Objective To investigate the relationship between meteorological factors and disease activity in patients with primary Sjögren's syndrome (pSS).

Methods Clinical data of 525 patients with pSS and meteorological factors such as mean monthly temperature, mean monthly relative humidity, mean monthly barometric pressure, mean monthly wind speed and total monthly rainfall at the time of admission were retrospectively collected. According to the European League for Rheumatology Sjögren's Syndrome Activity Index (ESSDAI), the patients were classified into stable disease group (ESSDAI score ≤ 5 points, n = 281) and disease activity group (ESSDAI score ≥ 5 points, n = 244). Comparison was made between the two groups in terms of routine clinical data and meteorological factors. Multiple logistic regression analysis was used to evaluate the effect of different factors on the activity of pSS.

Results The average monthly relative humidity, CRP, ESR, IgG, IgA, IgM and RF positive rate in the stable disease group were lower than those in the disease activity group (P ＜ 0.05 to P ＜ 0.01). The monthly average temperature, RBC, Hb, PLT, LY, NEU and Alb, complement C3 in the stable disease group were higher than those in the disease activity group (P ＜ 0.05 to P ＜ 0.01). Logistic regression analysis showed that RF positive, ESR increase and monthly average temperature decrease were independent risk factors for pSS disease activity (P ＜ 0.05 to P ＜ 0.01).

Conclusions Coldness may increase the disease activity of pSS. It is suggested that pSS patients should keep their living environment warm and dry and take appropriate methods to prevent disease activity.