Heavy babies are twice as likely to develop rheumatoid arthritis when they are adults compared to individuals born with an average birth weight, according to a study published by researchers from Hospital for Special Surgery.
Published in 2003, a case-control study of roughly 400 individuals in Sweden identified an association between high birth weight and rheumatoid arthritis. To see if this association played out in a larger population, Dr. Mandl and colleagues turned to a study of 87,077 women in the Nurses’ Health Study. Through statistical analysis, the investigators discovered that a birthweight of greater than 4.54 kg doubled the risk that a person would develop rheumatoid arthritis as an adult compared with individuals who had an average birth weight.
“There may be a relationship between being born over 10 pounds and getting rheumatoid arthritis later in life,” said Lisa Mandl, M.D., MPH, who led the study and is an attending rheumatologist at Hospital for Special Surgery (HSS) in New York City.
“If there was some way that you could prevent someone from getting rheumatoid arthritis by making sure their birth weight wasn’t over 10 pounds, this is a risk factor that could be modifiable. You can’t change someone’s age. You can’t change someone’s gender, but potentially you could change someone’s birth weight. This is however only speculative at this point.”
Heavy birth weight – more than 10 pounds – has been clearly linked to chronic disease such as type 2 diabetes mellitus, coronary heart disease and hypertension.
How does it happen? Scientists suggest that developing fetus may react differently to stressors from outside that prompt it to gain weight.
“In utero, the fetus will react appropriately to different stressors. However, this may preprogram the fetus so that when it gets out into the world, this preprogramming is not helpful out in the ‘real world’,” said Dr. Mandl.
In other words, the fetal environment may be preprogramming people’s brains or endocrine systems to be maladapted in later life. Environmental toxins, many of which act as endocrine disruptors, may also play part. Many cosmetic ingredients, as well as plastic components and food additives, are known endocrine disruptors.
Dr. Mandl says that patients with rheumatoid arthritis are known to have a dysregulated hypothalamic-pituitary-adrenal (HPA) axis, and this axis may be affected in utero. The HPA axis is the body’s neuroendocrine system that involves the hypothalamus, pituitary and adrenal glands; this system is responsible for handling stress by regulating the production of cortisol, neurotransmitters and key hormones.
According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, about 2.1 million people, or between 0.5 and 1 percent of the U.S. adult population, have rheumatoid arthritis, an autoimmune disease that causes chronic inflammation of the joints. The disease is more common in women and has no cure, but can be managed in a way that allows individuals to live productive lives.