Effects of exposure to glyphosate on oxidative stress, inflammation, and lung function in maize farmers, Northern Thailand

Abstract

Background Glyphosate is a herbicide which is commonly used in agricultural areas. However, previous studies on glyphosate exposure in farmers and their health are still scarce. Methods A longitudinal pre-post study was performed among maize farmers. Information from questionnaires, urine and blood samples, and lung function were collected a day before and a day after glyphosate application in the morning. The urine samples were analyzed using liquid chromatography-tandem mass spectrometry to detect glyphosate levels. Serum samples were analyzed to detect malondialdehyde (MDA), glutathione (GHS), and C-reactive protein (CRP) levels using thiobarbituric acid, dithiobisnitrobenzoic acid, and nephelometry, respectively. Lung function performances were measured using a spirometer. Results A total of 180 maize farmers met the study inclusion criteria. After glyphosate application, it was found that increased urinary glyphosate levels contributed to increased serum MDA (β = 0.024, 95% CI = 0.000, 0.0047) and decreased serum GHS (β = -0.022, 95% CI = -0.037, -0.007), FEV1 (β = -0.134, 95% CI = -0.168, -0.100), FEV1/FVC (β = -0.062, 95% CI = -0.082, -0.042) and PEF (β = -0.952, 95% CI = -1.169, -0.735). Conclusions Exposure to glyphosate during glyphosate application had significant effects on oxidative stress and lung function in maize farmers.

Acute health symptoms related to perception and practice of pesticides use among farmers from all regions of Thailand

“…However, most Thai farmers had limited budgets for farming, so they often used hand knapsack or motorized knapsack sprayers, and they never had access to use of a tractor sprayer. Our results were consistent with the study by Sidthilaw et al ( 50 ) which found that backpack sprayers were at greater risk of herbicide exposure than motorized pump sprayers. The backpack sprayers held the pesticide tank on their backs, and sprayed the pesticides by hands.…”

Glyphosate exposure and urinary oxidative stress biomarkers in the Agricultural Health Study

“…Given that 8-OHdG reflects oxidative stress–induced DNA damage, our findings for 8-OHdG also support the genotoxic potential of glyphosate in humans ( 12 ) and strengthen existing evidence from studies that have reported associations between glyphosate exposure and increased DNA damage, assessed as DNA strand breaks ( 39 ) or micronucleus formation ( 40 ). The associations we observed with MDA, an end product of ROS reaction with polyunsaturated fatty acids, further suggest that glyphosate may induce oxidative injury to cell membrane lipids ( 41 ) and are consistent with a recent study among 180 maize farmers in Thailand which reported a positive association between urinary glyphosate and serum MDA levels following glyphosate application ( 28 ). Conversely, another study of 93 Thai farmers who used glyphosate found no difference between pre- and postwork urinary MDA levels ( 26 ).…”

“…Findings from our study and several other human population studies to date ( 27 , 28 , 42 , 43 ) agree with in vitro and animal studies that have together provided strong evidence for the potential of glyphosate to induce oxidative stress ( 12 , 24 ). In particular, rodent studies have shown increased lipid peroxidation upon glyphosate exposure, as indicated by elevated MDA levels in blood or tissues of glyphosate-treated animals relative to untreated animals ( 12 , 24 ).…”

“…Glyphosate has been shown to induce oxidative stress in human cells and animal models [reviewed previously ( 12 , 24 )]; however, research in human populations is scarce. To our knowledge, only 4 studies among agricultural workers have investigated glyphosate exposure in relation to oxidative stress biomarkers ( 25-28 ), 2 of which reported positive associations ( 27 , 28 ). Notably, most of these studies had relatively small sample sizes; relied only on self-reported exposures; and lacked details on the timing, frequency, or history of glyphosate use.…”

Evaluation of Roundup® Toxicity in Human Lung Cells

“…Previous epidemiological studies in farmers reported that glyphosate usage was associated with numerous diseases, including adverse effects on respiratory system. Glyphosate exposure was found to induce oxidative stress and affect lung function in farmers [18]. For this purpose, in the current study, human bronchial epithelial (BEAS-2B) cells were chosen as a model for investigation of Roundup toxicity on lung tissue.…”