Relative Risk

The article on injuries in a large, urban school district, provides valuable information regarding school accidents and injuries. Indeed the authors have carried out the most extensive analysis to date of the nature of school injuries and they have undertaken some interesting analyses in an attempt to understand the influence of a variety of school factors on accident rates. However some of the data they report, specifically data in their tables 4, 5, and 6, may cause readers to misunderstand the concept of relative risk.</jats:p

Lactose Breath Hydrogen Test

The recent article by Barr et al, "Mucosal Function and Breath Hydrogen Excretion: Comparative Studies in the Clinical Evaluation of Children with Nonspecific Abdominal Complaints" (Pediatrics 68:526, 1981), provided some useful data on the utility of the lactose breath hydrogen test (LBHT) for the diagnosis of lactase deficiency in children with nonspecific abdominal complaints. However, two comments are in order. 1. Because new diagnostic tests must be compared to a "gold standard" test for evaluative purposes, the meat of this article resides in table 3, in which a LBHT is compared with lactase activity demonstrated on biopsy material.</jats:p

Hypercholesterolemia Screening Questioned

To the Editor.— The allure of screening has reached epic proportions in a medical world that apparently has difficulty finding enough to keep itself intellectually and gainfully occupied. A case in point, is the recent article by Steiner et al,1 entitled "Hypercholesterolemia in Adolescence: Effectiveness of Screening Strategies based on Risk Factors." Despite the fact that the authors clearly demonstrate that high-risk status as defined by either the 1985 or 1989 American Academy of Pediatrics (AAP) criteria (or both) is not predictive of high cholesterol levels in adolescents (Table 3 notes positive predictive values ranging from .09 to .11), the authors conclude with the startling statement that "Until all the related controversies surrounding cholesterol testing are more clearly understood, all adolescents must be screened to adequately identify those with hypercholesterolemia."</jats:p