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correspondence

Indian Pediatr 2011;48: 653-654

Reply

N Arlappa

Email: arlappan@yahoo.com


As the author stated, we have not assessed the night blindness, the early symptom of VAD in 12-24 month children. Only four children (0.1%) had night blindness among 3932 children of 1-2+ years i.e. 12-36 months. However, the four children are in the age group of 24-36 months. Since we divided the pre-school children into two age groups, we analyzed and presented the data accordingly.

Similarly, we have not presented the prevalence of conjunctival xerosis as an independent indicator of VAD, since it is the subjective sign of VAD. Thus, we just presented the prevalence of night blindness and conjunctival xerosis, as these are also the manifestations of VAD. Similarly, we neither mentioned them as sole indicators of VAD nor related them with socioeconomic status in text. Our entire focus in this communication is only on Bitot’s spot, an objective sign of VAD and blood vitamin A levels.

The author rightly pointed out that the blood retinol would decrease if the particular children were suffering from acute/chronic infections. In the present study, we have not estimated the C-reactive proteins to indicate acute/chronic infections. However, de pee and Omar reported that populations with a high prevalence of infection are also more likely to suffer from VAD [1]. Even if we estimated the C-reactive proteins and deleted the subjects with high C-reactive proteins, the prevalence of sub-clinical VAD may not differed have lot as NNMB reported the prevalence of fever and acute respiratory infections as 2.7% and 1%, a respectively for the corresponding period [2]. Similarly, the diets of rural pre-school children were grossly deficit in terms of vitamin A, where the median intakes were deficient by 66-81% as against the RDA of 400 µg. The median vitamin A intakes of 84% of pre-school children were not even 50% of their RDA [3].

Serum retinol is the preferred indicator for population level assessment of VAD, and it is the best-established biochemical indicator of vitamin A status [1]. Similarly, estimation of Serum retinol from dried blood spot (DBS) is a validated and established method [4-6].

The DBS methodology has been validated before it was operationalized. We have had external validation of the DBS and the conventional methodologies with Craft Technologies, Wilson, USA and currently taking part in the external Vital EQ programme of CDC, Atlanta, USA. We don’t believe that the methodology underestimates vitamin A value. There are limited studies to cite the subclinical deficiency of vitamin A. Using the conventional method, the subclinical deficiency of vitamin A was reported to be 55% in school children 6-18 years from a middle-income residential school near Hyderabad [6].

This survey was carried out during the year 2003.As, we are asked to submit the manuscript as "Short communication" we condensed the original manuscript to meet the word count.

References

1. Sasika de pee, Omar D. Biochemical indicators of vitamin A deficiency: Serum retinol and serum retinol binding protein. J Nutr. 132:2895S-901S.

2. National Nutrition Monitoring Bureau (NNMB). Diet 2002; and nutritional status of rural population. Hyderabad, India: National Institute of Nutrition (Indian Council of Medical Research), Hyderabad, India. Report No.21: 2002.

3. National Nutrition Monitoring Bureau (NNMB). Diet and Nutritional Status of Population and Prevalence of Hypertension Among Adults in Rural areas. Hyderabad, India: National Institute of Nutrition, Indian Council of Medical Research; Report No.24: 2006.

4. Craft NE, Bulex J, Valdez C, Li Y, Solmons NW. Retinol concentration in capillary dried blood spots from healthy volunteers: Method validation. Am J Clin Nutr. 2000; 72:450-4.

5. Sivakumar B, Nair KM, Sreeramulu D, Suryanarayana P, Ravinder P, Shatrugna V, et al. Effect of micronutrient supplement on health and nutritional status of school children: Biochemical status. Nutrition. 2006;22:S15-S25.

6. Arlappa N, Balakrishna N, Laxmaiah A, Raghu P, Vikas Rao V, Madhavan Nair K, et al. Prevalence of vitamin A deficiency and its determinants among the rural pre-school children of Madhya Pradesh, India. Ann Hum Biol. 2011;38:131-6.
 

 

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