Down syndrome (DS) is one of the most common genetic causes of intellectual disability among humans1 with an estimated prevalence of 14 per 10,000 live births in the US2 and an incidence of 1/800 live births worldwide3 and 1/600 live births in Egypt4. Congenital heart disease (CHD) is encountered in 40-63.5% of DS patients5 and is considered to be the most common cause of mortality among them6. Growth delay is one of the cardinal signs featuring children with DS3, characteristically the short stature7. However, about 30% of DS children suffer from obesity8. In general, around two-thirds of the mortality among the pediatric age group is related to nutritional deficiencies worldwide9. Inadequate nutrition and feeding problems are characteristically present in DS children10. In addition, the presence of other associated comorbidities such as CHDs increases the risk of malnutrition and failure to thrive among those children. On the other side, parental overprotection and the restricted pattern of their physical activity can aggravate their overweight11. Though there are some studies that addressed the nutritional status of DS children10, scanty studies had assessed it via a detailed micro- and macro-nutrient intake12 and fewer studies had assessed it among DS children with associated cardiopathies13 but up to our knowledge, those type of studies are almost absent among Egyptian children. Hence, this study aimed to evaluate the nutritional status of a group of Egyptian DS children through studying their dietary macro- and micronutrient intake and assessing their anthropometric measurements. Furthermore, we sought to study the effect of associated co-morbidities such as CHDs on the nutritional status of DS children by comparing those associated with congenital cardiopathies with their contemporaries without associated cardiopathies.
MATERIALS AND METHODS
This is a cross-sectional study that included 80 DS patients (48 males and 32 females). Based on the presence or absence of associated CHDs, the study population was classified into group I (with CHDs) and group II (without CHDs). All diagnoses were confirmed by transthoracic echocardiography. Infants below six months and children above five years of age, those with thyroid disorders and other associated anomalies that interfere with feeding, were excluded. This research protocol followed the principles of the Declaration of Helsinki and it was approved by the ethics committee of the Pediatric Department, Ain Shams University. Informed consent was obtained from the parents prior to participation in the study. Careful history was taken stressing on symptoms of cardiac disease, feeding difficulties, weight gain and anti-failure treatment given. In the 24 h dietary recall, the caregiver provided us with the approximate amount of every food item and beverage taken in the past 24 h (three main meals and snacks in between). In the food frequency questionnaire, the caregiver reported the quantities of food consumption based on household measures and the frequency of consumption of specific food items based on a multiple response grid in which the caregivers were asked to estimate how often a particular food or beverage was consumed. Categories used ranged from 'never' or 'less than six a week' to 'four per month.' Using our National Nutrition analysis software program and the Egyptian food composition tables, the nutrient value for each type and quantity of food item was analyzed and converted into calories, macro-nutrients (carbohydrates, proteins and fat) and micronutrients (iron, calcium, sodium, potassium, phosphorous, selenium, vitamins A, B1, B2, C and D). The values were referred to as a percentage from the recommended daily allowance (RDA) and dietary intake was considered unsafe (<50% RDA), unacceptable (50≤75% RDA), acceptable (75≤100% RDA), adequate (100≤120% RDA) or overconsumption (>120% RDA) based on the corresponding age and sex14,15.
Clinical examination was done for signs of heart failure, pulmonary hypertension and anthropometric measurements, which included the weight, height, occipitofrontal circumference and the left mid-upper arm circumflex. The weight was measured on a digital electronic scale. The scale was set at zero before the patient was placed on the scale and was checked weekly with known calibration weights. The height was measured by a tape measure permanently fixed to a wall or a door frame. The head was held firmly at the top of the board. The knees were flattened firmly to extend the legs entirely. The feet were together and flexed to a 90° angle with the child fully stretched. The child stood erect with the heels, buttocks and back of the head against the wall and the arms down and relaxed. The occipitofrontal circumference was measured using a non-stretchable plastic-coated tape that was placed superior to the supraorbital ridge adjusted around the occiput until the maximum circumference was obtained. The plane of the tape was the same on both sides of the head. Care was taken that the tape was placed evenly flat against the skull. Three measurements were obtained and the mean recorded. The left mid-upper arm circumference was measured while the patient is upright and the arm down in a fully relaxed position with the tape measure perpendicular to the long axis of the arm. Care was taken so that there was no pinching or gaping of the tape as it encircled the arm. Interpretation of weights and heights was made using the Z scores16. Three measurements were assessed; weight for age score (WAZ), height for age score (HAZ) and weight for height score (WHZ). According to the WHO global database on child growth and malnutrition17, a Z-score cut-off point of ≤-2SD defined WAZ as underweight, HAZ as stunting and WHZ as wasting and a cut-off point of >+2 SD defined high WHZ as overweight in children.
Statistical analysis: All statistical analyses were performed using the Statistical Package for Social Science (SPSS) version 22.0 for windows (SPSS Inc., Chicago, IL, USA). Numerical data was presented as Mean±standard deviation (SD). Non-numerical data was presented as frequency and percentage. The student's t-test was used for parametric quantitative data. A Chi-Square test was used to detect the relationship between two qualitative variables. The differences were considered significant if the probability (p) values were less than 0.05.
This study was conducted on 80 DS children. They were 48 (60%) boys and 32 (40%) girls. Their ages ranged from 7-57 months with a mean and SD of 21.66±12.01 months. Of the studied population, underweight, stunting and wasting were detected in 23.8, 45 and 11.3%, respectively, while 20% of them were overweight (Table 1). The studied population was divided into two groups; group I (38 children with associated CHDs) and group II (42 children without CHDs). Types of CHDs encountered in group I were atrioventricular septal defects (16, 42%), atrial septal defects (10,26.3%), ventricular septal defects (8, 21%) , combined aortic stenosis and patent ductus arteriosus (2, 5.5%), tetralogy of Fallot (1, 2.6%) and combined ventricular septal defect and patent ductus arteriosus (1, 2.6%). Group I children were significantly underweight, stunted and wasted when compared to group II (Table 2).
Table 3 shows the distribution of the dietary intake of energy, macro- and micro-nutrients in relation to the RDA among the studied population. Table 4 shows the percentage of food frequency among the studied population.
In terms of the RDA, the frequency of children who received an unsafe intake of carbohydrates, proteins, fat, calcium, vitamins A, B2 and D was significantly higher among the group I when compared to group II. Group I children showed significantly lower mean values of the daily intake of calories, macronutrients, minerals and vitamins B1 and D (Table 5 and 6).