Consumption of various plant-based psychotropic substances has been prevalent among humans since ancient times.1–4 Catha edulis is an evergreen shrub with mildly psychoactive properties, growing wild or cultivated in parts of Eastern Africa and the Arabian Peninsula. The plant is known by several regional names, such as khat (Ethiopia), qat (Yemen), qaad/jaad (Somalia), miraa (Kenya), mairungi (Uganda), muhulo (Tanzania), and hagigat (Hebrew).5,6 The tender leaves and young buds are chewed to attain states of mild euphoria and stimulation[Figure 1].⁶ Fresh leaves and stems are the favored parts of the plant. When chewed, it emits a characteristic odor and produces mild cocaine or amphetamine-like euphoria.6 The harvested leaves are usually packaged in plastic bags or wrapped in banana leaves to retain their moisture and freshness.

Khat is estimated to be chewed daily by over 10 million people in the Arabian Peninsula and East Africa.7 The habit is deeply rooted in the socio-cultural traditions of these regions and is particularly widespread in Kenya, Yemen, Djibouti, and Ethiopia.7–9 In Ethiopia, 32.5–42.0% of the adult population are reported to consume khat daily.10 Khat-chewing habit is reportedly spreading overseas also, especially in the USA, Europe, and Australia.11

Among the numerous chemicals found in the leaves of Catha edulis are alkaloids, glycosides, tannins, and amino acids such as tryptophan, glutamic acid, alanine, glycine, and threonine. The leaves also contain vitamins such as ascorbic acid, thiamine, riboflavin, niacin, and carotene; minerals including calcium, iron, manganese, zinc, copper, and toxic metals lead, and cadmium.6,12 Cathinone, with mild amphetamine-like properties, is the plant’s principal psychoactive ingredient.6,12

Concerning the adverse effects of khat-chewing, contradicting opinions are documented. Wold Health Organization (WHO) has positionedkhat as the least harmful substance in a group of psychoactive substances evaluated by a panel of experts with low abuse potential.13 At the same time, several potentially harmful effects of khat—physical, physiological, public health, and social—have been documented.5,8–10

Traditionally, khat leaves have been used to treat depression and for social and academic purposes. The adverse consequences of khat-chewing range from mild emotional instability and irritability to more severe ones such as impaired cognitive functioning, chronic gastritis, constipation, anorexia, weight loss, cirrhosis, urinary retention, impotence, tachycardia, arrhythmia, hypertension, vasoconstriction, and myocardial infarction.9,14–16 It is also claimed to be associated with impotence in men and increased sexual desire in women.17 However, the reported adverse effects cover a vast spectrum of medical issues and may not be amenable to focused intervention [Figure 2]. Therefore, further research is called to verify and summarize the presumed adverse effects and settle the controversies. This study was therefore planned to identify the major adverse effects of khat-use and its associated factors.

Methods

We used a cross-sectional design to conduct this study, which was carried out among the townspeople in Hosanna, southern Ethiopia, many of whom habitually chew the leaves of Catha edulis.18 The sample size was estimated by taking the prevalence of adverse effects attributed to khat use at an estimated 50% (due to absence of published data), 95% CI, 5% margin of error, and 10% non-response rate. Consequently, the required sample size was estimated at 424. We used a single population proportion formula that would be used for calculating the adequate sample size in prevalence study.19,20

n = (Z α2/2 p (1-p) )/d2

Here, n is the sample size, Z is the statistic corresponding to the level of confidence, p is the expected proportion, and d is the precision (corresponding to the effect size).

n =	(1.96 )2 0.5 (1-0.5)	= 385 + (10% × 385) = 424
	(0.05)2

This study was conducted between June and September 2016 and approved by the institutional review committee of Hosanna College of Health Sciences (Ref No. HHSC 56/2016/013). Informed oral consent was obtained from all participants before data collection after explaining the objectives of the research.

During our initial screening visits, potential participants were contacted, informed, and asked for their consent to participate in the main study. Subjects who were willing to participate were assigned a code number (for use as a sampling frame) and asked when and where they could be contacted (mobile phone number and public khat chewing place) later for data collection. They were assured that their contact details would be used only for research purposes. We excluded pregnant women from the study due to the possible confounding effect of pregnancy on weight and blood pressure (BP). We used randomly generated numbers to select each sub-unit from the created sampling frame.

WHO mental health and substance abuse questionnaires were translated and modified for the local population and used for data collection. The composite questionnaire comprised three sections. The first section sought demographic data such as age, sex, marital status, level of education, occupation, and religion. The second section had questions on the participant’s khat-use practices. The third section consisted of questions that sought perceptions of participants regarding the adverse health effects attributed to khat-chewing. The fourth section comprised physical measurement data and the fifth section had questions to assess the abuse potential of khat. The English version of the questionnaire was translated into Amharic, the official language of the region, by a team of language experts. The Amharic language version of the questionnaire was used to collect data. The original English version of the questionnaire is attached as supporting information in Appendix.

The weight, height, and BP of all participants were taken after they completed the self-administered questionnaire. The WHO STEPS procedure was followed to measure BP.21 A mercury sphygmomanometer with best-fit cuff size was used to measure BP. Two consecutive measurements were taken after the subject had rested for at least 3–5 minutes before and after a khat-chewing session. Most participants would start chewing at noon and stop around 6 PM. The measurements were taken while the participant remained seated, from the right arm with the arm placed at the heart level. We used the difference in levels of BP recorded before and after a khat-chewing session to evaluate the influence of khat use on BP. We measured the height using a fixed-height measuring instrument with the participants standing upright with their heel, back, and buttocks in contact with the wall. Weight was measured using a calibrated weighing scale on which the participant stood barefoot and wearing light clothing.

We analyzed the consistency of the data collection tool using a reliability scale test, and the tool was found to be internally consistent (Cronbach’s Alpha = 0.83).22 Data was entered into Epi-Info version 3.5.2 and exported to STATA software (StataCorp. 2007. Stata Statistical Software: Release 10. College Station, TX: StataCorp LP.). A p-value of < 0.050 was considered statistically significant. We used frequencies and proportions to describe the data. Bivariate and multivariate analyses were conducted using logistic regression to examine the association between the adverse effects of khat use and selected sociodemographic and behavioral correlates. The multivariate logistic regression model was derived through simultaneous entry analysis. Odds ratio (OR) was used to estimate the strength of associations. Microsoft Excel 2007 was used to create tables and figures.

For the physical harm, we asked the participants to respond to questions designed to assess the physical harms of khat-use. Each item had ‘Yes’ or ‘No’ responses. ‘Yes’ scored 1 and ‘No’ scored 0. The physical harm score was dichotomized to physical harm present (score ≥ the median score) or not present (score < the median score). Participants who scored above the median score of items were taken as ‘exposed to physical harm from khat use’.

For abuse potential, we adopted the WHO definition of substance dependence, as a cluster of physiological, behavioral, and cognitive phenomena in which the use of a substance or a class of substances takes on a much higher priority for a given individual than another behavior that once had greater priority. We used four items to measure the abuse potential of khat use. Here too, each item had ‘Yes’ or ‘No’ responses with ‘Yes’ scoring 1 and ‘No’ scoring 0. We dichotomized and defined the final average score into two categories. Category 0: participants with ‘low abuse potential’ (scored < the cohort’s median score), and Category 1: those with ‘high abuse potential’ (score ≥ the median score).

For adverse effects of khat-use, we used physical influences, social influences, and abuse potential of khat. The final score of these three constructs was dichotomized into adverse effects of ‘khat use present’ (score ≥ the median score) and adverse effects of ‘khat use absent’ (score < the median score).

Results

Of the 424 filled questionnaires received, those from N = 420 participants were valid and were chosen for the study. The selected participants comprised 336 (80.0%) male and 84 (20.0%) female. Their mean age was 28.7±5.6 years, with an overall age range of 17–55 years. Nearly half (201 of 420; 47.9%) were in the age group 30–34 years; 201 (47.9%; CI: 43.1–52.9) participants had completed higher education. A quarter (110; 26.2%) spent most of their lives with their siblings (not parents), 25.2% (n = 106) spent most of their life with their mothers only, while 65 (15.5%) participants spent most of their life with both parents [Tables 1 and 2].

Nearly half (46.9%) of the participants (42.9% of male and 63.1% of female) had been chewing khat for 4–10 years (median = 9.2 years). The majority (70.2%) of male and (57.1%) of female chewed khat daily. Most participants (78.2%) were in the habit of chewing khat for three hours in a single session (median = 3.2±0.8 hours).

The participants gave various reasons for their khat habit including: ‘for relaxation purposes’ (n = 154; 36.7%) and ‘social purposes’ (n = 25; 6.0%). Most (64.8%) subjects knew of the harms associated with chewing khat. While 171 (40.7%) participants (42.0% of males, 35.7% of females) used public khat-chewing rooms (Mekamiya Bet in local language), 90 (21.4%) preferred hotels [Tables 3 and 4].

Most (265; 63.1%) participants reported that they used other substances while chewing khat. Only male participants (295 of 336; 87.9%) used tobacco products while chewing khat. Most men (269; 80.1%) also revealed consuming alcohol after chewing khat.

Overall, 81.4% of khat chewers reported experiencing adverse effects of its use. Nearly half of participants (187; 44.5%) reported social problems, 102 (24.3%) acknowledged dependency, and 53 (12.6%) reported physical harm related to khat use. Evaluation of the overall score suggests that with a score of ≥ 4 in 275 (65.5%) of the participants, khat has a high potential of abuse [Table 5].

The influence of khat habit on participants’ nutritional status was assessed through self-reported data and measurement of body mass index (BMI). Most subjects (300; 71.4%) reported the habit had a negative influence on their food intake. This was supported by the fact that 220 (52.4%) participants had BMIs below the WHO minimum of 16 kg/m2 . The overall mean BMI was 16.0±2.0 kg/m2 (range = 12–28 kg/m2 .

A typical khat-chewing session was associated with a significant increase in the chewer’s BP. The mean systolic BP before khat-chewing was 112.0 mm Hg which rose to 130.5 mm Hg at the end of the chewing session, representing a mean rise of 30.5±6.0 mm Hg (range = 20–50 mm Hg). Mean diastolic BP also rose from 74.4 to 95.8 mm Hg after chewing and increase of 20.5±6.8 mm Hg (range = 10–40 mmHg). Out of the 336 male participants, 193 (57.4%) reported erectile problems.

Selected sociodemographic characteristics and behavioral correlates were tested for association with adverse effects of khat use. Use of other substances (p < 0.001), duration (p = 0.040), and frequency (p = 0.020) of khat use were significantly associated with adverse effects. The misuse potential of khat also significantly varied across sex (p = 0.060), religion (p = 0.002), duration of khat habit (p = 0.001), cited reasons for khat use (p = 0.007), and place commonly used to chew khat (p = 0.007).

The adverse effects were significantly higher among individuals who used other substances (tobacco, coffee, tea) while chewing khat (AOR = 4.80; CI: 2.86–8.22) than those who used khat only with water. The likelihood of adverse effects was significantly higher in individuals who used khat daily (AOR = 2.50; CI: 1.10–5.73) than in occasional users. The odds of harmful influences of khat use were significantly lower in individuals who were chewing khat for < 1 year (AOR = 0.50; CI: 0.26–0.97) than in those who had the habit for more than 10 years [Table 6].

Discussion

This study examined the adverse effects of chewing khat among users in the town of Hosanna. The vast majority (81.4%) experienced adverse effects. Being the first study to compute the adverse effects of khat use using constructs in different dimensions, there is a dearth of comparative data.

Our results suggest significant adverse effects on habitual and long-term khat users. The habit was more prevalent among our male participants, a finding consistent with reports on different populations in eastern Kenya.23 The frequency distribution of marital status of our participants suggested a higher prevalence of khat use in those who were divorced and single, albeit lacking statistical significance. It is possible that khat use is associated with social, marital, and productivity issues. The majority of our subjects were well-educated and knew of the harms of the habit. However, the adverse effects experienced were not significantly affected by the user’s educational level or knowledge.

A substantial proportion of our participants were in the habit of consuming other substances (tobacco, coffee, tea) while chewing khat. This finding is supported by a similar study in another Ethiopian town, Jimma, which reported cigarette smoking and alcohol use to be significantly associated with khat chewing.24,25 Taking of other substances (cigarettes, shisha, coffee, tea) with khat was significantly associated with harmful influences of khat use in the current study. There is no published data on the influence of the concomitant use of other substances with khat. These substances seem to facilitate increased consumption of khat, which in turn might increase khat’s adverse effects. It is also possible that the co used substances by themselves contribute to the adverse effects.

This study also examined the influence of khat use on the nutritional status of participants. Participant responses and BMI data suggest that khat-use was negatively influencing their nutritional status, which is consistent with existing understanding.26 We also identified that during the course of a khat-chewing session, the BP of the individual was likely to rise significantly, which also is consistent with other Ethiopian studies.15

The current study also identified khat use had adverse effects on the sexual and reproductive health of male subjects. Erectile problems, premature ejaculation, and failure to make penetrative sexual intercourse were the identified sexual problems associated with khat use.27,28 The self-reported findings from this study showed that 2.6% of participants experienced infertility. Previous studies have also shown similar findings.29,30 According to previous research, high-dose khat consumption may decrease sperm quality.29,30 While such a distressing outcome requires attention, the mechanisms by which khat may affect the male reproductive physiology have not been fully elucidated and warrant further study.

This study also tried to examine the misuse potential of khat. Unlike a previous report which attributed to khat only mild to moderate psychological dependence,31 the current study has detected a high potential of abuse. The contradicting opinions on the abuse potential of khat-use warrant further study. Furthermore, this study identified social influence, dependency, and physical harm as the priority harmful influences of khat use. This is consistent with other studies from the Horn of Africa and the Arabian Peninsula.7 Similarly, we identified that habitual khat-chewing worsened stroke and mental illness, which again is supported by previous studies.6,17

The present study has limitations. One is related to the cross-sectional design of the study due to which the temporal relationships between predictor variables and the outcomes could not be established. Moreover, the sample was confined to a single population which limited the power of the study. In addition, since the data was taken from one group and collected at one point in time, the extent to which the problems could be attributed to khat use alone. We recommend an exhaustive longitudinal exploration of the factors associated with the adverse effects of khat chewing behavior among different segments of the Ethiopian population.

Conclusion

This study suggests that habitual khat-chewing has high abuse potential and causes adverse health effects, which contradicts some previous assumptions. The duration and frequency of khat-chewing and co use of other substances were the major predictors of the habit’s adverse effects. Khat-use negatively influences nutrition intake, sexual and reproductive health, and BP. We also recommend a re-evaluation of khat’s potential as a substance of abuse by global drug abuse policymakers including WHO.

Disclosure

The author declared no conflicts of interest. Hosanna College of Health Sciences funded the study. The funder had no role in study design, data collection, and analysis, decision to publish, or preparation of the manuscript.

Acknowledgments

The author would like to thank Hosanna College of Health Sciences Research and Community Service. I am also grateful to Hosanna residents, data collectors, and the town health office for their cooperation during the process of data collection.

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