Pesticide in womb may promote obesity, study finds

by Janet Raloff, via ScienceNews.org,
A DDT breakdown product appears to be an ‘obesogen,’ but only in youngsters of normal-weight moms.

One-quarter of babies born to women who had relatively high concentrations of a DDT-breakdown product in their blood grew unusually fast for at least the first year of life, a study finds. Not only is this prevalence of accelerated growth unusually high, but it’s also a worrisome trend since such rapid growth during early infancy has—in other studies—put children on track to become obese.

Affected babies in the new study weighed no more than normal at birth, so growth in the womb was unaffected. Their moms were also normal weight—which is significant because babies born to overweight and obese women sometimes undergo rapid growth.

Carried out in Spain, the new— and still ongoing —study recruited more than 500 women to take part, beginning in the first trimester of their pregnancies. Blood collected upon entry was assayed for the presence of several common persistant chlorinated pollutants: DDT, its breakdown product DDE, hexachlorobenzene (a now-banned fungicide that still occurs inadvertently as a byproduct during the manufacturing of other chlorinated compounds), beta-hexachlorohexane (a contaminant of the insecticide lindane), and any of several dioxinlike polychlorinated biphenyls (fluids used as electrical insulators). Researchers continue to follow the babies born into the study (most of whom are now around 4 years old).

The study probed for correlations between pollutants in the moms’ blood and growth differences among their children. Only DDE exhibited such an association.

Babies born to normal-weight moms who had exhibited elevated blood-DDE levels (in the upper 25 percent of all participants) were twice as likely to grow rapidly during their first 6 months than were infants born to the least-exposed women (with DDE concentrations in the lowest 25 percent). By 14 months old, children whose exposures to DDE in the womb had been in the top 50 percent were four times as likely to be overweight—as indicated by a high body-mass-index, or BMI, score—when compared to children with lower exposures.

Although the heavier children were not obese, they will be followed to see if they become so, notes Michelle Mendez of the Center for Research in Environmental Epidemiology, in Barcelona, who led the new analyses.

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