The imbalance may reflect society's gender biases about stature, and may have serious health consequences: girls whose growth failure is caused by an underlying disease may be overlooked, or experience unnecessary delays in receiving a proper diagnosis. The results may also suggest that short but healthy boys are more likely to be subjected to unnecessary medical evaluations.
"Growth failure is a very sensitive indicator of a child's overall health, and should be evaluated with equal care for both boys and girls," said Adda Grimberg, M.D., F.A.A.P., a pediatric endocrinologist at The Children's Hospital of Philadelphia who led the research. "Instead, these referral patterns may result from social pressures implying that short stature is a more significant problem in boys than girls."
The study appears in the February issue of the Journal of Pediatrics.
The researchers reviewed the charts of all 278 children referred to the Diagnostic and Research Growth Center at Children's Hospital in 2001 for new evaluations of short stature or poor growth. Because the definitions of short stature use percentage cutoffs, rather than actual heights, roughly equal numbers of boys and girls would be expected among the referrals. Instead, the research team found that boys outnumbered girls by 182 to 96, nearly a two-to-one margin. The gender discrepancies were more pronounced starting at age 9.
Although girls were less likely to be referred than boys, the girls' height deficits were greater than those for the boys in the study. In other words, although all the children in the study were short, the girls were significantly shorter than the boys when compared to both the general population and to predictions based on their parents' heights.
The most disturbing finding of the study, said Dr. Grimberg, was that 41 percent of the girls were found to have an underlying disease that made them short, compared to 15 percent of the boys. Conversely, 38 percent of the boys were within normal height ranges, compared to 20 percent of the girls.
"Because our study looked only at the referred children, and not at all the children who were not referred, the meaning of this difference in underlying disease is not clear," said Dr. Grimberg. "It may indicate that diseases are being missed in girls who are not referred, or that the percentage of boys with disease is 'diluted' by the large numbers of healthy boys are being referred, or a combination of the two. Either way, both sexes lose."
A broad variety of diseases may cause short stature -- among them, hormone deficiencies, Turner syndrome (a chromosome abnormality found only in females), and gastrointestinal conditions such as celiac disease or inflammatory bowel disease. "Many of these diseases have better outcomes when they are treated early, so a delayed diagnosis can have serious medical consequences," said Dr. Grimberg. For example, if celiac disease, an intolerance to proteins in wheat, goes untreated, it may raise a child's risk of other autoimmune diseases, such as type 1 diabetes or thyroiditis.
On the other hand, she added, overzealous evaluation of boys who are short but healthy may carry its own social costs: "Evaluating and treating healthy boys reinforces the idea that their height is a medical problem, which may hurt the boys' self-esteem." Another factor, added Dr. Grimberg, is the fact that boys are more likely than girls to receive growth hormone treatments, which may cost $20,000 to $30,000 per year. "When growth hormone is prescribed in the absence of disease, the treatment is cosmetic, not medical."
Dr. Grimberg concluded that further studies among the general population of children could reveal the extent to which short girls with underlying disease are not being diagnosed. She also said the study highlights the need for greater attention to proper growth monitoring in children.
The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases (part of the National Institutes of Health) and a grant from the University of Pennsylvania Trustee's Council. Dr. Grimberg's co-authors were Jessica Katz Kutikov, M.D., also of Children's Hospital, and Andrew J. Cucchiara, Ph.D., of the University of Pennsylvania School of Medicine. All three authors were from the Penn School of Medicine.
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