RESUMO
LMS is a general monitoring method for fitting smooth reference centile curves in medical sciences. They provide the distribution of a measurement as it changes according to some covariates like age or time. This method describes the distribution of changes by three parameters; Mean, Coefficient of variation and Cox-Box power [skewness]. Applying maximum penalized likelihood and spline function, the three curves are estimated and fitted and optimum smoothness is expressed by three curves. This study was conducted to provide the percentiles of lipid profile of Iranian children and adolescents by LMS. Smoothed reference centile curves of four groups of lipids [triglycerides, total-LDL- and HDL-cholesterol] were developed from the data of 4824 Iranian school students, aged 6-18 years, living in six cities [Tabriz, Rasht, Gorgan, Mashad, Yazd and Tehran-Firouzkouh] in Iran. Demographic and laboratory data were taken from the national study of the surveillance and prevention of non-communicable diseases from childhood [CASPIAN Study]. After data management, data of 4824 students were included in the statistical analysis, which was conducted by the modified LMS method proposed by Cole. The curves were developed with a degree of freedom of four to ten with some tools such as deviance, Q tests, and detrended Q-Q plot were used for monitoring goodness of fit models. All tools confirmed the model, and the LMS method was used as an appropriate method in smoothing reference centile. This method revealed the distributing features of variables serving as an objective tool to determine their relative importance. This study showed that the triglycerides level is higher and HDL-C level is lower in Iranian children and adolescents than their counterparts in Western countries. Future studies with larger sample size and with higher density at the end points and equal distribution of measurements in changing limits of covariates would hopefully reach more precise findings
RESUMO
Screening of students' health problems could lead to timely prevention and control of many health disorders. This study aimed to determine the nationwide prevalence of common disorders through school health screening program in Iran. This cross-sectional national screening program was conducted in 2007-2008 among first-and third-grade-students in primary schools, first-grade-students of middle and high schools of all provinces in Iran. Data were obtained from 3,124,021 [81.9%] students reported from the whole country classified into 33 geographical zones. Of total students studied, 12.48% had weight abnormalities, 4.77% had visual disorders, 3.95% had head lice, 2.24% had behavioral disorders, and 0.6% had hearing disorders. Among students studied, 0.4%, 0.7%, 0.4% and0.8% had endocrine, psychological, neurological and genitourinary disorders, respectively. In addition, 2.1%, 1.9%, 1.8%, 0.8%0.5%, 0.3% and 0.3% of students had ear, nose and pharynx disorder, anemia, skin and hair, cardiac, abdominal, vertebral and lung problems, respectively. In elementary schools, 57.6% of first-grade-students with at least one disorder were managed in outpatient settings and 6% of them were hospitalized for more investigation. Among third-grade-students of elementary schools, these values corresponded to 13.2% and 1.1%, respectively. Among first grade students of middle and high schools, this prevalence was 58.5% and 44.6% and 1.2% and 0.3% of students were hospitalized for more investigation. This integrated school screening program revealed a considerably high prevalence of health disorders among school students. These results might help health policy makers to design future health promoting programs