High Birth Weight Linked to Rheumatoid Arthritis
Doubled risk observed in women who weighed more than 4.5 kilograms at birth
WEDNESDAY, July 2 (HealthDay News) -- In women, a high birth weight is independently associated with an increased risk of developing rheumatoid arthritis, according to the results of a study published in the August issue of the Annals of the Rheumatic Diseases.
Lisa Mandl, M.D., of the Hospital for Special Surgery in New York City, and colleagues assessed data on 87,077 women enrolled in the Nurses' Health Study, and identified 619 new cases of rheumatoid arthritis which were diagnosed between 1976 and 2002.
After adjusting for age, the researchers found that women who weighed more than 4.54 kilograms at birth had a doubled risk of developing rheumatoid arthritis compared to women who weighed 3.2-3.85 kilograms at birth (relative risk, 2.1). After adjusting for potential confounders and risk factors, they observed no change in this association (RR, 2.0). They also observed no change in the association after limiting cases to those with rheumatoid factor positive disease (RR, 2.1).
"The biology underlying this association is speculative, and the relative importance of fetal nutrition versus genotype is unknown," the authors conclude. "However, if fetal nutrition has an impact on future risk of rheumatoid arthritis, this could be a potentially modifiable risk factor. Further study of our observation that high birth weight is associated with an increased risk of rheumatoid arthritis could provide insight into the pathogenesis of rheumatoid arthritis. These data also provide further evidence for the importance of fetal environment as a crucible for future adult diseases."