Background/Purpose: Sugar-sweetened soft drink (SSSD) consumption is associated with weight gain, obesity, and increased risk of type 2 diabetes (T2DM) and cardiovascular disease (CVD). Previous studies have found that obesity may increase risk of rheumatoid arthritis (RA), while T2DM and CVD may share common pathways with RA development. We aimed to examine the relationship between SSSD intake and incident seropositive RA or incident seronegative RA in the Nurses’ Health Study (NHS) and Nurses’ Health Study II (NHS II), two large prospective cohort studies.

Methods: The NHS was established in 1976 and enrolled 121,701 US female registered nurses, ages 30–55 years. The NHS II was initiated in 1989 and comprised 116,430 female registered nurses, aged 25–42 years. RA cases were initially self-reported then confirmed by medical record review for 1987 ACR criteria. Seropositive RA was defined as positive RF or ACPA. SSSD consumption (colas and carbonated non-cola, but not low-calorie soft drinks) was assessed with a validated food frequency questionnaire (FFQ) completed every 4 years from 1980-2006 in NHS and 1991 – 2009 in NHS II. To reduce the measurement error and the potential reverse causality bias, we calculated average values from the preceding SSSD measures excluding the most recent dietary record. Time-varying Cox models were used to study the association between SSSD consumption and risk of seropositive and seronegative RA after adjusting for potential confounders. Pooled hazard ratio estimates from the two cohorts were calculated using a fixed effects model.

Results: During the 1,906,661 person-years of follow-up from 1980 to 2008 in NHS, 366 seropositive and 215 seronegative RA cases were confirmed, and during 1,524,433 person-years from 1991 to 2009 in NHS II, 197 seropositive and 105 seronegative RA cases were confirmed. In the pooled analysis after adjusting for age, smoking, alcohol, BMI, reproductive factors, physical activity, multivitamin use, , diet quality, and diabetes history, we found a significant positive association between SSSD and increased risk of seropositive RA (P for trend 0.005); women consuming ≥1 serving of SSSD per day had 1.71 (95% confidence interval 1.23-2.38) fold increased risk of developing seropositive RA compared to those consuming none or less than 1 serving per month (Table). However, we did not find any significant association between SSSD and seronegative RA in both cohorts.

Conclusion: Data from two large prospective cohort studies suggest that regular consumption of SSSD is associated with increased risk of developing seropositive RA in women.