In the study, the longer the breast feeding period, the lower the mother’s risk of developing rheumatoid arthritis (RA) in later life. Comparable use of oral contraceptives (OCs) or hormone replacement therapy (HRT) did not show a significant effect on the risk of developing RA.
Lead researcher Dr Mitra Keshavarz, of Malmö Hospital University, Sweden, said of the study, “Whilst other studies suggest that hormonal factors play a part in the development of RA, and we know that pregnancy can result in an improvement in RA symptoms, we wanted to investigate the long term effect of breast-feeding. This study specifically highlights the potential of naturally-induced hormones in protecting individuals from developing RA in the future.”
The study found that breast feeding for 13 or more months was associated with a reduced risk of developing RA (odds ratio 0.46; confidence interval 95 percent 0.24-0.91). For women with between one and twelve months history of breast feeding, the odds ratio was 0.74, with a 95 percent confidence interval (0.45-1.20) compared directly to those who had never breast fed.
The data was taken from a community-based health study incorporating information from the Swedish National Hospital Discharge and the National Cause of Death Register between 1991 and 1996, comparing health information from 136 women who later developed RA with that of 544 controls. Information on the use of OCs, HRT and other lifestyle factors was derived from a self-administered questionnaire and analysed by a team from Malmö University Hospital, Sweden.
All females with RA utilised in the case control group of the study were diagnosed according to the 1987 American College of Rheumatology (ACR) criteria for RA. Individuals were matched with four female controls for every case. Controls were identified as those alive and free from diagnosed RA when the index individual was diagnosed with RA.
MEDICA.de; Source: European League Against Rheumatism