Acute Changes in Thyroid Hormone Levels among Thai Pesticide Sprayers.

The objective of this study was to investigate the relationship of acute pesticide exposures and acute changes in thyroid hormones among Thai farmers. We recruited 78 farmers, who were scheduled to spray insecticides (chlorpyrifos and/or cypermethrin) or herbicides (paraquat and/or glyphosate). On the day before spraying, farmers collected their first morning void urine and went for blood collection. On the spray day, urine samples were collected at end of the spraying event and they were interviewed with questionnaires. The next morning, the first morning void urine and blood samples were collected. Blood samples were analyzed for thyroid hormones. Urine samples were analyzed for the metabolites of the pesticide sprayed. The results showed that the thyroid hormones, free triiodothyronine (FT3) and total triiodothyronine (T3) were significantly reduced as urinary chlorpyrifos metabolite increased the day after spraying. Total thyroxine (T4) significantly increased as cypermethrin metabolites increased the day after spraying. T4 significantly increased as urinary glyphosate levels increased; however, FT3 and T3 decreased significantly as urinary paraquat levels increased the day after spraying. These findings suggest that acute exposures to the pesticides chlorpyrifos, cypermethrin, paraquat and glyphosate can produce acute effects on the hypothalamic-pituitary-thyroid (HPT) axis, acutely altering thyroid hormone levels.

Longitudinal Study of Thyroid Hormones between Conventional and Organic Farmers in Thailand.

Many pesticides are endocrine-disrupting chemicals that can interfere with hormone levels. This study aimed to assess the longitudinal impact of exposure to pesticides on thyroid hormone levels, including Thyroid Stimulating Hormone (TSH), Free Triiodothyronine (FT3), Free Thyroxine (FT4), Triiodothyronine (T3), and Thyroxine (T4). Both conventional (i.e., pesticide using) and organic farmers were interviewed using questionnaires, and blood samples were collected at 7-9 a.m. to determine thyroid hormone levels for four rounds, with a duration of eight months between each round. A linear mixed model of the natural log of the individual hormone levels used random intercepts for subjects while controlling gender, baseline age, and body mass index (BMI) was used to compare between conventional and organic farmers or the impact of cumulative days of spraying insecticides, herbicides or fungicides. The estimated marginal means of the thyroid hormone levels (TSH, FT3, T3, and T4) estimated from the linear mixed models were significantly higher among the conventional farmers than organic farmers. As cumulative spray days of insecticide, herbicide or fungicide increased, TSH and FT3 increased significantly. FT4 decreased significantly as cumulative spray days of insecticide or fungicide increased. These findings suggest that the insecticides, herbicides, and fungicides sprayed by conventional farmers exert endocrine-disrupting activities, altering the hypothalamic-pituitary-thyroid (HPT) axis homeostasis.

Longitudinal Study of Metabolic Biomarkers among Conventional and Organic Farmers in Thailand.

The aim of this longitudinal study is to assess how pesticide use may impact metabolic biomarkers by collecting and comparing data from conventional (n = 13) and organic farmers (n = 225) every eight months for four rounds. Farmers were interviewed about family health history, food consumption behaviors, self-reported health problems, agricultural activities, and history of pesticide use. Systolic and diastolic blood pressure and body mass index (BMI) were measured. Blood samples were collected for total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), blood glucose, and triglycerides. A linear mixed model with random intercepts for subjects was used to compare the metabolic biomarkers between conventional and organic farmers and to examine the impact of the number of pesticide spray days for all four rounds after controlling for covariates. The conventional farmers reported using insecticides, herbicides, and fungicides. The marginal means for chemical farmers were significantly higher than organic farmers for total cholesterol, LDL, HDL, glucose, systolic and diastolic blood pressure, BMI, and waist circumference. Increasing the number of days of spraying either insecticides or fungicides was associated with an increase in HDL, LDL, and cholesterol levels. Increasing the number of herbicide spray days was associated with an increase in systolic and diastolic blood pressure and a decrease in BMI. These findings suggest that pesticide-using conventional farmers may be at higher risk of metabolic disease in the future.

Thyroid Hormones in Conventional and Organic Farmers in Thailand.

Pesticides can act as endocrine disruptors by different mechanisms including inhibition of iodine absorption, increases in thyroid hormone clearance, decreased cellular uptake of thyroid hormones, or changes in expression of thyroid hormone regulated genes. This study examined how exposure to pesticides impacts thyroid hormone levels, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), free T3 (FT3), and free T4 (FT4) by comparing conventional (n = 195) and organic farmers (n = 222), and by evaluating which types of pesticides might be associated with changes in thyroid hormone levels. Questionnaires were used to collect information about farmer characteristics, self-reported stress, agricultural activities, and history of pesticide use. Conventional farmers were asked to report the type and quantity of pesticides used each day. The TSH, FT3, T3, and T4 levels of conventional farmers were 1.6, 1.2, 1.3, and 1.1 times higher than those of organic farmers, respectively, after adjusting for covariates. Several specific herbicides had a significant relationship between the amount applied and an increase in thyroid hormone levels, after covariate adjustment. They included: paraquat (TSH, FT3 and T3); acetochlor (FT4); atrazine (TSH, FT3 and T3); glyphosate (T4); diuron (TSH) and the "other" herbicides including alachlor, propanil, and butachlor (FT4 and T3). The most commonly used herbicide among conventional farmers was glyphosate, followed by paraquat, 2,4-dichlorophenoxyacetic acid (2,4-D). These findings suggest that exposure to pesticides could impact the development of metabolic diseases and other health outcomes by altering the endocrine system (the thyroid hormone levels) through the hypothalamic-pituitary-thyroid (HPT) axis. This work is a part of a longitudinal study which will evaluate the sub-chronic effects of repeated exposure to different types of pesticides on thyroid hormone levels.

A Cross-Sectional Investigation of Cardiovascular and Metabolic Biomarkers among Conventional and Organic Farmers in Thailand.

Pesticide exposure has been implicated as a risk factor for developing a wide range of adverse health issues. Some examples are metabolic syndromes, including diabetes. This study investigated the relationship between current occupational use of pesticides and metabolic and cardiovascular biomarker levels among organic and conventional farmers in Thailand. In total, 436 recruited farmers were divided into two groups: conventional farmers (n = 214) and organic farmers (n = 222). Participants, free of diabetes, were interviewed and submitted to a physical examination. Serum samples were collected for clinical laboratory analyses, i.e., serum glucose and lipid profiles (triglycerides, total cholesterol, high-density lipoproteins, and low-density lipoproteins). Potential risk factors such as smoking, alcohol consumption, and heavy exercise were significantly different between the two groups. There were significant differences in terms of the years of pesticide use, pesticide use at home, sources of drinking water, and distance between the farmers' homes and farms between the groups. After adjusting for confounders, current conventional farmers had significantly higher abnormal body mass index (BMI), waist circumference, body fat percentage (% body fat), triglyceride, total cholesterol, and low-density lipoprotein values as compared to organic farmers. Conventional farmers had higher risk of many metabolic and cardiovascular risk factors as compared to organic farmers, putting them at higher risk of metabolic diseases in the future.

Nosocomial spread of class 1 integron-carrying extensively drug-resistant Pseudomonas aeruginosa isolates in a Thai hospital.

Fifty non-duplicate multiresistant isolates of Pseudomonas aeruginosa from a regional hospital in Northern Thailand were investigated for their antimicrobial susceptibility, presence of class 1 integrons and arrangement of gene cassettes as well as their genetic relationships. All but one isolate were classified as extensively drug-resistant P. aeruginosa (XDR-PA). Forty-one isolates (82%) were found to carry class 1 integrons. Amplification of the variable regions of class 1 integrons revealed seven diverse bands ranging in size from 0.7 kb to 7.0 kb. Sequence analysis of class 1 integron variable regions revealed the presence of several gene cassettes associated with resistance to aminoglycosides (aac, aad and aph), including the aac(3)-Ic cassette reported for the first time in Thailand. Gene cassettes encoding resistance to chloramphenicol (cmlA), ß-lactams (bla(PSE), bla(OXA) and bla(VEB)) and rifampicin (arr) were found. The putative small multidrug resistance protein (smr) and an open-reading frame with unknown function (orfD) were also detected. The aadA6-orfD cassette array was the most common integron found in this study. Integron-positive isolates had higher frequencies of antimicrobial resistance than isolates lacking integrons. Pulsed-field gel electrophoresis (PFGE) demonstrated the occurrence of horizontal gene transfer. Interestingly, a large number of XDR-PA isolates carrying identical integrons clearly exhibited the same PFGE pattern, indicating nosocomial spread of these isolates. The presence of XDR-PA carrying class 1 integrons is implicated in the possible spread of drug-resistant organisms, therefore screening for integron-positive P. aeruginosa might be necessary for protection against nosocomial infection.

Impact of pandemic influenza (H1N1) virus-associated community-acquired pneumonia among adults in a tertiary hospital in Thailand.

In July 2009, a pandemic influenza (H1N1) (pdm H1N1) virus epidemic emerged rapidly in Phitsanulok, Thailand. Adult cases of community-acquired pneumonia (CAP) were prospectively examined for pdm H1N1 virus infections by real-time PCR in a tertiary hospital in Phitsanulok from July to November 2009. Twenty-four cases of pdm H1N1 virus-associated CAP were confirmed, and their clinical features including bacterial infection, severity of disease, course of admission, treatment, and outcome were investigated. The median age of these cases was 39.5 years. Most cases appeared to be primary viral pneumonia, but only one case was positive for a urinary pneumococcal antigen. The median time from the onset of illness to admission was 4 days. All 24 patients received oseltamivir after admission. Twelve (50.0%) were defined as having severe CAP and 9 (37.5%) were diagnosed with acute respiratory distress syndrome (ARDS). During the study period, pdm H1N1 virus infections frequently caused severe CAP among young adults because of the delayed initiation of antiviral therapy. Of the 9 ARDS patients, 3 died of ventilator-associated pneumonia caused by multidrug-resistant Acinetobacter baumannii. Implementation of infection control targeting this pathogen is required in tertiary hospitals in Thailand.