Prenatal exposure to pesticide ingredient piperonyl butoxide and childhood cough in an urban cohort

Abstract

Rationale Previously we reported that airborne concentrations of cis-permethrin, but not trans-permethrin, measured during pregnancy in an inner city pediatric cohort was associated with cough by age 5. However, the effect of subsequent exposures to both permethrins during early childhood, and to piperonyl butoxide (PBO, a synergist for residential pyrethroid insecticides) remains to be elucidated. We hypothesized that prenatal and age 5-6 year measures of PBO and permethrins would be associated with cough at age 5-6 years in this cohort. Further, we explored the associations between these pesticides measures and wheeze, asthma, seroatopy, and fractional exhaled nitric oxide (FeNO). Methods PBO and permethrins were measured in personal air during the third trimester of pregnancy and indoor residential air at age 5-6 years (n=224). Health outcome questionnaires were administered to the mothers of 5-6 years old children. Indoor allergen specific and total immunoglobulin (Ig) E production was measured from sera collected at age 5, and FeNO was measured at 5-6 years. The hypotheses were tested using regression models adjusting for common confounders. Results Noninfectious cough was reported among 14% of children at age 5-6 years. Measures of prenatal PBO, but not age 5-6 year PBO or permethrins, increased the odds of cough [OR (95% CI): 1.27 (1.09-1.48), p<0.01; n=217]. No significant associations were found for other measured health outcomes. Conclusions Prenatal PBO exposure was associated with childhood cough. It is unclear whether the observed effect is due mainly to PBO itself or residential pyrethroids of which PBO is an indicator.

Environmental exposure to pesticides and respiratory health

“…This study found an association between prenatal exposure to PBO and non-infectious cough in children aged 5-6 years (OR 1.27, 95% CI 1.09-1.48, n=217), but not exposure to PBO measured at 5-6 years of age. There was no significant association with cis-and trans-permethrin in the air and cough measured prenatally or at the age of 5-6 years [36].…”

“…Moreover, the results of some studies have indicated that early exposure to pesticides up to the age of 4 years is the most relevant time window of exposure [30,31]. It was also shown that contact of the children in the first year of life with a mother who was herself in contact with pesticides in the case of occupational and/or residential exposure was likely to increase the likelihood of wheezing and childhood asthma [39,42], non-infectious cough in children aged 5-6 years [36], and wheezing in children under 18 years of age [43].…”

“…Furthermore, even when the precise nature of the pesticide was known, information regarding frequency, duration and/or intensity of exposure and pesticide formulation often remained scarce. Few studies have assessed direct personal exposure to pesticides by measurements, although this might not be the most accurate tool for assessing past exposures [34], and only two studies have focused on household use of pesticides or use in the garden [36,43].…”

“…Other authors had their own standardised questionnaire with questions such as: has a doctor ever diagnosed a respiratory health problem in your child? In the studies reported here, exposure was measured by assays of pesticide metabolites in blood and/or breast milk in eight of the studies carried out among children; environmental measurements of pesticides were conducted via individual air samplers in a single study [36]. In all other studies, pesticide exposure was assessed either through answers to the questionnaire on exposure, or the occupation of the parents, or the area of residence.…”

Dillapiol: A Pyrethrum Synergist for Control of the Colorado Potato Beetle

“…Recent reviews of PBO safety determined cases of subacute and chronic toxicity, including the induction of abnormal pigmentation in chicken feathers (Blankenship et al 2003) and hepatocellular tumors in mice when fed PBO in the diet (Kawai et al 2009). The most pertinent effects to human health were observed in children exposed to PBO in the womb that led to heightened risk of noninfectious cough at ages 5 and 6 years (Liu et al 2012). Because of these and other negative effects, PBO registration may not be renewed and alternative pesticide synergists will be required.…”