Heliyon (Sep 2024)

Establishment of age-specific reference intervals for serum 25-hydroxyvitamin D in a large pediatric population of Nanjing, China

  • Chenchen Xu,
  • Xun Chen,
  • Yajun Chen,
  • Zhifa Wen,
  • Feng Cheng

Journal volume & issue
Vol. 10, no. 17
p. e37409

Abstract

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Background: The reference intervals (RIs) is defined as the central 95 % range of reference values from healthy individuals. The establishment of appropriate medical RIs for specific populations is crucial for accurate diagnosis and treatment of disease. However, the RIs for 25-hydroxyvitamin D (25(OH)D) in Chinese pediatric individuals are currently not available. This retrospective study aimed to establish pediatric RIs for serum 25-hydroxyvitamin D (25(OH)D) in the Nanjing area of China. Methods: After data filtering and deletion of outliers, 133,562 serum 25(OH)D records were finally included in this study. The effects of age, sex, and season on 25(OH)D levels were assessed, and the 2.5 % and 97.5 % percentile points were applied as the lower limit and upper limit of the RIs, respectively. Results: Age-distribution analysis of serum 25(OH)D levels revealed that children aged 4–12 months old hold the highest 25(OH)D levels, and levels subsequently decreased with age while remaining relatively stable in children aged 7–15 years old. An analysis of sex-specific differences demonstrated that serum 25(OH)D levels in girls were significantly higher than those of boys 7 years old (P < 0.001). Season distribution revealed the highest 25(OH)D levels in autumn, followed by summer and winter, and finally spring. Considering the practicability of clinical application and Z tests according to CLSI C28-A3 guidelines, age-specific RIs for serum 25(OH)D were established. The calculated RIs for children 0–3 months, 4–12 months, 1–3 years, 4–6 years, and 7–15 years old, respectively, were 18.62–42.18, 22.20–45.60, 21.12–45.20, 17.16–38.20, and 15.56–34.39 ng/mL, respectively. Conclusions: The levels of serum 25(OH)D exhibited statistically significant age and season variations, and the establishment of age-specific RIs for serum 25(OH)D would be beneficial for clinical diagnosis and treatment.

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