In a new study of over 7,000 older women published in the journal Rheumatology, breastfeeding was shown to be associated with a lower risk of rheumatoid arthritis (RA).
Specifically, it showed that women who had breastfed their children were around half as likely to have RA, compared to women who had never breastfed.
The beneficial effects of breastfeeding for both mother and child are widely known, but previous studies on the association between breastfeeding and rheumatoid arthritis have been mixed. This cross-sectional study was to assess the relationship between RA, breastfeeding in a population of older women from South China, where cultural habits differ from those in the West, where most previous studies were conducted.
Professor Peymane Adab and colleagues used data from 7,349 women aged 50 years or older. Questionnaires were used to ascertain sociodemographic history, disease and lifestyle history, obstetric history, and breastfeeding history.
The women were also asked whether they had been diagnosed with RA, and were examined by a trained nurse to check their joints for any swelling or tenderness that may indicate RA.
The majority of women had had at least one live birth, and of these, over 95 percent had breastfed their children for at least one month. The average age for first pregnancy was 24 years, and the mean age for diagnosis of RA was 47.5 years.
Among women who had at least one live birth, and after adjusting for potential confounding factors, those who had ever breastfed were around half as likely to have RA.
Furthermore, there was a statistically significant trend of decreasing risk of RA with increasing duration of breastfeeding.
This is the first study to demonstrate a link between breastfeeding and lower risk of RA in a Chinese population, where breastfeeding was common practice and more prevalent than in many Western populations.
This study was based on a large population sample in the community, rather than being drawn from secondary care. As data were part of a larger study, the researchers were able to adjust for many potential confounding factors.
Women who took part in this study were born in the 1940s and 1950s, before China’s one-child policy was introduced in the late 1970s, and at a time when breastfeeding was more prevalent.
The consequent decline in breastfeeding supports the need for prospective studies to examine whether there will be a higher incidence of RA in the future, according to researchers.
More importantly, replication of the association between breastfeeding and lower risk of RA in a different population reinforces the need for further research to understand the hormonal mechanisms involved in the onset of RA, the researchers added.