Understanding the prevalence of rickets in Bangladesh
Rickets has long been a significant public health challenge in Bangladesh, affecting the growth and development of many children. While often associated with vitamin D deficiency, research in Bangladesh suggests that insufficient dietary calcium is the primary etiological factor. The prevalence figures vary depending on the study, methodology, and region, but they consistently point to a notable public health concern. Understanding the specific context of Bangladesh is crucial for effective intervention, as traditional Western assumptions about the cause of rickets do not fully apply.
National and Regional Prevalence Statistics
Several studies and national surveys have attempted to quantify the burden of rickets in Bangladesh, revealing important insights into its scope and geographical distribution.
- 2008 National Survey: A large-scale national survey involving 20,000 children aged 1–15 found a prevalence rate of 0.99% for visible rachitic deformities. This study included 16,000 rural and 4,000 urban children across all socioeconomic groups and divisions of the country.
- Helen Keller International Surveys: Earlier reports from Helen Keller International showed a prevalence of 0.26% among 21,571 children in 2000 and 0.12% among 10,005 children in 2004, suggesting some improvements over that period.
- High-Prevalence Areas: Certain regions exhibit significantly higher rates. For example, a more detailed survey in the Chittagong division found that 8.7% of children had at least one clinical sign of rickets, and the Cox's Bazar subdistrict was noted for its particularly high prevalence.
- Urban vs. Rural Differences: While national surveys offer a broad picture, some studies have highlighted differences. Urban slum children, for instance, face higher risks due to congested living conditions, limited sunlight exposure, and poor socio-economic status.
Primary Etiology: Calcium vs. Vitamin D Deficiency
Decades of research in Bangladesh have challenged the Western-centric view that rickets is solely a vitamin D deficiency disease. In a sun-rich country like Bangladesh, studies have shown that vitamin D levels are often not the primary problem, especially in children presenting after infancy.
- Dietary Shifts: A significant change in the Bangladeshi food system, moving towards high-rice diets with less variation, has led to a widespread decrease in dietary calcium intake. Sources like dairy products, small fish with bones, and calcium-rich vegetables have become less prominent in the average diet.
- Sufficient Vitamin D: Many studies found that children with rickets in Bangladesh had sufficient vitamin D levels, suggesting another underlying cause. Calcium deficiency stimulates the body to increase vitamin D synthesis, meaning serum vitamin D levels may appear normal or even elevated.
- Calcium as the Curative Factor: Clinical studies have shown that treatment with calcium supplements alone (350–1,000 mg elemental calcium daily) is curative for rickets in this population. This strongly supports the hypothesis that calcium deficiency is the key etiological factor in Bangladeshi nutritional rickets.
Key Risk Factors Beyond Nutrition
While nutrition is central, other socioeconomic and environmental factors contribute to the prevalence of rickets in Bangladesh.
- Socioeconomic Status: Lower family income and parental education levels are strongly associated with higher rates of rickets. Poor families often lack access to diverse, nutrient-rich foods.
- Family Size: Children from larger families face a higher risk, likely due to a greater division of available resources, including food.
- Exclusive Breastfeeding: Prolonged and exclusive breastfeeding, especially beyond six months, can pose a risk if the mother's own nutritional status is poor, as breast milk contains very little vitamin D.
- Gender: Studies have shown that male children are more likely to develop rachitic deformities than girls.
- Urban Slums: Residence in urban slum areas, with their characteristically congested and unhygienic environments, is another key risk factor identified by research.
Prevention and Treatment Strategies
Effective prevention and treatment of rickets in Bangladesh require a multi-faceted approach addressing both the nutritional causes and underlying socio-environmental factors.
- Nutritional Education: Community-based programs using drama and other educational tools have been used to shift dietary habits towards calcium-rich foods like small fish with bones, leafy greens, and sesame seeds.
- Food Fortification: The government and partner organizations have been involved in food fortification initiatives, though scaling these programs and ensuring quality control remain challenges. Recommendations include fortifying staple foods with both calcium and vitamin D.
- Supplementation: For high-risk groups, including infants and pregnant women, supplementation with calcium and vitamin D is a key intervention. However, coverage and implementation require improvement.
- Medical Treatment: The clinical approach to treatment in Bangladesh often involves a combination of vitamin D and calcium, as research shows this combination to be more effective than either alone. For severe deformities, surgical correction may be necessary.
Comparison of Rickets Etiology
| Feature | Rickets in Developed Countries (Typical) | Rickets in Bangladesh (Typical) |
|---|---|---|
| Primary Cause | Primarily Vitamin D deficiency | Primarily dietary Calcium deficiency |
| Age of Onset | Often within the first year of life | Typically presents after the first year |
| Key Dietary Deficit | Low intake of fortified dairy, insufficient sun exposure | Low intake of calcium-rich foods like dairy, small fish, leafy greens |
| Associated Factors | Use of sunscreen, reduced outdoor activity | Poor parental education, low income, large family size |
| Lab Findings | Low serum 25-hydroxyvitamin D | Elevated serum 1,25-dihydroxyvitamin D and PTH, often normal 25-hydroxyvitamin D |
| Treatment Focus | Vitamin D supplementation | Calcium and Vitamin D supplementation |
Conclusion
The prevalence of rickets in Bangladesh, while fluctuating, remains a significant public health issue. Research highlights that dietary calcium deficiency, rather than vitamin D deficiency alone, is the principal cause of nutritional rickets in the country. This finding has reshaped prevention and treatment strategies, emphasizing nutritional education, food system interventions, and appropriate supplementation. While national prevalence statistics provide a baseline, regional hotspots and socioeconomic disparities underscore the need for targeted, community-based interventions to reduce the burden of this debilitating but preventable disease. Continued collaboration between the government, NGOs, and the academic sector is vital to combat malnutrition and ensure the healthy development of children across Bangladesh. For more detailed clinical guidelines, health professionals can consult resources such as the International Centre for Diarrhoeal Disease and Research, Bangladesh (icddr,b).
