Seasonal variations in onset of symptoms in Crohn's disease

Seasonality in Flares and Months of Births of Patients with Ulcerative Colitis in a Chinese Population

“…The results of some studies suggest a degree of seasonality, with increased rates of UC flares being found in the spring and summer in an Italian population [5] or in spring and autumn in Swedish populations [7], while another study found monthly seasonality in symptomatic onset of UC in December and January in a Norwegian population [8]. However, other studies have not found any seasonal pattern of onset or relapse among patients with UC among British [11] and American populations [12].…”

“…It is currently believed that altered immunological function, resulting from an abnormal interplay between genetic susceptibility and environmental factors, significantly contributes to the mucosal inflammation of the intestinal tract [4]. To date, the environmental factors that contribute to the course of IBD have not been well defined, and while the results of some studies suggest that there may be seasonal variation in the natural history of IBD [5][6][7][8] as well as seasonality in month of birth of the patients [9,10], those of other studies do not reveal any such relationship [11][12][13]. All of these results, however, were based on data obtained from studies carried out in Western (=''developed'') countries.…”

Direct and Indirect Induction by 1,25-Dihydroxyvitamin D3 of the NOD2/CARD15-Defensin β2 Innate Immune Pathway Defective in Crohn Disease

“…12 and 13) have suggested that 1,25D deficiency may contribute to the pathogenesis of inflammatory bowel diseases (IBD), including Crohn disease (CD), a chronic incurable inflammatory condition, which is believed to arise from defective innate immune regulation of intestinal bacterial load (12,14). North-South gradients in rates of CD have been described in Europe and North America (12,15,16), although data concerning seasonal variations in CD relapse rates are conflicting (17)(18)(19). In addition, VDR gene polymorphisms correlate with susceptibility to CD and to ulcerative colitis (20,21).…”

Gender-Related and City- and Countryside-Related Differences in Patients with Ulcerative Colitis in a Chinese Population

“…In the present study, the mean age at onset of total patients was 42.05 years, in consistence with the multi-center investigation in T a b l e 3 . S e a s o n a l Ul c e r a t i v e Co l i t i s Di s e a s e On s e t o f Ma l e a n d F e ma l e , a n d Ur b a n a n d Ru r a l P a t i e n t s (4,5,27,28). In all patients, as shown in our study, the onset peaks of the patients occurred more frequently in the spring and summer, compared to the autumn and winter, but there was no difference of seasonality between male and female patients, or urban and rural populations, which suggests that seasonal factors have less effect on disease expression than lifestyle factors.…”