Search results
A total of 1543 studies were identified through electronic searches. Of these, 1532 studies were published, whereas 11 were master’s thesis. After duplications were excluded, and 1196 records were screened by title and abstract. Other 1,140 records were excluded by title and abstract, and he remaining 53 articles were screened further for quality eligibility and. From these, 21 articles were excluded since they were not eligible or failed quality criteria or contents were duplicated. Finally, 32 articles were included in the meta-analysis (Fig 1).
Characteristics of included studies
Overall six regions and one city administration were represented. Accordingly, 10 studies were conducted in educational institutions in Amhara Regional [20, 33, 36, 39, 45-50], 8 in Oromia Regional [13, 15, 17, 18, 40, 51-53], 5 in SNNPR [19, 26, 54-56], 2 in Addis Ababa [12, 57], 3 in Tigrai Region [14, 34, 58], in Harari Region [16], 1 in Somali Region [59], and 1 study done in both SNNPR and Oromia [60]. Three studies included in the meta-analysis were unpublished, master’s thesis [20, 34, 52].
There was a wide sample size difference among the studies ranging from 193 [58] to 3001 [46]. The highest prevalence of current use of any substance was 47.9% [35], 33.1% for khat consumption [40], 44.2% for alcohol [20], and 29.5% for smoking cigarettes [58]. All studies were conducted between 2002 and 2019 in high schools, preparatory schools, colleges, and Universities. Eight studies were conducted among high and preparatory schools [15, 16, 35, 49, 51, 56, 57, 60], 23 studies conducted among university students [12-14, 17-20, 26, 33, 34, 36, 39, 40, 46-48, 50, 52-55, 58, 59] and one study conducted among polytechnic college [45]. The mean age of the study participants ranges from 15.6 to 23 years (Table 1).
Table 1 Summary characteristics of studies included in meta-analysis of prevalence of current substance use among students in Ethiopia
Author year
|
Study area
|
Study population
|
Mean Age
|
Sample size
|
Khat
(%)
|
Alcohol
(%)
|
Smoking
(%)
|
any prevalence (%)
|
QA
|
Gebreslassie M, et al. 2013
|
Tigrai; Axum
|
University
|
22.3
|
756
|
27.9
|
32.8
|
9.3
|
44.8
|
8/9
|
Dida, et al. 2014
|
Oromia; Bale
|
Preparatory school
|
18.4
|
603
|
17.1
|
23.6
|
4.6
|
34.8
|
5/9
|
Tsegay G & Esmael A 2014
|
Amhara; Debre Markos
|
University
|
21.6
|
800
|
28.1
|
32.5
|
10.0
|
40.0
|
5/9
|
Aklog T et al. 2013
|
Amhara; Debre Markos
|
PT college
|
19.8
|
410
|
6.3
|
35.4
|
4.4
|
38.3
|
7/9
|
Kebede Y, 2002
|
Amhara; Gonder, Bahir Dar
|
University
|
20.0
|
1103
|
17.5
|
-
|
8.1
|
-
|
9/9
|
Tesfaye G et al. 2014
|
Oromia; Harmaya
|
University
|
20.9
|
1022
|
23.6
|
20.0
|
10.8
|
-
|
8/9
|
Kassa A et al. 2014
|
SNNP; Hawassa
|
University
|
20.7
|
586
|
-
|
-
|
-
|
35.7
|
8/9
|
Kassa A et al. 2016
|
SNNP; Hawassa
|
University
|
20.7
|
586
|
16.3
|
29.5
|
-
|
-
|
8/9
|
Fufa G et al. 2017
|
Somale; Jijiga
|
University
|
21.2
|
600
|
28.3
|
-
|
-
|
40
|
6/9
|
Abrha K, 2011
|
Tigrai; Mekelle
|
University
|
20.4
|
601
|
25.1
|
41.1
|
11.5
|
32.5
|
9/9
|
Mekonen T et al. 2017
|
SNNP, Wolaita Sodo
|
University
|
21.18
|
725
|
10.2
|
24.7
|
5.7
|
28.6
|
5/9
|
Adere A et al. 2017
|
Amhara; Woldia
|
University
|
20.74
|
655
|
10.4
|
29.7
|
6.4
|
31.5
|
8/9
|
Birhanu MA et al. 2014
|
Amhara; Woreta
|
GSS & PPS
|
17.25
|
651
|
13.8
|
40.9
|
6.8
|
47.9
|
8/9
|
Teshome G, 2012
|
Oromia; Adamma
|
University
|
21.84
|
728
|
20.7
|
-
|
-
|
-
|
8/9
|
Gebrehanna E et al. 2014
|
Amhara; Bahr Dar
|
University
|
21.2
|
3001
|
7.7
|
-
|
-
|
-
|
8/9
|
Wondimu GA at al. 2017
|
Amhara; Gondar
|
University
|
21.0
|
736
|
16.4
|
-
|
-
|
-
|
6/9
|
Abdeta T et al. 2017
|
Oromia; Jimma
|
University
|
21.9
|
619
|
23.9
|
-
|
-
|
-
|
8/9
|
Astatkie A et al. 2015
|
SNNP; Hawassa
|
University
|
21.4
|
1255
|
11.1
|
-
|
-
|
-
|
8/9
|
Deressa W & Azazh A. 2011
|
Addis Ababa, AAU
|
University
|
20.4
|
622
|
3.7
|
9.3
|
-
|
-
|
5/9
|
Dachew BA et al. 2015
|
Amhara; Gondar
|
University
|
21.3
|
836
|
13.6
|
-
|
-
|
-
|
5/9
|
Deresse A et al. 2014
|
Oromia, Haramaya
|
University
|
21.0
|
725
|
20.3
|
17.5
|
-
|
-
|
5/9
|
Birhanu B, 2014
|
Amhara, Debre Berhan
|
University
|
21.2
|
346
|
22.3
|
44.2
|
14.7
|
-
|
5/9
|
Dires E, et al. 2016
|
Oromia; Jimma
|
GSS
|
16.05
|
296
|
14.2
|
-
|
-
|
-
|
5/9
|
Lakew A, et al. 2014
|
Amhara, Ataye
|
GSS and PPS
|
17.21
|
332
|
13.25
|
-
|
-
|
-
|
5/9
|
Reda A, et al. 2012
|
Harari, Harar
|
GSS and PPS
|
16.4
|
1721
|
|
10.4
|
-
|
-
|
5/9
|
Meressa K et al. 2009
|
Oromia, Jimma
|
University
|
23.0
|
239
|
33.1
|
-
|
-
|
-
|
7/9
|
Teshome D & Gedif T 2013
|
Addia Ababa
|
GSS and PPS
|
16.93
|
2551
|
-
|
26.4
|
-
|
-
|
5/9
|
Dereje N, et al. 2014
|
Oromia and SNNPR
Jimma & Hawassa
|
GSS and PPS
|
15.6
|
1673
|
-
|
-
|
17.2
|
-
|
6/9
|
Eticha T & Kidane F, 2014
|
Tigrai, Mekelle
|
University
|
21.2
|
193
|
-
|
-
|
29.5
|
-
|
5/9
|
Alebachew W. et al. 2019
|
Oromia, Haramaya
|
University
|
23
|
251
|
|
8.0
|
-
|
-
|
4/9
|
Gebremariam et al., 2018
|
Amhara
|
University
|
21.6
|
617
|
5.7
|
16.9
|
3.1
|
-
|
6/9
|
Duko Bereket et al., 2019
|
SNNPR
|
GSS and PPS
|
16.8
|
564
|
6.9
|
15.1
|
-
|
-
|
6/9
|
Keys: AAU: Addis Ababa University, GSS: General Secondary School, PPS: Preparatory School, SNNPR: Southern Nations, Nationalities and people Region, QA: Quality assessment
The quality of assessment
The quality the studies assessed on the nine quality area. Accordingly, from the total studies, 27(84.38%) studies adequately addressed the target population and sampling was conducted in the approporiate way. In more than half, 17(53.13%) studies, the study subjects and the setting were not described in detail, 9(18.75%) studies data analysis was conducted without sufficient coverage of the identified sample or not clearly described, 14(43.75%) studies did not used a valid method to identifiy a current prevalecen of substance use or unknown, and 28(87.5%) studies data were not collecte in reliable way for all participants or not clearly described (supplementary: Table 2).
The prevalence of current use of any substance
A total of 11 studies; 10 published [14, 15, 19, 20, 36, 45, 47, 53, 59, 61], and 1 master’s thesis [34] with a total of 6,638 participants were included in the meta-analysis. Concerning regional representation, 4 studies [20, 36, 45, 47] were from Amhara Region, two [19, 61] from SNNPR, two studies [14, 34] from Tigrai Region, two [15, 53] from Oromia, and one [59] from Somali Region. Nine studies [14, 34, 36, 37, 45, 47, 53, 59, 61] were conducted among university students and two studies [15, 35] were conducted among high school and preparatory students. The prevalence of current use of any substance ranges from 28.6% [61] to 47.9% [20]. The pooled estimate of the current prevalence of any substance was 37.16% (95% CI: 33.39, 41.01). The analysis revealed the presence of substantial heterogeneity with (I2=90.55%, P<0.00) (Fig 2). However, there was no significant publication bias; Begg’s test p<1.00 and Egger’s test p<0.560.
The current prevalence of alcohol consumption
A total of 18 studies; 16 published [12-17, 20, 26, 36, 45, 47, 50, 53, 54, 56, 57] and two unpublished [20, 34] studies with a total of 14,206 participants were included in the analysis. From a total, six studies [20, 35, 36, 45, 47, 50] were from Amhara Region, four studies [13, 15, 17, 53] were from Oromia Region, two studies [12, 57] were from Addis Ababa, two studies [14, 34] were from Tigrai Region, three studies [54, 56, 61] were from SNNP, and one study [16] was from Harari Region. The prevalence of current alcohol use ranged from 8% among Haramaya University students [53] to 44.22% among Debre Birhan University students [20]. Four studies [15, 16, 20, 57] were done among general secondary, and preparatory schools, and all of the studies were done between 2011 and 2018. The pooled prevalence of current alcohol use was 24.97% (95% CI: 20.07, 30.20). The analysis showed that there was high heterogeneity among studies (I2=97.96%, P<0.00) (Fig 3). The analysis showed no significant publication bias; Begg’s test p<0.733 and Egger’s test p<0.331.
The prevalence of current khat consumption
A total of 27 studies; 24 published studies [12-15, 17, 18, 20, 26, 33, 36, 39, 40, 45-51, 53-56, 59], and three unpublished studies [20, 34, 52] with a total of 19,679 participants were included in the analysis. From the total studies, 11studies [20, 33, 36, 39, 45-50] were from Amhara Region, 8 studies [13, 15, 17, 18, 40, 51-53] were from Oromia Region, 4 [26, 54-56] were from SNNP, and two [14, 34] were from Tigrai, one [12] was from Addis Ababa and one [59] was from the Somali Region. The prevalence of current khat consumption ranges from 4% among Addis Ababa University students [12] to 33% in a study conducted among Jimma University students [40]. Five studies [15, 20, 49, 51, 56] were conducted in general secondary and preparatory school students, and 22 were conducted in university or college students. All studies were conducted between 2002 and 2018. The pooled prevalence of current khat consumption was 16.63% (95% CI: 13.57, 19.94). Significant heterogeneity was observed among studies (I2=97.25%, p<0.00) (Fig 4). However, there was no publication bias with Egger’s test (p<0.240), Begg’s test P< 0.044.
Fig 4 Forest plot of prevalence of current khat consumption among students in Ethiopia
The current prevalence of cigarette smoking
A total of 14 studies; 12 published, [13-15, 20, 26, 33, 36, 45, 47, 50, 53, 60] and two master’s thesis [20, 34] with a total of 10,213 participants were included in the analysis. From the total studies, seven studies [20, 33, 35, 36, 45, 47, 50] were from Amhara Region, two [14, 34] were from Tigrai Region, three studies [13, 15, 53] were from the Oromia Region, one [26] was from SNNP and one study [60] was conducted in SNNP and Oromia Regions. Three studies were done in general secondary and preparatory schools [15, 20, 60], 10 studies were conducted in university students [13, 14, 20, 26, 33, 34, 36, 47, 50, 53], and one study was done in polytechnic college [45]. The prevalence ranged from 3.1% in a study conducted Debre Birhan University [50] to 17.2% in a study conducted among general secondar and preparatory schools in Hawassa and Jimma Towns. The pooled prevalence of current cigarettes smoking among students was 8.57% (95% CI: 6.32, 11.12). There was significant heterogeneity within studies (I2=94.68%, P<0.00) (Fig 5). However, there was no significant publication bias (Begg’s test, P<0.192 and egger’s test, P< 0.743).
Subgroup analysis for any substance, alcohol, khat and smoking cigarette
Figure 6A show subgroup analyses of prevalence of current use of any substance, alcohol, khat and smoking cigarette by region to explore the sources of heterogeneity. Accordingly, the current prevalence any substance use was highest in the other category (n=1), 43.17(95% CI: 39.16, 47.24) followed by Amhara region (n=4), 39.35% (95% CI: 33.64, 46.26). The current consumption of alcohol (n=2), khat chewing (n=2) and smoking cigarette (n=3) was highest in Tigrai region 36.43% (95% CI: 33.89, 39.01), 26.66%(95% CI: 24.34, 29.05) and 15.62% (95% CI: 7.73, 25.60), respectively. There was significant between group heterogeneity for all substance use categories, P<0.000.
Figure 6B shows subgroup analysis of prevalence of currenty use of substance by sample size. The prevalence of current use of any substance was higher, 37.56% (95% CI: 33.22, 42.00) in studies with sample size range from 500 to 1000 (n=9). The current prevalence was highest in small sample size group (< 500) for alcohol (n=3) 27.42(9.18, 50.86), khat (n=6) 18.68(10.89, 27.97), and cigarette smoking (n=4) 14.89(6.16, 26.50).
Figure 6C reveals subgroup analysis of current use of subtances by level of education. The higher prevalence of current use of any substance was observed among high school students (grade 9-12) (n=2), 41.55% (95% CI: 38.83, 44.29). However, higher prevalence was observed among university or college studets; for alcohol (n=13) 25.27% (95% CI: 19.76, 31.20), khat (n=22) 17.30% (95% CI: 13.75, 21.16) and smoking cigarette (n=12) 9.80% (95% CI: 7.32, 12.58).
Meta-regression
To explore the sources of between study differences, we conducted meta-regression analysis, sample size, publication, proportion of female (%), and mean age for the use of any substance, alcohol, khat and smoking cigarettes. We found that the current use of any stubstance, khat and smoking cigarettes showed significant association with respective sample size. Accordingly, the prevalence of current use of any substance and hat decrease by 5.91x10-5 (P<0.029) and 5.81x10-5 (P<0.037), respectively, for unit increase in sample size. the prevalence of current smokig cigarette increases by 8.32x10-5 for unit increase in the sample size. However, year of study, proportion of female and the age were not associated with current use of any substance, alcohol, khat and cigarette smoking (Supplentary table: Table S3).