Effects of Pesticide Use on Semen Quality Among Farmers in Rural Areas of Sabah, Malaysia
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Journal of J Occup Health 2010; 52: 353–360 Occupational Health Effects of Pesticide Use on Semen Quality among Farmers in Rural Areas of Sabah, Malaysia Feroz HOSSAIN, Osman ALI, Urban J.A. D’SOUZA and Daw Khin Saw NAING School of Medicine, University Malaysia Sabah, Malaysia Abstract: Effects of Pesticide Use on Semen Key words: Exposure, Farmers, Pesticides, Semen Quality among Farmers in Rural Areas of Sabah, quality Malaysia: Feroz HOSSAIN, et al. School of Medicine, University Malaysia Sabah, Malaysia—Objectives: Declining semen quality and sperm count are growing To determine the relationship between semen quality risks for the fertility index. Epidemiologic studies have and exposure to pesticide residues. Methods: A cross- indicated a decline in sperm count and semen quality of sectional study was conducted among male farmers almost a half over the last five decades among healthy from 3 different communities in Sabah, Malaysia. A men all over the world. Pesticides have been proposed total of 152 farmers participated in this study of whom 62 farmers had been exposed to either paraquat or as one of the major causes for this decline. Pesticides malathion or both to varying extents. Questionnaires contaminate the environment, the soil and the agricultural were designed to record a history of pesticides produce food. As a result, human beings are exposed to exposure and other potential risk factors among pesticides through food, water, air, via tainted breast milk, farmers. All semen samples were collected, processed playing in the fields and later bringing pesticides into and analyzed by qualified personnel based on WHO their homes or through skin contact. guidelines. Volume, pH, sperm concentration, motility, There have been many studies of farmers with the goal morphology and WBC count were examined and of determining the effects of pesticide exposure. A recent recorded. The association between pesticide exposure study has shown that pesticide exposure causes lower and semen parameters was highly significant. Results: semen quality1). Also, there has been a decline in the The mean values of volume, pH, sperm concentration, concentration and motility of sperm and in the percentage motility, and WBC count were significantly less in the exposed group than in compared with the non-exposed of morphologically normal spermatozoa in fertile men 2) group, with p<0.005. Those who were exposed to that is independent of the age of the men . One study pesticides had greater risk of having abnormal semen showed a significant decline in semen quality over the parameters than those in with the non exposed group, past 50 yr3). Many other international studies have with p values of less than 0.05. The comparison provided significant evidences of reduction in semen between semen qualities such as lower sperm count, quality or lower sperm count being associated with motility and higher percentage of sperm abnormality exposures to agricultural pesticides4). of those exposed to different types of pesticides Malathion, a pesticide in the organophosphate chemical (paraquat and malathion) showed no significant family, is the most commonly used insecticide in the differences. Conclusion: The results showed a world. Many studies have been conducted on significant decline in semen quality with a decline in organophosphate insecticides in relation to their adverse sperm count, motility and higher percent of teratospermia among subjects with pesticide exposure, reproductive effects on humans. Known studies on 5, 6) and those who were exposed to pesticides had organophosphate pesticide, such as malathion and significantly 3 to 9 times greater risk of having abnormal methyl parathion7), have demonstrated their adverse semen parameters. effects on male and female reproductive system, with (J Occup Health 2010; 52: 353–360) alterations in sexual behavior, decrease in fertility/sperm count, loss of fetus during pregnancy, lactation problems Received Jan 18, 2010; Accepted Sep 1, 2010 as well as premature menopause being the potential Published online in J-STAGE Sep 30, 2010 manifestations. Laboratory rodent model studies have Correspondence to: F. Hossain, R 1–6, Indah Court Likas, 88400 accumulated a significant body of evidence confirming Kotakinabalu, Sabah, Malaysia (e-mail: [email protected], data regarding the reproductive toxicity of low doses of [email protected]) pesticides7, 13). 354 J Occup Health, Vol. 52, 2010 The adverse health effect of pesticide exposure on male reproduction is a topic of considerable concern in Materials and Methods environmental, occupational and reproductive 1) Research design and methodology epidemiology. In recent years, scientists have become A cross-sectional study was undertaken to investigate more aware that human-made chemicals may disrupt the relationship between pesticide exposure and their reproductive function in both wildlife and humans8). effects on semen parameters. Ethical clearance for the Recent discoveries of the hormone disrupting properties conduct of the study was obtained from the School of of some pesticides at low exposures9) have raised interest Medicine, University Malaysia Sabah. Before being in how low-dose acute or chronic pesticide exposures— enrolled in the study, male farmers were informed of the the types of exposures that can currently occur both purpose of the study, procedures, benefits and possible occupationally and environmentally—impact human risks involved. They were also told that all information spermatogenesis. Both animal toxicology and human as well as biological samples and data obtained for the epidemiologic studies have shown that pesticides may study would remain confidential. Written consent to operate through a hormonal or genotoxic pathway to participation was voluntarily obtained from all of the affect spermatogenesis10). Most of the pesticides induce participants in the study prior to their participation. result in disruption in the normal endocrine axis and there are many rodent studies in the literature. In the 2) Selection of study area 1930s, studies involving laboratory animals have This study was conducted among male farmers from 3 demonstrated the estrogenic properties of a number of different communities in Sabah, Malaysia, namely industrial chemicals, including pesticides such as Kundasang, Telupid and Papar. A total of 152 farmers paraquat, methyl parathion, endosulphan and participated in this study after we had obtained their dichlorodiphenyltrichloroethane (DDT)11). Paraquat is informed consent and all of them successfully provided highly toxic to animals and has serious and irreversible semen samples. Participation in the study by a number delayed effects if absorbed. As little as one teaspoonful of subjects was impeded by local larger group was of the active ingredient is fatal and death occurs up to 30 difficult as their religious practices and cultural beliefs days after ingestion. Paraquat is also toxic if absorbed did not allow them, since people were less literate. Based through the skin but at spray strength paraquat has of on a statistician’s advice, the appropriate numbers of relatively low acute toxicity. A study of Malaysian voluntarily willing participants were randomly selected plantation sprayers cited health problems after exposure as a statistically viable sample for the study. The present to paraquat12). Dermal exposures to low doses of paraquat study may pave the way for highlighting the need for in rats resulted in cytotoxic and genotoxic germ cell extensive studies world-wide. sequelae in male rats13). There are number of animal studies highlighting the adverse effects of low doses of 3) Grouping of human beings subjects pesticides on reproductive functions and spermatogenesis. Based on the occupation and exposure farmers were Laboratory studies paves the way for the determination divided into two groups: of the toxicity profiles of these pesticides and chemicals, The farmers who were exposed to pesticides were community and clinical studies among the human allocated to the exposed group. The number of exposed population are necessary to evaluate the full extent of group n=62; and the farmers who gave no history of the adverse effect, especially among the pesticide exposed exposure to pesticides were allocated to the non farming communities. exposed group and the number of non-exposed group Most of the farming practices in the Sabah state of n=90. Malaysia involve usage of a variety of pesticides on vegetables, fruits, paddy and palm oil plantations. 4) Semen collection and seminal fluid analysis Farmers use these pesticides without proper protective Semen collection: measures and their risk of exposure is quite high. Though A semen sample was collected by masturbation into a paraquat and other organophosphate pesticides are banned sterile wide-mouth glass container in a laboratory at each by the government, their illegal usage of the same is community health station. Sexual abstinence of 2–3 days common. Random interviews before the actual study prior to collection of semen was advised to the suggested various risks of exposure to pesticide residues. participants. It was adequate for the accurate assessment Based on these findings, a cross-sectional study was of semen quality. Information on date, time and spillage conducted to explore into the toxicity effects of pesticides were recorded and coded on each sample. The samples among on farmers, semen quality among the farmers in were kept in an incubator at 36–37°C