Vitamin D Deficiency among Patients Visiting a Tertiary Care Hospital: A Descriptive Cross-sectional Study

ABSTRACT Introduction: Vitamin D deficiency is a common condition prevalent among both developed and developing countries where it is seen mostly in females. It has been linked to various skeletal and non-skeletal diseases. This study was done to find out the prevalence of Vitamin D deficiency and clinical features of deficient patients attending the outpatient department of a tertiary care hospital. Methods: This descriptive cross-sectional study was done among the patients attending the outpatient department of a tertiary care hospital in Kathmandu, Nepal. The study was conducted from May 2019 to July 2019. The ethical approval was taken from the Institutional Review Committee (ref no. 310520113). Convenient sampling was done. The collected data was entered in Microsoft Excel and was analyzed in the Statistical Package for the Social Sciences (SPSS) version 26. Results: Out of 481 participants, the prevalence of vitamin D deficiency was 335 (69.6%) (65.49-73.71 at 95% Confidence Interval). Severe vitamin D deficiency was seen in 78 (16.2%) and insufficient vitamin D in 77 (16%) of the patients. The mean serum vitamin D concentration by gender was 22.38±17.07ng/ml in males and 18.89±15.25ng/ml in females. A total of 263 (54.6%) females and 72 (14.97%) males had vitamin D deficiency. The most common symptoms found in vitamin D deficiency patients were fatigue 187 (55.8%), muscle cramps 131 (39.1%), generalized myalgia 125(37.31%), bone and joint pain 111 (33.13%). Conclusions: Vitamin D deficiency was prevalent especially in females and elderly people. Fatigability was present in more than half of the vitamin D deficient patients.


INTRODUCTION
Vitamin D is a fat-soluble prohormone, which is involved in the regulation of the physiological processes. 1 It is found in two forms; ergocalciferol (Vitamin D2) found in plants and fungi, and cholecalciferol (Vitamin D3) from the sun. 2 Vitamin D deficiency is defined as "25hydroxyvitamin D level of less than 20ng per millimeter (50nmol per liter)". 3,4 It has been estimated that around one billion people have Vitamin D deficiency or insufficiency. 5 Vitamin D deficiency shows its high prevalence in the developed countries and the regions of Asia, the Middle East, and India mostly in women. 6 According to several studies, 40-100% of the US and European population are deficient in Vitamin D. 7,8 The factors causing Vitamin D deficiency could be due to changes in the lifestyle based on the socio-cultural practice, inadequate sun exposure and the food consumed that are rarely fortified with Vitamin D. 9 Its deficiency has been linked to different musculoskeletal and non-skeletal complications like congestive heart failure, peripheral vascular disease, hypertension, diabetes mellitus. 10  As patients were enrolled using the convenient sampling, we doubled the size and considering 20% non-respondent rate, the total sample of 481 patients was taken for measurement of vitamin D.
Data collected in semi-structured questionnaire regarding demographics, clinical features like fatigue, body ache, muscle cramps, joint pain, low backache, and medical history of diabetes, hypertension, chronic kidney disease, and Ischemic heart diseases (IHDs). Body mass index was used to define the weight status. Serum Vitamin D3, which is 25 hydroxyvitamin D [25(OH) D], was estimated by a fully-automated chemiluminescence immunoassay.
Vitamin D deficiency was defined as 25(OH) D less than 20ng/ml, Vitamin D insufficiency as 20 -29ng/ml, and Vitamin D sufficiency as ≥30ng/ml, and Vitamin D toxicity as more than 100ng/ml. Vitamin D levels less than 10ng/ml were regarded as a severe deficiency. 2,11 The data collected was entered in Microsoft Excel and was analyzed in the IBM Statistical Package of the Social Sciences (SPSS) version 26. Demographic data and clinical variables were analyzed by descriptive analysis. Results are expressed as mean ± standard deviation for quantitative variables and percentage for qualitative variables like symptoms.

RESULTS
A total of 481 participants were included in the study. Overall, vitamin D deficiency was found in 335 (69.6%) (65.49-73.71 at 95% Confidence Interval). Insufficiency was seen in 77 (16%) patients. Among the participants, 69 (14.3%) had the sufficient vitamin D levels (

DISCUSSION
The results of this cross-sectional study done in a tertiary care hospital of Kathmandu, Nepal showed the prevalence of Vitamin D deficiency as 69.6%, of insufficiency as 16%, and sufficient Vitamin D in 14.3%. The prevalence was higher among older ages and females. A severe deficiency was seen in 16.2% of the studied population. The rates of Vitamin D deficiency found in this study are markedly higher than in many western countries like in Germany, Austria, and the Netherlands, in North Europe (Denmark, Finland, Ireland, and Poland), Canada, and the United Kingdom which have shown the prevalence of vitamin D deficiency from 10-55.5%. [11][12] Mariam Omar et al. reported a deficiency of 76.1% and insufficiency of 15.2% among the population of Benghazi, a sunny second-largest city in the east of Libya. 2 Our results share similar vitamin D deficiency status with some parts of Africa, Asia, and the Middle East. The prevalence of vitamin D deficiency in Egypt was 77%, insufficiency was 15%, and 9% of the population has sufficient Vitamin D levels. In Qatar, 83-91% of the population is deficient in Vitamin D. 2,13 Vitamin D deficiency is considered to be a public health problem worldwide. Female gender is one of the most important predictors of vitamin D deficiency. 2  Our study has demonstrated a high prevalence of vitamin D deficiency among patients visiting in our center. A larger multicentric or community based study with a diverse sample population should be conducted in the future to find out a more accurate prevalence. Similarly, other studies that further look into the association between gender and age and other comorbidities with vitamin D levels in Nepalese are warranted.

CONCLUSIONS
Vitamin D deficiency was prevalent especially in females and elderly people. Fatigability was present in more than half of the vitamin D deficient