RA is an inflammatory disease with arthritis at multiple joints and is linked to morbidity and mortality outcomes. Smoking has long been implicated as a key RA risk factor.

Sparks and colleagues used data from NHSII questionnaires collected biennially between 1989 and 2017 from 90,923 women aged 35-52 years. Researchers used participant medical records to confirm incident RA and serostatus.

Statistical modeling was used to assess the direct effect of each passive smoking exposure on RA risk, as well as to control for other factors such as personal smoking.

A 75-percent higher risk of RA was found in individuals who experienced passive childhood exposure to parental smoking. This risk increased in participants who themselves became active smokers. Over the median follow-up of 27.7 years, 532 women in the cohort developed confirmed incident RA cases — the majority of which were seropositive.

Maternal smoking during pregnancy and years lived with smokers beyond age 18 showed no significant link with incident RA risk.

The study is limited by the absence of men. The team intends to continue with longitudinal studies that encompass both men and women, as to provide critical insight into other rheumatoid conditions and even 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 lead and co-corresponding author Kazuki Yoshida, MD, ScD, of the 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.”

Source: Medindia