Dietary intake of vitamin d during adolescence and risk of adult onset systemic lupus erythematosus and rheumatoid arthritis

Hiraki LT et al. – The authors did not find associations between adolescent dietary vitamin D intake and adult RA or SLE risk among women in Nurses' Health Study (NHS) and NHSII suggesting that other time periods during the life–course should be studied.

Methods

• Food frequency questionnaires (FFQs) concerning high school diet completed by 73,629 NHS (1986) and 45,544 NHSII participants (1998) were used to calculate nutrient intakes during adolescence.
• Incident RA and SLE cases prior to 2006 NHS and 2007 NHSII, were confirmed by medical record review.
• Cox proportional hazards models calculated relative risks (RR) and 95% CI of incident RA and SLE according to quintile cutoffs of vitamin D intake.
• Age– and calorie–adjusted and multivariable–(including sun–exposure factors) adjusted analyses were completed.
• Random effects models were used to meta–analyze estimates of association from the two cohorts.

Results

• Incident RA was confirmed in 652 NHS and 148 NHSII participants, and SLE in 122 NHS and 54 NHSII participants over a mean follow–up of 351 (NHS) and 209 months (NHSII).
• Age– and calorie–adjusted and multivariable–adjusted models did not show significant associations between adolescent vitamin D intake and risk of adult onset RA or SLE.

[more...]