Children run less risk of being sensitive to allergens if there is a dog in
the house in the early years of their lives, scientists have found.
The conclusion, based on a six-year study of 9,000 children, adds weight to
the theory that growing up with a pet trains the immune system to be less
sensitive to potential triggers for allergies such as asthma, eczema and hay
fever.
The “hygiene theory” of allergy holds that modern life has simply become too
clean, meaning that babies’ immune systems are not exposed to enough germs
to develop normally.
Having a dog provides enough dirt of the right kind, the new German study
suggests. But it may be important that baby meets dog early enough to affect
the immune system as it develops. “Our results show clearly that the
presence of a dog in the home during subjects’ infancy is associated with a
significantly low level of sensitisation to pollens and inhaled allergens,”
said Joachim Heinrich of the National Research Centre for Environmental
Health in Munich.
The same protective effect was not seen in children who had frequent contact
with dogs but none at home.
Previous studies have suggested that exposure to pets may have a protective
effect against allergies but many of these studies were based on
retrospective questioning of subjects about their exposure.
The new study did not require anybody to remember anything. The children were
followed from birth to the age of six. This is likely to make for more
reliable results.
In the European Respiratory Journal, Professor Heinrich and
colleagues say that the blood of children raised in households with dogs
contained fewer markers for allergy, such as antibodies to pollen, house
dust mites, cat and dog dander, and mould spores. But actual experience was
rather less encouraging. Those children raised alongside a dog were no less
likely to develop asthma or other allergies than were the other children. So
while their blood samples suggested they were not susceptible, their
experience suggested they were.
“It is not crystal clear why this is so,” Professor Heinrich said. He hopes
that the protective effect may show up later in life and is continuing to
follow the children’s progress. Further assessments will be made when they
reach the age of 10.
In the meantime, he does not recommend that parents get a puppy. “Until we
understand the mechanisms underlying this protective effect from dogs, we
will not be able to draw any further conclusions or make any
recommendations,” Dr Heinrich said.
Doctors who specialise in allergy have found advising parents difficult. Where
children already have allergies, cats and dogs tend to make them worse by
exposing them to allergens from the pets’ coats.
But more recent evidence has tended to show that early exposure to cats, dogs,
and to farm animals is neutral or even protective. Children raised on farms
appear to be protected against all sorts of allergens, not just those
produced by farm animals.
Other studies similar in design to Professor Heinrich’s have produced
equivocal findings. Some suggest early exposure to cats increases the risk,
others that it diminishes it. Yet others find no effect one way or the other.
But one study published in the Journal of Allergy and Clinical Immunology
in 2002 found that asthma symptoms were reduced in homes that owned a dog,
and probably also in those that owned a cat.
Dr Guy Marks, of the Institute for Respiratory Medicine in New South Wales,
concluded in 2002 that parents should neither be advised to rid their homes
of pets, nor acquire them as a prevention against asthma. Further research
was needed, he concluded.
This may well be coincidence but I used to suffer from every cold and stomach bug in town during my mid twenties, but having had my black labrador for a few months I noticed a significant improvement in my general health. It could well be due to spending more time outdoors of course....
James, Macclesfield, UK
Sorry, I meant "pet-free", not "pet-ridden".
Luisa Bozzo, Torino,
This is no use at all. "the blood tests were fine but the patient still got allergies' indicates the blood tests are wrong.
I grew up with cats, dogs, horses, mould spores and dust mites and I was ill to the point of death on a number of occasions and still suffer severe allergies to this day.
Thalia, London,
Dr Guy Marks is no doubt sponsored in his research by the highly lucrative asthma drug industry. His findings completely ignore the emotional dimension of children raised with dogs. Children raised on farms are probably too busy and too full of fresh air and common sense to suffer.
I Whittaker, London,
I would suggest that pets can have a more positive influence on children than parents. In some cases they are probably more intelligent.
Jim Wills, Brisbane, Australia
I went through allergy testing twice, and had to give up the pets, even though I was allergic to other things. My parents and doctors had the mindset that if one has allergies, the pets had to go. We raised our kids with pets, and they did not have near the amount of allergies I had. Go figure!
Wendy Wilson, Springfield, IL, USA
My husband grew up in a spotless pet-ridden city flat and developed quite a few mild allergies (pollens, animal coats, detergents, etc.). After marriage, and life in an ordinary suburb household with dog, allergies have disappeared. Can pets (or love) have an effect on adults, too?
Luisa Bozzo, Torino,
Hmm, my parents and grandparents have no allergies. but we had pet dogs since I was born and the adults had no inkling that each time I suffered an almost deadly asthma attack, it could have been dog related. After the dogs died, I raised cats and became allergic to them too..go figure
bernadette, toronto, canada
My daughter is been diagnose with Asthma at the age of 2 plus Chronic Upstrubtive Lung Dicease at the age of 7. She is 15 today and lived her life with a dog. Her illnesses are controlled
M, Durban, South Africa
We used to have a very peaceloving and intelligent dog at home when I was a kid, a foundling, a Labrador. She was called Lano, after the Llanos in Latin America by that colour, near the Andes. I later discovered that Lanoo also means disciple in Tibetan. That is how I found Maitreya.
Jaap den Haan, Namen,
There is an established genetic element to allergies. You could expect parents with several allergies, would be less likely to buy dogs. Parents with no allergies would be more likely to buy dogs. Wouldn't this have a confounding effect on the research - kids would just inherit parent's pattern?
Mec, Perth,
No Sean, it doesn't.
That article refered to zoonotic disease. This one refers to common allergens and general 'dirt'.
Tom, Cardiff,
So what. Always believed in a good dirty upbringing with dogs; children & g.child.s.
Children who attend daycare or playgroups cut their risk of the most common type of childhood leukaemia by around 30%
This equates to 1 in 2000 reduced to 1 in 2857 or real life percentages 0.0005% to 0.00035%!!
M. Cawdery, Portadown, Co. UK, EU.
I think there are somethings in life one cannot define, the power of love heals better then anything (because of the mind/ emotions), after reading the above, perhaps it just about learning how to protect, be protected and loved unconditionally which gives one the edge to fight subconsciously.
Babar Kureshi, Islamabad, Pakistan
The good professor cant be much of scientist if he concludes that there is "this protective effect from dogs" therefore confusing correlation with causation.
Steve Bush, Cirencester, UK
I was brought up during the WW2 years, lived rough, was dirty for much of the day, played in bombed-out buildings ... this from the age of two onwards. We were known as 'Latch Key Kids'. Anybody would take us in. No alergies, ever, and I'm now 70 yrs old ... it's a bit of a mystery, isn't it?
Dave Jones, Isle of Wight, UK
Yet another of those typically "scientific" reports... Which, almost by definition, means "inconclusive"...!!!
John Jay, Walton on Thames, UK
If this is true, then I dread to think how bad my allergies would be had I grown up in a pet-free environment. As it was, I was exposed from birth to animals in and around the house. My allergies first appeared when I was about 7 or 8 and became progressively more severe. Go figure.
Sophie, Cambridge,
@Katy, Manchester
Your one-off experience does not count for anything against the results of the study. If you read the article, you will see that it does not say "people with dogs don't get asthma" anywhere.
bob, london,
Sarah, France: "I'm no expert, but my first thought was that people who have pets are less likely (or able!!) to to be house proud, too."
....erm... riiiight.
I'm no expert either, but my first thought happened to be that people with pets are less likely (or able!!) to go paragliding. IRRELEVANT!
Jamie, Halifax, West Yorkshire
My parents had a dog in my early years - Jasper the Border Collie had to go and live with Granny as I was so allergic to him. i'm also allergic to other animal fur - it triggers sthma attacks. As the rest of family are not allergic in the same way - maybe it's just one of those things?!
Katy, Manchester,
Doesn't this article broadly contradict the one published last week cautioning dog-owners not to let their pets sleep on the bed?
Sean, Surrey, UK
I'm no expert, but my first thought was that people who have pets are less likely (or able!!) to to be house proud, too.
Sarah, Carcassonne, France
My experience is the opposite; I grew up on a farm and am allergic to hay, straw, grass pollen, horses (I had a pony) dust mites and mould (it was a a damp old house). My exwife grew up in Cambridge and is allergic to flowering trees, for which the city is famous. Perhaps we became "oversensitised?"
Alex, London, UK
looking forward to the result of this research
Lynn, Peking,