Cancer mortality among agricultural workers from Serrana Region, state of Rio de Janeiro, Brazil

One of the proposed hypotheses to explain the higher incidence of specific-site cancers among agricultural workers is their higher exposure to pesticides. The role of pesticide exposure in morbidity and mortality profiles in Brazil is not well known. Therefore, in order to contribute to increase knowledge on this subject, an ecological analysis aiming to investigate cancer mortality among agricultural workers in an important agricultural area of the Rio de Janeiro State, Brazil, was performed. All causes of death for male workers 30-69 years old provided by the National Mortality Information System between 1979 and 1998 were evaluated. To estimate cancer mortality risks of selected sites, mortality odds ratio (MOR) was employed, and three reference populations were used. Higher mortality of esophagus, stomach, and larynx cancer in agricultural workers 50-69 years old was observed in the period from 1979 to 1988 and of esophagus and stomach cancer from 1989 to 1998. Agricultural workers 30-49 years old showed higher, but not statistically significant, mortality by stomach, esophagus, liver, testis, and prostate cancer, and soft-tissue sarcoma in the period of 1979-1988, and by testis and penis cancer, leukemia, and soft-tissue sarcoma in the period of 1989-1998. Despite the limitations of ecological approaches concerning causality ascertainment, we believe that this study raises questions of the possible role of pesticide exposure on the cancer mortality profile among Brazilian agricultural workers.     

Pancreatic cancer mortality and organochlorine pesticide exposure in California, 1989-1996

BACKGROUND: Occupational studies have suggested a possible link between organochlorine pesticides and the occurrence of pancreatic cancers. California maintains a death file and a pesticide reporting system that allows examination of this relationship for residents of high use areas. METHODS: We employed a mortality odds ratio design to compare deaths from pancreatic cancer (1989-1996) with a random sample of non-cancer deaths. Using pesticide data for three agricultural counties, we classified 102 ZIP codes in quartiles of pesticide usage for 1972-1989. Using logistic regression we estimated the effect of pesticide applications by ZIP code controlling for possible confounders. RESULTS: Among long-term residents, pancreatic cancer mortality was elevated for those living in ZIP codes with the highest use of four pesticides: 1,3-dichloropropene (1,3-d), captafol, pentachloronitrobenzene (PCNB), and dieldrin. No dose-response relationship was observed. CONCLUSIONS: Our study suggests increased pancreatic cancer mortality among long-term residents in areas of high application rates of 1,3-d (an EPA-classified probable human carcinogen), captafol, pentacholoronitrobenzene (PCNB), and dieldrin.     

Pesticide exposure and low birth weight prevalence in Brazil

Introduction

Brazil is one of the major global consumers of pesticides and exposure to these substances can affect fetal growth.

Objective

To estimate the correlation between pesticide sales in 1996 and the prevalence of low birth weight during the period 1996–1998 in Brazil.

Method

This ecological study employed secondary data aggregated at the level of Brazilian micro-regions (cluster of cities). Prevalence of low birth weight in 1996, 1997, and 1998 was obtained from the Brazilian health databases, and per capita pesticides sales in 1996 obtained from the Brazilian Institute of Geography and Statistics were utilized as an indirect measure of population exposure to these chemicals. Spearman correlation coefficient and Prevalence Ratio by quartiles were estimated, considering per capita pesticide sales and the prevalence of low birth weight.

Results

A total of 552 micro-regions were analyzed (446 non-urban and 106 urban). In rural areas, the per capita pesticide sales were directly associated with higher prevalence of children born with low birth weight (r = 0.403), with birth weights between 1500 and 2500 grams (r = 0.366), and very low birth weight birth (r = 0.476). All correlations were statistically significant (p < 0.001). On the other hand, in urban areas there was no significant correlation. There was a gradual increase in the prevalence of low birth weight according to the quartiles of pesticide consumption.

Conclusions

Pesticide per capita sales may affect the prevalence of newborns with low birth weight in non-urban micro-regions of Brazil, indicating the need to strengthen policies and actions to protect the health of populations exposed to pesticides.     

Self-reported residential pesticide use and survival after breast cancer

IntroductionPrevious investigations found elevated mortality after breast cancer in association with biomarkers of persistent organochlorine pesticides in non-occupationally exposed women. We hypothesized that lifetime residential pesticide use, which includes persistent and non-persistent pesticides, would also be associated with increased mortality after breast cancer.MethodsA population-based cohort of 1505 women with invasive or in situ breast cancer was interviewed in 1996–1997, shortly after diagnosis, about pre-diagnostic lifetime residential pesticide use. Participants were followed for mortality through 2014 (595 deaths from any cause and 236 from breast cancer, after 17.6 years of follow-up). Pesticides were examined as 15 individual categories; a group of seven used for lawn and garden purposes; a group of eight used for nuisance-pest purposes; and all combined. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and breast cancer-specific mortality. Modification by estrogen receptor (ER) status, body mass index, and long-term residence was examined.ResultsEver use (HR = 0.77, 95%CI = 0.63–0.95) and higher lifetime applications (4th quartile: HR = 0.62, 95%CI = 0.47–0.81, p_trend = 0.3) of the lawn and garden group of pesticides were inversely associated with all-cause mortality, compared to never use. The inverse association for lawn and garden pesticide use was limited to ER positive (vs. negative) tumors (p_interaction = 0.05). Nuisance-pest pesticides, and all groups combined, were not associated with all-cause or breast cancer-specific mortality.ConclusionsContrary to our hypothesis, lifetime residential use of lawn and garden pesticides, but not all combined or nuisance-pest pesticides, was inversely associated with all-cause mortality after breast cancer.     

Mortality due to cancers of the brain and lymphatic tissues and leukemia as a function of agriculture pesticide use in Quebec (1976-1985)

Potential hazards associated with the use of agricultural pesticides are a growing concern for society. We describe the relationships between the mortality data for cancers of the brain, the lymphatic tissues and leukemia, and the spatial distribution of agricultural pesticide use for 34 drainage basins in Quebec, from 1976-1985. The basins were grouped into three categories (low, intermediate, and high exposure) according to the level of sales of pesticides. For cancers of the lymphatic tissues among women 35 to 64 years of age, a high relative risk (RR) was observed (RR = 1.91, 95% Confidence Interval = 1.14, 3.18) in basins highly exposed to pesticides compared to those with low exposure. Analysis of correlation for this cancer at 34 basins showed significant associations between geographical distributions of the Standardized Mortality Ratio (SMR) and those of numerous variables indicative of pesticide use in agriculture. Agreement between the results for mortality data in this exploratory study and the results from another study on cancer incidence data for 1982-1983, supports the hypothesis of a potential relationship between the use of pesticides in agriculture and cancer of the lymphatic tissues.     

Acid haze air pollution and breast and colon cancer mortality in 20 Canadian cities

Sulfur dioxide absorbs ultraviolet light in the region of the spectrum which is most active in forming vitamin D on the skin. Sulfate particles reflect light at this wavelength. High concentrations of these pollutants (acid haze) may lead to vitamin D deficiencies in exposed populations. Epidemiologic and laboratory evidence suggests that vitamin D plays a role in reducing risk of colon and breast cancer. We examined the association between sulfur dioxide and ultraviolet-light-blocking aerosols in 20 Canadian cities, and age-adjusted breast and colon cancer mortality rates in the census divisions encompassing these cities. Statistically significant positive associations were found between these two measures of air pollution and age-adjusted mortality rates for colon cancer in women (multiple r = +.74, p = 0.003), and men (multiple r = +.61, p = 0.03), and breast cancer in women (multiple r = +.69, p = 0.007). Mortality rates for all other reported cancer sites were also examined, and no statistically significant positive associations were found consistently in both sexes. The ecological nature of this study is emphasized, and the possibility that an indirect association could explain these findings is discussed.     

Epidemiologic evidence for different roles of ultraviolet A and B radiation in melanoma mortality rates

PURPOSE: The action spectrum of ultraviolet radiation mainly responsible for melanoma induction is unknown, but evidence suggests it could be ultraviolet A (UVA), which has a different geographic distribution than ultraviolet B (UVB). This study assessed whether melanoma mortality rates are more closely related to the global distribution of UVA or UVB. METHODS: UVA and UVB radiation and age-adjusted melanoma mortality rates were obtained for all 45 countries reporting cancer data to the World Health Organization. Stratospheric ozone data were obtained from NASA satellites. Average population skin pigmentation was obtained from skin reflectometry measurements. RESULTS: Paradoxically, melanoma mortality rates decreased with increasing UVB in men (r = -0.48, p < 0.001), and women (r = -0.57, p < 0.001), and with increasing UVA in both sexes. By contrast, rates were positively associated with increasing UVA/UVB ratio in men (r = + 0.49, p < 0.001) and women (r = + 0.55, p < 0.001). After multiple adjustment that included controlling for skin pigmentation, only UVA was associated with melanoma mortality rates in men (p < 0.02) with a suggestive but non-significant trend present in women (p = 0.12). CONCLUSIONS: UVA radiation was associated with melanoma mortality rates after controlling for UVB and average pigmentation. The results require confirmation in observational studies.     

Cancer risk and parental pesticide application in children of Agricultural Health Study participants

Parental exposure to pesticides may contribute to childhood cancer risk. Through the Agricultural Health Study, a prospective study of pesticide applicators in Iowa and North Carolina, we examined childhood cancer risk and associations with parental pesticide application. Identifying information for 17,357 children of Iowa pesticide applicators was provided by parents via questionnaires (1993-1997) and matched against the Iowa Cancer Registry. Fifty incident childhood cancers were identified (1975-1998). Risk of all childhood cancers combined was increased [standardized incidence ratio (SIR) = 1.36; 95% confidence interval (CI), 1.03-1.79]. Risk of all lymphomas combined was also increased (SIR = 2.18; 95% CI, 1.13-4.19), as was risk of Hodgkin's lymphoma (SIR = 2.56; 95% CI, 1.06-6.14). We used logistic regression to explore associations between self-reported parental pesticide application practices and childhood cancer risk. No association was detected between frequency of parental pesticide application and childhood cancer risk. An increased risk of cancer was detected among children whose fathers did not use chemically resistant gloves [odds ratio (OR) = 1.98; 95% CI, 1.05-3.76] compared with children whose fathers used gloves. Of 16 specific pesticides used by fathers prenatally, ORs were increased for aldrin (OR = 2.66), dichlorvos (OR = 2.06), and ethyl dipropylthiocarbamate (OR = 1.91). However, these results were based on small numbers and not supported by prior biologic evidence. Identification of excess lymphoma risk suggests that farm exposures including pesticides may play a role in the etiology of childhood lymphoma.     

Mortality among workers exposed to polychlorinated biphenyls (PCBs) in an electrical capacitor manufacturing plant in Indiana: an update

An Indiana capacitor-manufacturing cohort (n=3,569) was exposed to polychlorinated biphenyls (PCBs) from 1957 to 1977. The original study of mortality through 1984 found excess melanoma and brain cancer; other studies of PCB-exposed individuals have found excess non-Hodgkin lymphoma and rectal, liver, biliary tract, and gallbladder cancer. Mortality was updated through 1998. Analyses have included standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) using rates for Indiana and the United States, standardized rate ratios (SRRs), and Poisson regression rate ratios (RRs). Estimated cumulative exposure calculations used a new job-exposure matrix. Mortality overall was reduced (547 deaths; SMR, 0.81; 95% CI, 0.7-0.9). Non-Hodgkin lymphoma mortality was elevated (9 deaths; SMR, 1.23; 95% CI, 0.6-2.3). Melanoma remained in excess (9 deaths; SMR, 2.43; 95% CI, 1.1-4.6), especially in the lowest tertile of estimated cumulative exposure (5 deaths; SMR, 3.72; 95% CI, 1.2-8.7). Seven of the 12 brain cancer deaths (SMR, 1.91; 95% CI, 1.0-3.3) occurred after the original study. Brain cancer mortality increased with exposure (in the highest tertile, 5 deaths; SMR, 2.71; 95% CI, 0.9-6.3); the SRR dose-response trend was significant (p=0.016). Among those working >or= 90 days, both melanoma (8 deaths; SMR, 2.66; 95% CI, 1.1-5.2) and brain cancer (11 deaths; SMR, 2.12; 95% CI, 1.1-3.8) were elevated, especially for women: melanoma, 3 deaths (SMR, 5.99; 95% CI, 1.2-17.5); brain cancer, 3 deaths (SMR, 2.87; 95% CI, 0.6-8.4). These findings of excess melanoma and brain cancer mortality confirm results of the original study. Melanoma mortality was not associated with estimated cumulative exposure. Brain cancer mortality did not demonstrate a clear dose-response relationship with estimated cumulative exposure.     

Regression analysis of pesticide use and breast cancer incidence in California Latinas

An evaluation of pesticide use data and breast cancer incidence rates in California Hispanic females was conducted via a regression analysis. The analysis used 1988-2000 data from the California Cancer Registry, the population-based cancer registry that monitors cancer incidence and mortality in California. It also used pesticide use data from 1970-1988 from the California Department of Pesticide Regulation. California is the leading agricultural state in the United States, and more than a quarter of all pesticides in the United States are applied there. Hispanic (Latina) females are commonly employed in agricultural operations. The authors performed regression analysis of county-level specific pesticide use data (pounds of active ingredients applied) for two classes of pesticides, organochlorines and triazine herbicides, against the breast cancer incidence rates among Latinas, controlling for age, socioeconomic status, and fertility rates, using negative binomial regression models. A total of 23,513 Latinas were diagnosed with breast cancer in California during the years 1988-1999. Risk of breast cancer was positively and significantly associated with age and socioeconomic status, and inversely and significantly associated with fertility levels. With respect to pesticides, breast cancer was positively associated with pounds of the organochlorines methoxychlor (adjusted incidence rate ratio [IRR] for highest quartile = 1.18; confidence interval [CI] = 1.03-1.35) and toxaphene (IRR = 1.16; CI = 1.01-1.34). No significant associations were found for the triazine herbicides atrazine and simazine.     

Fonofos exposure and cancer incidence in the agricultural health study

BACKGROUND: The Agricultural Health Study (AHS) is a prospective cohort study of licensed pesticide applicators from Iowa and North Carolina enrolled 1993-1997 and followed for incident cancer through 2002. A previous investigation in this cohort linked exposure to the organophosphate fonofos with incident prostate cancer in subjects with family history of prostate cancer. OBJECTIVES: This finding along with findings of associations between organophosphate pesticides and cancer more broadly led to this study of fonofos and risk of any cancers among 45,372 pesticide applicators enrolled in the AHS. METHODS: Pesticide exposure and other data were collected using self-administered questionnaires. Poisson regression was used to calculate rate ratios (RRs) and 95% confidence intervals (CIs) while controlling for potential confounders. RESULTS: Relative to the unexposed, leukemia risk was elevated in the highest category of lifetime (RR = 2.24; 95% CI, 0.94-5.34, Ptrend = 0.07) and intensity-weighted exposure-days (RR = 2.67; 95% CI, 1.06-6.70, Ptrend = 0.04), a measure that takes into account factors that modify pesticide exposure. Although prostate cancer risk was unrelated to fonofos use overall, among applicators with a family history of prostate cancer, we observed a significant dose-response trend for lifetime exposure-days (Ptrend = 0.02, RR highest tertile vs. unexposed = 1.77, 95% CI, 1.03-3.05; RRinteraction = 1.28, 95% CI, 1.07-1.54). Intensity-weighted results were similar. No associations were observed with other examined cancer sites. CONCLUSIONS: Further study is warranted to confirm findings with respect to leukemia and determine whether genetic susceptibility modifies prostate cancer risk from pesticide exposure.     

Variation in mortality rates in Australia: correlation with Indigenous status, remoteness and socio-economic deprivation

BACKGROUND: The aim of this study was to study ecological correlations between age-adjusted all-cause mortality rates in Australian statistical divisions and (1) the proportion of residents that self-identify as Indigenous, (2) remoteness, and (3) socio-economic deprivation. METHODS: All-cause mortality rates for 57 statistical divisions were calculated and directly standardized to the 1997 Australian population in 5-year age groups using Australian Bureau of Statistics (ABS) data. The proportion of residents who self-identified as Indigenous was obtained from the 1996 Census. Remoteness was measured using ARIA (Accessibility and Remoteness Index for Australia) values. Socioeconomic deprivation was measured using SEIFA (Socio-Economic Index for Australia) values from the ABS. RESULTS: Age-standardized all-cause mortality varies two-fold from 5.7 to 11.3 per 1,000 across Australian statistical divisions. Strongest correlation was between Indigenous status and mortality (r = 0.69, p < 0.001). Correlation between remoteness and mortality was modest (r = 0.39, p = 0.002) as was correlation between socio-economic deprivation and mortality (r = -0.42, p = 0.001). Excluding the three divisions with the highest mortality, a multiple regression model using the logarithm of the adjusted mortality rate as the dependent variable showed that the partial correlation (and hence proportion of the variance explained) for Indigenous status was 0.03 (9 per cent; p = 0.03), for SEIFA score was -0.17 (3 per cent; p = 0.22); and for remoteness was -0.22 (5 per cent; p = 0.13). Collectively, the three variables studied explain 13 per cent of the variability in mortality. CONCLUSIONS: Ecological correlation exists between all-cause mortality, Indigenous status, remoteness and disadvantage across Australia. The strongest correlation is with Indigenous status, and correlation with all three characteristics is weak when the three statistical divisions with the highest mortality rates are excluded. Intervention targeted at these three statistical divisions could reduce much of the variability in mortality in Australia.     

Exposure to multiple pesticides and risk of non-Hodgkin lymphoma in men from six Canadian provinces

Non-Hodgkin lymphoma (NHL) has been linked to several agricultural exposures, including some commonly used pesticides. Although there is a significant body of literature examining the effects of exposure to individual pesticides on NHL, the impact of exposure to multiple pesticides or specific pesticide combinations has not been explored in depth. Data from a six-province Canadian case-control study conducted between 1991 and 1994 were analyzed to investigate the relationship between NHL, the total number of pesticides used and some common pesticide combinations. Cases (n=513) were identified through hospital records and provincial cancer registries and controls (n=1,506), frequency matched to cases by age and province of residence, were obtained through provincial health records, telephone listings, or voter lists. In multiple logistic regression analyses, risk of NHL increased with the number of pesticides used. Similar results were obtained in analyses restricted to herbicides, insecticides and several pesticide classes. Odds ratios increased further when only 'potentially carcinogenic' pesticides were considered (OR[one pesticide]=1.30, 95% CI=0.90-1.88; OR[two to four]=1.54, CI=1.11-2.12; OR[five or more]=1.94, CI=1.17-3.23). Elevated risks were also found among those reporting use of malathion in combination with several other pesticides. These analyses support and extend previous findings that the risk of NHL increases with the number of pesticides used and some pesticide combinations.     

Deaths from pesticide poisoning in South Korea: trends over 10 years

Objectives  Pesticide poisoning is a major cause of death in the world. The objective of this study was to examine the trends of pesticide poisoning deaths and their epidemiologic characteristics in South Korea. Methods  We evaluated the age-standardized mortality rates from pesticide-related deaths (intentional self-poisoning, accidental poisoning, assault, undetermined intent poisoning) in South Korea from 1996 through 2005, using registered death data obtained from the Korea National Statistical Office. The regional rurality index was calculated and correlation analyses were used to estimate the association with pesticide poisoning mortality. Results  The number of pesticide poisoning deaths from 1996 through 2005 was 25,360, which accounted for 58.3% of the total poisoning fatalities. The age-standardized mortality rates by pesticide poisoning significantly increased from 4.42 to 6.42 per 100,000 population, whereas the total death rate was decreased in the same period. Intentional self-poisoning was the majority cause of death from pesticides (84.8% of total pesticide poisoning deaths). The majority of the pesticide poisoning deaths were men, over 50 years old, with education less than middle school, and residing in rural areas. The rate of pesticide poisoning deaths was the highest in the farming period and was significantly correlated with the rurality index of each region. Conclusions  Pesticide poisoning deaths substantially increased during the 10-year study period, and showed demographic, seasonal and regional variations. More intensive intervention efforts to reduce pesticide mortality should become a public health priority in South Korea.     

Fatal traffic accidents and their association with the infant mortality rate and adolescence

This ecological study evaluates the association between fatality rates in traffic accidents (FR-V) and the study variables: infant mortality rate (IMR), proportion of young drivers involved in motor vehicle accidents (MVA) with casualties, and the proportion of young residents from 1995 to 1998 in the Brazilian State capitals and the Federal District. There was an important association between the MVA fatality rate and IMR (r = 0.57; p = 0.002), that is, the less developed a society, the higher its traffic mortality rate. No significant association was found between the proportion of young drivers in MVA with casualties and the MVA fatality rate (r = -0.27; p = 0.184). Nevertheless, the strong association observed between the proportion of young residents and the MVA mortality rate (r = 0.59; p = 0.002) suggests a possible correlation between traffic mortality and adolescence.     

Pesticides and childhood cancers.

To evaluate the possible association between pesticides and the risk of childhood cancers, epidemiologic studies published between 1970 and 1996 were critically reviewed. Thirty-one studies investigated whether occupational or residential exposure to pesticides by either parents or children was related to increased risk of childhood cancer. In general, the reported relative risk estimates were modest. Risk estimates appeared to be stronger when pesticide exposure was measured in more detail. Frequent occupational exposure to pesticides or home pesticide use was more strongly associated with both childhood leukemia and brain cancer than either professional exterminations or the use of garden pesticides. Occupational pesticide exposure was also associated with increased risk of Wilms'' tumor, Ewing''s sarcoma, and germ cell tumors. Residence on a farm, a proxy for pesticide exposure, was associated with increased risk of a number of childhood cancers. Although increased risk of some childhood cancers in association with pesticide exposure is suggested by multiple studies, methodological limitations common to many studies restrict conclusions; these include indirect exposure classification, small sample size, and potential biases in control selection. Opportunities for methodologic improvement in future studies of pesticides and childhood cancers are described.     

Ecological study on residences in the vicinity of AM radio broadcasting towers and cancer death: preliminary observations in Korea

Objectives Public health concern about the health effects of radio-frequency electromagnetic fields (RF-EMFs) has increased with the increase in public exposure. This study was to evaluate some health effect of RF exposure by the AM radio broadcasting towers in Korea.Methods We calculated cancer mortality rates using Korean death certificates over the period of 1994–1995 and population census data in ten RF-exposed areas, defined as regions that included AM radio broadcasting towers of over 100 kW, and in control areas, defined as regions without a radio broadcasting tower inside and at least 2 km away from the towers.Results All cancers-mortality was significantly higher in the exposed areas [direct standardized mortality rate ratio (MRR) =1.29, 95%CI=1.12–1.49]. When grouped by each exposed area and by electrical power, MRRs for two sites of 100 kW, one site of 250 kW and one site of 500 kW, for all subjects, and for one site of 100 kW and two sites of 250 kW, for male subjects, showed statistically significant increases without increasing trends according to the groups of electric power. Leukemia mortality was higher in exposed areas (MRR=1.70, 95% CI=0.84–3.45), especially among young adults aged under 30 years (0–14 years age group, MRR=2.29, 95% CI=1.05–5.98; 15–29 age group, MRR=2.44, 95% CI=1.07–5.24) .Conclusions We observed higher mortality rates for all cancers and leukemia in some age groups in the area near the AM radio broadcasting towers. Although these findings do not prove a causal link between cancer and RF exposure from AM radio broadcasting towers, it does suggest that further analytical studies on this topic are needed in Korea.