'Pigpen Effect' may trigger asthma in kids

[Guest guest]

*'Pigpen Effect' may trigger asthma in kids*

By STEVE STERNBERG

USA Today

03/29/2006

http://www.delawareonline.com/apps/pbcs.dll/article?AID=/20060329/LIFE/603290314\

/-1/NEWS01

Half a century ago, when Pigpen was new to the Peanuts gang, Charlie

Brown asked him the obvious question: " Pigpen, why are you always so dirty? "

Pigpen, his face ringed with grime, offered this sage response: " I have

affixed to me the dirt and dust of countless ages. "

He isn't the only one. Even kids as clean as Charlie Brown are wreathed

in invisible halos of dirt and dust that can be detected using small

personal monitors, research shows.

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For children who have allergic asthma, that can be a problem. Their

not-so-angelic halos can make them sick.

" Each kid has his own individual pollution cloud, " says lead author

Rabinovitch of the National Jewish Medical and Research Center in

Denver. " What's in it depends on what's in their house, what's in their

school and what their daily experience is. " Even serious scientists such

as Rabinovitch have begun to call this the Pigpen Effect, a nod to

" Peanuts " creator Schulz, who introduced Pigpen in 1954.

Scientists have known for a long time that dust and dirt make allergies

worse, especially in inner-city areas. A study of 1,528 children,

financed by the National Institutes of Health, found that a child's

symptoms and cost of care can be significantly reduced by spending

$1,469 per family on counseling, cleaning and buying such supplies as an

impermeable mattress and pillow cover.

But the Inner-City Asthma Study, reported in 2004 by Meyer Kattan of

Mount Sinai School of Medicine in New York and colleagues, focused on

allergens at home and not on what children carry with them.

Rabinovitch, of the National Jewish Medical and Research Center, chose

to focus his study of the Pigpen Effect on a highly allergenic protein

called endotoxin. A component of the pollution cloud, it comes from

bacteria that are everywhere in the environment, including on pets.

No two days are the same.

Researchers hoped to answer a question that puzzles doctors and parents

of children with asthma: Why do kids who have asthma get better and

worse from one day to the next? They also aimed to clarify a related

question: How do pets complicate a child's asthma even when the child is

involved in activities away from home?

But there's a curious wrinkle to the new research as well. That's

because other studies have shown that exposure to lots of endotoxin

before allergies develop - usually through contact with insect dust,

pets and farm animals - can prime the immune system to become tolerant

to the things that often promote allergies. In these kids, endotoxin

exerts a protective effect.

In the specialized world of allergy, the theory underlying this research

has become known as 'the hygiene hypothesis.' Multiple studies now

suggest that it may be grounded in fact. But, as in so many areas of

science, the facts are anything but clear-cut.

" It's very murky, " Rabinovitch says. " In some kids, [endotoxin from]

cockroach and dust mites is associated with allergy, even when they're

younger. In others it may be protective. But the hygiene hypothesis

basically asks whether a kid has allergies or not and why. That's

different than asking why kids who have asthma get better or worse. "

The distinction is important, Rabinovitch says, because once a person

has allergies, dust, dirt and pets make matters worse.

" When patients see these studies [supporting the hygiene hypothesis],

they're excited about keeping their pets, because they're hearing that

their pets are good for them, " he says. " The problem is that once they

have allergies, when they're exposed to pet allergens, they're going to

get sick. "

The researchers studied students ages 6 to 13 who attended the National

Jewish Medical and Research Center's Kunsberg School and whose asthma

would interfere with their performance and attendance in ordinary

schools. Rather than vacuum up house dust, which has been used in past

studies as a proxy for personal exposure, each child in this study wore

a monitor equipped with a filter fine enough to capture airborne endotoxins.

It's not just the environment

The kids were studied in two groups; 10 were monitored for one month and

14 for two months in 2000. The researchers assessed the children's

asthma severity by measuring their breathing and by asking the children

to log the severity of their symptoms using a daily scoring system.

Researchers compared readings from the kids' own monitoring with those

from monitors in the environment.

The monitors showed that personal exposures to endotoxin were

" significantly higher " than the levels the kids were exposed to in the

environment, supporting the notion that children, like Pigpen, are

surrounded by a personal cloud.

" One kid may have very different exposure than a second kid, "

Rabinovitch says.

The bigger the child's endotoxin cloud, the more airway obstruction he

had to endure, researchers reported in the Sept. 26 Journal of Allergy

and Clinical Immunology. Researchers also looked at activities that

influence endotoxin exposure.

They concluded, Rabinovitch says, that " pets are not good for asthma. If

you play with a cat or a dog on a given day, you will get a high dose of

endotoxin. If you live with a cat or dog, you will get the maximum dose. "

Your child's own " pollution cloud " of dust and other allergens may be a

factor in causing asthma, researchers say.

STUDIES

One researcher chose to focus his study of the " Pigpen Effect " on a

highly allergenic protein called endotoxin. Endotoxin, one component of

the pollution cloud, comes from bacteria that are everywhere in the

environment, including on pets. No two days are the same.

Copyright © 2006, The News Journal.

*1: * Am J Respir Crit Care Med. 2006 Feb 16; [Epub ahead of print]

*Particulate Levels are Associated with Early Asthma Worsening in

Children with Persistent Disease.*

Rabinovitch N, Strand M, Gelfand EW.

Division of Allergy and Immunology, Department of Pediatrics,

National Jewish Medical and Research Center, Denver, CO, USA.

Rationale: Ambient particulate concentrations have been associated

with variable physiological effects in children with persistent

asthma taking controller medications. Objective: To determine

whether exposure to particulate matter has immediate effects on

asthma control in children with persistent disease. Methods and

Measurements: In a school-based cohort, 73 children primarily with

moderate and severe asthma were followed daily over one or two

winters (2001-2002, 2002-2003) in Denver. The association between

ambient fine particulate, bronchodilator use and urinary leukotriene

E4 levels was assessed. Results: Daily concentrations of fine

particulate peaked in the morning hours when children were commuting

to school. In a multivariable analysis which controlled for

meteorology, time trends and upper respiratory infections, an

increase of one interquartile range (IQR) in morning maximum fine

particulate levels was related to an average increase of 3.8% in

bronchodilator usage at school (95% confidence interval (CI) = 0.2,

7.4%; p= 0.04). Children with severe asthma demonstrated

significantly stronger associations (8.1% increase; 95% CI=2.9,

13.4%; p=0.003) than those with mild/moderate disease (1.6%

increase; 95% CI=-2.2 to 5.4%; p=0.41; p=0.03 for difference between

groups). Morning maximum fine particulate levels were also

associated with urinary leukotriene E4 measured during school hours

(average increase of 6.2% per IQR increase; 95% CI=1.9 to 10.5%;

p=0.006). These associations were not discernable when 24-hour

averaged concentrations were utilized. Conclusions: Peak

concentrations of ambient fine particulate are associated with early

increases in bronchodilator use and urinary leukotriene E4 levels

among children with persistent asthma, despite the use of controller

medications.

PMID: 16484676

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*2: * J Allergy Clin Immunol. 2005 Nov;116(5):1053-7. Epub 2005 Oct

10.

<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Display & dopt=pubmed\

_pubmed & from_uid=16275375>

*Importance of the personal endotoxin cloud in school-age children

with asthma.*

Rabinovitch N, Liu AH, Zhang L, Rodes CE, Foarde K, Dutton SJ,

JR, Gelfand EW.

Department of Pediatrics, National Jewish Medical and Research

Center, 1400 St, Denver, CO 80206, USA. rabinovitchn@...

BACKGROUND: A number of studies have observed associations between

the amount of endotoxin in urban dust and chronic asthma severity,

but a direct relationship between personal exposure to household

endotoxin and acute asthma worsening has not yet been defined.

OBJECTIVE: We sought to investigate the relationship between

day-to-day changes in personal endotoxin exposure and asthma

severity. METHODS: In the winter and spring of 1999 through 2000,

endotoxin exposures were monitored in asthmatic schoolchildren by

using portable, as opposed to stationary, monitors designed to

measure inhalable and respirable particulate matter less than or

equal to 2.5 and 10 microm in diameter. Children were followed with

daily measurements of FEV(1) and asthma symptoms. RESULTS: Over a

24-hour period, median daily personal endotoxin exposures ranged

from 0.08 EU/m(3) (measured at a particulate matter size range

</=2.5 microm in diameter) to 0.37 EU/m(3) (measured at a

particulate matter size range </=10 microm in diameter). Personal

exposures were significantly (P < .001) higher than endotoxin

measurements from either indoor or outdoor stationary monitors.

Moreover, individual exposures did not correlate with stationary

measurements, suggesting that exposures derived from sources in

close proximity to the children's personal activities might be

better correlated with disease severity. Increases in personal

endotoxin exposures were associated with decreased FEV(1) values and

increased symptoms. CONCLUSIONS: These findings demonstrate the

importance of using personal monitoring to both measure and

correlate endotoxin exposure with asthma severity.

PMID: 16275375

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