Childhood Cancer in Texas Counties with Moderate to Intense Agricultural Activity

Department of Epidemiology, University of Texas at Houston, School of Public Health, Houston, Texas, USA.
Journal of agricultural safety and health 02/2007; 13(1):9-24. DOI: 10.13031/2013.22308
Source: PubMed


With few established risk factors, cancer remains the second leading cause of death for children in the U.S. Agricultural pesticide use is one of many suspected factors that may contribute to the etiology of childhood cancer. This study tests the hypothesis that birth in Texas counties with moderate to intense agricultural activity increases childhood cancer risk. This case-control study analyzed 6974 cases and controls ages 0 to 14, identified through the Texas Cancer Registry and Texas birth records, respectively. Exposure data were obtained from the Census of Agriculture. Percent cropland in the county of birth and total county-specific pesticide exposure incorporating the EPA's carcinogenicity classification served as surrogates for pesticide exposure. Cancer sites examined include: all cancers, leukemia, lymphoma, CNS tumors, and several specific subsites. Elevated, although not statistically significant, ORs for the association between birth in counties with > or =50% cropland were produced for all CNS tumors (OR = 1.3, 95% CI = 0.9-1.8), astrocytoma (OR = 1.4, 95% CI = 0.8-2.2), and PNET (OR = 1.3, 95% CI = 0.7-2.5). A similar pattern was not observed using the index of total county-specific pesticide exposure. Although imprecise, these exposure assessment methods represent novel applications of agricultural census data. Although a pattern of increased risk was observed between percent cropland and CNS tumors, this study's results do not support an association between birth in Texas counties with moderate to intense agricultural activity and childhood cancer. Due to study limitations, such an association should not be ruled out. Future research should incorporate individual-level data from various sources to increase precision and decrease misclassification in the exposure assessment.

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    • "The greater RRs in the 1980s cohorts may reflect exposures that occurred in childhood, because those individuals were ≤30 years old when they died. Exposure to pesticides in utero and during childhood is a potential risk factor for the development of brain cancer [42,43]. Humans may be exposed to pesticides from several sources, including pesticides present in food and in agricultural and residential areas [44]. "
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    ABSTRACT: Background Individuals who live in rural areas are at greater risk for brain cancer, and pesticide exposure may contribute to this increased risk. The aims of this research were to analyze the mortality trends and to estimate the age-period-cohort effects on mortality rates from brain cancer in two regions in Rio de Janeiro, Brazil. Methods This descriptive study examined brain cancer mortality patterns in individuals of both sexes, >19 years of age, who died between 1996 and 2010. They were residents of a rural (Serrana) or a non-rural (Metropolitan) area of Rio de Janeiro, Brazil. We estimated mortality trends using Joinpoint Regression analysis. Age-period-cohort models were estimated using Poisson regression analysis. Results The estimated annual percentage change in mortality caused by brain cancer was 3.8% in the Serrana Region (95% confidence interval (CI): 0.8–5.6) and -0.2% (95% CI: -1.2–0.7) in the Metropolitan Region. The results indicated that the relative risk was higher in the rural region for the more recent birth cohorts (1954 and later). Compared with the reference birth cohort (1945–49, Serrana Region), the relative risk was four times higher for individuals born between 1985 and 1989. Conclusions The results of this study indicate that there is an increasing trend in brain cancer mortality rates in the rural Serrana Region in Brazil. A cohort effect occurred in the birth cohorts born in this rural area after 1954. At the ecological level, different environmental factors, especially the use of pesticides, may explain regional disparities in the mortality patterns from brain cancers.
    BMC Cancer 05/2014; 14(1):320. DOI:10.1186/1471-2407-14-320 · 3.36 Impact Factor
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    • "Neither birth weight nor maternal age changed the magnitude or precision of the point estimates for total cancers and the major ICCC cancer groups, so these variables were dropped from the final models. In a related analysis using additional years of study data from the parent casecontrol study, paternal education was evaluated (as a surrogate for socio-economic status) and was not found to be an apparent confounder for total childhood cancers or for the more common cancer subtypes (Walker et al., 2007). Hence, final models were adjusted for birth date, gender and race/ethnicity. "
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    ABSTRACT: Agricultural pesticide applications have the potential for significant drift beyond the target spray area and may result in exposure to non-farming residents in surrounding communities. Using geographic information system (GIS) methods, 1778 childhood cancer cases and 1802 controls born in Texas between 1990 and 1998 were assigned probable agricultural pesticide exposure based on proximity of birth residence to crop fields. Multivariate modeling was used to estimate odds ratios and 95% confidence intervals for selected cancers. For most childhood cancers, we found no evidence of elevated risk associated with residential proximity at birth to cropland. There was an overall pattern of increased risk for germ-cell tumors but the odds ratios were based on few number of exposed cases. There was also some indication of increased risk for non-Hodgkin lymphoma (NHL) and Burkitt lymphoma, but point estimates were imprecise and not statistically significant. Previous studies have assessed pesticide exposure primarily based on parental occupational history or household use, while our focus was on agricultural pesticides and so may represent a different array of chemical agents occurring at lower doses.
    International journal of hygiene and environmental health 08/2008; 212(2):186-95. DOI:10.1016/j.ijheh.2008.06.002 · 3.83 Impact Factor
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    ABSTRACT: Although several studies have found no change or a decreased risk of childhood cancer in twins, few have controlled for potential confounders such as birth weight. We examined the association of birth plurality and childhood cancer in pooled data from five U.S. states (California, Minnesota, New York, Texas, and Washington) using linked birth-cancer registry data. The data, excluding children with Down syndrome or who died before 28 days of life, included 17,672 cases diagnosed from 1980 to 2004 at ages 28 days to 14 years and 57,966 controls with all cases and controls born from 1970 to 2004. Analyses were restricted to children weighing <or=4,000 g at birth. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using unconditional logistic regression adjusting for sex, gestational age, birth weight, birth order, maternal age, maternal race, state of birth, and birth year. Children who were multiples had no difference in risk of cancer overall (OR, 0.93; 95% CI, 0.82-1.07), but a borderline reduced risk of Wilms' tumor (OR, 0.65; 95% CI, 0.39-1.09). For children diagnosed <2 y of age there was a reduced risk of Wilms' tumor (OR, 0.27; 95% CI, 0.09-0.86) and neuroblastoma (OR, 0.46; 95% CI, 0.25-0.84) and an increased risk of fibrosarcoma (OR, 5.81; 95% CI, 1.53-22.11). Higher-order multiple birth (triplets or higher) was not associated with childhood cancer. Our analysis suggests that mechanisms other than birth weight and gestational age may influence the lower risk of Wilms' tumor and neuroblastoma in multiple births.
    Cancer Epidemiology Biomarkers & Prevention 01/2009; 18(1):162-8. DOI:10.1158/1055-9965.EPI-08-0660 · 4.13 Impact Factor
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