While breathing in secondhand smoke is known to harm kids' lungs, new research suggests that children whose parents smoked are also more prone to developing rheumatoid arthritis later in life.
"Our findings give more depth and gravity to the negative health consequences of smoking in relation to [rheumatoid arthritis], one of the most common autoimmune diseases," said lead author Dr. Kazuki Yoshida, of the division of rheumatology, inflammation and immunity at Brigham and Women's Hospital, in Boston.
Rheumatoid arthritis is an inflammatory disease characterized by arthritis in multiple joints. Several genetic and environmental factors contribute to rheumatoid arthritis risk, and personal smoking is the most well-established environmental risk factor. But research into the link between secondhand smoke and rheumatoid arthritis risk has been limited.
To learn more, the researchers analyzed data from nearly 91,000 U.S. women in a long-term health study.
Those with childhood exposure to parents' secondhand smoke had a 75% higher risk of rheumatoid arthritis, and the risk was even higher among those who became smokers themselves.
A mother's smoking during pregnancy and years lived with smokers after age 18 were not significantly linked with rheumatoid arthritis risk, according to the report published Aug. 18 in the journal Arthritis & Rheumatology.
"This relationship between childhood parental smoking and adult-onset [rheumatoid arthritis] may go beyond rheumatology," Yoshida said in a hospital news release. "Future studies should investigate whether childhood exposure to inhalants may predispose individuals to general autoimmunity later in life."
The researchers noted that their study was limited because it did not include men. They plan to continue their research with both men and women.