Anthropometric Measures and Risk of Rheumatoid Arthritis in the French E3N Cohort Study

We aimed to assess the relationships between anthropometric measures and risk of rheumatoid arthritis (RA). The E3N cohort included 98,995 women (aged 40-65 years at the recruitment) who completed mailed questionnaires on reproductive factors, lifestyle, and health-related information, including anthropometric measures, every 2-3 years. Cox proportional hazards regression models with age as the time scale and adjusted on known RA risk factors were used to estimate hazard ratios (HRs) and 95% confidence intervals for the risk of incident RA in the overall population (n = 78,452) and after stratification on smoking exposure. Incident RA diagnosis was validated in 698 women. Abdominal obesity (waist circumference >88 cm) was associated with RA (HR = 1.2 (1.0-1.5)), independent of BMI; whereas obesity, defined as BMI >= 30 kg/m(2), was marginally associated with RA (HR = 1.26 (0.9-1.5), ptrend = 0.0559). Taking lean body shape (BS) as reference, medium BS at puberty (HR = 1.3 (1.0-1.7)) and medium-large BS at perimenopausal period (HR = 1.5 (1.1-1.9)) were associated with the risk of RA among never-smoker women, independent of BMI. Regarding BS trajectory, taking constantly lean BS as reference, constantly large BS from puberty to perimenopause was associated with RA among non-smokers (HR = 2.10 (1.2-3.6)), independent of BMI.