BackgroundProtein energy malnutrition (PEM) is a condition that results from inadequate intake of both macronutrients and micronutrients, leading to a lack of energy. The condition can manifest quickly or gradually, ranging from mild to severe. It predominantly affects children in low-income countries who do not receive enough calories and proteins. In developed nations, it is more prevalent among older individuals. PEM is more common in children as they consume less protein. In rare cases in developed countries, it may result from fad diets or a lack of knowledge about children's nutritional requirements, especially in cases of milk allergy. Vitamin D plays a critical role in bone growth and development by facilitating the absorption of calcium and phosphorus from food and supplements. Additionally, vitamin D has been linked to a reduced risk of infections, immune system disorders, diabetes, high blood pressure, and heart disease.Aims and objectivesThe primary objective of this study is to evaluate serum vitamin D levels and their relationship with health complications in children affected by PEM. The specific aim is to estimate the serum vitamin D levels in children with PEM who exhibit symptoms of being underweight, stunting (limited linear growth), wasting (abrupt weight loss), or edematous malnutrition (kwashiorkor). Additionally, this study seeks to analyze the correlation between serum vitamin D levels and the associated health problems in children with PEM.Materials and methodsThis cross-sectional study employed an analytical research approach. A total of 45 children with PEM participated in the study. Data were collected through a venipuncture method, and serum vitamin D level was assessed using an enhanced chemiluminescence method. The children's pain was assessed using a visual analogue scale, and developmental delay was evaluated using an assessment chart. Data were analyzed using SPSS Version 22 (IBM Corp., Armonk, NY).ResultsThe study's results indicate that a considerable proportion of children, specifically 46.6%, were deficient in vitamin D, whereas 42.2% exhibited insufficiency and only 11.2% had sufficient levels of the vitamin. Pain assessment using the visual analogue scale classification revealed that 15.6% of children reported no pain, 60% reported mild pain, and 24.4% reported moderate pain. The mean and standard deviation of vitamin D levels correlated with developmental delay were 4.22±0.212 and 5.34±0.438, respectively. Similarly, the mean and standard deviation of vitamin D levels correlated with pain were 4.22±0.212 and 2.98±0.489, respectively. The Pearson correlation coefficient for vitamin D levels and pain was 0.010, with a significant level of 0.989, significantly lower than the tabulated value at a 5% significance level.ConclusionBased on the study's findings, it was concluded that children who suffer from PEM are at a risk of developing vitamin D deficiency, which can result in adverse health outcomes, including developmental delay and pain.