Long-term dietary quality and risk of developing rheumatoid arthritis in women

Abstract

Objectives To evaluate the association between long-term dietary quality, measured by the 2010 Alternative Healthy Eating Index (AHEI-2010), and risk of rheumatoid arthritis in women. Methods We prospectively followed 76,597 women in the Nurses’ Health Study aged 30–55 years and 93,392 women in the Nurses’ Health Study II aged 25–42 years at baseline and free from rheumatoid arthritis or other connective tissue diseases. The lifestyle, environmental exposure and anthropometric information were collected at baseline and updated biennially. Cumulative follow-up rates were more than 90% for both cohorts. The primary outcome was rheumatoid arthritis alone with two subtypes of the disease: seropositive and seronegative rheumatoid arthritis. RESULTS During 3,678,104 person-years, 1,007 RA cases were confirmed. In the multivariable-adjusted model, long-term adherence to healthy eating patterns was marginally associated with reduced RA risk. To assess potential effect modification by age at diagnosis, we stratified by age. Among women ≤ 55 years old, better quality diet was associated with lower RA risk (HRQ4 vs Q1: 0.67; 95% CI: 0.51 to 0.88; p trend: 0.002), but no significant association was found for women >55 years (p interaction: 0.005). When stratifying by serostatus, the inverse association among those aged ≤55 years was strongest for seropositive RA (HRQ4 vs Q1: 0.60; 95% CI: 0.42 to 0.86; p-trend: 0.003). Conclusion A healthier diet was associated with a reduced risk of RA occurring at 55 years of age or younger, particularly seropositive RA.

Inflammatory dietary pattern and risk of developing rheumatoid arthritis in women

“…FFQs assessed dietary intake over the previous year, ranking frequency of each food/beverage on a scale from never or <1/month to ≥6 servings/day [6, 7]. FFQs were administered in 1984, 1986, and every four years until 2010 in the NHS and 1991 and every four years until 2011 in the NHSII.…”

“…We investigated EDIP and RA risk, overall and stratified by serologic status and by pre-specified age groups. We previously found differences in metabolic/dietary RA risk factors related to age of onset ≤55 or >55 years old [5, 6, 12]. We used that age cutpoint as an a priori hypothesis due to different RA clinical phenotypes based on age of onset and as an approximation of completion of menopausal transition.…”

“…We previously reported that a healthier dietary pattern was associated with lower RA risk, particularly seropositive RA risk for women aged ≤55 years [6]. However, the dietary quality measure investigated was developed for other chronic diseases [6]. …”

Genetic and environmental risk factors for rheumatoid arthritis

“…These include lower intake of vitamin D and antioxidants, and higher intake of sugar, sodium, red meats, protein and iron, with increased risk for RA (76–82). In addition, in a large-scale prospective study of nurses in the United States, a generally healthy diet has been associated with a decreased risk for seropositive RA, although specific dietary factors were not identified (83). Furthermore, a finding that has been relatively consistent across many studies is that a higher intake of fish as well as omega-3 fatty acids have been consistently linked to decreased risk for RA across a number of studies, including studies where dietary data was collected prior to incident RA (84–88).…”

“…In addition, healthy lifestyles including lower body mass index and healthier diets that are defined differently across studies but in general are low in sugar and animal fats, and high in fruits, whole grains and vegetables, have been associated with decreased risk for RA (83, 88, 92). In one study of 55 autoantibody positive individuals without IA at baseline, high body mass and ongoing smoking were associated with the highest risk for developing future RA (93), suggesting that these factors may act as additional risks for progression from autoimmunity to classifiable disease.…”