Effects of alcohol consumption and smoking on risk for RA: results from a Swedish prospective cohort study

Abstract

ObjectiveSeveral, but not all studies, have shown a dose-dependent inverse association with alcohol consumption and rheumatoid arthritis (RA), whereas smoking is an established risk factor for RA. We aimed to study the association between alcohol consumption and RA incidence and investigate a potential interaction between alcohol and smoking habits, regarding RA incidence.MethodsWe used a prospective cohort study, based on 41 068 participants with detailed assessment of alcohol intake, smoking and potential confounders at baseline in 1997. We ascertained a total of 577 incident cases of RA during a mean of 17.7 years of follow-up through linkage to nationwide and essentially complete databases. Multivariate Cox proportional hazards models were used to estimate HR with 95% CI. Interaction on the additive scale between alcohol and smoking was estimated by calculating the attributable proportion due to interaction (AP).ResultsOverall, alcohol consumption was associated with a 30% reduced incidence of RA (HR 0.69, 95% CI 0.55 to 0.86) with a dose–response relationship (p value for trend <0.001) which remained significant after stratification by age and smoking habits. The positive association between smoking and RA incidence was reduced with increasing alcohol consumption (p value for trend <0.001). A synergistic effect was observed between alcohol and smoking (AP 0.40, 95% CI 0.15 to 0.64), indicating that 40% of the cases among the double exposed are due to the interaction per se.ConclusionsOur findings suggest an inverse association between alcohol consumption and RA incidence, and a synergistic effect between alcohol and smoking.

Alcohol Consumption and Risk of Rheumatoid Arthritis among Chinese Adults: A Prospective Study

“…To date, of the 10 prospective studies exploring alcohol consumption and RA risk, the majority (6 of 10) found no significant association between alcohol consumption and RA risk [ 8 , 15 , 27 , 28 , 29 , 30 ], whereas others found that moderate alcohol consumption was associated with a lower risk of RA [ 7 , 25 , 31 , 32 ]. One nested case-control study that matched on sex, reported sex-specific analyses of the association between alcohol consumption and RA risk [ 15 ].…”

“…Furthermore, the relationship between alcohol consumption and RA risk may be affected by a variety of confounding factors. Whereas smoking and certain genetic factors have been identified as factors that affect the relationship between alcohol consumption and RA risk [ 6 , 7 ], it is possible that there are cultural or socioeconomic factors that can also impact the association between alcohol consumption and RA. Accounting for confounding factors has been inconsistent in previous prospective cohort studies.…”

“…Individuals may stop drinking due to the presence of certain underlying conditions, related to RA. Furthermore, there may be an interaction that has not been fully explored, such as between alcohol consumption and other factors (e.g., sex), that may affect the association between alcohol consumption and RA risk [ 6 , 7 , 8 ].…”

Association of Healthy Lifestyle Behaviors and the Risk of Developing Rheumatoid Arthritis Among Women

“…Our past NHS cohort studies, and those from other populations, have shown that smoking and obesity were strongly associated with an increased risk of RA, in particular seropositive RA (7–9). We also found that more hours of recreational physical activity and healthier eating, as measured by the Alternative Healthy Eating Index (AHEI), were associated with reduced RA risk (10).…”

“…We also found that more hours of recreational physical activity and healthier eating, as measured by the Alternative Healthy Eating Index (AHEI), were associated with reduced RA risk (10). Moderate alcohol consumption (5.0–9.9 gm/day versus none) was associated with a reduction in RA risk (9,11).…”