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 Although they had never been smokers themselves, women in the study
who lived with two or more smokers as a child had a 20 percent
higher risk of miscarriage, and those who were exposed to smoke five
or more times per week had a 14 percent greater risk of losing a
pregnancy, compared to women not exposed to secondhand smoke in
childhood.
Nonsmokers who grew up with one smoker in the house, or were around
smoke less than five times per week, didn’t appear to have any
change in their miscarriage risk.
“Our findings support the enactment of stringent national smoke-free
laws and strict enforcement in China, and promotion of smoke-free
homes to protect children, as well as the need for campaigns to
change social norms of smoking and passive smoking,” the authors
wrote in Tobacco Control.
Shanshan Yang, a researcher at the Institute of Geriatrics at the
Chinese PLA General Hospital in Beijing, and colleagues analyzed
survey data for almost 20,000 women age 50 and older who live in
Guangzhou, China.
About 57 percent of the women had been exposed to secondhand smoke
during childhood, that is, before age 18.
The study had some limitations because the participants had to rely
on memories of childhood, and the researchers were not able to
assess how old the women were when they had their miscarriages or if
they were exposed to secondhand smoke during their pregnancies.
Lucy Popova, a researcher with the Georgia State University School
of Public Health in Atlanta, said there are considerable differences
in smoking habits between the U.S. and China.
“In the U.S., smoking rates between men and women are pretty close;
in China, very few women smoke while a majority of men smoke. There
are also other factors (indoor smoking policies and rules, social
norms) that might affect the rates of exposure to secondhand smoke
in childhood,” she said.
However, Popover said the potential biological mechanisms linking
secondhand smoke exposure and pregnancy loss would be the same no
matter where the mother lives.
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“So while a study might find different numbers of women with heavy
childhood exposure to secondhand smoke, the relationship between
exposure and pregnancy loss most likely will still be there,” she
said.
She pointed out that three other studies, conducted in the U.S. and
cited in the new report, have also shown that childhood secondhand
smoke exposure is linked with pregnancy loss.
Popova added that according to the U.S. Surgeon General, there are
no safe levels of exposure to secondhand smoke, even brief exposure
causes immediate harm, and the only way to protect nonsmokers from
the dangerous chemicals in secondhand smoke is to eliminate smoking
indoors.
The authors of the report didn’t respond to a request for comment.
SOURCE: http://bit.ly/2j1dieP Tobacco Control, online December 23,
2016.
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