 Corresponding author: Christin Natalia Kalembang Department Of Child Health, Faculty of Medicine Udayana University/Sanglah Hospital, Bali, Indonesia. Copyright © 2021 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Vitamin D Insufficiency as Risk Factor of Severe Pneumonia in Children Christin Natalia Kalembang * , Ayu Setyorini Mestika Mayangsari, Komang Ayu Witarini, Ni Putu Siadi Purniti, I Made Kardana, I Gusti Ngurah Made Suwarba and I Gusti Agung Ngurah Sugitha Adnyana Department Of Child Health, Faculty of Medicine Udayana University/Sanglah Hospital, Bali, Indonesia. GSC Advanced Research and Reviews, 2021, 09(02), 058–065 Publication history: Received on 10 October 2021; revised on 13 November 2021; accepted on 15 November 2021 Article DOI: https://doi.org/10.30574/gscarr.2021.9.2.0271 Abstract Severe pneumonia is an infectious disease with high morbidity and mortality in children under five. Several risk factors of severe pneumonia have been established, one of them is vitamin D insufficiency. Risk factors for severe pneumonia can help clinicians to provide better quality of life. This research aimed to prove that vitamin D insufficiency is a risk factor for severe pneumonia in children. This analytical study with case-control design performed in children aged 2 months until 59 months old. Case consisted of 42 subjects who suffered severe pneumonia, while control consisted of 42 subjects who suffered pneumonia. Both groups fulfilled the eligibilities and matched proportionally based on age. The study was conducted from June 2019 to March 2021, level of 25(OH) D was checked in both groups. Data was analyzed by Chi-square test and logistic regression with significant level set at p<0, 05. Total eighty-four subjects with median age 11, 5 month were included in this study and most of them were male (59, 5%). The risk factors of severe pneumonia was vitamin D insufficiency with adjusted odds ratio 4.71 (CI95% 1.15-19.31, p=0.031) and exposure of cigarette smoke with adjusted odds ratio 5.19 (CI95% 1.76-15.31, p=0.003). There was no association of gender, mild malnutrition, non-exclusive breastfeeding and incomplete immunization in this study. Vitamin D insufficiency is a risk factor for severe pneumonia in children. Keywords: Severe pneumonia; Vitamin D insufficiency; Risk factor; Children 1. Introduction Pneumonia is an infectious disease that is the main cause of death in children under five worldwide. The incidence of pneumonia diagnosed based on clinical symptoms occurs in developing countries around 150.7 million new cases per year and11-20 million or 7-13% occurs in as severe pneumonia that required hospitalization. To date, in developed countries there is no comparable data available. However, population-based research reported that the incidence of pneumonia among children less than five years old showed more than 95% occurs in developing countries [1]. The incidence of pneumonia increases yearly, according to data from Indonesian health profile 2016, the incidence of pneumonia based on recalled memory of having been diagnosed with pneumonia by health workers in previous month before the survey on infants in Indonesia from the last few years since 2014 ranging was 20-30%. In 2015 there was an increase, 63.45% of cases and in 2016 it increased into 65.27% [1]. It is estimated that there were 1,346 pneumonia patients in Denpasar and 1,352 patients were treated (100.43%). The Health Department of Bali Province estimated the number of pneumonia cases that occur in children under five was 2.05% from total number of children under five[2].