ABSTRACT
In this paper, various stochastic ordering properties of a parametric family of weighted distributions and the associated mixture model are developed. The effect of stochastic variation of the output random variable with respect to the parameter and/or the underlying random variable is specifically investigated. Special weighted distributions are considered to scrutinize the consistency as well as the usefulness of the results. Stochastic comparisons of coherent systems made of identical but dependent components are made and also a result for comparison of Shannon entropies of weighted distributions is developed.
ABSTRACT
OBJECTIVE: To determine the relationship between cord blood 25-hydroxyvitamin D [25 (OH) D] concentrations and the subsequent risk of acute lower respiratory tract infection (ALRI) in the first 2 years of life. PATIENTS AND METHODS: Cord blood from 206 newborns was tested for 25 (OH) D. Medical records covering the first 2 years of life were reviewed, and the diagnosis of ALRI was recorded. RESULTS: Sixty-two (30.1%) infants developed ALRI in their first 2 years of life, of whom 49 (79%) infants had bronchiolitis and 13 (21%) infants had pneumonia. Concentrations of 25 (OH) D were lower in infants who developed ALRI compared with those did not (p < 0.0001). Vitamin D deficiency was associated with increased risk of ALRI (p = 0.000). CONCLUSION: Low cord blood 25 (OH) D levels are associated with increased risk of ALRI in the first 2 years of life.
Subject(s)
Fetal Blood/metabolism , Respiratory Tract Infections/blood , Vitamin D/analogs & derivatives , Acute Disease , Age Factors , Child, Preschool , Female , Gestational Age , Humans , Infant , Infant, Newborn , Logistic Models , Male , Maternal Age , Prospective Studies , Respiratory Tract Infections/epidemiology , Risk Factors , Saudi Arabia/epidemiology , Vitamin D/bloodABSTRACT
AIM OF STUDY: To standardize the growth parameters for Saudi children aged 3-18 years living at high altitude and to investigate the appropriateness of using the National Center for Ilealth Statistics (NC(IIS) growth standards for the assessment of children's growth at this high attitude area. SUBJECTS AND METHODS: The present study follows a cross-sectional study design. A total of 13,580 native Saudi children (7,193 boys and 6,387 girls) aged 3-18 years living in Abha City (Elevation: 3,100 meters above sea level) constituted the study's sample. All chronically and acutely ill children were excluded. The data regarding the children were obtained from the well-baby clinics at primary health care centers and nurseries, as well as primary, intermediate and secondary schools. The percentiles for the weight and height and the body mass index (BMI) were calculated separately for the boys and the girls using one-year intervals. BMI values above the 95th and below the 5th percentiles were considered as diagnostic for obesity and underweight, respectively. RESULTS: Median values of weight and height for Saudi's children (both boys and girls) were lower than their corresponding values for children in the USA. Median values of the BMI for the Saudi's boys were almost identical to those of the USA's NCHS median values through all ages that were studied. On the other hand, the median values for the BMI were almost identical for the Saudi's and USA's girls aged 3-9 years. However, after the age of 9 years the differences in the median values for the BMI were increased progressively due to the higher values for the Saudi's girls. CONCLUSIONS: The use of the NCHS growth standards is not appropriate for the assessment of growth of children that live in the high altitude area of Abha and further studies are needed to determine the exact impact of high altitude on the growth patterns in children.
Subject(s)
Adolescent Development/physiology , Altitude , Child Development/physiology , Obesity/diagnosis , Adolescent , Age Factors , Anthropometry/methods , Body Height , Body Mass Index , Body Weight , Child , Child, Preschool , Cross-Sectional Studies , Female , Humans , Male , Physical Examination/standards , Reference Standards , Saudi ArabiaABSTRACT
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