Prediagnostic blood levels of organochlorines and risk of non‐Hodgkin lymphoma in three prospective cohorts in China and Singapore

Abstract

Specific organochlorines (OCs) have been associated with non‐Hodgkin lymphoma (NHL) with varying degrees of evidence. These associations have not been evaluated in Asia, where the high exposure and historical environmental contamination of certain OC pesticides (e.g., dichlorodiphenyltrichloroethane [DDT], hexachlorocyclohexane [HCH]) are different from Western populations. We evaluated NHL risk and prediagnostic blood levels of OC pesticides/metabolites and polychlorinated biphenyl congeners in a case–control study of 167 NHL cases and 167 controls nested within three prospective cohorts in Shanghai and Singapore. Conditional logistic regression was used to analyze lipid‐adjusted OC levels and NHL risk. Median levels of p,p′‐dichlorodiphenyldichloroethylene (p,p′‐DDE), the primary DDT metabolite, and β‐HCH were up to 12 and 65 times higher, respectively, in samples from the Asian cohorts compared to several cohorts in the United States and Norway. An increased risk of NHL was observed among those with higher β‐HCH levels both overall (3rd vs. 1st tertile OR = 1.8, 95%CI = 1.0–3.2; ptrend = 0.049) and after excluding cases diagnosed within 2 years of blood collection (3rd vs. 1st tertile OR = 2.0, 95%CI = 1.1–3.9; ptrend = 0.03), and the association was highly consistent across the three cohorts. No significant associations were observed for other OCs, including p,p′‐DDE. Our findings provide support for an association between β‐HCH blood levels and NHL risk. This is a concern because substantial quantities of persistent, toxic residues of HCH are present in the environment worldwide. Although there is some evidence that DDT is associated with NHL, our findings for p,p′‐DDE do not support an association.

Insecticide use and risk of non‐Hodgkin lymphoma subtypes: A subset meta‐analysis of the North American Pooled Project

“…A study of prediagnostic serum concentrations of organochlorines, including β‐ and γ‐HCCH, in a cohort from Maryland found no association with NHL risk, however, this analysis was based on a small number of cases 48 . More recently, a pooled analysis of East Asian cohorts with substantially higher blood concentrations of organochlorines than in Western populations, reported a significant association between β‐HCCH levels and NHL risk, but not p,p′‐DDE levels 49 …”

“…48 More recently, a pooled analysis of East Asian cohorts with substantially higher blood concentrations of organochlorines than in Western populations, reported a significant association between β-HCCH levels and NHL risk, but not p,p 0 -DDE levels. 49 In contrast to studies of well-characterized organochlorine compounds, fewer studies have examined pyrethrins and other inorganic agents. We observed a fivefold increase in FL risk associated with 10 or more years of pyrethrum use, as well as significant associations with ever use.…”

“…Furthermore, comparing subtype-specific associations across studies conducted in different time periods is complicated by changes in lymphoma classifications. Depending on the ICD coding used at the time of data collection and analysis, the phenotype defini-HCCH levels and NHL risk, but not p,p 0 -DDE levels 49. In contrast to studies of well-characterized organochlorine compounds, fewer studies have examined pyrethrins and other inorganic agents.…”

The role of pesticides in the etiology of lymphoma: A systematic review

“…The measurement of target analyses was performed using a chromatography isotope dilution high resolution mass spectrometer (GC-IDHRMS). Case-control pairs were analyzed sequentially in the sequential batch and laboratory workers were blinded according to the control status of the samples [25].…”

“…Cancer records [19], SEER coding scheme for the classification of NHL and its subtypes [19], WHO Lymphoma Classification [23], International Classification of Oncology [24], InterLymph Consortium Classification [6], socio-demographic information questionnaire form [19,23,24], questionnaire form examining the use of pesticides [6,19,24], CAREX database [23] were used. Gas chromatograph and chemistry analyzer were used to perform laboratory analyses in two studies [25,26]. It was found that the use of herbicides had a small but significant effect on the risk of some NHL subtypes, however, it did not affect the risk of NHL in general.…”