The Tapachula Study has several goals, all related to assessing health effects of early–life exposure to DDT and its metabolites. In this study, researchers enrolled 872 mother-infant pairs during 2002-2003; study deliveries occurred at either of two hospitals in Tapachula, a city in the state of Chiapas, southern Mexico. The study was done in Chiapas because it has the highest incidence of malaria cases in the country. Although use of DDT in Mexico ceased in the late 1990s, the median measured levels of DDE (the main metabolite of DDT) among women in the study were ~24 microg/L, about what would be expected in an area where DDT use for agriculture and mosquito control had been routine.
The mothers provided blood specimens at delivery, were given a questionnaire, and anthropometric measurements were performed on the infants. Maternal serum for all subjects was analyzed for DDT/DDE. Contrary to the original hypothesis, the researcher team found no evidence that DDE had antiandrogenic effects on the male offspring (Longnecker et al., 2007).
The mother-child pairs were followed approximately every two months during 2004–2005 to assess duration of breast feeding, child growth, and the occurrence of infectious diseases in the children. Unlike some previous studies, the researchers found no association of DDE exposure with length of lactation (Cupul-Uicab et al., 2008). At this time data analyses are ongoing to see if associations are present for other outcomes ascertained during follow-up.