An Occupational and Environmental Health Research Hub for
Improving Agricultural Health in Southeast Asia
Agricultural workers in Southeast Asia (SE Asia ) use increasing amounts of pesticides.
Workshop to identify gaps in research for the development of occupational and environmental health policies.
NIH Fogarty Funded GeoHealth Hub
As part of our U.S. National Institute of Health Fogarty International Center GeoHealth Hub planning grant, CWEND organized a Workshop to examine and prioritize the Occupational and Environmental Health (OEH) research needs of healthcare and informal sector workers (our target population). During that project we produced a workshop report, and four background papers on occupational safety and health (OSH) in Thailand for each of the target sectors. For links to these publications see our Outreach Section.
When NIH Funded our 5 year GEOHealth Hub Research and Training grant our focus was Improving Agricultural Health in Southeast Asia. . The funded research project was a prospective repeated measures study to evaluate sub-chronic change in hypothalamic–pituitary–thyroid (HPT) axis and hypothalamic-pituitary-adrenal (HPA) axis hormones and risk factors for metabolic syndrome comparing organic and pesticide use farmers over a 2 year follow-up. See Results below.
In 2012, the International Labor Organization (ILO) reported that there were approximately 1.3 billion agricultural workers worldwide. Almost 60% of these agricultural workers were in developing countries, with a great majority found in the Asia-Pacific region. In Thailand, agricultural work is an economic foundation of the nation and rural areas are home to more than 70% of the population. Among the working population, 42% work in agriculture (16.7 million), with 93% of these agricultural workers in the informal sector and 44% female.
Little is known about the accident and injury rates or the chronic disease experience of agricultural workers in Thailand or other Southeast Asian countries. Likewise, few studies have described the ergonomic risks of agricultural work. In addition, demand for higher agricultural yields has contributed to the continuing annual increase in pesticide imports throughout Southeast Asia, with pesticide poisonings common throughout the region.
CWEND GeoHealth Hub projects in this sector include:
Our NIH Fogarty R21 project on Brain Disorders in the Developing World. Pregnant women were recruited as subjects from partner hospitals in three provinces in Thailand to investigate whether in-utero organophosphate pesticide exposure, as measured by urinary metabolites, along with mild to moderate iodine insufficiency produced synergistic effects on neonatal neurodevelopment, as measured by the Brazelton Newborn Behavioral Assessment Survey (BNBAS) in newborns and by EEG/ERP (Electroencephalogram/Event Related Potential) testing in 4 month old babies. See Outreach Section for publications.
Our NIH Fogarty GeoHealth Hub planning grant collected health questionnaires from over 1100 health care workers (patient care and non-patient care) and over 630 informal sector workers (agriculture, salt farm, bird cage makers, stone sculptors, and rubber tappers) at our 5 partner sites. For access to questionnaires see our Outreach Section. During our GEOHealth Network meetingthe questionnaire results were presented and reviewed with our partners and used to develop the proposed surveillance and hazard assessment follow-up. Manuscripts reporting these results are in preparation.
Our NIH Fogarty GEOHealth Hub Research grant (U01) focused on examining the impact of pesticides as endocrine disrupters. Results from this are below:
After adjusting for confounders, current conventional farmers had significantly higher abnormal BMI, waist circumference, % body fat, triglycerides, total cholesterol, and LDL values at baseline, as compared to organic farmers (Pub #9). We followed up with a a longitudinal analysis (4 rounds data) and again found that conventional farmers had higher metabolic biomarkers than organic farmers. We also found a significant association between the number of days of pesticide spraying and levels of cholesterol, HDL, LDL, blood pressure and BMI. These findings support the proposal that the pesticide exposures of conventional farmers increase the risk of metabolic and cardiovascular risk factors that are linked to long term metabolic disease (CVD, stroke, diabetes) (Pub #11).
After adjusting for covariates, the thyroid hormones (4/5) of conventional farmers were higher than those of organic farmers at baseline. Several specific herbicides had a significant relationship between the amount applied and an increase in thyroid hormone levels (Pub #10). We followed up with a longitudinal analysis covering 4 rounds and again found that conventional farmers had higher thyroid levels than organic farmers and that increasing the cumulative number of spray days of pesticides significantly increases the level of TSH and fT3. This finding supports the proposal that pesticide use by conventional farmers may alter the endocrine system through the HPT axis and could impact the development of metabolic diseases (Pub #12).
Based on repeated measures (3 rounds) of 4 daily cortisol measurements, conventional farmers had significantly depressed levels of cortisol for ¾ measures compared to organic farmers. Conventional farmers also had significantly lower total cortisol over the day, cortisol awaking response (CAR) and had higher bedtime cortisol and more blunted Diurnal Cortisol Slope (DCS) than organic farmers. The cumulative number of spraying days was associated with lower cortisol levels, AUC, CAR, and higher bedtime cortisol and more blunted DCS. These findings suggest that pesticide use can impact the HPA axis which has been linked with increased risk of type 2 diabetes, obesity, metabolic syndrome and cardiovascular mortality (Pub #13).
We also conducted repeated measures evaluation of the impact of acute pesticide exposures (spray day) on acute changes in HPT/HPA axis hormone status among pesticide using farmers (Pubs #14-17). We also examined accidents and ergonomic problems faced by organic and conventional farmers (Pub # 18).
Informal Sector Workers
Informal sector workers are those not recognized or protected under the legal and regulatory frameworks of national governments. Without legal protections or access to social social supports, workplace safety is often lacking, contracts and benefits usually do not exist, working time is long, income low and skills development possibilities scarce. In Thailand the informal sector accounts for about 63% of the working populationa and workplace accident rates are ten times higher than for formal sector workers.
Common groups of informal sector workers include: 1) industrial home work in labor-intensive industries like footwear, electronics, garment production and cigarette rolling, 2) crafts production workers such as basket-weavers, bird cage makers, pottery makers, stone sculptors, and ornaments makers; 3) people who make and sell food on the street or in small stores; 4) personal service workers like maids, child care providers, masseuses, beauticians, barbers; 5) agricultural workers working on family farms.
Each of these groups face a wide range of occupational hazards. In our outreach section we provide information on our research in these areas.
Health Care Workers
As a result of their labor, healthcare workers are exposed to significant health risks including exposures to infectious diseases, musculoskeletal strain, latex products, workplace stress, violence, and hazardous substances.
Healthcare workers are also on the forefront of emerging disease outbreaks and are called upon to provide services under difficult situations, including man-made conflicts and natural disasters.
In Thailand there are about 300,000 employees who work in the health care industry, with about 75% providing direct patient care. The remainder work in maintenance and housekeeping, food services, laboratories or laundry services. Health care workers experience about 19% of all reported work-related illnesses in Thailand.
In our CWEND GeoHealth Hub workshop report (see Outreach Section) we identified several gaps in research and polices for the protection of health care workers including:
Lack of research to confirm the relationship between occupational exposures and health risks and outcomes
Lack of standard criteria for prevention and control measures for healthcare workers during disease outbreaks
Insufficient knowledge about occupational health risk and safety among healthcare workers
Lack of epidemiologic research on non-direct care workers in the healthcare sector
In addition to the occupational safety and health (OSH) concerns regarding agriculture, the diverse ecosystems found in Southeast Asia are under threat from unsustainable development, especially from the move toward intense industrial agriculture and aquaculture expansion and increasing industrialization and urbanization. With climate change, sea level rise is projected to bring devastating floods to Southeast Asia. Rice culture especially relies on large quantities of water, and at present urban centers and the rapidly emerging industrial sector are all competing for water. Water conservation and water quality maintenance are key concerns at present and for the future. Thus, the areas of Agricultural Health and the overlap with Environmental Sustainability will provide many opportunities for research to policy initiatives in the future
Other ongoing concerns in Southeast Asia include widespread air pollution from mobile sources, power plants and industrial sites. CWEND partners have been active in research that documents exposures and examines the health impacts of air pollution. See the Outreach Section for publications in this area.