[GSBN] health (ill) effects of earthen floors

[strawnet at aol.com]

 Thanks Derek for articulating the issues and arguing against bad science - so well! And thanks to Bill for his articulations as well.

Desert David Eisenberg

 

 

-----Original Message-----
From: Derek Roff <derek at unm.edu>
To: Global Straw Building Network <GSBN at sustainablesources.com>
Sent: Thu, Jan 5, 2012 12:01 pm
Subject: Re: [GSBN] health (ill) effects of earthen floors


"you can't argue with the science"


We can, and should, argue with bad science.  And even more against bad reporting and the erroneous conclusions which are often drawn from scientific research.  I read the articles cited in the "Paving Paradise" link that Bruce sent.  Only one of those articles presents anything resembling science.  That article, "Hookworm and Poverty" by Peter Hotez, offers no direct evidence to support the idea that hookworms are transmitted effectively by contact with earthen floors, and several direct and indirect reasons for supposing that the main transfer mechanisms require contact with soil outside the home.  Specifically, the article says the hookworm larva need moist soil, and do best in soils with low clay content and low compaction.  This means that an earthen floor would be far less conducive to hookworm transmission than exterior soils.  The article also mentions that parasite infection levels vary with profession in a given area, with the highest levels found among agricultural workers who work on and in moist soils.  The article says that parasite infection is very strongly linked to severe poverty, but the mechanisms are not well understood.  The frequency of dirt floors is mentioned as a possibility, but even the validity of the statistical correlation is questioned in the article text.   


It is quite clear that contact with feces is the main problem and the primary element of infection and transmission.  Addressing this problem would be far more valuable and far-reaching for the health of the people involved, compared to paving earthen floors, but it is more complex and harder to evaluate.  Governments love concrete programs, in all senses of the word.  A highly visible, easily countable program is easier to fund and justify, and you don't have to worry about proving primary and secondary effects, positive or negative.  


The linked article, "Inexpensive flooring change improves child health in urban slums" says, "replacing dirt floors with cement appears to be at least as effective for health as nutritional supplements".  It reports "a nearly 20 percent reduction in the presence of parasites" in Torreon, along with "Almost 13 percent fewer episodes of diarrhea" and " A 20 percent reduction in incidences of anemia".  


"Paving Paradise" article cites this article as the source for the figures that it presents in this sentence:  "Kids in houses that moved from all-dirt to all-concrete floors saw parasitic infestation rates drop 78 percent; the number of children who had diarrhea in any given month dropped by half; anemia fell more than four-fifths".  


I find it rather bizarre that the figures in "Paving Paradise" are so dramatically different from those in the article which it cites as evidence.  I'm thinking it is evidence of really bad reporting.  Both the numbers and the general conclusions of "Paving Paradise" don't seem to be justified by the supporting documents which it provides.  




The apparent, although questionable, statistical link between paving earthen floors and decreasing parasite levels, is worthy of more investigation.  But until we have better evidence, I don't think any reliable conclusions are possible.  


Derelict



Derek Roff
derek at unm.edu



On Jan 5, 2012, at 9:31 AM, Bruce King wrote:


Happy New Year, baleheads!


I came across the article linked below about how adding concrete over earthen floors has a measurable positive impact on occupant health--  especially children's.  Many of us think "Yuck!" at the idea of concrete instead of earthen floors, but you can't argue with the science.


Anyone have a rebuttal or additional relevant information?  At the very least, this seems like something we natural building types should take a cool-headed look at.


Paving Paradise - by Charles Kenny | Foreign Policy
http://www.foreignpolicy.com/articles/2012/01/03/paving_paradise







Thanks,


Bruce "Cool Head Cold Feet" King


bruce at bruce-king.com
(415) 987-7271


Twitter: @brucekinggreen


blog: bruceking.posterous.com

Skype: brucekingokok














 
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