A study of more than 7,000 older Chinese women found a correlation between breastfeeding and a decreased chance of developing rheumatoid arthritis (RA) later in life.  

Published in the journal Rheumatology, the study included questionnaires completed by nearly 7,350 women 50 years old and older. The survey included questions designed to determine each participant's disease and lifestyle history, in addition to their breastfeeding and obstetric history, among other things. Besides being asked whether or not they had been diagnosed with RA, each woman was examined for joint swelling or tenderness that may have indicated the condition.

The majority of those involved reported having at least one live birth. Ninety-five percent of the women in this group breastfed for at least one month. The mean age of the participants' first pregnancy was 24 while the mean age for diagnosis of RA was 47.5.

After adjusting for confounding factors, the researchers determined that those women who had ever breastfed were about half as likely to go on to develop RA. Moreover, the study showed that the longer the women breastfed, the better their chances became in avoiding the condition.

"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 researchers wrote in a statement. "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."

The study is the first to detect a link between breastfeeding a decreased risk of RA in a Chinese population. In China, the scientists noted, breastfeeding was more common than many Western populations. Based on their findings, the researchers argue that research into the hormonal mechanisms behind RA is needed.