[escepticos] DDT y sentido común

[Pedro J Hernández González]

Ramon Diaz-Alersi escribió:
> El día 15/09/06, Pedro J Hernández González
> <pedroj.hernandezgonzalez en gobiernodecanarias.org 
> <mailto:pedroj.hernandezgonzalez en gobiernodecanarias.org>> escribió:
>
>     El tema salió varias veces en la lista y personalmente quedé bastante
>     convencido de que los efectos nocivos del DDT son francamente
>     discutibles como para obviar sus efectos beneficiosos. Ahora
>     parece que
>     algunos empiezan a planterselo
>
>     http://news.bbc.co.uk/2/hi/science/nature/5350068.stm
>
> Pues no sé que decirte ¿No estaremos ante otro de esos casos de que no 
> es bueno para nosotros, pero sí para los pobrecitos del tercer munndo? 
Claro que nosotros no tenemos Malaria
> Lo digo por este reciente artículo español:
Interesante referencia. ¿Hay más estudios al respecto?. Recuerda el 
artículo que citaba en otro mail
Loannidis JPA 2005. Why most published research findings are false 
<http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0020124>. 
PLoS Med 2(8): e124.
que precisamente advierte
The probability that a research claim is true may depend on study power 
and bias, the number of other studies on the same question, and, 
importantly, the ratio of true to no relationships among the 
relationships probed in each scientific field. In this framework, a 
research finding is less likely to be true when the studies conducted in 
a field are smaller; when effect sizes are smaller; when there is a 
greater number and lesser preselection of tested relationships; where 
there is greater flexibility in designs, definitions, outcomes, and 
analytical modes; when there is greater financial and other interest and 
prejudice; and when more teams are involved in a scientific field in 
chase of statistical significance-

saludos
>
>  Am J Epidemiol. 2006 Sep 12;
> In Utero Exposure to Background Concentrations of DDT and Cognitive 
> Functioning among Preschoolers.
>
> * Ribas-Fito N, * Torrent M, * Carrizo D, * Munoz-Ortiz L, * Julvez J, 
> * Grimalt JO, * Sunyer J.
>
> Respiratory and Environmental Health Research Unit, Institut Municipal 
> Investigacio Medica (IMIM), Barcelona, Catalonia, Spain.
>
> p,p'-DDT (bis[p-chlorophenyl]-1,1,1-trichloroethane) is a persistent 
> organochlorine compound that has been used worldwide as an 
> insecticide. The authors evaluated the association of cord serum 
> levels of DDT and its metabolite, 
> 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE), with 
> neurodevelopment at age 4 years. Two birth cohorts in Ribera d'Ebre 
> and Menorca (Spain) were recruited between 1997 and 1999 (n = 475). 
> Infants were assessed at age 4 years by using the McCarthy Scales of 
> Children's Abilities. Organochlorine compounds were measured in cord 
> serum. Children's diet and parental sociodemographic information was 
> obtained through questionnaire. Results showed that DDT cord serum 
> concentration at birth was inversely associated with verbal, memory, 
> quantitative, and perceptual-performance skills at age 4 years. 
> Children whose DDT concentrations in cord serum were > 0.20 ng/ml had 
> mean decreases of 7.86 (standard error, 3.21) points in the verbal 
> scale and 10.86 (standard error, 4.33) points in the memory scale when 
> compared with children whose concentrations were <0.05 ng/ml. These 
> associations were stronger among girls. Prenatal exposure to 
> background, low-level concentrations of DDT was associated with a 
> decrease in preschoolers' cognitive skills. These results should be 
> considered when evaluating the risk and benefits of spraying DDT 
> during antimalaria and other disease-vector campaigns.
>
> Saludos.
>
>
> -- 
> Ramón Díaz-Alersi
> ------------------------------------------------------------------------
>
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-- 
Pedro J. Hernández
Ecos del futuro
http://ecos.blogalia.com