Rationale: The Third National Health and Nutrition Examination Survey (NHANES III) reference is currently recommended for interpreting spirometry results, but it is limited by the lack of subjects younger than 8 years and does not continuously model spirometry across all ages. Objectives: By collating pediatric data from other large-population surveys, we have investigated ways of developing reference ranges that more accurately describe the relationship between spirometric lung function and height and age within the pediatric age range, and allow a seamless transition to adulthood. Methods: Data were obtained from four surveys and included 3,598 subjects aged 4-80 years. The original analyses were sex specific and limited to non-Hispanic white subjects. An extension of the LMS (lambda, mu, sigma) method, widely used to construct growth reference charts, was applied. Measurements and Main Results: The extended models have four important advantages over the original NHANES III analysis as follows: (1) they extend the reference data down to 4 years of age, (2) they incorporate the relationship between height and age in a way that is biologically plausible, (3) they provide smoothly changing curves to describe the transition between childhood and adulthood, and (4) they highlight the fact that the range of normal values is highly dependent on age. Conclusions:The modeling technique provides an elegant solution to a complex and longstanding problem. Furthermore, it provides a biologically plausible and statistically robust means of developing continuous reference ranges from early childhood to old age. These dynamic models provide a platform from which future studies can be developed to continue to improve the accuracy of reference data for pulmonary function tests.

Growth references are useful in monitoring a child's growth, which is an essential part of child care. The aim of this paper was to provide updated growth references for Polish school-aged children and adolescents and show the prevalence of overweight and obesity among them. Growth references for height, weight, and body mass index (BMI) were constructed with the lambda, mu, sigma (LMS) method using data from a recent, large, population-representative sample of school-aged children and adolescents in Poland (n = 17,573). The prevalence of overweight and obesity according to the International Obesity Taskforce definition was determined with the use of LMSGrowth software. Updated growth references for Polish school-aged children and adolescents were compared with Polish growth references from the 1980s, the Warsaw 1996–1999 reference, German, and 2000 CDC references. A positive secular trend in height was observed in children and adolescents from 7 to 15 years of age. A significant shift of the upper tail of the BMI distribution occurred, especially in Polish boys at younger ages. The prevalence of overweight or obesity was 18.7% and 14.1% in school-aged boys and girls, respectively. The presented height, weight, and BMI references are based on a current, nationally representative sample of Polish children and adolescents without known disorders affecting growth. Changes in the body size of children and adolescents over the last three decades suggest an influence of the changing economical situation on anthropometric indices.

In this article, we describe an extension to the egen functions zanthro() and zbmicat() (Vidmar et al., 2004, Stata Journal 4: 50-55). All functionality of the original version remains unchanged. In the 2004 version of zanthro(), z scores could be generated using the 2000 U.S. Centers for Disease Control and Prevention Growth Reference and the British 1990 Growth Reference. More recent growth references are now available. For measurement-forage charts, age can now be adjusted for gestational age. The zbmicat() function previously categorized children according to body mass index (weight/height 2) as normal weight, overweight, or obese. "Normal weight" is now split into normal weight and three grades of thinness. Finally, this updated version uses cubic rather than linear interpolation to calculate the values of L, M, and S for the child's decimal age between successive ages (or length/height for weight-for-length/height charts).

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The study provides BP references for oscillmetric device, based on a current, nationally representative sample of normal-weight Polish children and adolescents. The normative values of BP were compared taking into consideration the height and BMI differences, the pubertal spurt, the methods of BP measurement and percentile construction.