Multi residue analysis of pesticides in wheat and khat collected from different regions of Ethiopia

Apparent Khat chewers exposure to DDT in Ethiopia and its potential toxic effects: A scoping review

Dichlorodiphenyltrichloroethane (DDT) is an insecticide, a member of dirty dozen persistent organic pollutants, used widely in the world until it was banned in the 1970s.The banning of DDT was strengthened by the Stockholm Convention in 2001. DDT is allowed only for malaria control in Ethiopia. However, farmers are misusing DDT and applying it to Khat (Catha edulis) farming. So, this review analyzes available data in the literature on the current trend, application, occurrence, fate and effects of DDT and its metabolites, dichlorodiphenyldichloroethane (DDD), dichlorodiphenyldichloroethylene (DDE), in the chewable parts of Khat. Generally, the concentration level of DDT, DDD, and DDE, designated as DDTs, is detected in different farmlands of Ethiopia. Some of the DDTs concentrations detected are very high (141.2-973 μg/kg (Gelemso), 194.4-999 μg/kg (Aseno) and 6253-8413.3 μg/kg (Gurage), and these concentrations may indicate increasing recent unmonitored application of DDT on Khat leaves. Some of the detected concentrations of DDT in the literature were above the maximum residue limit (MRL) set by FAO/WHO (100 μg/kg) and the European Commission 10 μg/kg in vegetables and 50 μg/kg in cereals. DDT exposure of Khat chewers linked to the concentration of DDT on Khat leaves and the amount of Khat consumed. DDT might pose health risks to chewers due to chronic toxicity, bioaccumulation, persistent and endocrine disruption properties.

Exposure to DDT and HCH congeners and associated potential health risks through khat (Catha edulis) consumption among adults in South Wollo, Ethiopia

Khat (Catha edulis) chewing is widespread in the region of East Africa. Even low levels of organochlorine pesticides (OCPs) in khat could induce public health concern. In a market-based study, from five popular khat varieties, a total of 35 composite khat samples were analyzed for dichlorodiphenyltrichloroethane (DDT) and its main transformation products, and four hexachlorocyclohexane (HCH) isomers. Extraction was carried out by quick, easy, cheap, effective, rugged and safe method (QuEChERS). OCP concentrations were determined by head space solid phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS). Every sample contained β-HCH above the maximum residue limit set by the European Commission. For total DDT, this was the case for 25.7% of the samples. The ratios of (p,p'-DDD + p,p'-DDE) to p,p'-DDT were less than one for 85% of khat samples, demonstrating recent use of DDT in khat farmlands. Conversely, the ratio of β-HCH to total HCH varied from 0.56 to 0.96, implying historical input of technical HCH. Assuming a daily chewable portion of 100 g, dietary intakes of p,p'-DDT, total DDT and total HCH by adults ranged from 3.12 to 57.9, 6.49 to 80.2 and 39.2 to 51.9 ng (kg body weight)^-1 day^-1, respectively. These levels are below acceptable levels suggested by international organizations. Chewing khat showed lower non-cancer health risk, but showed relatively higher cancer risk in terms of OCPs. Because khat is chewed without being subjected to any treatment, uncertainties associated with estimated intakes and health risks should be low. Therefore, this practice is of great concern.

Organochlorine pesticide residues in tea and their potential risks to consumers in Ethiopia

Tea is the most frequently consumed drink in the sphere; next to the water. However, tea can be contaminated by different pesticides particularly those outdated pesticides which have been familiar as one of the main difficulties in Ethiopia and contaminate the food commodities. From a study done in south west of Ethiopia, Dichlorodiphenyltrichloroethane (DDT) and endosulfan were detected in commonly consumed food items. Therefore, the main aim of this study was to analyze the residue of organochlorine pesticides (OCPs) in tea collected from the market and assessing their risks to consumers. 19 different tea samples were randomly collected from supermarkets in Jimma town and Addis Ababa city. In the analytical procedure, QuEChERS (Quick, Easy, Cheap, Rugged, and Safe) method was applied for the extraction of tea samples. The finding of the study revealed that, five OCPs (aldrin, γ-chlordane, DDT, endrin, and dibutylchlorepoxide) were detected at a concentration of 0.1465, 0.167, 0.2044, 0.3067 and 0.4089 mg kg⁻¹ in domestic tea, respectively, while endosulfan sulfate, methoxychlor, and heptachlor epoxide were detected at a concentration of 0.258, 0.458 and 1.427 mg kg-1 in imported tea samples respectively. From the pesticides detected, the mean concentration of DDT (0.292–0.825 mg kg⁻¹) is above the Maximum Residue Limits (MRLs) established by China (0.2 mg kg⁻¹). The estimated daily intake (EDI) of γ-chlordane and endrin were above the acceptable daily intakes (ADIs), this indicates that there is a health risk for tea consumers. The detection of pesticide residues in tea reveals that there is the widespread use of OCPs in the study area for agricultural purposes or as vector control. Therefore, strict regulation of pesticides during production, importing, sale, and application in the field is important for Ethiopia.

Environmental and Health Risks of Pesticide Use in Ethiopia

BACKGROUND

There are frequent reports of unsafe pesticide use in many parts of Africa. Ethiopia is the second most populous nation in Africa with around 80% of the population still depending on agriculture which intensively uses pesticides. A number of studies have examined pesticide-related health and environmental risks in Ethiopia. However, most of these studies have been small in scale and it is therefore challenging to get a general overview of the extent of health risks and level of environmental contamination in the country.

OBJECTIVES

The aim of the present study was to synthesize and summarize contemporary knowledge on pesticide-related risks and relevant gaps in Ethiopia.

METHODS

An electronic database search and gathering of grey literature were done to collect information on the risks of pesticide use in Ethiopia. The electronic search was conducted using MEDLINE (via PubMed) without any publication date or language specifications. The Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) checklist was used as guide in the creation of this review.

DISCUSSION

A synthesis of the reviewed studies showed evidence of health risks due to occupational pesticide exposure, surface water pollution with pesticides that could cause chronic health risks to the public, evidence of pesticide contamination of the environment (e.g., soil organisms, fish, bee colonies and wildlife) and local as well as international consumer risks due to pesticide residues in food items. In addition, there have been frequent reports of health and environmental hazards in association with cut-flower farms. There is also evidence of direct use of DDT (dichlorodiphenyltrichloroethane) on food crops and detection of DDT residues in surface water, soil and human breast milk. Those reported risks might be due to lack of knowledge among farm workers, negligence of farm owners, absence of post-registration monitoring systems and poor implementation of both national and international regulations in Ethiopia due to poor institutional capacity.

CONCLUSIONS

The health and environmental risks of inappropriate use of pesticides requires action by all concerned bodies. Improved institutional arrangements for enforcement of regulations, awareness and further intervention studies could lessen the high risks of pesticide misuse.

COMPETING INTERESTS

The authors declare no competing financial interests.

Pesticide Residue Analysis of Khat Leaves and Health Risks among Khat Chewers in the Amhara Region, Northwestern Ethiopia

Introduction

Farmers use a large number of pesticides to increase the productivity of Khat cultivation. Since Khat is consumed by many Ethiopians as a habit, there may be a significant concentration of pesticide residues in Khat leaves which result in adverse effects among the exposed population. Excess use of pesticides in Khat causes cancer, genotoxicity, and endocrine disturbances. The current study aimed to determine the concentration of selected pesticide residues on Khat leaves samples and to estimate the possible health risk on consumers.

Methods

Thirty Khat samples were collected from Khat cultivators in the Amhara region, Ethiopia. Pesticide residue extraction and cleanup of Khat samples were performed using the QuEChERS method. Data were also collected about personal variables and Khat consumption habits. The pesticide concentrations were determined and the health risks were estimated.

Results

Profenofos, dimethoate, and chlorpyrifos were detected in 6 (20%), 24 (80%), and 28 (93.3%) Khat samples, respectively. However, diazinon was detected in two samples and endosulfan I was not detected. The average concentration of chlorpyrifos, dimethoate, profenofos, and diazinon in Khat samples was 75.39 ± 20.26, 130 ± 48.94, 242.45 ± 119.79, and 81.5 ± 21.0 μg/kg, respectively. The HQ for diazinon was greater than 1 which shows the chronic health risks associated with intake of diazinon among Khat chewers. The acute health risks associated with intake of profenofos and diazinon were minimal. Discussion. Pesticide residue exposure is a risk factor for cardiac complications, reduction in antioxidant defense system, and developing neurological symptoms. All the pesticides were higher than the European Union Maximum Residue Levels (EU-MRL). Diazinon has the potential to cause higher chronic health risks. Chronic Khat chewers in the region may face potential health risks from pesticide residues. Awareness creation among people in the study area is necessary to avoid the adverse health effects of pesticide residues.

Acute Hepatitis in a Yemeni Immigrant Associated with Khat: A "Biological Amphetamine" Carried in Cultures

Viral infections, alcohol, hepatic steatosis, autoimmunity medications and herbal supplements are common etiologies of hepatitis. Khat (Catha Edulis) is a commonly used recreational substance in East African and Middle Eastern countries. Khat has been reported in the literature to be associated with hepatotoxicity, which can present in several forms, including chronic liver disease. The possible pathogenesis of liver injury could be secondary to biochemical components of Khat itself or additives such as pesticides or preservatives. An autoimmune mechanism of liver injury has also been postulated, supported by sparse evidence. We present a case of a Yemeni immigrant with acute hepatitis whose fear about social norms and breaching confidentiality made it challenging to identify Khat as being the underlying cause. A 34-year-old man from Yemen presented with right upper quadrant pain of one day duration. He had predominantly elevated transaminases with mild elevation in bilirubin. His investigations were negative for the viral, metabolic or biliary etiology. A persistent focus on clinical history and the well-established physician–patient relationship revealed a history of Khat use. The liver biopsy finding of lobular hepatitis was compatible with drug-induced liver injury and established the finding of Khat hepatotoxicity. Subsequently, the patient improved with conservative management.

Khat chewing in pregnant women associated with prelabor rupture of membranes, evidence from eastern Ethiopia

Introduction

Prelabor rupture of membranes (PROM) is a major factor that affects pregnancy outcome. Results from previous studies have suggested that there is an association between pregnant women, khat chewing and preterm birth, but evidence of association with PROM is sparse. This study therefore aims at identifying association between khat chewing in pregnancy and premature rupture of membranes in eastern Ethiopia.

Methods

A health facility-based cross-sectional study was conducted among 1688 pregnant women who came for delivery service in Harar town, Eastern Ethiopia between June to October in 2016. Data were collected using a pre-tested structured questionnaire and checklist to extract data from the medical record. The association between khat and PROM was examined using logistic regression analysis. A statistical significance was declared at p-value < 0.05.

Results

Of the 1688 pregnant women who participated in the study, 397 had prelabor rupture of the membranes, representing a proportion of 23.5% [(95% CI: (21.5, 25.6%)]. Of these 397 prelabor rupture of the membranes 198 (31.53%) were from Khat chewing mothers and, 199(18.77%) were from non-khat chewing mothers. After controlling for potential confounders, the multivariable logistic regression analysis revealed the odds of PROM was 1.51 times higher among khat chewed pregnant women [AOR = 1.51; 95% CI; (1.11, 2.07)] were had no khat chewing.

Conclusion

This study found a significant association between khat chewing in pregnancy and PROM. Efforts to reduce PROM need to consider prevention of khat chewing in pregnancy. A specific strategy need to protect pregnant women from khat chewing.

Evaluation of Khat (Catha edulis) Use as a Risk Factor of Cancer: A Systematic Review

Background:

Conducting systematic review to evaluate plant use as a risk factor to cancer could be challenging. A systematic and well-balanced method should be applied to accommodate in vivo and in vitro studies to make a final decision. In this article, khat, a recreational plant used in some Arabic and African regions, was employed as an example to systematically determine its relationships to the premalignant and cancerous conditions.

Methods:

Systematic database search was performed to recruit original human, animal or in vitro studies on khat and cancer. Sixteen studies fulfilled the inclusion criteria and subjected to assessment using Risk of Bias (RoB). Office of Health and Translation (OHAT) approach was used to rate the confidence level in the body of evidence. The evidence was integrated to establish the relationships between khat, premalignant conditions and cancer.

Results:

Seven out of eight studies showed that khat causes premalignant oral lesions with moderate evidence level. Four studies showed that khat causes cancer with low evidence level and another three studies showed that khat has anti-cancer effect with moderate to high evidence level. Only one study suggested that khat is unrelated to cancer.

Conclusion:

RoB and OHAT approach are reliable systematic tools to evaluate plant risk to cancer and provide objective and uniform summary regardless of the study type. In conclusion, our pooled analysis did not find a direct relationship between khat and cancer but anti-cancer effect would require to be proofed on human studies.

Occurrence of organochlorine pesticide residues in biological and environmental matrices in Africa: A two-decade review

The widespread use of organochlorine pesticides (OCPs), essentially for the control of insects and the cultivation of food crops, has led to the pollution of ecosystems. Despite being banned several years ago in the developed world, extensive use remains ongoing on the African continent. This review summarizes the occurrence, distributions, sources, and trends of OCPs in seven environmental matrices (atmosphere, water, sediments, soils, biota, human fluids and food products) in Africa. Findings in this review revealed that α-HCH, β-HCH dichlorodiphenyltrichloroethane (DDTs), and endosulfans were the most persistent OCP residues in the African environment, particularly DDTs in breast milk samples occurring in levels above the WHO stipulated limits, thus indicating a call for concern. Also, there was paucity of data available on OCP concentrations in ambient air. Future research efforts should prioritize testing these pollutants in the atmosphere, especially in countries where they are used more frequently. While most POP analysis studies used gas chromatography coupled to electron capture detector or mass spectrometer, it is recommended that further studies should use more sensitive analytical techniques such as gas chromatography with tandem mass spectrometry (GC-MS/MS), or gas chromatography coupled to high-resolution mass spectrometry (GC-HRMS). These instruments allow for the detection of secondary and tertiary metabolites, especially those found in water, biota and food products, which are critical vectors of OCPs to human and animal bodies. Training of farmers and other domestic users on the handling of pesticides is proposed.

High Density Supercritical Carbon Dioxide for the Extraction of Pesticide Residues in Onion with Multivariate Response Surface Methodology

The excessive use of pesticides is a serious health problem due to their toxicity and bioaccumulation through the food chain. Due to the complexity of foods, the analysis of pesticides is challenging often giving large matrix effects and co-extracted compounds. To overcome this problem, a selective and “green” supercritical fluid extraction method was developed, using neat carbon dioxide as a solvent at pressures of up to 800 bars. A Box–Behnken response surface experimental design was used, with the independent variables of density (0.70−1.0 g mL⁻¹), temperature (40−70 °C), and volume (10−40 mL) of solvent, and the dependent variable of extracted amount of pesticides. The optimum extraction condition was found at the use of 29 mL of supercritical CO₂ at 0.90 g mL⁻¹ and 53 °C (corresponding to 372 bars of pressure). It was observed that increasing the density of CO₂ significantly increased the extraction recovery of endrin and 2,4′-dichlorodiphenyldichloroethane. Matrix-matched calibration curves showed satisfactory linearity (R² ≥ 0.994), and LODs ranged from 0.2 to 2.0 ng g⁻¹. Precision was lower than 11% and recoveries between 80%–103%. Thus, the developed method could efficiently be used for trace analysis of pesticides in complex food matrices without the use of organic solvents.

Organochlorine pesticides in commercial Pacific salmon in the Russian Far Eastern seas: Food safety and human health risk assessment

Concentration of organochlorine pesticides (OCPs) (α-, β-, γ- hexachlorocyclohexane (HCH), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDD), dichlorodiphenyldichloroethylene (DDE)) in four species of Pacific salmon (pink, chum, chinook, and sockeye) are presented. OCPs in salmon organs increased in the following order: muscle < liver < eggs < male gonads. Concentrations of the OCP in salmon organs increased in following order: DDE < γ-HCH < α-HCH. The level of pollutants in salmon is compared with the sanitary and epidemiological norms of Russia and other countries. Cancer and noncancer hazard ratios through consumption of salmon in Russian Far East for both men and women also were summarized. Noncancer and cancer hazard ratio values were far below threshold values (<1.0).

Khat chewing increases the risk for developing chronic liver disease: A hospital-based case-control study

The chewing of the leaves of Catha edulis (khat) has been implicated in the development of liver disease, but no controlled observations have been undertaken. The objective of the present study was to determine whether khat chewing is associated with development of chronic liver disease (CLD). A case-control study was conducted at two public hospitals in Harar, Ethiopia, between April 2015 and April 2016. A consecutive sample of 150 adult hospital attendees with CLD were included as cases, and 300 adult hospital attendees without clinical or laboratory evidence of CLD were included as controls. Khat consumption was quantified in "khat years"; 1 khat year was defined as daily use of 200 g of fresh khat for 1 year. A logistic regression model was used to control for confounders. There was a significant association between chewing khat and the risk for developing CLD (crude odds ratio, 2.64; 95% confidence interval [CI], 1.56-4.58). In men, this risk, following adjustment for age, alcohol use, and chronic hepatitis B/C infection, increased with increasing khat exposure; thus, compared to never users the adjusted odds ratios were for low khat exposure 3.58 (95% CI 1.05-12.21), moderate khat exposure 5.90 (95% CI 1.79-19.44), and high khat exposure 13.03 (95% CI 3.61-47.02). The findings were robust in a post hoc sensitivity analysis in which individuals with identifiable risk factors for CLD were excluded.

CONCLUSION

A significant association was observed between chewing khat and the risk for developing CLD, and in men the association was strong and dose-dependent, suggesting a causal relationship; as the prevalence of khat chewing is increasing worldwide, these findings have major public health implications. (Hepatology 2018;68:248-257).

Qat use and esophageal cancer in Ethiopia: A pilot case-control study

BACKGROUND

Qat (Catha edulis) chewing is reported to induce lesions in the buccal mucosa, irritation of the esophagus, and esophageal reflux. Case series suggest a possible etiological role in oral and esophageal cancers. This pilot study aimed to generate preliminary estimates of the magnitude and direction of the association between qat use and esophageal cancer (EC) risk and to inform the logistics required to conduct a multi-center case-control study.

METHODS

Between May 2012 and May 2013, 73 EC cases (including 12 gastro-esophageal junction cases) and 133 controls matched individually on sex, age, and residence were enrolled at two endoscopy clinics and a cancer treatment hospital in Addis Ababa. A face-to-face structured questionnaire was administered. Qat use was defined as ever having chewed qat once a week or more frequently for at least one year. Odds ratios were calculated using conditional logistic regression.

RESULTS

Only 8% of cases resided in Addis Ababa. Qat use was more frequent in cases (36%) than in controls (26%). A 2-fold elevation in EC risk was observed in ever qat chewers compared with never users in unadjusted conditional logistic regression (OR = 2.12; 95% CI = 0.94, 4.74), an association that disappeared after adjusting for differences in tobacco use, consumption of alcohol and green vegetables, education level, and religion (OR = 0.95; 0.22, 4.22). Among never tobacco users, however, a non-significant increase in EC risk was suggested in ever qat users also after adjustment. Increases in EC risk were observed with ever tobacco use, alcohol consumption, low consumption of green vegetables, a salty diet, illiteracy, and among Muslims; the four latter associations were significant.

CONCLUSIONS

This pilot study generated EC risk estimates in association with a habit practiced by millions of people and never before studied in a case-control design. Results must be interpreted cautiously in light of possible selection bias, with some demographics such as education level and religion differing between cases and controls. A large case-control study with enrolment of EC cases and carefully matched controls at health facilities from high-risk areas in the countryside, where the majority of cases occur, is needed to further investigate the association between qat use and EC.

Pharmacological and Toxicological Effects of Catha edulis F. (Khat)

Khat chewing is deeply rooted in the culture and tradition of communities in khat belt countries, and its consumption is spread to other countries through the suitcase trade. The aim of this article is to review current knowledge on the chemistry, social, pharmacology and toxicology of khat and its use. Khat produces effect invariably in every system, which is harmful or beneficial in some instances. Harmful effects are observed in heavy users, although firm evidence is lacking. Chewing khat acutely elicits states of euphoria, which is followed by low mood. Khat contains alkaloids with psychostimulant properties, but the effect cannot be totally explained by these alkaloids. It is also not clear whether the effect produced in some organs like liver could be attributed to khat or pesticides sprayed during farming. Although the evidence indicates that khat has adverse effects in most organs, our understanding of the complex interaction between use and effect is incomplete, and causal relationships have not yet been described. Moreover, khat has positioned itself well in the social, economic and political arena. Thus, a multidisciplinary research is required to understand the different dimensions and come up with ways that maximize the benefit while minimizing the risk. Copyright © 2017 John Wiley & Sons, Ltd.

Exposure to DDT and its metabolites from khat (Catha edulis) chewing: Consumers risk assessment from southwestern Ethiopia

Khat (Catha edulis) is one of the most consumed plant in the horn of African countries. However, it is a stimulant plant that has several side effects on the health of consumers. On top of that, the khat leaves used for human consumption are often contain contaminants such as pesticide residues. The present study aims to investigate the level of DDT residue and its metabolites (p'p-DDE, p'p-DDD, o'p-DDT and p'p-DDT) in khat samples and to undertake exposure assessment to consumers. The khat samples were collected from local markets in southwestern Ethiopia. Consumption survey was undertaken using 24 h recall method for both male and female khat consumers. The finding showed that 80% of the khat samples contained DDT and its metabolites. Some of the residues were above the maximum residue limit (MRL) set by Food and Agricultural Organization (FAO). The concentration of p'p-DDE and p'p-DDT in khat were in the range of 0.033-0.113 and 0.010-0.026 mg/kg, respectively. High concentration of the metabolite (p'p-DDE) compared to the parent compound (p'p-DDT) revealed the historical use of DDT in the study area. Probabilistic exposure analysis indicated that the mean and 97.5 percentile (P97.5), of the estimated daily intake of total DDT were 0.002 and 0.006 mg/kg bw/day, respectively. The study concluded that khat consumers are exposed to the stimulant effect of the plant as well as DDT and its metabolites in Jimma zone.

Organochlorine pesticide contamination of foods in Africa: incidence and public health significance

Organochlorine pesticides (OCPs) have been used worldwide, particularly in Africa, for several decades. Although many are banned, several African countries still use OCPs especially for the prevention and control of malaria. OCPs are characterized by their bio-accumulation in the environment, especially in the food chain, where they find their way into the human body. Despite no clear epidemiological studies confirming hazardous effects of these chemicals on human health, many studies have reported positive associations between the use of OCPs and neurological and reproductive disorders, and cancer risk. There is a clear gap in published reports on OCPs in Africa and their potential health hazards. Thus, the aim of this review is to summarize the incidence of OCP contamination in various foods in Africa, to demonstrate the potential transmission of these chemicals to people and to discuss their possible health hazards.

Khat chewing and cirrhosis in Somaliland: Case series

BACKGROUND

Khat chewing is common especially among men in East Africa and Yemen. It is generally viewed by the populace as a benign social custom. Several studies of ethnic Somali immigrants to Western countries suggest an association between khat chewing and hepatotoxicity, but the risk of hepatotoxicity related to khat chewing within African settings is not documented.

AIM

To identify and describe liver disease without evidence of alcohol exposure or infectious etiology in khat chewers.

SETTINGS

A university-affiliated teaching hospital in Somaliland.

METHODS

Cases of cirrhosis of unknown cause were identified from the clinical practice of Al Hayatt Hospital in Borama, Somaliland, during 14 months beginning December 2012.

RESULTS

Eight Somali men aged 27-70 years living in Somaliland were identified with cirrhosis of otherwise unknown cause. All chewed khat habitually for many years (15-128 bundles per day times years of use). A liver biopsy of one man was consistent with khat hepatotoxicity. Four of the eight men died during the study period.

CONCLUSION

Khat chewing may be associated with health consequences including severe hepatotoxicity with cirrhosis.

Neuropsychological functioning among chronic khat users in Jazan region, Saudi Arabia

BACKGROUND

Khat chewing effects in the central nervous system are attributed to cathinone and cathine, which are structurally related to amphetamine. However, studies on neuropsychological problems arising from khat use in humans are not extensive and have only included observational and single-case studies. The aims of this study were to (1) to examine neuropsychological functions among khat chewers, and (2) to determine factors affecting neuropsychological outcomes among khat chewers.

METHODS

A sample of 70 adult male khat chewers and a control group of 72 nonchewers were recruited from the Jazan region in southwest Saudi Arabia. A questionnaire examining socioeconomic background, medical and occupational history, education, and khat chewing behaviors was administered. Neuropsychological performance was assessed using computerized tests from the Behavioral Assessment and Research System (BARS) that assessed learning, episodic and working memory, motor speed/coordination, attention/information processing speed, sustained attention, set-shifting/response inhibition, and perceptual functions; noncomputerized tests, Trail Making A and B, Block Design, and Benton Visual Retention tests were also administered.

RESULTS

Khat chewers performed significantly worse on 3 out of 14 neuropsychological subtests compared with the control group, representing learning, motor speed/coordination, and set-shifting/response inhibition functions. Age and educational level were identified as predictors of neuropsychological outcomes of khat chewers.

CONCLUSIONS

The chronic chewing of khat leaves is associated with deficits in some neuropsychological functions, which may affect the mental and neurological health of communities in which khat chewing is a common habit.

Qat Chewing and Risk of Potentially Malignant and Malignant Oral Disorders: A Systematic Review

BACKGROUND

Qat (also known as Khat, Kat and Miraa) is a green-leaved plant (Catha edulis). It is a shrub indigenous to Yemen and certain parts of eastern Africa. Chewing the leaves, which have sympathomimetic and euphoric effects, has been documented in many countries and increased with worldwide migration. The effect of long-term chewing Qat on the oral cavity is unknown.

OBJECTIVE

A systematic review was performed to identify any associations between Qat chewing and the occurrence of potentially malignant and malignant oral disorders.

METHODS

Medline and the Web of Science were searched for articles published before May 2014 without limits with regard to publication date and language.

RESULTS

From a total of 890 papers identified, 17 English papers reported potentially malignant or malignant oral disorders and Qat chewing. One additional paper in Arabic language was identified from reviewing the list of references of eligible papers. It was found that exposure to Qat may be associated with potentially malignant and malignant oral disorders, but methodological issues, such as inadequate study design, sample size, selection of study subjects, clinical evaluations of outcome and limited adjustment for confounders, limit the strength of the evidence base in this area.

CONCLUSION

The association between Qat chewing and potentially malignant and malignant oral disorders remains debatable and requires further investigations.

Before the ban--an exploratory study of a local khat market in East London, U.K

BACKGROUND

Khat is a green leaf with amphetamine-like effects. It is primarily used among people in Africa, the Middle East and in the diaspora communities from these countries. Prior to the prohibition of khat in the UK on 24 June 2014, there was almost no information available on key aspects of the local khat market.

METHODS

A cross-sectional study was conducted in 2012 using snowball sampling, Privileged Access Interviewing and area mapping in order to identify khat sale establishments. Data was collected via face-to-face interviews using mixed methods for data collection. This included information about the establishments selling khat, khat pricing and its use among different ethnic minority groups, in addition to the potential sale of khat to children and risk assessment (e.g., use of pesticides on khat).

RESULTS

Five out of seven sellers identified agreed to participate. Sellers described their khat sale establishments as 'community centres' which included, for example, a restaurant basement. The sellers' history of selling khat ranged between 1-15 years and khat's sale took place between 2pm-10pm. Miraa (e.g., Lara) from Kenya was the most popularly used khat variety, sold in pre-wrapped bundles of approximately 250 g costing £3 each and delivered four days a week. Harari (e.g., Owdi) from Ethiopia was sold in 200 g, 400 g and 1 kg bundles, priced between £5 and £20 and delivered two days a week. The primary benefit of khat use was reported to be social interaction. The customers were predominantly adult males of Somali origin. Most sellers claimed a self-imposed ban on sales to children under 18 years old. Khat bundles had no labelling describing variety or weight and sellers had no knowledge of the use of pesticides on khat and did not advertise the risks associated with khat use.

CONCLUSIONS

Khat selling establishments were businesses that did not adhere to trade standards regulations (e.g., labelling khat bundles). They claimed to provide a community service (facilitating social interaction) to their predominately Somali customers. Without a better understanding of the dynamics of the khat market there is a risk that both health and social needs of the vulnerable populations involved in the market continue to go unaddressed. Future research should track changes in the now illicit khat market in order to evaluate the social and public health implications following the recent changes to the current U.K. regulatory environment regarding khat.

Determination of organochlorine pesticide residue levels in chewable parts of the khat (Catha edulis) plant

In this study, the levels of DDT and its metabolite residues were determined in chewable parts of Catha edulis plants grown in the southern part of Ethiopia. The levels of p,p'-DDT and p,p'-DDE were found to be in the range of 10.8-19.7 and 3.5-18.6 μg/kg, respectively. These data revealed that the residue being detected is from recent applications. The estimated daily intake of total DDT from C. edulis consumption was calculated to be in the range between 0.0278 and 0.0747 μg/kg, which is significantly lower than the FAO/WHO guideline. However, this may not guarantee safety, as the application of DDT extends to vegetables as well. Even though the use of DDT was banned in Ethiopia for agriculture purposes, detectable levels are still being observed. The results of the study necessitate the need for awareness creation among the people in the community.

Pesticide residue evaluation in major staple food items of Ethiopia using the QuEChERS method: a case study from the Jimma Zone

Samples of maize, teff, red pepper, and coffee (green bean and coffee bean with pulp) were collected from a local market in the Jimma Zone, Ethiopia. Samples were analyzed for the occurrence of cypermethrin, permethrin, deltamethrin, chlorpyrifos ethyl, DTT and its metabolites, and endosulfan (α, β). In the analytical procedure, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction methodology with dispersive solid phase extraction clean up (d-SPE) technique was applied. Validation of the QuEChERS method was satisfactory. Recovery percentages of most pesticides were in the range of 70% to 120%, with good repeatability (%relative standard deviation < 20). The limit of detection and limit of quantification varied between 0.001 µg/g and 0.092 µg/g and between 0.002 µg/g and 0.307 µg/g, respectively. The main pesticides detected were DDT, endosulfan, cypermethrin, and permethrin. All of the pesticides analyzed were detected in red pepper and green coffee bean. Residues of DDT in coffee pulp significantly differed (p < 0.01) from other food items except for red pepper. The concentration of pesticides in the food items varied from 0.011 mg/kg to 1.115 mg/kg. All food items contained 1 or more pesticides. Two-thirds of the samples had residues below corresponding maximum residue limits, and the remaining one-third of samples were above the maximum residue limits. These results indicate the need for a good pesticide monitoring program to evaluate consumer risk for the Ethiopian people.

Khat (Catha edulis): A systematic review of evidence and literature pertaining to its harms to UK users and society

The use of khat ( Catha edulis) has been associated with a large number of physiological and societal harms, leading to calls for it to be controlled in the UK. The evidence of these harms is often equivocal, limited by confounding factors, or entirely anecdotal: high-powered, quality-controlled studies are lacking. Regardless, the body of relevant literature indicates that the once socially-regulated use of khat has been eroded. Some individuals have developed excessive consumption patterns, either using khat daily or in binge-sessions, though daily consumption is not necessarily problematic per se. The majority of users seem to use khat in moderation, where the associated harms appear low. For excessive users, harms associated with khat are greater, particularly relating to mental health. Social harms also seem to be largely related to excessive khat use rather than khat use itself. Even in cases of excessive khat use, however, causal relationships between chewing and harms have not been described. More research is required to establish the role of khat in liver disease, coronary problems, cancers of the digestive tract and incidents of domestic violence. Studies should consider the likeliness that certain users are more vulnerable to developing patterns of excessive khat use due to an interwoven set of factors such as social health determinants and pre- and post-migration experiences.

Levels of organochlorine pesticides residues in human adipose tissue, data from Tabasco, Mexico

The objective of this study was to determine the levels of organochlorine pesticides HCB, α-β-γ-HCH, p,p'-DDE, o,p'-DDT and p,p'-DDT in 150 adipose tissue of inhabitants of Tabasco, Mexico. The following pesticides were detected: p,p'-DDE in 100% of samples at mean 1.034 mg/kg; p,p'-DDT in 96.7% at mean 0.116 mg/kg; o,p'-DDT in 78.7% at mean 0.022 mg/kg and β-HCH in 58.0% at mean 0.049 mg/kg. The pooled sample was divided according to sex of donors (75 female and 75 male). Significantly higher levels of all organochlorine pesticides in females were found. The sample was divided into three age's ranges (15-28, 29-45 and 46-84 years). The mean and median levels of β-HCH, p,p'-DDE and Σ-DDT increase significantly (p < 0.05) from the first to the second and third group. The presence of organochlorine pesticide residues in Tabasco inhabitants is still observed, indicating sources of exposure to the pesticides.

Khat use is associated with increased response conflict in humans

OBJECTIVE

Khat consumption has become a worldwide phenomenon broadening from Eastern Africa and the south west of the Arabian Peninsula to ethnic communities in the rest of the world. Only few studies have systematically looked into cognitive impairments in khat users. We studied whether khat use is associated with changes in the emergence and resolution of response conflict, a central cognitive control function.

METHOD

Khat users (n = 16) and khat-free controls (n = 16) were matched in terms of sex, ethnicity, socio-economical situation, age, alcohol and cannabis consumption, and IQ (Raven's Progressive Matrices). Groups were tested on response conflict, as measured by the Simon task.

RESULTS

Khat users performed significantly slower than controls and were more strongly affected by stimulus-induced response conflict.

CONCLUSIONS

Khat use is associated with specific impairments in behavioral control: general slowing and less efficient resolution of response conflicts, which is likely to impair decision making in everyday life.