Aug. 21, 2008 -- Childhood risk factors, including exposure to dogs and respiratory infections, can boost the chances of snoring later in a life, according to a team of researchers.
"Early-life environments can affect if you are a snorer or not later in life," Karl Franklin, MD, PhD, the study's lead author and a physician at University Hospital in Umea, Sweden. The study is published in Respiratory Research.
But other experts familiar with the study findings say more research is needed. Even Franklin acknowledges that the research is no reason to give up the idea of childhood pets.
Franklin and a team of Nordic researchers polled men and women ages 25 to 54 -- all residents of Sweden, Norway, Iceland, Denmark, and Estonia -- and got responses from 15,556.
Researchers asked them about their childhood, such as whether they had a dog or other pets, whether they were hospitalized for respiratory infections before age 2, and whether they had recurrent ear infections. They asked about family size, parental education, and mothers' ages.
Then they asked if participants currently snored. They found that 18%, or 2,851, were habitual snorers -- defined as loud and disturbing snoring at least three nights per week.
Risk Factors for Snoring
They found that four childhood factors were independently associated with later snoring:
- Being hospitalized for a respiratory infection before age 2 boosted the risk of later snoring by 1.27 times.
- Suffering from recurrent ear infections as a child raised the risk 1.18 times.
- Growing up in a family with more than five members increased risk 1.04 times.
- Exposure to a dog in the home as a newborn boosted risk of later snoring 1.26 times
Franklin decided to look at early exposures and later risk of snoring, following a trend in medical research of looking at how many adult diseases, such as cardiovascular and diabetes, can be traced to childhood experiences and exposures.
Exactly why the exposures he found associated with snoring ups the risk is not known, he says.
"Perhaps these things, like dogs, infection, might increase the size of the tonsils," he says, and that in turn might boost the risk of snoring.
"This doesn't say much to me," she says of the findings. Early infection is the most feasible of the risk factors associated with boosting snoring risk, she says. "It's not clear how the dog and the large family is associated with snoring."
The two known major risk factors for snoring, she says, are obesity and the structure of the throat in individuals.
The infection exposure and the dog exposure are the links to snoring that make the most sense, says another expert, Christopher C. Randolph, MD, associate clinical professor at the Yale Center for Allergy, Asthma & Immunology in Waterbury, Conn. "Certainly individuals who are exposed to severe airway episodes, have recurrent [ear infections], live in large families where infection is common, and have a dog may be more likely to develop an immunologic ... response in the airways leading to tonsillar and or adenoid [enlargement] and narrowing of the airway leading to snoring," he says.
He also calls for more study. And Franklin stresses that more research is needed before advising parents to do anything. "I think we should do more studies before we take the dogs away."