Abstract: Background: Rickets is a common health problem in Egypt and leads to frequent morbidities. There is insufficient information about its prevalence and risk factors. Objective: Studying the prevalence and clinical characteristics of rickets in the age group (6-36 months) in New Damietta city using a clinical score with x-ray as a gold standard. Materials and Methods: About 300 children, aged from 3-36 months, selected from the pediatric outpatient clinic at Damietta University hospital by systematic random sample (every 3rd child) on a day work (3 days/week) in the period from April, 2011 till December, 2012. Each child enrolled in the study was submitted to history taking, thorough clinical examination and radiographic examination. The studied cases were classified into two groups according to the presence of rickets by x-ray: Rachitic group and non-rachitic group. Results: Rickets was present radiologically in 35 cases (11.7%) out of 300 children. Rachitic group was younger than the non-rachitic group with the mean age (9.9±4.3, 16.5±7.4) respectively, p = 0.00. Most of rachitic children had spent little time under the sun and living in overcrowded houses. Most rachitic children had motor developmental delay (74.3%) with high statistical significant difference, p = 0.00. The most frequent sign was rachitic rosaries 74.3%, followed by thickened epiphysis and delayed closure of fontanel 62.9 and 60%, respectively. The most sensitive clinical signs were Harrison’s sulcus and parietal bossing 100%. Conclusion: Rickets is a major health problem in Damietta governorate, as its prevalence is 11.7%, especially with young age, overcrowding and low social class.
INTRODUCTION
Rickets is failure of mineralization of growing bone which can occur only before fusion of the epiphyses1. Nutritional rickets is distinct from other types of rickets in that it is merely caused by a simple deficiency in vitamins and nutrition2. Nutritional rickets should be viewed as having a spectrum of pathogenic mechanisms, which lie between 3 milestones3, classic vitamin D deficiency and pure calcium deficiency4. In between these 2 are those with marginal to low vitamin D stores and a diet deficient in calcium or high in phytates5.
Accurate global information on the prevalence of rickets is necessary so as to be able to document high risk groups and to determine changes associated with efforts to reduce the risk of rickets in these at-risk groups and communities6.
Understandably, much of recent literature on the prevalence of nutritional rickets has come from industrialized countries experiencing a resurgence of clinic presentations with rickets4. However, the greatest burden of disease world-wide appears to be in Africa, the Middle East and Asia7. In Egypt, rickets is multifactorial and rachitic children living in Egypt have some distinct characteristics8.
Rickets is characterized by bony deformity and stunted growth5, which is frequently encountered problem in our local community. There is a lack of researches, which studied the prevalence of rickets in Egypt. In order to estimate the magnitude of rickets in our local community and its relation to various epidemiological factors, the present study was conducted to find out the prevalence of rickets among infants and children aged from 3-36 months, attending the pediatric outpatient clinic at Damietta University Hospital.
MATERIALS AND METHODS
The present cross sectional study consisted of 300 children, aged 6-36 months, chosen from outpatient clinic, at Al-Azhar University Hospital (New Damietta) during the period from April, 2011 till December, 2012 on a day study (3 days/week). Patients with major congenital anomalies, chromosomal abnormalities, chronic liver disease, chronic renal disease or receiving anticonvulsant therapy were excluded from the study.
Each child enrolled in the study was submitted to detailed history, thorough clinical examination, anthropometric measurements and ratios. A standardized questionnaire was also used to gather social and demographic information. Each child was subjected to clinical scoring of rickets through the method of Opie et al.9 (Table 1) which included 7 clinical signs. Each child with any clinical sign of Opie et al.9 score is submitted to radiological examination through x-ray of both hands, which is considered as a "Gold standard" for diagnosing rackets. Rickets is considered radiological if these features are present: Broadening and cupping of the epiphyseal ends increased joint space, frying of the epiphyseal ends and zone of preparatory calcification10.
The statistical analysis was performed using an IBM compatible computer and statistics for SPSS 16.0 statistical package. For qualitative data, frequency and percent distributions were calculated and for comparison between groups, the chi square (χ2) test was used. For quantitative data, mean and standard deviation (SD) were calculated and for comparison between two groups, the independent samples t test was used. Sensitivity was calculated from the equation (true positive/true positive+false negative). Specificity was calculated from the equation (true negative/true negative+false positive). For interpretation of results, p<0.05 was considered significant11.
RESULTS
Prevalence of definite (radiological) rickets in studied children was 11.7%. The mean age was (9.9±4.3 to 16.5±7.5 years) for rachitic and non-rachitic children, respectively (p = 0.00). Advanced birth order is a significant risk factor in rachitic children (Table 2).
| Table 1: | Guidelines for diagnosis of rickets according to Opie et al.9 method |
| 0: No rickets, 1-3: Suspicion of rickets | |
| Table 2: | Age and birth order of studied cases |
| *Significant | |
| Table 3: | Rachitic scoring of the studied cases according to Opie et al.9 method (n = 300) |
| Table 4: | Relative frequency of clinical diagnostic signs of rickets among rachitic group |
| Table 5: | Sensitivity and specificity of Opie et al.9 scoring in relation to the x-ray |
According to Opie et al.9 method, 253 children (84.3%) had score 0 (no rickets), 21 children (7%) had score 1-3 (suspicious rickets), 17 children (5.7%) had score 4-6 (mild rickets) and 9 children (3.0%) had score 6+ (moderate to severe rickets) as shown in Table 3.
Table 4 shows relative frequency of clinical diagnostic signs of rickets among rachitic group, the most frequent sign was rachitic rosaries 74.3%, followed by thickened epiphysis and delayed closure of fontanel (62.9 and 60%), respectively. The marfan’s sign was found in 34.3% of cases. The most sensitive clinical signs were Harrison’s sulcus and parietal bossing 100% (Table 5).
DISCUSSION
Vitamin D deficiency and associated rickets are re-emerging as a major public health problem in some developed and developing countries12. Middle East is a region that registers some of the highest rates of rickets worldwide, this is in large part explained by limited sun exposure, cultural practices and by dark skin color and low calcium intake rather than vitamin D deficiency in several countries in Africa13. A recent global consensus on prevention and management of nutritional rickets recommended that implementation of international rickets prevention programs, including supplementation and food fortification is urgently required14. Thus, it is necessary to evaluate the prevalence of rickets in our community.
In the present study, rickets was reported radiologically in 35 cases out of 300 cases representing 11.7%. There are wide geographical variations in the frequency of rickets among children worldwide. There are no recent available data regarding the prevalence of rickets in Egypt. These results indicate that rickets continues to be a major local health problem, this it should be put into consideration for early intervention as well as stressing on prophylaxis against rickets through early vitamin D supplementation. Results of the present study were in agreement with Najada et al.15 who reported that 47 infants (10.6%) out of the 443 were found to have nutritional rickets. On the other hand, this prevalence is slightly higher than that reported by Kabir et al.16 and Thacher et al.17 who reported that, in some places, nutritional rickets is merely reported sporadically, while in other areas, up to 9% of the childhood population is clinically affected. On the other hand, the prevalence of the present study was lower than that recorded in Qatar18, as the prevalence of rickets was estimated as 23.9%. It must be emphasized that, there has been a lack of consistency globally in how rickets is diagnosed. Consequently, it has been difficult to compare rates of rickets longitudinally and from one country to another. It is hypothesized that clinical diagnostic criteria alone lead to over diagnosis of rickets19. Another explanation of those differences may attribute to difference of cultural practices and feeding habits between different places20.
The rachitic group was younger than the non-rachitic group, which was expected as the prolongation of exclusive breast feeding until the age of 1 year without vitamin D supplementation is an important factor leading to the development of rickets in the rapid growth period of infancy21. Most of the rachitic cases had advanced birth order, which may explained by the fact that vitamin D deficiency in the pregnant and lactating mother predisposes to the development of rickets in the breastfed infant, which increase with repeated pregnancies22.
The most frequent sign was rachitic rosaries 74.3%, followed by thickened epiphysis and delayed closure of fontanel (62.9 and 60%), respectively. In a retrospective study at Saudi Arabia included 283 infants diagnosed with nutritional rickets were between 6 and 14 months of age, the most common physical signs of rickets were wide wrist (29%), rachitic rosaries (28%) and frontal bossing (16%)21. The rachitic rosaries are among the early manifestations of nutritional rickets23. Thus, it is likely to be found in all cases presenting with rickets. Thickened epiphysis and rachitic rosaries are caused by disrupted endochondral ossification and mineralization at the epiphyses with accumulation of excessive disorganized hypertrophic (referring to zone of hypertrophy) cartilage the metaphysis widen and appear clinically as swollen joint. As this is the usual pathophysiology of rickets and it is expected to become more common manifestations1.
Regarding the Opie et al.9 scoring in relation to the x-ray for diagnosis of rickets, it was found that the most sensitive scores were 4 or more with the sensitivity (100%), this make this test valid to diagnose mild to severe rickets. The present study is a unique one in estimation of sensitivity and specificity of different clinical signs and different Opie scores in relation to radiological diagnosis of rickets.
In the present study, simple methods are used for evaluation of a very common local health problem without the need for extensive investigations, which might be troublesome for patients with low socioeconomic levels. The validity of Opie et al.9 score is as a reliable tool, allowing physician for early diagnosis of rickets with subsequent early treatment.
CONCLUSION
Rickets continue to be a major health problem in Damietta governorate as its prevalence among infants was 11.7%. Young age, advanced birth order, overcrowding and low social class appears to be the most important risk factors. The most frequent clinical signs are rachitic rosaries and thickened epiphysis. Finally, both clinical signs and Opie score grading had a considerable values of sensitivity and specificity especially in moderate to severe cases, which makes clinical diagnosis of rickets a useful methods for rickets assessment.