Seasonal variation of the onset of presentations in stage 1 sarcoidosis

Abstract

Sarcoidosis is a chronic disease with an unknown aetiology. Our aim was to evaluate the pattern of seasonality of stage 1 sarcoidosis subjects who had symptoms by all cases, by age and by both genders. In this study, we used Roger's test for cyclic variation to prove that this seasonal variation was more than chance. Four hundred ninety-two consecutive patients with sarcoidosis who presented different clinical symptoms were included in this retrospective cohort study. According to the chest X-ray examinations, 185 patients had stage 1, while 307 patients in control group had stage 0, 2, 3 and 4 sarcoidosis. The demographic features, presenting clinical features, course of the disease, initial diagnostic methods and both the month and the age at the initial diagnosis for each patient were analysed on chart reviews. Roger's test for cyclic variation was used to determine the significance of any seasonal variation of incidence. Otherwise, t-test was used. The distribution of cumulative monthly presentations for patients with stage 1 peaked in April (108% above the average) and was lowest in October, November and December (48% below the average) (p < 0.001). Seasonality of the control group peaked in May (84% above the average) and was lowest in August (69% below the average) (p < 0.001). The seasonal pattern of subjects within both groups was influenced by some age groups and by both genders (p < 0.05). Some differences in the amplitude of the seasonal variation by age and by both genders increase the possibility of interactions among age, gender and the disease. Further well-designed and prospective studies are required to better understand the importance of our findings and the pathogenesis of the disease.

Seasonal clustering in inflammatory bowel disease: a single centre experience

“…Similarly, anti-flu drugs were used relatively more often during the colder months, according to the Turkish Ministry of Health reports. In addition to upper respiratory tract infections, using these types of medications may contribute to the development of IBD in genetically susceptible individuals [18]. In contrast, enteric infections are seasonally related in Turkey, being more common during the summer months.…”

“…The monthly distribution of symptoms was used to investigate clustering by cumulative diagnosis per month during the 12-year study period. The graphical data presentation was based on the cumulative monthly means, expressed as the percentage above or below the mean monthly value during the entire study period [16,18]. The amplitude of seasonal variation was described by the total seasonal variation.…”

“…Kruskal-Wallis test and Roger's test for cyclic variation were used to determine any seasonal variation of incidence [16,18]. This statistical analysis determines a simple harmonic cyclic trend, by dividing a circle into 12 equal sectors and plotting the monthly frequencies as coordinates (x and y) in the corresponding sectors in the circle.…”

“…So far, the seasonality of IBD has not been reported in Eastern countries. Turkey is a country that straddles two continents, lying 97% within Asia as well as bordering Europe and represents a unique opportunity to explore the seasonality of IBD in this Eastern population [18].…”

Pathogenesis of sarcoidosis

“…More stringent diagnostic workup in an occupational setting leads to a decrease of sarcoidosis incidence and increase in other granulomatous disorders [42,51]. Seasonal and geographic variations with a predominance of the diagnosis in the springtime and an increased incidence in moderate to subpolar climate zones or areas near the coastline point to an animate etiological agent in the environment [9,52,53]. In aggregate, there is mounting epidemiologic evidence of inanimate or animate agents in the environment capable of inducing sarcoidosis or being an etiological cofactor.…”