Mortality of California agricultural workers

Proportionate mortality among current and former members of the United Farm Workers of America, AFL-CIO, in California 1973-2000

CONTEXT

To further investigate mortality among farm workers, a proportionate mortality ratio (PMR) analysis was conducted among the membership of the United Farm Workers of America (UFW), a farm worker labor union, for the years 1973-2000 in the state of California.

PURPOSE

This report compares proportionate mortality for 118 causes of death in the UFW and the general United States population, adjusting for age, sex, race and calendar year of death. In addition, an exploratory analysis was conducted comparing deaths in the UFW to deaths in the California Hispanic population.

METHODS

A roster of members of the UFW was compared to the death certificate master files of the state of California for the years 1973 to 2000. Matches were detected using automated techniques and visual review. PMR and associated confidence intervals were calculated using the National Institute for Occupational Safety and Health Life Table Analysis System using deaths in the U.S. as the standard. A similar analysis was conducted limiting attention to the time period 1988-2000 and using deaths in the California Hispanic population as the standard.

FINDINGS

There were a total of 139,662 members of the union included in the linkage that yielded 3,977 deaths in the time period 1973-2000. Proportionate mortality in the farm workers was significantly elevated for respiratory tuberculosis, malignant neoplasms of the stomach, biliary passages, liver and gallbladder, and uterine cervix, diabetes mellitus, cerebrovascular disease, cirrhosis of the liver, and "other diseases of the digestive system." Transportation injuries including motor vehicles deaths, deaths from machine injuries, unintentional poisonings and assault and homicide were significantly elevated as well. Farm workers were at significantly lower risk of death from HIV-related disease, malignant neoplasms of the esophagus, intestine, pancreas, lung, urinary bladder, melanoma, and brain, all cancer deaths, "other diseases of the nervous system," ischemic heart disease, conductive disorder, "other diseases of the heart," emphysema, "other respiratory diseases," and symptoms and ill-defined conditions. These results were similar when using California Hispanic deaths as the standard for the years 1988-2000. There was still excess proportionate mortality from tuberculosis, cerebrovascular disease and unintentional injuries among the UFW members and lowered mortality from HIV related deaths, all cancer deaths combined and diseases of the heart.

CONCLUSIONS

These results include some unique findings in regard to both excess and deficits of mortality that may be explained by the Hispanic ethnicity and recent immigration of the cohort.

Mortality among a Cohort of Female Farm Residents in New York State

A retrospective cohort study of mortality among 6,405 female farm residents who were New York Farm Bureau members, or spouses or relatives of members, was conducted from 1980 through 1993. Similar to previous findings for male farmers, the cohort experienced significantly lower mortality rates for all causes combined (including malignant neoplasms and cardiovascular disease), compared with rural nonfarm female residents. These findings suggest that farmers and farm residents of both genders have favorable habits with respect to several lifestyle factors. The results of this study were consistent with those from other studies of farm populations worldwide.

National farmworker database: establishing a farmworker cohort for epidemiologic research

BACKGROUND

There is little research into the long-term health effects of pesticides and other agricultural exposures among seasonal and migrant farmworkers in the United States. We present results of a feasibility study that established a cohort of farmworkers for use in epidemiologic research.

METHODS

Subjects consisted of migrant and seasonal farmworkers who joined the cohort while seeking social services through members of the Association of Farmworker Opportunity Programs (AFOP) and were entered in the National Farmworker Database (NFD) between the end of 1997 and March 1999. We designed an add-on interview with information that enhanced the utility of the database for epidemiologic research.

RESULTS

We recruited and obtained basic demographic and employment information on 5,597 farmworkers at very modest cost and effort. Subjects were mostly seasonal (61.5%), female (56.7%), and Hispanic (67.4%), with a median age of 27. Most (62.6%) had not completed high school; almost all (99.1%) reported being U.S. citizens or permanent residents, an eligibility requirement for some of the services provided by AFOP. The majority (62.5%) had engaged in farmwork for less than 10 years, but had performed a wide variety of tasks on different crops, including row crops and tree fruits. Picking was the most common task reported. Most subjects had performed farmwork in Florida, North Carolina, Texas, Michigan, or Georgia. For usual source of health care, 63.7% reported use of U.S. hospitals or emergency rooms/clinics, 42.0% U.S. private physicians, and 29.7% migrant health clinics. Among subjects reporting a prior diagnosis of cancer, primary sources of health care for treatment of that cancer included U.S. private physicians (61.9%), U.S. hospitals or emergency rooms/clinics (23.8%), and migrant health clinics (10.5%).

CONCLUSIONS

Results suggest that by adding a brief interview to the existing NFD data collection process, which was designed for other purposes, it is feasible to create an efficient tool for conducting longitudinal epidemiologic research among farmworkers.

Etiology and pathogenesis of airway disease in children and adults from rural communities

Asthma is the most common chronic disease of childhood and affects nearly 5 million children. The prevalence and severity of childhood asthma have continued to increase over the past decade despite major advances in the recognition and treatment of this condition. A comparison of urban and rural children suggests that the etiology of airway disease is multifactorial and that unique exposures and genetic factors contribute to the development of asthma in both settings. The most important environmental exposure that distinguishes the rural environment and is known to cause asthma is the organic dusts. However, animal-derived proteins, common allergens, and low concentrations of irritants also contribute to the development of airway disease in children and adults living in rural communities. A fundamental unanswered question regarding asthma is why only a minority of children who wheeze at an early age develop persistent airway disease that continues throughout their life. Although genetic factors are important in the development of asthma, recurrent airway inflammation, presumably mediated by environmental exposures, may result in persistent airway hyperresponsiveness and the development of chronic airway disease. Increasing evidence indicates that control of the acute inflammatory response substantially improves airflow and reduces chronic airway remodeling. Reducing exposure to agricultural dusts and treatment with anti-inflammatory medication is indicated in most cases of childhood asthma. In addition, children with asthma from rural (in comparison to urban) America face multiple barriers that adversely affect their health e.g., more poverty, geographic barriers to health care, less health insurance, and poorer access to health care providers. These unique problems must be considered in developing interventions that effectively reduce the morbidity and mortality of asthma in children from rural communities.

Cancer among migrant and seasonal farmworkers: an epidemiologic review and research agenda

There are an estimated three million hired migrant and seasonal farmworkers in the United States. Adults and children may be exposed to mutagenic and potentially carcinogenic pesticides during planting, weeding, thinning, and harvesting crops. Field conditions that provide little opportunity to wash skin or clothing to minimize pesticide absorption may intensify exposure. Little is known, however, about the occurrence of cancer in migrant or seasonal farmworkers. Most cancer epidemiologic research on agricultural populations has focussed on farm owner/operators. The few studies that have evaluated cancer in farmworkers suggest that, like farm owner/operators, they may be experiencing excesses of multiple myeloma and cancers of the stomach, prostate, and testis. A few studies suggest that the farmworkers may differ from farmers by experiencing excesses of cancers of the buccal cavity and pharynx, lung, and liver. Cervical cancer was elevated in female farmworkers in one study. Descriptive data and etiologic research on cancer among farmworkers and family members are urgently needed. Feasibility evaluations, however, should precede etiologic investigations because of possible difficulties in studying this population of workers. Issues that need to be evaluated include assessing where and when farmworkers and family members are diagnosed and/or treated for malignancies, the ability of farmworkers to provide histories of crops, locations, and years worked and living conditions, the ability of agricultural experts to determine likely pesticide exposures based on such farmworkers' histories, the ability to obtain information on potential confounding factors, the ability to recontact or determine vital status of specific farmworkers over time, the suitability of conducting studies in home-base vs. upstream counties, and the ability to study agriculturally related malignancies in persons who have left farm work before the disease occurs.

Respiratory disorders in agriculture

Work in agriculture is associated with exposure to respiratory biohazards. The most important airborne substances include grain dust and its constituents, bacteria and metabolites (endotoxin), fungi and metabolites (glucan), and storage mites. The degree of dysfunction in exposed persons depends on the biological potency and concentration of exposure as well as on individual susceptibility. Airborne contaminants frequently occur in concentrations and compositions that challenge the defence mechanisms of the lung. This may be of particular importance in the case of susceptible workers and minors, whose exposure by the virtue of family-type operations is difficult to avoid. Epidemiological and clinical studies have contributed to the identification of associations between respiratory disorders and agricultural exposures. Chronic bronchitis, asthma, hypersensitivity pneumonitis, organic dust toxic syndrome and chronic airflow limitation have been found to occur in agricultural workers. Clinical and experimental studies have advanced the understanding of immunologic and non-immunologic mechanisms involved in respiratory responses to a wide spectrum of inhaled organic dusts. Although the evidence has provided substantial insight into the occurrence and pathogenesis of respiratory disorders in agriculture, further investigation is necessary. There is a need for research involving accurate assessment of exposures and their respiratory effects. There is also a need for the establishment of preventive programs, with emphasis on reduction of harmful exposures. Increasing concern about respiratory disorders in agriculture justifies further scientific effort in both areas.

Health status of the rural elderly according to farm work history: the Iowa 65 + rural health study

In a geographically defined survey of 3,097 rural Iowans who were at least 65 yr of age, we examined the association between prior farm experience (greater than or equal to 25 yr) and various measures of current health status; we controlled for age, current working status, and, where appropriate, smoking and alcohol consumption. Health status was indexed by self-reported morbid conditions, symptoms, and physical function. After controlling for smoking behavior, it was found that both men and women with previous farm exposure currently experience a greater prevalence of all nine respiratory symptoms employed in the study relative to non-farmers. Farm men report a lower prevalence of Parkinson's disease and prostate conditions, but report a greater prevalence of stroke and a lower level of self-perceived health status. Women with a farm work history experience a greater level of physical function and fewer symptoms associated with mental illness. Overall significant benefits as well as risks associated with a history of farm work were identified. However, of those who survived to age 65, extended exposure to farm work did not have a major impact on the overall current health status of men and women.