AB0327 RHEUMATOID ARTHRITIS PATIENTS HAVE VITAMIN-D DEFICIENCY COMPARED TO AGE SEX MATCHED CONTROL. WHAT CONTRIBUTE TO THIS DEFICIENCY?

Abstract

Background: Vitamin-D (vit-D) is believed to have an immunomodulatory and anti-inflammatory action. As a result, low vit-D has been proved to increase susceptibility to the development and to increase the inflammatory activities of rheumatoid arthritis (RA). This study looked at 25-vit-D level in RA patients and in their matched age and sex controls, and investigated what contribute to the risk of low 25-vit-D in RA. Objectives: The study looked at RA diseases activities, renal function, demographic features and blood biochemistry relation to 25-vit-D level. Methods: 62 RA patients and 82 control were recruited for the study. 25-vit-D level, RA diseases activity parameters and blood biochemistry (full blood count, liver function test, and renal profile) were obtained on the same day. Estimated glomerular filtration rate (eGFR) calculated with Modification of Diet in Renal Disease (MDRD) formula. Body mass index (BMI) calculated as mass (kg)/Height (m)2. Univariate regression analysis was carried out to determine the relationship between 25-vit-D level and all the parameters of interest (as above). Results: 65 RA, and 82 controls matching for age (48±13 years for RA, and 47±14 years for the controls, p=0.58) and sex (57 F (88%), M=8 (12%) RA, 67 F (82%), 5 M (18%) controls, p=0.23) were included for the study. The mean 25-vit-D level was 41±31 nmol/l for the RA patients (normal range: 50-80), and 52±33 nmol/l for the controls (p=0.03). Univariate linear regression among RA patients revealed a positive linear relationship between 25-vit-D level and age of the patients (p=0.02, CI: 0.08, 1.24), creatinine level (p=0.01, CI: 0.13, 0.96), body surface area (p=0.02, CI: 9.47, 111), body mass index (BMI) (p=0.03, CI: 0.17, 3.18), and calcium level (p=0.04, CI: 1.38, 69.6). 25-vit-D level was negatively associated with eGFR (p=0.04, CI: -0.20, -0.01), microalbuminuria level (p=0.03, CI: -0.26, -0.00), and CRP level (P=0.03, CI: -0.47, - Conclusion: Vit-D receptors are present in most cells in the body and in the T and B lymphocytes. The active form of vit-D (1, 25 vit-D) is one of the most potent modulators of the immune system. Hence, the negative relationship between 25-vit-D and CRP support 25-vit-D deficiency role in the exacerbation of the inflammatory status, and possibly in the subclinical renal impairment; as shown by the negative association between eGFR and the 25-vit-D. The relation between the subclinical renal impairment and the vit- D deficiency is further supported by e the negative linear relationship between 25-vit-D and the urine microalbumin level and the positive linear relationship association between 25-vit-D and the serum creatinine level. The positive association between 25-vit-D and the age of the participants might reflect the awareness of the older population about the importance of sun exposure for health. Screening for vit- D deficiency might be an important step to detect subclinical renal insufficiency in RA. Vit-D supplement might help in ameliorating the inflammation of RA and the subclinical renal impairment especially its well known that our general population is already Vit-D deficient and this worsen by the inflammatory conditions that they develop.