Dioxin concentrations in breast milk of Vietnamese nursing mothers: a survey four decades after the herbicide spraying.

In an operation by United States Armed Forces during 1961 to 1971, large quantities of herbicides were sprayed in South Vietnam. These herbicides contained 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-tetraCDD), the most toxic congener of dioxins. Several decades after the herbicide spraying ceased, dioxin concentrations in the environment and human remained elevated in the sprayed areas. Breast milk samples from 520 nursing mothers residing in areas including the hot spots as well as the sprayed and unsprayed areas were collected to quantify the levels of dioxins. The total toxic equivalents of 2,3,7,8-substitued PCDDs/PCDFs in breast milk of mothers living in the hot spots, and the sprayed and unsprayed areas were 14.10 pg/g lipid, 10.89 pg/g lipid, and 4.09 pg/g lipid for primiparae and 11.48 pg/g lipid, 7.56 pg/g lipid, and 2.84 pg/g lipid for multiparae, respectively, with significant differences in the values among the three areas. In the hot spots, dioxin levels were highly correlated with the residency of mothers after adjustment for their age and parity.

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

OBJECTIVES: To clarify the association between dioxin concentrations in breast milk and food group intake in herbicide-sprayed and nonsprayed areas in Vietnam. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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 30-40 years had passed.

A GIS study of dioxin contamination in a Vietnamese region sprayed with herbicide.

OBJECTIVES: The American-Vietnam War ended over 35 years ago, but dioxins still remain in human tissue and Vietnam's environment. The main objective of this study was to assess the correlation between dioxin concentration in soil, sediment and breast milk in one of the areas sprayed with herbicide, namely Cam Chinh commune, Quang Tri province, using a geographic information system (GIS). METHODS: The concentration of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in soil, sediment and breast milk samples was determined and the data analyzed using the geostatistical log-normal Kriging algorithm. RESULTS: The mean dioxin levels in soil and breast milk in the sprayed area were significantly higher than those in the non-sprayed area. The distribution pattern of PCDDs and PCDFs in soil was different, and there were no significant correlations between the estimated dioxin levels in soil obtained by the Kriging method and those in breast milk. CONCLUSIONS: The possibility remains that another exposure route, such as exposure to herbicides used during the Vietnam War, might affect dioxin levels in breast milk, although more soil data are needed to make more reliable geographical estimations.

Residual congener pattern of dioxins in human breast milk in southern Vietnam.

This study evaluated residual congener patterns of dioxin/furan (=PCDD/DF) related to tactical herbicides aerially sprayed over the regions of southern Vietnam through Operation Ranch Hand. The study focused on Cam Chinh (CC) commune, Quang Tri province (an area sprayed with tactical herbicides), and the Cam Phuc (CP) commune, Ha Tinh province (a non-sprayed area). Breast milk samples for analysis were collected in September 2002 and July 2003 from lactating primiparous and multiparous mothers born after the war (<31 years old). We found the levels of each congener in the CC commune were higher than in the CP commune, and determined specificity in the PCDD/DF congener pattern in CC commune samples by cluster analysis. The congener pattern is characterized by higher (the hexa-, the hepta-, and the octa-) chlorinated PCDD/DFs; this appears to be the same profile as that presented by pentachlorophenol (PCP), rather than 2,4,5-trichlorophenoxy acid (2,4,5-T) contaminated with 2,3,7,8-TCDD. A GC/MS study in the 1970s detected the chlorophenols 2,4-di and 2,4,6-trichlorophenol in some Agent Orange samples, which contained, like PCP, a wide variety of PCDD/DF congeners. In this context, it may be expected that certain tactical herbicides contaminated with various chlorophenol impurities, have a unique congener pattern when compared with pure 2,4,5-T formulations.

Relation of long-term body weight change to change in lipoprotein particle size in Japanese men and women: the INTERMAP Toyama Study.

OBJECTIVE: This study investigated the relationship between changes in lipoprotein particle size and body weight change over a 9-year period in Japanese adult men and women. METHODS: Among 299 INTERMAP Toyama Study participants aged 40-59 in 1997, 260 were followed up in 2006 (129 men and 131 women). Their body weight and lipoprotein particle sizes were measured in 1997 and 2006. Nuclear Magnetic Resonance spectroscopy was used for the measurement of lipoprotein particle size. RESULTS: The number of small LDL particles decreased from 774.3 to 617.4 nmol/L in men (p=0.005) while the number increased from 353.2 to 414.5 nmol/L in women (p=0.028) over this period. No significant changes in mean body weight were noted in either sex. Nine-year body weight change was positively associated with changes in the numbers of small LDL particles (men, r=0.37, p<0.001; women, r=0.21, p=0.018), but inversely associated with changes in LDL particle size (men, r=-0.30, p=0.001; women, r=-0.16, p=0.066) and HDL particle size (men, r=-0.42, p<0.001; women, r=-0.42, p<0.001). These relationships were similar even when adjusted for age, baseline body mass index, baseline values for LDL and HDL particle sizes, and other factors. The number of small LDL particles increased in both men and women in the body weight gain group. In the body weight loss group, the number of small LDL particles decreased in men but did not decrease in women. CONCLUSION: This 9-year observational study showed that the number and size of lipoprotein particles were strongly influenced by long-term body weight change.

The impact of sleep interruptions on vital measurements and chronic fatigue of female caregivers providing home care in Japan.

The purposes of this study were to examine the impact of sleep interruptions on diurnal changes in blood pressure and chronic fatigue in middle-aged and elderly caregivers by using a cross-sectional quantitative method. Thirty-five female caregivers who were not taking antihypertensive and/or sleeping drugs were recruited for this study. Blood pressure was monitored over a 24 h period. Sleeping or waking periods were monitored with an actigraph. Fatigue was determined from a self-administered questionnaire. Participants were classified into four groups by cause of sleep interruption. One-way analysis of variance showed no differences in blood pressure, but hypertension was prevalent (40%). Sleep duration differed significantly, with the longest duration for those scheduled to wake up for care. Substantial variations were identified in the eight subcategories of chronic fatigue, with those without sleep interruption having the worst profile. This suggests that multiple factors in addition to sleep interruption affect the care burden.