Recent studies link vitamin D deficiency with depression; however evidences from the Nepalese population are scarce. The current study explored the association between vitamin D deficiency and depression among 300 adults of 18 years and above age residing in eastern Nepal. Validated Nepali version of the Beck Depression Inventory scale (BDI-Ia) was used to determine depressive symptoms and a BDI cutoff score of ≥ ۲۰ was considered as clinically significant depression. Sociodemographic data were collected using semi-structured questionnaire. Blood samples were collected to measure serum 25-hydroxy vitamin D (25(OH)D) and classify vitamin D status (deficient, insufficient and sufficient). We used Chi-square test to identify the association of sociodemographic variables and vitamin D status with clinically significant depression. We found a significant association of gender, geographical location of residence, marital status, religion and vitamin D status with clinically significant depression. Binary logistic regression model was used to examine the likelihood of clinically significant depression among vitamin D deficient individuals. Vitamin D deficiency was significantly associated with increased odds of clinically significant depression even after adjusting for confounding variables. This finding suggests Vitamin D deficient people have increased odds of having clinically significant depression.

Introduction

Depression is a mental disorder which diminishes the functioning and quality of life. World Health Organization (WHO) had identified depression as a leading cause of disability worldwide affecting 300 million people (World health organization, 2017). Major depressive episodes (MDE) starts typically during early to mid-adulthood, which is the most productive part of one’s life (Kessler et al., 2013). Even, when diagnosed and treated with medication the chronic recurrent nature of the disease and non-compliance to medication pose as a major challenge. Non-compliance to medication occurs mainly due to the fear of dependence, emergence of side effects to medication and the high cost of treatment (Penckofer et al., 2010). This leads to high relapse rate adding further to the global burden of the disease. Hence, one needs to examine other modifiable risk factors that can be targeted to prevent and treat depression besides medication. Over the past decade, a substantial amount of observational and animal experimental studies have confirmed a broader role of vitamin D in health and disease, including mental health (Ganji et al., 2010; Atoum et al., 2017; Kočovská et al., 2017; Williams et al., 2014). The demonstration of Vitamin D receptor (VDR) in the pre-frontal cortex and the limbic system have elucidated the role of vitamin D in maintenance of mood, affect and cognitive functions (Eyles et al., 2005; Schlögl et al., 2014; Di Somma et al., 2017). Similarly, empirical evidences have also identified a link between vitamin D deficiency and depression (Penckofer et al., 2010; Ganji et al., 2010). A meta-analysis examining the relationship between vitamin D and depression reported inverse relation between depression and vitamin D level (Ju et al., 2013). However, majority of these studies have been conducted in other parts of the world which are not representative of Nepalese population. The sociocultural complexities of Nepalese population due to its diverse caste and ethnic groups, religious practices, latitude, gender differences are important factors that cannot be undermined as they could have potential confounding effect. This urges us to take a deeper insight into the matter in our part of the world. To address these variations we examined the association between serum 25-hydroxyvitamin D [25(OH)D] concentrations and depressive symptoms in a Nepalese population after considering for probable confounding factors.

چکیده

مطالعات جديد، كمبود ويتامين D را با افسردگي مرتبط مي دانند؛ هرچند شواهدي در اين مورد، در بين جمعيت كشور نپال اندك است. مطالعه ي حاضر، ارتباط بين كمبود ويتامينD و افسردگي را در ميان ۳۰۰ فرد ۱۸ سال و به بالا، مقيم غرب نپال، بررسي كرد. نسخه ي معتبر نپالي مقياس افسردگي Beck، براي تعيين افسردگي استفاده شده و نمره ي برش بالاي ۲۰، به عنوان افسردگي باليني معنادار، در نظر گرفته شد. داده هاي آماري نفوس، با استفاده از پرسشنامه ي نيمه ساختارمند، جمع آوري گرديد. نمونه هاي خوني، براي اندازه گيري هيدروكسي۲۵ ويتامينD، جمع آوري شد و مقدار ويتامينD، به سه رده ي: كمبود، ناكافي و كافي، طبقه بندي شد. از آزمون chi-square براي تشخيص ارتباط متغيرهاي آماري نفوس و مقدار ويتامينD با افسردگي باليني معنادار، استفاده كرديم.