Smoking and exposure to secondhand smoke is tied to infertility in women and early menopause, according to a new study.
Compared to women who never smoked and those exposed to the least secondhand smoke, women who smoked or were exposed to the most secondhand smoke were more likely to have problems getting pregnant and more likely to enter menopause before age 50, researchers found.
Andrew Hyland of the Roswell Park Cancer Institute in Buffalo, New York, who led the research, said earlier studies had linked smoking to reproductive issues in women, but few had looked at links between secondhand smoke and infertility and early menopause.
“The literature really wasn’t clear – particularly with secondhand smoke,” Hyland told Reuters Health.
Hyland and colleagues analyzed data on 88,732 U.S. women who enrolled in the Women’s Health Initiative Observational Study between 1993 and 1998, when they were between the ages of 50 and 79.
Based on questionnaires the women completed at the start, about 15 percent met the criteria for infertility, which is the inability to get pregnant for at least a year. About 45 percent also met the criteria for early menopause, which occurs before age 50.
Compared to women who never smoked, researchers found that those who reported being active smokers at some point in their lives were 14 percent more likely to have infertility and 26 percent more likely to enter menopause early.
Women who smoked the most reported entering menopause about two years earlier than women who didn’t smoke, the researchers report in the journal.
Women who never smoked but were exposed to the most secondhand smoke were 18 percent more likely to have problems getting pregnant and to enter menopause at an early age, compared to women who never smoked and were exposed to the least amount of secondhand smoke.
Children exposed to tobacco smoke at home are up to three times more likely to have attention deficit hyperactive disorder (ADHD) than unexposed kids, according to a new study from Spain.
The association was stronger for kids with one or more hours of secondhand smoke exposure every day, the authors found. And the results held when researchers accounted for parents’ mental health and other factors.
“We showed a significant and substantial dose–response association between (secondhand smoke) exposure in the home and a higher frequency of global mental problems,” the authors write in Tobacco Control.
According to the Centers for Disease Control and Prevention, two of every five children in the U.S. are exposed to secondhand smoke regularly.
Alicia Padron of the University of Miami Miller School of Medicine in Florida and colleagues in Spain analyzed data from the 2011 to 2012 Spanish National Health Interview Survey, in which parents of 2,357 children ages four to 12 reported the amount of time their children were exposed to secondhand smoke every day.
The parents also filled out questionnaires designed to evaluate their children’s mental health. According to the results, about eight percent of the kids had a probable mental disorder.
About seven percent of the kids were exposed to secondhand smoke for less than one hour per day, and 4.5 percent were exposed for an hour or more each day.
After taking the parent’s mental health, family structure and socioeconomic status into consideration, children who were exposed to secondhand smoke for less than one hour per day were 50 percent more likely to have some mental disorder compared to kids not exposed at all.
And children who were habitually exposed to secondhand smoke for an hour or more each day were close to three times more likely to have a mental disorder.
In addition, kids exposed to it for less than one hour per day were twice as likely to have ADHD as kids who weren’t exposed, and children exposed for an hour or more on a daily basis were over three times more likely to have ADHD.
“The association between secondhand smoke and global mental problems was mostly due to the impact of secondhand smoke on the attention-deficit and hyperactivity disorder,” the authors wrote.
The study looks at a single point in time and cannot prove that secondhand smoke exposure causes mental health problems, the study team cautions.
Frank Bandiera, a researcher with the University of Texas Health Science Center in Houston who was not involved in the study, liked that the researchers “controlled for parents’ mental health in the new study because that could be a confounder.”
But, he added that the study might be limited because, although the questionnaires are thought to be valid, the mental disorders were not actually diagnosed by physicians.
“We’re not sure if it’s causal or not,” Bandiera told Reuters Health. “I think (the research) is still in the early stages and the findings are inconclusive.”
He also said that since secondhand hand smoke has been related to a lot of physical diseases, parents should avoid smoking around their kids.
“We need to sort it out more, so we’re not sure yet, but just as a precaution, I don’t think parents should smoke at home – they should keep their kids away from secondhand smoke,” Bandiera said.
Lucy Popova, from the Center for Tobacco Control Research and Education at the University of California, San Francisco, said there is a lot of evidence about the harms of secondhand smoke on physical wellbeing.
“But research on effects of secondhand smoke on mental health have been really just emerging and this study really contributes to this growing body of evidence that exposure to secondhand smoke in children might be responsible for cognitive and behavioral problems,” she said.
Popova, who wasn’t involved in the study, said no amount of secondhand smoke is safe – any exposure is bad.
“So parents should not expose their children – the best thing to do is quit,” she said. “And this will not only not expose their children to the secondhand smoke, but will also let them enjoy their life with their children longer.