Patterns of 25-Hydroxyvitamin D3, Calcium Status, and Anemia in the Saudi Population: A Cross-Sectional Study

Abstract

Background: Emerging evidence suggests an intricate relationship between vitamin D, Ca²⁺, and inflammation-driven anemia. We, thus, investigated the patterns of serum 25(OH)D₃, Ca²⁺, ferritin, and iron in healthy and anemic members of the Saudi population.

Methods: A population-based, retrospective, cross-sectional study was designed to analyze data for 14,229 subjects, aged 3-110 years, obtained from Al-Borg Medical Laboratories, over a six-year period (2014-2020). Gender and age differences were analyzed for 25(OH)D₃, Ca²⁺, hemoglobin, ferritin, and iron.

Results: Vitamin D deficiency was extremely prevalent (98.47%) irrespective of age or gender, despite an increasing trend with age, in clear contrast to serum Ca²⁺. Ferritin was significantly lower in young adult and adult females, compared to elderly females, whereas iron was significantly reduced in females; in particular, adult females compared to young adults or elderly adults. Only anemic adult males had significantly lower 25(OH)D₃, while Ca²⁺ was consistently significantly diminished in anemics of all age groups, independent of gender. Notably, hypocalcemic subjects were 2.36 times more likely to be anemic. Moreover, ferritin, but not iron, was significantly diminished in anemics, which was only evident in young adults and adults. However, both ferritin and iron showed positive correlation with hematocrit, hemoglobin, MCH, MCHC, and MCV.

Conclusions: Despite being significantly lower in anemics, 25(OH)D₃ is not particularly associated with anemia, while hypocalcemia is associated with an increased risk for anemia. Assessment of vitamin D and Ca²⁺ status may be valuable in the clinical management of anemia in the Saudi population.

Keywords: Saudi Arabia; anemia; biomarker; calcium; vitamin D.

Figure 1

Effect of gender and age on 25(OH)D₃ and Ca²⁺ levels. Mean ± SEM of serum 25(OH)D₃ in males and females (A), in age groups of both genders (B), of males (C), and of females (D). Mean ± SEM of serum Ca²⁺ in males and females (E), in age groups of both genders (F), of males (G), and of females (H). * (p < 0.05), ** (p < 0.01), *** (p < 0.001), and **** (p < 0.0001) indicate significant difference, while ns indicates no significance.

Figure 2

Effect of gender and age on ferritin and iron levels. Mean ± SEM of serum ferritin in males and females (A), in age groups of both genders (B), of males (C), and of females (D). Mean ± SEM of serum iron in males and females (E), in age groups of both genders (F), of males (G), and of females (H). ** (p < 0.01) and *** (p < 0.001) indicate significant difference, while ns indicates no significance.

Figure 3

Distribution of Hb level in study subjects. Mean ± SEM of Hb levels in males and females (A), in age groups of both genders (B), of males (C), and of females (D). * (p < 0.05), ** (p < 0.01), and **** (p < 0.0001) indicate significant difference, while ns indicates no significance.

Figure 4

25(OH)D₃ levels in healthy and anemic subjects. Mean ± SEM of serum 25(OH)D₃ in healthy and anemics (+) of both genders (A), of males (B), of females (C), in age groups of both genders (D), of males (E), and of females (F). * (p < 0.05), ** (p < 0.01), *** (p < 0.001), and **** (p < 0.0001) indicate significant difference, while ns indicates no significance.

Figure 5

Ca²⁺ levels in healthy and anemic subjects. Mean ± SEM of serum Ca²⁺ in healthy and anemics (+) of both genders (A), of males (B), of females (C), in age groups of both genders (D), of males (E), and of females (F). * (p < 0.05) and **** (p < 0.0001) indicate significant difference, while ns indicates no significance.

Figure 6

Ferritin levels in healthy and anemic subjects. Mean ± SEM of serum ferritin in healthy and anemics (+) of both genders (A), in males (B), in females (C), in age groups of both genders (D), of males (E), and of females (F). ** (p < 0.01), *** (p < 0.001), and **** (p < 0.0001) indicate significant difference, while ns indicates no significance.

Figure 7

Iron levels in healthy and anemic subjects. Mean ± SEM of serum iron in healthy and anemics (+) of both genders (A), of males (B), of females (C), in age groups of both genders (D), of males (E), and of females (F). ns indicates no significance.

Figure 8

Correlation analysis of 25(OH)D₃ and Ca²⁺ with anemia indices. (A) Pearson correlation matrix of ferritin and iron and CBC parameters. (B) Simple linear regression of 25(OH)D₃, Ca²⁺, and iron with CBC parameters. (C) Simple linear regression of 25(OH)D₃, Ca²⁺, ferritin, and iron with age.