Brigham and Women’s Hospital and Harvard Medical School, USA
Bing Lu has completed his MD from China and PhD in Biostatistics from the University of North Carolina at Chapel Hill. He is an Assistant Professor of Medicine at Harvard Medical School and is an Associate Professor (Adjunct) at Albert Medical School of Brown University. He has published more than 90 papers in reputed journals and has been serving as an Editorial Board Member of several international journals.
The objective of this study was to examine the relationship between being overweight or obese and developing rheumatoid arthritis (RA) in two large prospective cohorts, the nurses’ health study (NHS 1984-2014) and nurses’ health study II (NHSII 1991-2013). We followed 76,597 women aged 30-55 years enrolled in NHS and 93,392 women aged 25-42 years in NHSII at baseline and free from RA or other connective tissue diseases, who provided lifestyle, environmental exposure and anthropometric information through biennial questionnaires. We used the pooled data from two large cohorts and assessed the association between time-varying body mass index (BMI) in WHO categories of normal, overweight and obese (18.5≤25, 25.0≤0, ≥30.0 kg/m2) and incident RA meeting the 1987 American College of Rheumatology (ACR) criteria. We estimated HRs for overall RA and serologic subtypes with Cox regression models adjusted for potential confounders. During 4,832,369 person-years of follow-up, we validated 1220 incident cases of RA. There was a significant trend toward increased risk of all RA among overweight and obese women [HR (95% CI): 1.23 (1.08, 1.40) and 1.36 (1.17, 1.58), p for trend=0.001]. Among RA women aged 55 years or younger, this association appeared stronger [HR 1.48 (1.20, 1.81) for overweight and 1.76 (1.42, 2.20) for obese women (p trend <0.001)]. In conclusion, risks of RA were elevated among overweight and obese women, particularly among young or middle aged women.