MONDAY, Oct. 20, 2008 (HealthDay News) -- A rise in the number of low birth weight infants in the United States is a major reason why there's an increased rate of a common type of birthmark called infantile hemangioma, a new study finds.
"Hemangiomas are benign tumors composed of blood vessels. Our institution has seen a dramatic increase in the number of infants presenting for care with hemangiomas. We believe the results of this study provide an explanation for this emerging pediatric health issue," study author Dr. Beth Drolet, professor of dermatology and pediatrics at Medical College of Wisconsin and medical director of pediatric dermatology and birthmarks and vascular anomalies clinic at Children's Hospital of Wisconsin, said in a college news release.
Being female, white and premature were previously identified as risk factors for hemagniomas, but this study concluded that low birth weight is the most statistically significant risk factor.
"For every 1.1 pound decrease in birth weight, the risk of hemangioma increased by ninefold," Drolet said.
For this study, the researchers compared 420 children diagnosed with infantile hemangiomas and 353 children less than 2 years old diagnosed with other types of skin anomalies.
Drolet said the "link to low birth weight may explain why physicians believe more infants are developing hemangiomas. Based on low birth weight statistics, we estimate that the incidence of infantile hemangiomas has increased by 40 percent in the last 20 years."
The researchers noted that 8.2 percent of infants born in the United States in 2005 weighed less than 5.5 pounds, the highest percentage since 1968 and a higher rate than in most industrialized countries. One reason for the rise in low birth weights in the United States may be the 38 percent increase since 1990 of low birth weight in white, non-Hispanic infants.
The study appears in the November issue of the Journal of Pediatrics.
It's not known what actually causes hemangiomas, which may result in permanent scarring or other medical issues. There are no FDA-approved treatments for the condition.
The Hospital for Sick Children in Toronto has more about hemangiomas.