Occupational health among migrant and seasonal farmworkers: the specific case of dermatitis

Occupational health studies of agricultural workers have generally excluded migrant and seasonal farmworkers, and this population experiences a high degree of health risk from agricultural exposures. A survey of dermatologic disorders among migrant and seasonal farmworkers will be used to illustrate this point. Data from a recent field study are presented to illustrate epidemiologic approaches to studying dermatologic disorders in farmworkers and risk factors for dermatitis. This study suggests there is generally a high health risk to agricultural workers and this study also suggests methods to investigate other acute and chronic diseases among agricultural workers.     

Green tobacco sickness and skin integrity among migrant Latino farmworkers

BACKGROUND: Green tobacco sickness (GTS) affects approximately one-quarter of tobacco workers. The primary aim of this analysis is to expand existing knowledge of GTS risk factors by delineating the association of measures of skin integrity with the prevalence of GTS among Latino farmworkers. METHODS: Data are from a longitudinal study of skin disease among 304 North Carolina Latino farmworkers conducted in 2005. RESULTS: 18.4% of the farmworkers met the GTS case definition. Self-reported rash increased the odds of having GTS in the bivariate (OR 2.29, 95% CI 1.21, 4.35), and multivariate analyses (OR 3.30, CI 2.17, 5.02). Self-reported itch (OR 3.54, CI 2.38, 5.24) and superficial wounds (OR 2.49, CI 1.15, 5.39) had a significant relationship to GTS in the bivariate analysis. CONCLUSIONS: These analyses extend current knowledge of GTS risk factors to include skin integrity. Farmworkers with rash and other skin conditions can protect these affected skin areas from exposure to the tobacco plant to reduce their risk of GTS.     

Prenatal exposure to pesticides: a feasibility study among migrant and seasonal farmworkers.

BACKGROUND: Migrant and seasonal farmworkers have a high potential for pesticide exposures, yet are rarely included in epidemiologic studies. This study examined the feasibility of assessing prenatal exposures to pesticides and other compounds in pregnant Hispanic farmworkers. METHODS: Nine women completed a survey about work experiences during pregnancy. Maternal urine, cord blood, and placenta samples were obtained at delivery for analysis of 51 analytes, including 6 phenoxy acid or triazine herbicides, 21 organochlorine insecticides, 10 PCBs, and 14 volatile organic compounds. RESULTS: Seven of 51 analytes were found in the biological samples. DDE, DDT, dichlorbenzene, toluene, trimethylbenzene, and endosulfan sulfate were detected in cord blood samples, and 2,4-D in urine from one or more women. CONCLUSIONS: We documented the feasibility of following farmworkers to assess in utero exposure to pesticides and other contaminants, and demonstrated exposure to these compounds. Difficulties in measuring pesticides with short half lives were noted.     

Cancer Incidence among Pesticide Applicators Exposed to Permethrin in the Agricultural Health Study

Background

Permethrin is a synthetic pyrethroid insecticide widely used in agriculture, in public health, and in many U.S. homes and gardens.

Objective

In this study we evaluated the incidence of cancer among pesticide applicators exposed to permethrin in the Agricultural Health Study (AHS).

Methods

A total of 49,093 pesticide applicators were included in this analysis of the AHS, a prospective cohort study of licensed pesticide applicators in Iowa and North Carolina. Detailed information on pesticide exposure and lifestyle factors was obtained from self-administered questionnaires completed in 1993–1997. Average length of follow-up since applicator enrollment in the cohort was 9.14 years. We used two permethrin exposure metrics: a) lifetime days applicators personally mixed or applied permethrin and b) intensity-weighted lifetime days (lifetime days weighted by estimated intensity of exposure). We used Poisson regression analysis to estimate relative risks (RRs) and 95% confidence intervals (CIs) for malignancies by tertiles of exposure.

Results

We found no associations between permethrin and all malignant neoplasms combined, or between permethrin and melanoma, non-Hodgkin lymphoma, leukemia, or cancers of the colon, rectum, lung, or prostate. We found elevated and statistically significant risks for multiple myeloma in the highest tertiles of both lifetime exposure-days (RR = 5.72; 95% CI, 2.76–11.87) and intensity-weighted lifetime exposure-days (RR = 5.01; 95% CI, 2.41–10.42), compared with applicators reporting they never used permethrin; these results are based on only 15 exposed cases. These findings were similar across a variety of alternative exposure metrics, exposure categories, and reference groups.

Conclusions

This study found no association with most cancers analyzed. Although the suggested association with multiple myeloma was based on a small number of cases, it warrants further evaluation.     

The value and hazards of standardization in clinical epidemiologic research

The statistical standardization of rates produces a single summary value that converts crude rates of occurrence into "standardized" rates that are adjusted for differences in the composition of compared populations. Although the process is well described in the epidemiologic literature and is regularly applied in comparisons of large populations, many investigators are not familiar with three important hazards that are magnified for the smaller groups studied in clinical epidemiologic research. This report contains a new "symmetrical" outline of the direct and indirect standardization processes, and an illustration of three pragmatic hazards: (1) Because the direct standardizing factor uses the observed stratum-specific rates, and because any stratum-specific rates that depend on small denominators may be misleading or unstable, the indirect method is preferred when the observed strata have small denominators. (2) Both the direct and indirect standardizing methods are highly vulnerable both to the choice of reference population and to the boundaries chosen when strata are demarcated or consolidated. The standardized rates can be altered dramatically according to differences in the stratum proportions of the reference population, or to distinctions produced when standardizing strata are consolidated. (3) If the stratum-specific rates and stratum proportions have different patterns of variation across the strata of the compared groups, the use of a single summary value--no matter what method of standardization is applied--may obscure cogent patterns of variation and significant differences in the stratum-specific rates. These hazards can be overcome if the studied group and the reference population are carefully compared for inconsistent variations in the stratum-specific rates and proportions before any standardizing procedure is applied. In many instances, the best approach may be to compare the unaltered stratum-specific rates, without standardization.     

Cancer and other causes of death among Wisconsin farmers

Computerized mortality listings for Wisconsin for 1968-1976 were used in proportional mortality ratio (PMR) and proportional cancer mortality ratio (PCMR) analyses to evaluate mortality patterns among Wisconsin farmers. Examination of PCMR trends by per capita county level of agricultural production was limited to the youngest birth cohort (1905-1958) and cancer sites associated with farming exposures in either the present or previous analyses. Among all Wisconsin farmers, significantly decreased PMRs were seen for tobacco- and alcohol-related causes of death, while excesses occurred for accidental causes, asthma, and cancer of the stomach, prostate, eye, and lymphatic and hematopoietic systems. Elevated PCMR's for leukemia and all lymphopoietic cancer and cancers of the stomach, rectum, eye occurred in farmers born 1905-1958, while deficits were observed for cancer of the pancreas and the category, "all other cancers." Increases in PCMR's with level of various agricultural activities were largely associated with cancers of other lymphatic tissue (2/3 of which were multiple myeloma) and the rectum. Certain agricultural exposures were also positively associated with deaths due to cancers of the prostate, brain, lymphosarcoma and reticulosarcoma, and all lymphopoietic cancers. No positive PCMR gradients were observed for leukemia and malignancies of the stomach and eye. Modern chemical practices in farming may account for some of the patterns noted.     

Cervical cancer among Hispanic women: assessing the impact on farmworkers

The purpose of this paper was to review the literature on Hispanic populations to outline: 1) demographics; 2) general health status; 3) cervical cancer incidence and mortality; 4) Pap smear screening rates; and 5) barriers to preventive care services. The methods: MEDLINE, Med66, Med75, and Med85 files, from 1966 to 1999, were searched for key words Hispanic health, cervical cancer and Hispanics, cervical cancer and Mexico, migrants and health, agricultural occupational health, farmworkers and cancer, and farmworker health. AGRICOLA (1982–98) was searched for key words farmworker health, agricultural workers and health, and agriculture and cancer. The results show that Hispanic immigrant women may have cervical cancer incidence rates ranging between the California rates for 1991–93 (19.8/100,000) and for Mexico in 1990 (115–220 per 100,000). Mortality rates for the same periods were 3.9/100,000 and 16.11/100,000 respectively. While survey results report Hispanic Pap smear rates above 70%, these surveys count urban women who do not share the barriers to care experienced by poor rural Hispanics. Since validated self-reports of survey responses are 20–50% lower than reported lower rates and Pap smear screening persist in Hispanic Pap evaluations and are reflected in higher morbidity and mortality from cervical cancer. That targeted community interventions have been successful in raising Pap smear rates among poor Spanish-speaking women. Such interventions should be a priority for preventive health care policy and practice.     

Cancer and other causes of death among male and female farmers from twenty-three states

Occupation and industry codes on death certificates from 23 states for 1984–1988 were used to evaluate mortality risks among white and nonwhite, male and female farmers. Proportionate mortality and proportionate cancer mortality ratios were calculated using deaths among nonfarmers from the same states to generate expected numbers. Among farmers there were 119,648 deaths among white men, 2,400 among white women, 11,446 among nonwhite men, and 2,066 among nonwhite women. Deficits occurred in all race-sex groups for infective and parasitic diseases, all cancer combined, lung cancer, liver cancer, diseases of the nervous system, multiple sclerosis, hypertension, and emphysema. As reported in other studies, white male farmers had excesses of cancer of the lymphatic and hematopoietic system, lip, eye, brain, and prostate. Excesses of cancers of the pancreas, kidney, bone, and thyroid were new findings. Regional patterns were evident, particularly among white men. Significant excesses for accidents, vascular lesions of the central nervous system (CNS), and cancers of the prostate tended to occur in most geographic regions, while excesses for mechanical suffocation, non-Hodgkin's lymphoma, and cancers of the lip, brain, and the lymphatic and hematopoietic system were limited to the Central states. Increases among nonwhite men were similar to those in white men for some causes of death (vascular lesions of the CNS and cancers of the pancreas and prostate), but were absent for others (lymphatic and hematopoietic system, lip, eye, kidney, and brain). Women (white and nonwhite) had excesses for vascular lesions of the CNS, disease of the genitourinary system (white women only), and cancers of the stomach and cervix (nonwhite women only). Cancer of the buccal cavity and pharynx was slightly elevated among women, and white women had nonsignificant excesses of multiple myeloma and leukemia. Excesses for leukemia and non-Hodgkin's lymphoma occurred among white men and women, but not among nonwhites. Excesses for several types of accidental deaths were seen among all race-sex groups. © 1993 Wiley-Liss, Inc.     

Cancer risks among workers exposed to metalworking fluids: A systematic review

Metalworking fluids (MWFs) are commonly used in a variety of industrial machining and grinding operations. The National Institute for Occupational Safety and Health (NIOSH) estimates that more than one million workers are exposed to MWFs. NIOSH conducted a comprehensive and systematic review of the epidemiologic studies that examined the association between MWF exposure and cancer. Substantial evidence was found for an increased risk of cancer at several sites (larynx, rectum, pancreas, skin, scrotum, and bladder) associated with at least some MWFs used prior to the mid-1970s. This paper provides the evidence pertaining to cancer at these sites. Cancer at those sites found to have more limited or less consistent evidence for an association with MWF (stomach, esophagus, lung, prostate, brain, colon, and hematopoietic system) will not be discussed in this paper but are discussed in the recent NIOSH Criteria for a Recommended Standard-Occupational Exposure to MWFs. Because the changes in MWF composition that have occurred over the last several decades may not be sufficient to eliminate the cancer risks associated with MWF exposure, reductions in airborne MWF exposures are recommended. Am. J. Ind. Med. 33:282–292, 1998. Published 1998 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

An epidemiologic study of irritable bowel syndrome in adolescents and children in South China: a school‐based study

Background To explore the prevalence of irritable bowel syndrome (IBS) among school‐aged children in South China, and identify distribution characteristics and contributing factors. Methods Primary, middle and high school students (n= 2013) were recruited from schools in Shanghai. Students completed two questionnaires, one for IBS in adolescents and children and the Screen for Child Anxiety Related Emotional Disorders (SCARED). Results (1) The prevalence of IBS among students was 20.72% and the incidence increased with age. (2) Several physical factors and overuse of analgesics were significantly associated with IBS. (3) The prevalence of anxiety disorder was higher in older students, and in females vs. males. Students with IBS tended towards anxiety‐related emotional disorders (38.14% vs. 18.96%). (4) IBS students scored higher in all SCARED categories. Within IBS students, those who frequently sought medical care reported higher scores in the somatization/panic category. Conclusion (1) Irritable bowel syndrome is a common disorder among adolescents in South China and prevalence increases with age. (2) Gastrointestinal infection, abuse of analgesics and psychological factors might be related to the incidence of IBS. (3) The tendency towards anxiety‐related emotional disorders also increases with age, suggesting a possible correlation with IBS and underlining the importance of positive family and school environments. Although the prevalence of anxiety‐related emotional disorders was higher in females than males, this trend was not correlated with the occurrence of IBS.     

An agenda for future research on HIV and sexual behaviour among African migrant communities in the UK

The epidemiology of the recent rise in HIV cases in Britain highlights the need for more research among the heterosexual African migrant population. New research should not, however, only extend the limited number of studies that describe observable patterns in sexual health but should also seek to determine their underlying social causation. To achieve this, both methodological and ontological shifts are necessary in the existing research paradigm; we advocate that a broad range of qualitative techniques be deployed both to uncover the empirical details of specifically African sexual behaviours and to highlight and explore the 'relational' nature of sexual decision-making. Rather than fixing on individuals, analysis must situate them within the broader discursive and material frames that structure the boundaries of decision-making. In addition, researchers need to utilise the parallel literature on the social embeddedness of HIV in Africa to inform analysis of the British context. It would then be possible to address the crucial question of whether the social conditions known to cause high-risk behaviours and facilitate transmission in Africa persist, or are transformed, after migration to the UK. A key, and neglected, dimension of this is the role of spatial context in relational sexual decision-making and the constitution of social relationships in particular arenas. This needs further thought, particularly in relation to domestic space and gender identities. We believe that the research agenda proposed herein has much to contribute to interventions and service provision. Nevertheless, we are mindful of the need for self-reflexivity about our role in the production of powerful knowledges about sex. Our final proposal is that researchers seek ways to work with, not on, African communities in order to facilitate their own informed management of sexual health.     

S-Ethyl-N,N-dipropylthiocarbamate Exposure and Cancer Incidence among Male Pesticide Applicators in the Agricultural Health Study: A Prospective Cohort

Background

The Agricultural Health Study (AHS) is a prospective cohort study of licensed pesticide applicators from Iowa and North Carolina enrolled between 1993 and 1997. EPTC (S-ethyl-N,N-dipropylthiocarbamate) is a thiocarbamate herbicide used in every region of the United States. The U.S. Environmental Protection Agency reports that EPTC is most likely not a human carcinogen; however, the previous epidemiologic data on EPTC exposure and cancer risk were limited.

Objectives

The purpose of this study was to examine cancer incidence and EPTC use in 48,378 male pesticide applicators enrolled in the AHS.

Methods

We estimated the rate ratio (RR) and 95% confidence intervals (CIs) for all cancers and selected cancer sites using Poisson regression. We assessed EPTC exposure using two quantitative metrics: lifetime exposure days and intensity-weighted lifetime exposure days, a measure that accounts for application factors that modify personal exposure likelihood.

Results

Among the 9,878 applicators exposed to EPTC, 470 incident cancer cases were diagnosed during the follow-up period ending December 2004 compared with the 1,824 cases among individuals reporting no use. Although EPTC was associated with colon cancer in the highest tertile of both lifetime exposure days and intensity-weighted lifetime days (RR = 2.09; 95% CI, 1.26–3.47 and RR = 2.05; 95% CI, 1.34–3.14, respectively) and the trend test was < 0.01 for both, the pattern of RR was not monotonic with increasing use. There was a suggestion of an association with leukemia. No other associations were observed.

Conclusion

In this analysis, EPTC use appeared to be associated with colon cancer and leukemia. However, given the relatively small number of cases in the highest exposure tertile, results should be interpreted with caution, and further investigations are needed.