To examine the association between alcohol consumption and markers of inflammation in preclinical rheumatoid arthritis (RA).
We studied 174 incident RA cases with stored blood collected 1-16 years prior to RA symptoms (preclinical RA), from the Nurses' Health Study. Alcohol intake was measured using a detailed food frequency questionnaire administered every 4 years, prior to blood collection. Plasma was tested for biomarkers of inflammation, including high-sensitivity C-reactive protein (hsCRP), anti-cyclic citrullinated peptide (anti-CCP) antibodies, interleukin-6 (IL-6), and soluble tumor necrosis factor receptor II (sTNFRII). Generalized additive models were used to identify structure in the relationship between each biomarker and cumulative average alcohol intake. Then general linear models were used for multivariable adjusted analyses with appropriate polynomial terms of alcohol consumption.
After controlling for age at blood collection, smoking, parity and duration of breastfeeding, menopausal status, oral contraceptive use, body mass index, and the time between blood collection and RA onset, we found that the daily alcohol consumption showed a U-shaped association with IL-6 levels in RA patients, prior to symptoms. We also found an inverse relationship between alcohol intake and sTNFRII levels, but no associations with hsCRP or anti-CCP levels.
These results demonstrate an association between alcohol consumption and markers of inflammation, including IL-6 and sTNFRII, in RA patients, prior to the occurrence of symptoms.