According to Dewailly et al., "For many years young native children from Nunavik have had a high incidence of infectious diseases, in particular meningitis, bronchopulmonary, and middle ear infections. Otitis media [middle ear infections] and the damage it can cause to hearing is a major problem for Inuit children and adults. In fact, Inuit in Nunavik report hearing loss as their most common chronic health problem."

The causes for this unusual pattern of infectious diseases is uncertain, but plausibly linked to the high levels of organochlorine chemicals experienced prenatally in the womb by Inuit children. Dewailly et al. explore this hypothesis by measuring organochlorine (OC) levels in breast milk shortly after birth and testing whether OCs are associated with rates of inner ear infections early in life. They find that higher levels of OCs indeed are associated with an increased rate of these infections.

What did they do?
Dewailly et al. measured levels in mother's milk of 10 PCB congeners and 8 chlorinated pesticides or metabolites (p,p´-DDE, mirex, heptachlor epoxide, chlordane, hexachlorobenzene, endrin, and dieldrin). Milk samples were taken shortly after birth and used as an index to in utero exposure. Then during the first year of life they examined participating infants' health status three times in the first 12 months, paying particular attention to the incidence of ear infections. Blood samples were also taken during these examinations and used in immune system assays.

What did they find?
Acute ear infections were the most frequent health problem in these infants, with 81% experiencing at least one episode. The frequency of ear infections did not differ among breast-fed vs. bottle-fed infants.

Infants ranking higher in organochlorine exposure (as measured in breast milk) were more likely to experience ear infections than those ranking lower. None of the measured immunological parameters were related to OC exposure in breast milk.

Dewailly et al.'s results do not allow them to identify which OC compounds could be responsible for the Inuit infants susceptibility to ear infections. The associations between inner ear and exposures were most consistent for DDE and HCB, but concentrations of the OCs in general were highly correlated with one another.

Talk to us: email