Yanan WANG1, Fengwei ZHANG2, Shanshan WANG2, Xuechai SHANG2, Siyuna LUO2, Hongjuan ZHOU2, Huaping SHI2, Long CAI2

1Clinical Laboratory, Yuhang District MCH Hospital, Hangzhou City, PR China
2Laboratory of Rheumatism Department, Zhejiang TCM & WM Hospital, Hangzhou City, PR China

Keywords: Anti-cyclic citrullinated peptide antibody, rheumatoid arthritis, vitamin D


Objectives: This study aims to assess the relationship between serum vitamin D and anti-cyclic citrullinated peptide (anti-CCP) antibody levels, as well as disease activity in patients with newly diagnosed rheumatoid arthritis (RA).
Patients and methods: These measurements were conducted between January 2014 and June 2014. Serum 25-hydroxy vitamin D (25-OH-D), anti- CCP antibody, and erythrocyte sedimentation rates were measured in a cohort of 154 patients (66 males, 88 females; mean age 53.5±12.4; range 29 to 79 years) with early RA. A control group of 60 healthy participants (25 males, 35 females; mean age 51.4±10.3; range 25 to 75 years) was only evaluated for serum 25-OH-D levels. Disease activity was measured by calculating the 28-Joint Disease Activity Score. Blood samples were drawn from cubital veins. After centrifugation, serum was collected and stored under minus 20 degrees.
Results: Vitamin D deficiency was more prevalent in RA group compared with control group (48.70% vs. 30.00%, p<0.05). Serum 25-OH-D levels were lower in RA group (19.46±8.20 ng/mL) than control group (23.18±6.71 ng/mL) (p<0.05). In the RA group, serum 25-OH-D levels were negatively correlated to anti-CCP antibody levels (rs= –0.360, p<0.001), erythrocyte sedimentation rate (rs= –0.270, p<0.001), age of patients (rs= –0.602, p<0.001), and disease activity (rs= –0.249, p<0.05), respectively. Serum 25-OH-D level did not vary according to sex in the RA group. In control group, females had lower serum 25-OH-D level (p=0.001, rs=0.404). In addition, serum 25-OH-D level was also negatively associated with age in control group (p<0.001, rs= –0.578). There were no differences between RA group and control group in terms of age and sex ratio.
Conclusion: Serum 25-OH-D level was negatively correlated to anti-CCP antibody level and disease activity, which implied the therapeutic role of serum 25-OH-D in RA.

Conflict of Interest

The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Financial Disclosure

This work was supported by grants from The Intramural Research Start-up Fund of Zhejiang TCM & WM Hospital and Science and Technology Plan Projects of Zhejiang Medicine and Health Program (2014KYA184).