Med J 2005;4:537-41.  Back to cited text no. 5    
6.Halket JM, Karasu Z, Murray-Lyon IM. Plasma cathinone levels following chewing khat leaves (Catha edulis Forsk). J Ethnopharmacol 1995;46:111-3.  Back to cited text no. 6    
7.National institute on Drug abuse InfoFacts: Khat ml ( accessed on 18/12/20070).  Back to cited text no. 7    
8. Bawazeer AA, Hattab AS, Morales E. First cigarette smoking experience among secon­dary school students in Aden, Republic of Yemen. East Mediterr Health J 1999;5:440-9.  Back to cited text no. 8  [PUBMED]  
9.Chobanian A, Bakris J, Black H, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Eva­luation, and Treatment of High Blood Pressure. AMA 2003;289:2560-71.  Back to cited text no. 9    
10.Kaufman J, Asuzu M, Mufunda J, Forrester T, Wilks R, Luke A. Relationship between blood pressure and body mass index in lean populations. Hypertension 1997;30:5-16.  Back to cited text no. 10    
11.Hassan N, Gunaid AA, Murray Lyon IM. Khat (Catha edulis): health aspects of khat chewing. East Mediterr Health J 2007;13: 706-18.  Back to cited text no. 11    
12.Patkar A ,Hill K, Batra V, Vergare M, Frank M, Leone T. Comparison of Smoking Habits Among Medical and Nursing Students. Chest 2003;124:1415-20.  Back to cited text no. 12    
13.Lei Z, Jingheng H, Jianzhong J. Smoking among Shanghai medical students and the need for comprehensive intervention stra­tegies. Health Promotion Int 1997;12:27-32.  Back to cited text no. 13    
14. e-health-obesity (accessed on 18/12/2007).  Back to cited text no. 14    
15.Raja'a Y, Mohanna M. Overweight and Obesity among Schoolchildren in Sana'a City. Ann Nutr Metab 2005;49:342-5.  Back to cited text no. 15    

Correspondence Address:
Al Khader N Laswar
Director of Health Affairs, Aden Associate professor of Surgery, Aden University, P.O. Box 201, Aden
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Source of Support: None, Conflict of Interest: None

PMID: 19736493

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