2 persistent environmental pollutants may still have adverse effects on infant growth

Washington: A new study has revealed exposure to two persistent environmental pollutants may affect infant growth.

As per Norwegian Institute of Public Health's study, even though the levels of the two environmental pollutants have declined over the last 20 years, they may still have adverse effects on children's development.

Researchers investigated whether exposure to two persistent organic pollutants before and after birth was associated with rapid growth in infancy, a known risk factor for obesity in later life: polychlorinated biphenyl 153 (PCB153), a chemical used extensively in windows and electrical equipment in Norway before being banned in the 1990s and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), a metabolite of the controversial pesticide 1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane (p,p?-DDT), now only used in malaria control.

Due to their long half-lives, these pollutants accumulate and become concentrated in the food chain. Humans are exposed to them through food, particularly seafood and breast milk.

The researchers found that maternal levels of DDE (indicating the levels to which the foetuses were exposed to in utero) were significantly associated with rapid growth in early life. They also found that levels of PCB153 in milk and the amount transferred through breastfeeding were associated with decreased infant growth and falling below expected growth curves.

Principal Investigator Merete Eggesbo said that although PCB and DDE levels have declined markedly over the last 20 years, the study shows that even the lower levels that European infants are exposed to today may affect their development. This is important information for regulatory bodies, and emphasises the need to continue to reduce these pollutants in the environment.

She added that they also need to identify any unwanted effects from pollutants transferred through breast milk so they can establish optimal breastfeeding recommendations.

Even though this is the largest study to date in this field and the results are convincing, there is always the risk of unmeasured and unknown confounding factors. Also the data, especially about breastfeeding, have certain degrees of inaccuracy that may have diminished our results. The inconsistency across cohorts also indicates factors involved that we do not yet understand.