RESEARCH - Breast feeding, but not use of oral contraceptives, is associated with a reduced risk of RA

June 2, 2009

Ann Rheum Dis. 2009 Apr;68(4):526-30. Epub 2008 May 13.

Breast feeding, but not use of oral contraceptives, is associated with

a reduced risk of rheumatoid arthritis.

Pikwer M, Bergström U, Nilsson JA, sson L, Berglund G, Turesson C.

Department of Rheumatology, Malmö University Hospital, 205 02 Malmö, Sweden.

OBJECTIVE: To determine whether breast feeding or the use of oral

contraceptives (OCs) affects the future risk of rheumatoid arthritis

(RA) in a community-based prospective cohort.

METHODS: A community-based health survey (18 326 women) was linked to

regional and national registers, and incident cases of RA were

identified. All women with a diagnosis of RA after inclusion in the

health survey (n = 136) and four female controls for every case, who

were alive and free from RA when the index person was given a

diagnosis of RA, were included in a case-control study. Data on

lifestyle factors at baseline were derived from a self-administered

questionnaire. Potential predictors were examined in logistic

regression models.

RESULTS: 136 women with incident RA were compared with 544 age-matched

controls. A longer history of breast feeding was associated with a

reduced risk of RA (OR 0.46 (95% CI 0.24 to 0.91) for women who had

breast fed for >/=13 months and OR 0.74 (95% CI 0.45 to 1.20) for

those who had breast fed for 1-12 months, compared with those who had

never breast fed). The protective effect of longer breast feeding

remained significant after adjustment for smoking and level of

education in multivariate models, and point estimates were protective

also when the analyses were restricted to parous women. Neither parity

nor OC use had any significant effect on the risk of RA.

CONCLUSION: In this study, long-term breast feeding, but not OC use,

was associated with a significant reduction in the risk of RA.

PMID: 18477739

Not an MD

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