High cortisol and cortisone levels are associated with breast milk dioxin concentration

Dioxin is one of the most toxic chemical substances known and is a persistent environmental contaminant. During the Vietnam War (1961–1971), the US Air Force sprayed over 80 million litres of chemical herbicides on southern battlefields for general defoliation and crop destruction. This chemical herbicide was contaminated with highly toxic 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin-TCDD). Although the war in Vietnam ended more than 40 years ago, dioxin hot spots are still found in and around three former US airbases. TCDD accumulates in the fatty tissues of the body as a result of the lipophilic nature of dioxin. Dioxin concentrations in the breast milk of women in the sprayed areas in Vietnam are still higher than those in the breast milk of women in the nonexposed areas. Some of the adverse effects associated with dioxin exposure may be considerably mediated by alterations in endocrine function.

Kido et al. conducted this study with the aim to further elucidate the relationship between dioxin exposure and steroid hormone levels in the serum and saliva of Vietnamese mothers by using a larger number of subjects residing in a dioxin hot spot (Phu Cat) and a nonexposed area (Kim Bang). Another aim was to compare salivary steroid hormone levels with serum steroid hormone levels.

Dioxin concentrations in the breast milk of women from the dioxin hot spot were three to four times higher than those in the breast milk of women from the nonexposed area. Good correlations were found between the levels of six steroid hormones in saliva and those in serum respectively. Salivary and serum cortisol and cortisone levels in women from the dioxin hot spot were significantly higher than those in women from the nonexposed area.

These results suggest that dioxin influences steroidogenesis in humans and that saliva samples can be used for hormone analysis and are therefore excellent specimens in epidemiological studies.

Read full article at Kido et al. (2014) European Journal of Endocrinology 170; 131-139; DOI: 10.1530/EJE-13-0410