Agricultural Chemical Use and Congenital Cleft Lip and/or Palate

Abstract

A case-control study utilizing vital records and ecologic, surrogate exposure measures was conducted in Iowa and Michigan. The study hypothesis anticipated an excess risk of clefts among fetuses exposed during the peak agricultural chemical use period (April through November) coincident with their first trimester of gestation. To examine this hypothesis, multiple regression techniques were used to aid identification of potential confounders; additional analyses, stratified on the potential confounders, were performed using two chemical exposure indices. The major findings of these analyses suggest: (1) an agricultural chemical effect (using the multiple exposure index) controlling for season of conception; (2) no independent effect of season of conception (thus the null hypothesis is not rejected); and (3) little chemical/season interaction. These results imply that if exposures to agricultural chemicals are, in fact, risk factors for clefts, an expanded model that accounts for multiple pesticidal exposures may be more sensitive than consideration of season of exposure, as originally hypothesized.

Potential parental exposure to pesticides and limb reduction defects.

“…Unlike two previous studies (7,11), the current investigation did not find an association between maternal residence in an agricultural county or high pesticide-use county and the risk of congenital malformations among their children. In contrast with the results for occupation, there was no difference in risk between the cases of associated limb reduction defects and isolated limb reduction defects when compared with normal referents.…”

“…Some human studies have demonstrated a positive relationship between parental agricultural activity and malformations other than limb reduction defects and stillbir ths (6)(7)(8).…”

Chemical exposure during pregnancy and oral clefts in newborns

“…Even so, relatively little attention has been paid to hundreds of chemical formulations and their effects on the health of populations. In light of these arguments, Gordon & Shy (1981) raised the hypothesis that intrauterine exposure to agricultural chemicals in farming areas during periods of peak use of pesticides and herbicides, especially in the first trimester, could be associated with increased risk of birth defects. This ecological study displayed the peculiar limitations of generalizing data, but shows independent effects of exposure to these products for the occurrence of clefts.…”

“…Although they are etiologically distinct, both involve genetic and environmental components in their development (Finnell et al, 1998). Although facial clefts have been reported for centuries, their etiology has not been clearly established (Gordon & Shy, 1981). Different factors have been described to explain such clefts, including insufficient embryological development, partial failure in the fusion of the medial nasal processes, and developmental abnormalities.…”

Birth defects among children born to a population occupationally exposed to pesticides in Colombia.

“…In spite of this concern, very few epidemiologic studies have been conducted to ascertain the possible relationship (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). So far, no maternal preconceptional or prenatal exposure to pesticides has been recognized as teratogenic (1).…”