The determinants of thyroid function among vegetable farmers with primary exposure to chlorpyrifos: A cross-sectional study in Central Java, Indonesia.

Objectives: Occupational pesticide exposure, chlorpyrifos (CPF) in particular, may adversely affect the thyroid. The purpose of this study was to evaluate the determinants of thyroid function as indicated by the serum concentration of thyroid-stimulating hormone (TSH) among Indonesian vegetable farmers with primary exposure to CPF. Methods: A total of 151 vegetable farmers participated in this study. The sociodemographic and occupational characteristics of the participants were obtained using a structured interviewer-administered questionnaire. A validated quantitative method was used to estimate the cumulative exposure level (CEL). Serum TSH, thyroglobulin (Tg), free thyroxine (FT4), and urinary iodine excretion (UIE) were measured in the laboratory. The difference in TSH concentrations according to CEL and other characteristics were analysed using the Mann-Whitney U test. A multiple linear regression model was used to evaluate the potential determinants of TSH. Results: The mean age was 50 (SD 9.4) years. The median concentrations of TSH, FT4, and Tg/FT4 ratio were 1.46 mIU/L, 1.17 ng/dL, and 6.23 × 102, respectively. We observed that higher TSH concentrations were found among those with a higher Tg/FT4 ratio, were classified as high CEL, and had lower UIE or FT4. Conclusions: Our findings show that Tg/FT4 ratio, CEL, FT4, UIE concentrations, and post-spraying days were determinants of TSH concentrations among farmers with primary exposure to CPF. These results indicate that farmers are exposed to agents with thyroid-disrupting properties, thus supporting previous evidence showing the potential for thyroid disorders in agricultural populations exposed to pesticides.

The Role of CYP2B6*6 Gene Polymorphisms in 3,5,6-Trichloro-2-pyridinol Levels as a Biomarker of Chlorpyrifos Toxicity Among Indonesian Farmers.

OBJECTIVES: One of the most widely used pesticides today is chlorpyrifos (CPF). Cytochrome P450 (CYP)2B6, the most prominent catalyst in CPF bioactivation, is highly polymorphic. The objective of our study was to evaluate the role of CYP2B6*6, which contains both 516G>T and 785A>G polymorphisms, in CPF toxicity, as represented by the concentration of 3,5,6-trichloro-2-pyridinol (TCPy), among vegetable farmers in Central Java, Indonesia, where CPF has been commonly used. METHODS: A cross-sectional study was conducted among 132 vegetable farmers. Individual socio-demographic and occupational characteristics, as determinants of TCPy levels, were obtained using a structured interviewer-administered questionnaire and subsequently used to estimate the cumulative exposure level (CEL). TCPy levels were detected with liquid chromatography-mass spectrometry. CYP2B6*6 gene polymorphisms were analyzed using a TaqMan® SNP Genotyping Assay and Sanger sequencing. Linear regression analysis was performed to analyze the association between TCPy, as a biomarker of CPF exposure, and its determinants. RESULTS: The prevalence of CYP2B6*6 polymorphisms was 31% for *1/*1, 51% for *1/*6, and 18% for *6/*6. TCPy concentrations were higher among participants with CYP2B6*1/*1 than among those with *1/*6 or *6/*6 genotypes. CYP2B6*6 gene polymorphisms, smoking, CEL, body mass index, and spraying time were retained in the final linear regression model as determinants of TCPy. CONCLUSIONS: The results suggest that CYP2B6*6 gene polymorphisms may play an important role in influencing susceptibility to CPF exposure. CYP2B6*6 gene polymorphisms together with CEL, smoking habits, body mass index, and spraying time were the determinants of urinary TCPy concentrations, as a biomarker of CPF toxicity.

Epstein-Barr virus nuclear antigen-1 is useful as therapeutic efficacy marker in serum but not in saliva of nasopharyngeal cancer patients who underwent radiotherapy.

INTRODUCTION: Nasopharyngeal carcinoma (NPC) is a multifactorial disease with genetic, viral, environmental and lifestyle-related risk factors. Epstein-Barr virus (EBV) can promote the oncogenic transformation of an infected cell into malignant. EBV encodes many stimulating products including Epstein-Barr virus nuclear antigen-1 (EBNA-1) which plays a key role in the regulation of gene expression and replication of the genome in the latent period of infection. EBNA-1 in serum and tumour tissue of NPC patients correlates with NPC prognosis. Moreover, the presence of EBV DNA in serum samples from NPC patients' blood circulation can be used as an early marker in the diagnosis of NPC. OBJECTIVE: The objective of this study was to find effective methods for monitoring the progress of NPC patients undergoing radiotherapy and therapeutic efficacy by observing the changes in EBV DNA in serum and saliva. METHODOLOGY: The pre-experimental design compared blood and saliva taken from a pre-test and post-test group of NPC patients before and after radiation therapy. The concentration of EBV DNA was measured in the serum and saliva after amplification using quantitative polymerase chain reaction (qPCR) with compatible primers for the EBNA-1 gene. The data were statistically analysed by paired T-test. RESULTS: Highly significant (p = 0.0001) increase in cycle threshold qPCR and decrease in the mean concentration of EBV DNA (p = 0.0001) were observed in serum samples, but no significant changes were observed in saliva. CONCLUSIONS: The results suggest that EBV DNA in serum can be used as the gold standard and a marker for monitoring the response to radiation therapy in NPC patients, whereas the examination of EBV DNA from saliva samples is not accurate and thus, not appropriate.

Cumulative exposure characteristics of vegetable farmers exposed to Chlorpyrifos in Central Java - Indonesia; a cross-sectional study.

BACKGROUND: Agriculture is a major economic sector in Indonesia. Chemical pesticides are widely being used in agriculture for controlling pest. There is a growing concern that pesticide exposure, particularly chlorpyrifos (CPF) exposure, combined with other occupational characteristics that determine the level of exposure, can lead to further health impacts for farmers. Our objective was to evaluate the cumulative exposure characteristics among farmers exposed to CPF by using a validated algorithm. METHODS: We conducted a cross-sectional study of 152 vegetable farmers aged 18-65 who actively used CPF for at least 1 year in Central Java, Indonesia. Subject characteristics were obtained using a structured interviewer-administered questionnaire, addressed for sociodemographic and work-related characteristics. The cumulative exposure level (CEL) was estimated as a function of the intensity level of pesticide exposure (IL), lifetime years of pesticide use and the number of days spraying per year. CEL was subsequently classified into two groups, high and low exposure groups. The difference in characteristics of the study population was measured using Chi-square, independent-t or Mann-Whitney test. Association between CEL and its characteristics variables were performed by multiple linear regression. RESULTS: Seventy-one subjects (46.7%) were classified as the high exposure group. The use of multiple pesticide mixtures was common among our study population, with 94% of them using 2 or more pesticides. 73% reported direct contact with concentrated pesticides product, and over 80% reported being splashed or spilt during preparation or spraying activity. However, we found that the proportion of proper personal protective equipment (PPE) use in our subjects was low. Higher volume of mixture applied (p <  0.001) and broader acres of land (p = 0.001) were associated with higher cumulative exposure level, while using long-sleeved clothes and long pants (p <  0.05) during pesticide spraying were associated with lower cumulative exposure after adjusted for age and gender. CONCLUSIONS: These findings indicate an inadequate knowledge of using pesticides properly. Thus, we recommend comprehensive training on pesticide usage and encourage proper PPE to reduce the exposure level.

Gene promoter polymorphism of RUNX2 and risk of osteoporosis in postmenopausal Indonesian women.

OBJECTIVES: Osteoporosis is a metabolic bone disease of reduced bone mass density (BMD) and elevated risk of fracture due to an imbalance in bone formation and resorption. The risk and incidence of osteoporosis increase towards advanced age, particularly in postmenopausal women, and the risk is known to be affected by the variation in the expression of the associated regulatory genes. This work aimed to clarify the impact of variation in RUNX2 (runt domain transcription factor 2), which is an osteoblast-specific transcription factor that normally stimulates bone formation and osteoblast differentiation, regarding single-nucleotide polymorphism within RUNX2 promoter (P1) and risk of osteoporosis in postmenopausal Indonesian women. METHODS: Using DNA sampling from blood, the variation at the single-nucleotide polymorphism (-330, G→T, rs59983488) at the RUNX2 P1 promoter was investigated using polymerase chain reaction-restriction fragment length polymorphism for 180 consenting postmenopausal Indonesian women. The subjects were examined for bone mass density and classification to normal and those with osteopenia or osteoporosis by T-scoring with dual-energy X-ray absorptiometry. Chi-square testing and logistic regression were mainly used for statistical assessment. RESULTS: The results showed a general trend with increased risk of osteoporosis associated with the genotype TT (mutant type) and the corresponding T allele of the tested polymorphism of RUNX2 promoter P1. The trend was, however, not significant in multivariate testing adjusted for age and time after menopause. CONCLUSION: To confirm the potential risk with TT genotype would require testing of a much larger sample of subjects. As the tested single-nucleotide polymorphism only represents one of the relevant candidate locations of RUNX2, the results are taken nevertheless to suggest an impact by overall RUNX2 variation in the risk of osteoporosis in Indonesian postmenopausal women.

Follicle-stimulating hormone receptor polymorphisms in women with normogonadotropic anovulatory infertility.

OBJECTIVE: To assess the incidence of different FSH receptor genotypes in normogonadotropic anovulatory infertile women (World Health Organization class II) and normo-ovulatory controls and to correlate these genotypes with baseline characteristics and ovarian responsiveness during ovulation induction. DESIGN: Cross-sectional study. SETTING: University hospital. PATIENT(S): Thirty normo-ovulatory controls and 148 normogonadotropic anovulatory infertile women. INTERVENTION(S): All participants underwent a standardized evaluation that included cycle history, body mass index measurement, and transvaginal ultrasonography of ovaries. Fasting blood samples were obtained for endocrine evaluation. Ovarian responsiveness to FSH in normogonadotropic anovulatory infertile women was assessed during ovulation induction, and DNA was analyzed to determine the FSH receptor genotype. MAIN OUTCOME MEASURE(S): Prevalence of FSH receptor polymorphisms, baseline serum FSH levels, amount of FSH administered, duration of stimulation, and ovarian response dose. RESULT(S): The Thr/Thr 307 genotype was significantly less prevalent (52% vs. 23%) and the Ser/Ser 680 polymorphism was significantly more prevalent (40% vs. 16%) in patients compared with controls. Normogonadotropic anovulatory infertile women with the Ser/Ser 680 polymorphism presented with higher median FSH serum levels (5.2 IU/L [range, 2.4-9.7 IU/L]) than did those with the Asn/Asn 680 (4.6 IU/L [range, 1.4-5.8 IU/L) and Asn/Ser 680 (4.5 IU/L [range, 1.8-9.7 IU/L) variants. However, ovarian responsiveness to FSH was similar among anovulatory women with the various polymorphisms. CONCLUSION(S): Normogonadotropic anovulatory infertile patients have a different FSH receptor genotype than do normo-ovulatory controls. Although this characteristic is associated with increased baseline FSH serum levels, altered ovarian sensitivity to exogenous FSH during ovulation induction could not be established.