The relationship of vitamin D to the MHAQ index, activity disease, and inflammation in a sample of Syrian rheumatoid disease patients

Background: Vitamin D has an immunomodulatory and anti-inflammatory role, and its deficiency has been linked with many autoimmune disorders, including rheumatoid arthritis (RA). The correlation ship between the severity of RA and serum levels of vitamin D is a subject of immense interest and therapeutic implications. Patients and Methods: A total of 100 patients previously diagnosed with RA were collected from visitors to the rheumatology clinic at the university hospital and their ages were over 18 years. The serum vitamin D value and the C-reactive protein (CRP) value were measured, and the Disease Activity Score CRP28 (DAS28CRP) and Modified Health Assessment Questionnaire (MHAQ) score were calculated to determine the severity and effectiveness of the disease and its relationship to vitamin D deficiency. Results: The average age of the patients ranged according to the patient’s age (46.03±11.291), we note that individuals whose ages ranged from 26 to 65 accounted for the largest percentage (94%), 83% of women (83) and 17% men (17), and the mean score for sun exposure was 15.80±5.446. Patients were individuals diagnosed with the disease between 5 and 10 years were the highest group, with a percentage of 31%. A total of 72% of the patients were not treated with corticosteroids, and 43% of the patients were treated with vitamin D. We found that the number of patients using biologic medications was 18%, and the number of patients using disease-modifying anti-rheumatic drugs was 88%. The mean of DAS28 was moderate in 63% of patients, and the average of the MHAQ score was 0.80±0.334. We found that there is no statically significant correlation between the serum vitamin D level and DAS28/CRP (P=0.733), and there is also no statically significant correlation between the serum value of vitamin D and the medications used, whether biological or disease-modifying anti-rheumatic drugs (P=0.361). In addition, there is also no significant correlation between the serum vitamin D level and MHAQ score (P=0.100). Conclusion: There was no significant relationship between vitamin D deficiency and the disease activity or severity in a sample of patients with RA.


Introduction
Rheumatoid disease is a systemic immune condition that mainly affects joints, especially the small ones [1] .It affects 0.5-1% of the world's population in middle age and women more than men [1] .
Vitamin D plays a role in the modulation of cell growth, immune function, and reducing inflammation.Many genes that regulate cell proliferation, differentiation, and apoptosis are modulated partially by vitamin D [2] .The role of vitamin D in modulating immune function is supported by the discovery of vitamin D receptors (VDRs) in peripheral mononuclear blood cells [3] .Vitamin D causes the downregulation of antigen-presenting cells, inhibition of T-cell proliferation, and decreased production of T helper cell-1 cytokines IL-2, interferon-gamma, and tumor necrosis factor-alpha [2] .Some studies have shown an association between deficiency of this disease because of its significant role in immune responses and the prevalence and severity of autoimmune diseases such as RA [3] .
The immunomodulatory activities of vitamin D might be particularly efficient in rheumatoid arthritis (RA) patients and

HIGHLIGHTS
• Vitamin D has an immunomodulatory and antiinflammatory role.• 100 patients previously diagnosed with rheumatoid arthritis were collected; their ages were over 18 years.• There is no statically significant correlation between the serum vitamin D level and DAS28/CRP, the medications used, or Modified Health Assessment Questionnaire (MHAQ) score.• There was no significant relationship between vitamin D deficiency and the disease activity or severity in a sample of Syrian patients with rheumatoid arthritis.
support a therapeutic role of vitamin D in these patients [2] .The VDRs have been demonstrated in macrophages, chondrocytes, and synovia cysts in rheumatoid synovium and at sites of cartilage erosion in RA patients [3] .In RA patients, measurement of vitamin D levels is particularly important as its deficiency is highly prevalent in this group.Vitamin D may also have a role in modulating RA disease activity [4] .The distribution of vitamin D deficiency may be attributable to dietary habits, demographic features, ethnicity, and geographic distribution [3,4] .Vitamin D deficiency predisposes to the development of RA and burdens further by leading to severe disease activity.Multiple studies have corroborated this above finding [2][3][4][5] .However, some studies have refuted these associations [6] .The relationship between the severity of RA and levels of vitamin D is a subject of immense interest and therapeutic implications, as we do not have any data about this subject in Syria hence the study was undertaken to compare the serum levels of vitamin D in the healthy population and RA patients and to correlate vitamin D levels with the RA disease activity.

Study design and sample size calculation
A cross-sectional study was conducted in our Rheumatology Department at University Hospital between 30 January 2022 and 30 January 2023.The ethical Committee of Damascus University had approved this study (IRB 23954, AS) and our study was compatible with the Helsinki Declaration.

Sample size
The sample size was 100 patients with rheumatoid disease, with a confidence interval of 95% and a predictive value of 0.05, calculated according to Stephen's equation: N is the community size; Z the standard score corresponding to the significance level of 0.95 and equal to 1.96; D the error percentage, equal to 0.05; P the ratio of property availability and neutrality = 0.50.

Inclusion criteria
All patients who were diagnosed according to the classification criteria of the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) 2010 [7] , and who were older than 18 years and had a sun exposure score of more than three enrolled in this study.Patients with rheumatoid disease who take corticosteroids for no more than three months due to, results of differentiated studies on its use [8,9] and patients taking vitamin D supplements were also included because the goal is to evaluate the effectiveness of the disease and its relationship with vitamin D, regardless of its source [10] .

Methods
Personal and demographic information, smoking, duration of the disease, medications taken by the patient, comorbidities, and the presence of family history of other autoimmune diseases.The index of exposure to sunlight was also calculated (Table 1), and body mass index (BMI), and vitamin D analysis (after fasting all night or at least 12 h) were performed for all patients.

Vit D analysis
Use the kit (ROCH 09038078190 VITAMIN D Total G3 Elec*) after an overnight fast or at least a 12-h fast was used for the quantitative measurement of vitamin D3 {25 (OH)-D3} in serum.
The estimation process was done in the Biotech ELX-800 autoanalyzer.The assay utilized a competitive ELISA technique with a selected monoclonal antibody recognizing 25(OH)-vitamin D. Vitamin D levels were recorded and analyzed in both the groups and correlated with the disease activity of RA.Serum vitamin D level was considered normal if its value was more than 20 ng/ml.
In comparison, a level between 12 and 20 ng/ml is insufficient serum vitamin D, and a serum level of less than 12 ng/ml indicates a deficiency serum vitamin D. A serum value higher than 100 ng/ml is considered vitamin D intoxication [20] .

Study tools
The question was also asked about the use of sunscreen and where to apply sunscreen.Disease Activity Score CRP28 (DAS28/CRP), the patients are divided into three groups according to the disease activity: severe disease activity (DAS28CRP > = 5.1), moderate disease activity (< DAS28CRP < 5.13.2), and mild disease activity (DAS28CRP > 3.2) [21] .The modified health assessment questionnaire (MHAQ) is one of the scores most used for measuring the functional status of rheumatoid arthritis (RA) patients.The score of the questionnaire is the sum of the individual item scores divided by 10 or the mean of the item scores if 8 or 9 items are completed.The HAQ-II is not to be scored if fewer than 8 items are completed [22] .The work has been reported in line with the STROCSS criteria [23] .

Static analysis
All statistical analyses were performed using SPSS software (version 26.0).Frequency (percent) and mean standard deviation (SD) were used to describe qualitative and quantitative variables, respectively.To study the significance of the association between any two descriptive variables, the χ 2 test was applied Shapiro-Wilk normality test was performed for numerical variables that are not normally distributed, and the Mann--Whitney U-test was to compare the means of two independent samples, that is, it is used to infer that the mean of one of the two samples is statistically different from the mean of the other sample, and it is used when the distribution of one or both samples does not follow a normal distribution.A P value less than 0.05 was considered statistically significant.

Descriptive data
The average age of the patients ranged according to the patient's age (46.03 11.291), we note that individuals whose ages ranged from 26 to 65 accounted for the largest percentage (94%), 83% women (83) and 17% men (17), and 29% of females in the studied do not wear the hijab, 22% of patients were smokers.The mean of the body mass index (BMI) was 24.67 3.761.And 7% of patients had a family history of RA.The percentage of people who do not wear sunscreen was 95%, and the mean score for sun exposure was 15.80 5.446 (Table 2).
Patients were individuals diagnosed with the disease between 5 and 10 years were the highest group, with a percentage of 31% (Table 3).We found that the positive RF value reached 92%, which is a high percentage, and the positive anti-CCP percentage reached 66%.72% of patients do not treat with corticosteroids, and 43% of patients are treated with vitamin D. The percentage of those who take a dose of vitamin D between 5 and 20 thousand units per week is 39%, and those who take a dose of vitamin D of 50 thousand units per month are 3%, and those who take a thousand units per day are 1%.We found that the number of patients using biologic medications was 18%, and the number of patients using disease-modifying anti-rheumatic drugs (DMARDs) was 88%.The mean of CRP was 2.073 2.72 mg/dl, DAS28 was moderate in 63% of patients, and the average MHAQ score was 0.80 0.334 (Table 4).
The mean serum vitamin D value was 23.39 15.53 ng/ml.The percentage of individuals with sufficient vitamin D was 53%, the percentage of individuals with insufficient vitamin D was 27%, and the percentage of those suffering from vitamin D deficiency was 20%.Table 2 shows all the data.

Analytical data
Based on the previous data, we found that there is no statically significant correlation between the serum vitamin D level and DAS28/CRP (P = 0.733), and there is also no statically significant correlation between the serum value of vitamin D and the medications used, whether biological or DMARDs (P = 0.361).
In addition, there is also no significant correlation between the serum vitamin D level and MHAQ score (P = 0.100).

Discussions
In this research, the aim was to investigate the relationship between vitamin D levels, and the disease activity of 100 patients with RA were studied.We found no statistically significant correlation between vitamin D level, disease activity, and MHAQ score.
Although some studies support the use of vitamin D supplements to improve the disease activity in RA patients, few studies did not find an association use of vitamin D supplements improving the disease activity in RA patients such as a study (de la Torre Lossa, et al [6] ) It was conducted on 100 patients with a sample similar to ours, and the average serum value of vitamin D was close to our result, Polasik, et al [24] , which was conducted on 35 female RA patients and 38 age-and sex-matched healthy controls.Also, disease activity was not associated with vitamin D deficiency, and Craig et al [25] .A study of 266 African American women found results similar to ours.Although some studies support the role of vitamin D in the incidence of RA and the disease activity [9,11] , the reason for the difference may be due to sweat and exposure to sunlight, in addition to the fact that many patients with rheumatoid disease may suffer from chronic pain more than the actual effectiveness of the disease [26] .
We have found no correlation linking the disease activity to vitamin D deficiency in the patients of our study.This may be due to the oral intake of vitamin D by 40% of the sample, in addition to reliance on the sun exposure index, as patients who had less than 3 were excluded.Also, most of our patients were from the middle age group, not the elderly.More than half of the patients had moderate disease activity, while those who were severs active were only 15%.Vitamin D deficiency did not exceed 20% of the total number of patients, the role of treatment in terms of DMARDs and biologics may also play a role in disease recovery, as patients were often adherent to their medications and visits to the rheumatology clinic.
Despite this, we recommend conducting research on a larger number of patients and avoiding taking patients who take vitamin D as medicinal supplements.We also recommend maintaining the daily dose of vitamin D for patients because of its overall benefit [2][3][4][5] .

Limitations
There were some limitations in our study.First, the one-center study.Second the limited sample in Damascus.Finally, 40% of patients are taking oral vitamin D, in addition to reliance on the sun exposure index, as patients who had less than 3 were excluded.Also, most of our patients were from the middle age group, not the elderly.More than half of the patients had moderate disease activity.All of these limitations limited the generalizability and power of the conclusions.

Conclusion
Giving vitamin D to patients with rheumatoid arthritis did not play a significant role in the effectiveness of the disease and MHAQ in a sample of Syrian patients, as a number of the patients were of middle age and had good exposure to sunlight, and some of them took vitamin D. It should be conducted on a larger sample and from multiple Syrian medical centers, including patients who take vitamin D so we can generalize our results.

Table 1
Weekly score of sun exposure.

Table 2
Demographic data of the study.The points from each of domain's A through D are added and the sum is considered to be the total score.A total score of greater than or equal to 6 is needed to classify a patient as having definite RA.The patient's infection points are calculated, and we need 6 or more to consider whether the patient has rheumatoid disease.
a Joint injury.b Immune serology.c Serum inflammatory factors.d Continuing injury.