Nutrition has been known as a predominant factor associated with stunting. However, some studies have discovered a genetic contribution in calcium absorption that will affect growth, known as the VDR gene. The aim of this study was to assess the association between VDR gene polymorphism and dietary intake towards height-for-age z-score (HAZ) of elementary school children in Malang District, East Java. This study analyzed the baseline of a randomized trial in East Java, Indonesia. School children aged 8-10 years old (n = 142) were included in this study. Energy, protein, calcium, and vitamin D intakes were obtained using 4-day 24-h dietary recalls. Two SNPs located in the promoter region of VDR gene were selected (rs11568820 and rs4516035) and analyzed using Real-Time PCR. The result showed a significant correlation between energy and protein intake with HAZ of the children (p = 0.030 and p = 0.016, respectively). The association between VDR gene and HAZ was not found (p > 0.05). Adjusted by other factors, protein intake was significantly correlated with HAZ (β = 0.034, 95% CI 0.015-0.052, p < 0.001, adj. R2 = 0.089). The children in our study had a favorable VDR gene genotype, however the effect of VDR gene promoter activity might not be revealed due to very low vitamin D and calcium intake to stimulate intestinal calcium absorption which in turn affects HAZ.
Keywords: Indonesia; VDR gene; calcium; children; dietary intake; height-for-age z-score (HAZ); stunting; vitamin D.