using the data from the nurses’ study, researchers were able to confirm incident ra and serostatus among participants and then use statistical modelling to ascertain the risk of the three types of passive smoking while controlling for other factors, such as the impact of personal smoking. over the 27.7-year median follow-up period of the study, 532 women were diagnosed with incident ra, 352 of which were seropositive, or positive for ra autoantibodies. while passive smoking during childhood led to the 75 per cent increase in risk of ra, the other two categories — maternal smoking during pregnancy and living with smokers after the age of 18 — did not exhibit the same significant association with ra.
the study was limited by the absence of men from its subject pool, something researchers intend to address with subsequent longitudinal research. they hope further study will help paint a clearer picture of other rheumatoid conditions and even shed more light on other autoimmune diseases.
“our findings give more depth and gravity to the negative health consequences of smoking in relation to ra, one of the most common autoimmune diseases,” said kazuki yoshida, lead and co-corresponding author of the study at brigham’s division of rheumatology, inflammation and immunity. “this relationship between childhood parental smoking and adult-onset ra may go beyond rheumatology — future studies should investigate whether childhood exposure to inhalants may predispose individuals to general autoimmunity later in life.”