Impacts of Pesticide Use on Semen Characteristics among Rice Famers in Kienxuong District, Thaibinh Province, Vietnam

This case-control study assessed the effects of pesticide use on semen characteristics among rice farmers of Kienxuong District, Thaibinh Province, Vietnam. Semen samples of 1,036 rice farmers were obtained by manual masturbation and screened at Commune Health Stations. Of these, 156 abnormal semen samples were identified; 314 rice farmers with normal semen were recruited as controls. The semen characteristics (volume, sperm concentration, total sperm count, motility, vitality and morphology) of the cases were considerably poorer than the controls. Factors associated with abnormal semen after adjusting for age, smoking and alcohol drinking by logistic regression were: distance of less than 300 meters from household to rice fields and duration of work over 10 years as a farmer (adjusted OR = 3.16, 95% CI: 1.97-5.05 and adjusted OR = 3.98, 95% CI: 2.20-7.21, respectively). Rice farmers without personal protective equipment (PPE) when spraying pesticides and without pesticide training (adjusted OR = 3.05, CI: 1.92-4.85 and adjusted OR = 1.90, CI: 1.14-3.16, respectively) were also at risk for abnormal semen compared to controls. These findings showed the strength of association between pesticide use and abnormal semen characteristics among rice farmers in Kienxuong District, Thaibinh Province, Vietnam. creased significantly in Southeast Asia (FAO, 2005; Hoe, 2005) and Vietnam (Trung and Ky, 2001; Hoe, 2005). Results from several scientific studies have indicated temporal and regional changes in male reproductive health. Additionally, a possible decline in semen characteristics has been observed and reported in many studies (Leto and Frensilli, 1981; Auger et al, 1995; Swan et al, 1997). Experts in male fertility and epidemiologists (Auger et al, 1995; Fisch and Goluboff, 1996; Irvine et al, 1996; Swan et al, 1997, 2000; Emanuel et al, 1998) have extensively explored and disputed the findings of Carlsen et al (1992), who showed a significant decline in semen quality over the past 50 years on meta-analysis of 61 studies. INTRODUCTION Reduction of sperm count, lower motility and lower normal sperm morphology are associated with a higher probability of infertility (Anne, 2000; ADAM, 2003). The adverse effects of pesticides on the male reproductive system, especially semen characteristics, is a major health problem all over the world. World pesticide use is high for all pesticide types (EPA, 2001). Imported pesticides have inSOUTHEAST ASIAN J TROP MED PUBLIC HEALTH 570 Vol 38 No. 3 May 2007 Several international studies have shown evidence of reduction in semen quality or lower sperm counts due to agricultural pesticides. (Wyrobek et al, 1981; Bigelow et al, 1998; Padungtod et al, 1999, 2000; Tan et al, 2002; Marmol-Maneiro et al, 2003; Swan et al, 2003; Kamijima et al, 2004; Meeker et al, 2004; Perry et al, 2006). Based on these findings, we conducted a case-control study to identify the impact of pesticide use on semen characteristics among rice farmers in Kienxuong District, Thaibinh Province, Vietnam. MATERIALS AND METHODS Approval of this study was obtained from the Thaibinh Medical University Ethics Committee, Vietnam. Before being enrolled in the study, male farmers were informed of the purpose of the study, procedures, benefits and possible risks involved. Male farmers were also told that all information and biological samples obtained in this study would remain confidential, and they had the right to refuse to participate and could terminate the participation at any time. All of the participants in the study were required to sign a consent form prior to their participation. This study was conducted among male farmers from 5 communes in Kienxuong District, Thaibinh Province, Vietnam. The total number of rice farmers asked to participate in the study was 1,655, of whom 1,036 (62.59%) consented and successfully provided semen samples.