Association between dioxin concentrations in breast milk and food group intake in Vietnam

Kae Saito,Nguyen Ngoc Hung,Kenji Tawara,Rie Naganuma,Teruhiko Kido,Dang Duc Nhu,Muneko Nishijo,Hideaki Nakagawa,Le Hong Thom,Hiroyuki Suzuki,Chiaki Sakakibara,Kaoru Kusama,Phung Tri Dung

doi:10.1007/s12199-009-0106-9

Abstract

To clarify the association between dioxin concentrations in breast milk and food group intake in herbicide-sprayed and nonsprayed areas in Vietnam. This survey was conducted in August 2007 in sprayed and nonsprayed areas, respectively. The interviews were performed using a questionnaire to obtain information on personal characteristics and usual dietary intake. Eighty mothers of sprayed area and 42 mothers of nonsprayed area participated in the study. Breast milk was analyzed for concentration of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Multiple regression analysis showed that location (sprayed or nonsprayed area) has the highest association with the toxic equivalents (TEQ)-PCDDs, TEQ-PCDFs, and TEQ-Total rather than other factors. In the sprayed area, the adjusted R (2) values of regression were approximately 0.1. On the other hand, the adjusted R (2) values in the nonsprayed areas were higher than those in the sprayed area, i.e., between 0.2 and 0.3, and showed that there were significant associations with body mass index (BMI) in all models. Dioxin exposure was less affected by usual dietary intake in the sprayed area than in the nonsprayed area in Vietnam. It was clear that past exposure rather than present dietary intake may affect present dioxin concentrations in breast milk in the sprayed area in Vietnam. This study suggests that present dioxin concentrations in breast milk were maintained by continuous past exposure even after 30-40years had passed.

Highlights

During the Vietnam War, herbicide was sprayed over forests and villages in Central and Southern Vietnam to defoliate the vegetation between 1961 and 1971
Dioxins refer to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls, which are lipophilic compounds that bind to sediment and organic matter in the environment and which have a tendency to accumulate in the fatty tissues of animals and human beings
Study areas were designated in the north-central area of Vietnam, namely the Cam Chinh commune in the Cam Lo district of Quang Tri province, where herbicides were sprayed during the war, and the Cam Phuc commune in the Cam Xuyen district of Ha Tinh province, which was not sprayed with herbicides during the war

Summary

Introduction

During the Vietnam War, herbicide was sprayed over forests and villages in Central and Southern Vietnam to defoliate the vegetation between 1961 and 1971. Because dioxins are lipid soluble and tend to accumulate in adipose tissue, such as seafood, meat, dairy products, and eggs, the highest concentrations are accumulated in human tissue through the food chain. These studies suggest that human intake of dioxin has been decreasing for several decades [2,3,4,5,6]. Several studies have reported positive correlations between the intake of fish and dairy products and dioxin concentrations in breast milk, which are the specific factors influencing the accumulation of dioxin in humans [7,8,9]. There have, been few studies in Vietnam, in spite of the fact that a great deal of herbicide was sprayed there

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