Ahmad A. Al Omar

Consanguinity and major genetic disorders in Saudi children: a community-based cross- sectional study

BACKGROUND AND OBJECTIVES There is a high rate of consanguinity in Saudi Arabia; however, information on its relationship with genetic disorders is limited. The objective of this cross-sectional study was to explore the role of consanguinity in genetic disorders. SUBJECTS AND METHODS The study sample was determined by a multistage probability random sampling procedure. Consanguinity status was obtained during household visits. Primary care physicians performed a history and physical examination of all children and adolescents younger than 19 years, and all cases of genetic diseases were recorded. The chi-square test was used to compare proportions. RESULTS During the two-year study period (2004–2005), 11 554 of 11 874 (97%) mothers answered the question on consanguinity, and 6470 of 11 554 (56%) were consanguineous. There was no significant association between first-cousin consanguinity and Down syndrome (P=.55). Similarly, there was no significant association with either sickle cell disease (P=.97) or glucose-6-phosphate dehydrogenase deficiency (P=.67) for first-cousin consanguinity. A borderline statistical significance was found for major congenital malformations (P=.05). However, the most significant association with first-cousin consanguinity was congenital heart disease (CHD) (P=.01). Finally, no significant association was found for type 1 diabetes mellitus (P=.92). For all types of consanguinity, similar trends of association were found, with a definite statistically significant association only with CHD (P=.003). CONCLUSION The data suggest a significant role of parental consanguinity in CHD. However, a relationship between consanguinity and other genetic diseases could not be established. The effect of consanguinity on genetic diseases is not uniform and this should be taken into consideration in genetic counseling.

Comparison of the 2005 growth charts for Saudi children and adolescents to the 2000 CDC growth charts.

BACKGROUND AND OBJECTIVES The 2000 CDC growth charts for the United States, a revision of the National Center for Health Statistics/World Health Organization (NCHS/WHO) growth charts, were released in 2002 to replace the NCHS/WHO charts. We evaluated the differences between the CDC growth charts and the Saudi 2005 reference to determine the implications of using the 2000 CDC growth charts in Saudi children and adolescents. SUBJECTS AND METHODS The Saudi reference was based on a cross-sectional representative sample of the Saudi population of healthy children and adolescents from birth to 19 years of age. Measurements of the length/stature, weight and head circumference were performed according to expert recommendations. The CDC charts from birth to 20 years were based on a cross-sectional representative national sample from five sources collected between 1963 and 1994. The data from the CDC study including the 3rd, 5th, 50th, 95th, and 97th percentiles were plotted against the corresponding percentiles on the Saudi charts for the weight for age, height for age, weight for height for children from 0 to 36 months and weight for age, stature for age and body mass index for children 2 to 19 years of age. RESULTS There were major differences between the two growth charts. The main findings were the upward shift of the lower percentiles of the CDC curves and the overlap or downward shift of the upper percentiles, especially for weight, weight for height, and BMI. CONCLUSION The use of the 2000 CDC growth charts for Saudi children and adolescents increases the prevalence of undernutrition, stunting, and wasting, potentially leading to unnecessary referrals, investigations and parental anxiety. The increased prevalence of overweight and obesity is alarming and needs further investigation.

Regional variation in prevalence of overweight and obesity in Saudi children and adolescents

Background/Aims: There are limited data on regional variation of overweight and obesity in the Kingdom of Saudi Arabia. Therefore, the aim of this report is to explore the magnitude of these variation in order to focus preventive programs to regional needs. Setting and Design: Community-based multistage random sample of representative cohort from each region. Patients and Methods: the study sample was cross-sectional, representative of healthy children and adolescents from 2 to 17 years of age. Body mass index (BMI) was calculated according to the formula (weight/height2). The 2000 center for disease control reference was used for the calculation of prevalence of overweight and obesity defined as the proportion of children and adolescents whose BMI for age was above 85th and 95th percentiles respectively, for Northern, Southwestern and Central regions of the Kingdom. Chi-square test was used to assess the difference in prevalence between regions and a P value of <0.05 was considered significant. Results: The sample size was 3525, 3413 and 4174 from 2-17 years of age in the Central, Southwestern and Northern regions respectively. The overall prevalence of overweight was 21%, 13.4% and 20.1%, that of obesity was 9.3%, 6% and 9.1% in the Central, Southwestern and Northern regions respectively indicating a significantly-lower prevalence in the Southwestern compared to other regions (P<0.0001). Conclusions: This report revealed significant regional variations important to consider in planning preventive and therapeutic programs tailored to the needs of each region.

Blood pressure standards for Saudi children and adolescents.

BACKGROUND AND OBJECTIVES Blood pressure levels may vary in children because of genetic, ethnic and socioeconomic factors. To date, there have been no large national studies in Saudi Arabia on blood pressure in children.Therefore, we sought to establish representative blood pressure reference centiles for Saudi Arabian children and adolescents. SUBJECTS AND METHODS We selected a sample of children and adolescents aged from birth to 18 years by multi-stage probability sampling of the Saudi population. The selected sample represented Saudi children from the whole country. Data were collected through a house-to-house survey of all selected households in all 13 regions in the country. Data were analyzed to study the distribution pattern of systolic (SBP) and diastolic blood pressure (DBP) and to develop reference values. The 90th percentile of SBP and DBP values for each age were compared with values from a Turkish and an American study. RESULTS A total of 16 226 Saudi children and adolescents from birth to 18 years were studied. Blood pressure rose steadily with age in both boys and girls. The average annual increase in SBP was 1.66 mm Hg for boys and 1.44 mm Hg for girls. The average annual increase in DBP was 0.83 mm Hg for boys and 0.77 mm Hg for girls. DBP rose sharply in boys at the age of 18 years. Values for the 90th percentile of both SBP and DBP varied in Saudi children from their Turkish and American counterparts for all age groups. CONCLUSION Blood pressure values in this study differed from those from other studies in developing countries and in the United States, indicating that comparison across studies is difficult and from that every population should use their own normal standards to define measured blood pressure levels in children.

The prevalence of neurological disorders in Saudi children: a community-based study.

There are limited data on the pattern and prevalence of pediatric chronic neurologic conditions in the region. Therefore, the objective of this study was to establish the prevalence of these disorders in the Kingdom of Saudi Arabia. A multistage probability sampling design was used to select a random sample of Saudi households representative of the Saudi population. A total of 45 682 Saudi children were screened. Of these children, 313 had a chronic major neurologic disorder indicating a prevalence of 68.5 per 10 000 children, which was the highest among all chronic diseases in children. Mental retardation and cerebral palsy were the most common neurologic disorders among Saudi children with a prevalence rate of 26.3/10 000 and 23.4/10 000, respectively. The finding that major neurologic disorders are the most common pediatric chronic disorders in the Kingdom of Saudi Arabia indicates that priority should be given to research and education as well as health care planning.

Pattern of sex differences in growth of Saudi children and adolescents.

BACKGROUND Although variations in growth between boys and girls have been reported, detailed descriptions according to age and growth parameters are not available. OBJECTIVE The goal of this study was to determine the pattern and magnitude of differences in growth between boys and girls according to age that justify separate growth charts. METHODS The data set was based on a cross-sectional representative sample of the Saudi population of healthy children and adolescents from birth to 19 years of age. Body measurements (length, height, weight, and head circumference) were performed according to standard recommendations; body mass index was also determined for each subject. The difference in growth between boys and girls was assessed based on z scores and percentiles (5th, 50th, and 95th) of growth parameters using 2 age groups (0-3 years and 2-19 years). The significance of the difference between boys and girls for any growth parameter was tested by ANCOVA. RESULTS A total of 35,279 children and adolescents from birth to 19 years of age satisfied the criteria for growth measurements. There were 17,880 boys and 17,399 girls; all were Saudi nationals. The Saudi boys were generally taller and heavier than girls up to approximately 7 to 10 years of age. Thereafter, girls generally were taller and heavier than boys from 10 to 14-15 years of age. After that, boys again were taller and heavier. Similar variations were observed for body mass index and head circumference. The difference between boys and girls for each growth parameter was highly significant (P < 0.001). CONCLUSIONS Based on analysis of these Saudi children and adolescents, the difference in growth between boys and girls was not uniform but depended on age. However, the pattern was remarkably consistent across all growth parameters and appears to reflect the timing of maturation between boys and girls.

The implications of using the world health organization child growth standards in Saudi Arabia

The World Health Organization (WHO) has recently released a new child growth standard that it recommends for international use. The objective of this study was to demonstrate the differences and the implications of using the WHO child growth standards on Saudi children. The Saudi reference was based on a cross-sectional sample of the population of healthy children and adolescents from birth to 19 years of age. The WHO sample was selected from privileged households in some countries. Percentile construction and smoothing were performed using the lambda, mu, sigma (LMS) methodology in both studies. The data from the WHO study including the 3rd, 5th, 50th, 95th, and 97th percentiles were plotted on the Saudi charts for weight for age, height for age, and weight for height. There are major differences between the 2 studies. Compared with the Saudi charts, the WHO lower percentiles (third and fifth) are shifted upward, whereas the upper percentiles are shifted downward. The use of the WHO standards in Saudi Arabia and possibly in other countries of similar socioeconomic status increases the prevalence of undernutrition, stunting, and wasting, potentially leading to unnecessary referrals, investigations, and parental anxiety. Clear guidelines should be developed by WHO experts to guide clinicians in developing countries in the proper use of the standards not only to determine prevalence but also in the daily clinical assessment of the growth of children

Liver size in Saudi children and adolescents.

BACKGROUND/AIM To examine the liver size in Saudi children and adolescents. METHODS A large sample of children was selected from the general population by multistage random probability sampling for the assessment of physical growth. A random subsample of children-newborns to 18 years old-was taken from this larger sample for this study. Liver size below the costal margin and liver span along the midclavicular line were determined by physicians. Data were analyzed using SPSS software and medians and standard deviations were calculated. RESULTS Between 2004 and 2005, 18 112 healthy children up to 18 years of age were examined. All were term and appropriate for gestational age. There were 9 130 boys and 8 982 girls, yielding a nearly 1:1 male to female ratio. The maximum palpable liver size below the costal margin was 2.4 cm. The median and + 2 SD liver span at birth were 4 and 6.9 cm, respectively. There was no difference in the liver span between boys and girls of up to 60 months of age. Thereafter, a difference could be seen increasing with age, with girls having smaller liver spans than boys. CONCLUSION This manuscript reports the liver size in Saudi children and adolescents. The data should help physicians in the interpretation of liver size determined by physical examination of children and adolescents.

The LMS and Z scale growth reference for Saudi school-age children and adolescents.

Background/Aim: To establish L, M, and S parameters and z score reference for the assessment of nutrition and growth of Saudi school-age children and adolescents. Subjects and Methods: Data from the original cross-sectional study were reanalyzed. The L, M, and S parameters and z scores were calculated for weight, height and body mass index for school-age children and adolescents. Results: A total of 19,299 subjects from 5 to 18 years of age were included. All were Saudi nationals and 9,827 (50.9%) were boys. The L M S parameters and z scores for weight for age, height for age, and BMI for age for boys and girls are presented in detailed tables across the age of commonly used z scores (+3, +2, +1, 0, -1, -2, -3). Graphs corresponding to the same parameters (weight, height, and BMI) showing the main z scores across all ages from 5 to 18 years are illustrated. Conclusion: This report provides the first reference for nutritional status and growth of Saudi school-age children and adolescents. This tool is essential for more accurate assessment of growth and nutrition in various clinical conditions and research.