We read the recently published articles on vitamin D deficiency in the journal [1,2], and wish to raise certain related issues. We believe that the true burden of vitamin D deficiency/insufficiency and its associations cannot be estimated unless a standard consensus definition is used. At least, for the studies having important public health implications, the adherence to the "consensus definitions" is desirable, as the prevalence of the problem varies with the definition used. The cut-offs used for defining deficiency/insufficiency by Singh, et al [1] are based on a decade-old study. Almost all the current guidelines state that vitamin D3 level <12 ng/ml should be considered deficient, 12-20 ng/mL as insufficient and >20 ng/mL as sufficient [3,4]. The nutrition-based studies have shown that a level of 20 ng/mL would meet the needs of 97.5% of the population [3,4]. Singh, et al [1] used a cutoff of 11-32 ng/mL for defining insufficiency, which includes many babies with sufficient levels [1]. Hence, their conclusions should be interpreted carefully. It would have been helpful if the results were shown as odds ratio (Odds of having neonatal sepsis in presence of vitamin D deficiency), and the dose relationship of vitamin D levels with sepsis could be presented. It will help in better risk-stratification and will have therapeutic implications too.

Conversely, the consensus definition of neonatal sepsis is lacking until now and the definitions that are currently used in various studies vary greatly [5]. This extreme degree of variability makes the interpretation difficult. In this study [1], the criteria used for defining various categories of neonatal sepsis are extremely confusing and differ greatly from the somewhat "agreeable definition" of neonatal sepsis. We acknowledge that this variability may be due to the lack of consensus on the best definition of neonatal sepsis.

Vitamin D deficiency is reported to be quite prevalent in India, and there is a recognized need for prophylactic supplementation during infancy. However, as highlighted by a recent survey [6], the practice of prescribing routine vitamin D supplementation varies greatly. Therefore, there is an urgent need for the researchers to use a single, scientific, and consensus-based definition for defining vitamin D deficiency, so that clear evidence-base is provided for guidelines on routine vitamin D supplementation in infancy.

1. Singh P, Chaudhari V. Association of early-onset sepsis and vitamin D deficiency in term neonates. Indian Pediatr. 2020;57:232-4.

2. Kumar RK, Das H, Girish SV, Nevilebasappa A. Prevalence of vitamin D deficiency among newborns. Indian Pediatr. 2020;57:258-9.

3. Randev S, Kumar P, Guglani V. Vitamin D Supple-mentation in childhood - A review of guidelines. Indian J Pediatr. 2018;85:194-201.

4. Khadilkar A, Khadilkar V, Chinnappa J, et al. Prevention and Treatment of Vitamin D and Calcium Deficiency in Children and Adolescents: Indian Academy of Pediatrics (IAP) Guidelines. Indian Pediatr. 2017;54:567-73.

5. McGovern M, Giannoni E, Kuester H, et al. Challenges in developing a consensus definition of neonatal sepsis. Pediatr Res. 2020;88:14-26.　

6. Dabas A, Bharadwaj M, Shah D, Gupta P. Online survey of vitamin D supplementation practices in children and adolescents.　Indian Pediatr. 2020;57:749-50.

We thank the readers for taking interest in our study [1]. As rightly pointed out, levels for vitamin D deficiency have been a source of contention. The International Association of Endo-crinology defined a vitamin D level of 21-29 ng/mL as insufficiency and <20 ng/mL as deficiency in adults [2]. However, the levels of vitamin D insufficiency and deficiency are not clearly defined and the discussion about the prevalence of vitamin D deficiency is ongoing [3]. The cut-off levels used in our study were based on a study in neonates [4], as we did not have Indian guidelines in place at that time. IAP consensus statement on vitamin D [5] was published after we completed our study. Indian studies can now be done taking these values as guidelines for our population. Association of dose relationship of severity of vitamin D deficiency with sepsis and odds ratio will definitely provide information on risk stratification, and other researchers are encouraged to address this.

Sepsis in neonates still needs definitions that can be followed practically by neonatal centers. The definition used by us was the most practical in our setting, as it has taken clinical criteria and laboratory investigations as parameters in a scoring system for defining sepsis [6]. Non availability of micro ESR in our setup prevented us from using neonatal sepsis definitions which incorporate it in the scoring system [7].

1. Singh P, Chaudhari V. Association of early-onset sepsis and vitamin D deficiency in term neonates. Indian Pediatr. 2020;57:232-4.

2. Holick MF, Binkley NC, Bischoff-Ferrari HA, et al. Endocrine Society. Evaluation, Treatment, and Prevention of Vitamin D Deficiency: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2011;96:1911-30.　

3. Shah D, Gupta P. Vitamin D deficiency: Is the pandemic for real? Indian J Community Med. 2015;40:215-7.

4. Cetinkaya M, Cekmez F, Buyukkale G, Erener-Ercan T, Demir F. Lower vitamin D levels are associated with increased risk of early-onset neonatal sepsis in term infants. J Perinatol.2015; 35:39-45.

5. Khadilkar A, Khadilkar V, Chinnappa J, et al. Prevention and　Treatment of Vitamin D and Calcium Deficiency in Children and Adolescents: Indian　Academy of Pediatrics (IAP) Guidelines. Indian Pediatr. 2017;54:567-73.

6. Puopolo JP, Eichenwald EC, Stark AR. Bacterial and fungal infections. In: Manual of Neonatal Care Cloherty, 6th Edition, Lippincott Williams and Wilkins; 2008.p.274-300.

7. Singh M. 16 Perinatal infections. In: Care of the Newborn. 8th edition, CBS publishers and distributors: 2015. p.267-98.