Season and region of birth as risk factors for coeliac disease a key to the aetiology?

Abstract

BackgroundCoeliac disease (CD) incidence has increased in recent decades, characterised by variations according to sex, age at diagnosis, year of birth, month of birth and region of birth. Genetic susceptibility and exposure to gluten are the necessary factors in CD aetiology, although several environmental factors are considered.MethodsA nationwide prospective cohort longitudinal study was conducted consisting of 1 912 204 children aged 0–14.9 years born in Sweden from 1991 to 2009. A total of 6569 children were diagnosed with biopsy-verified CD from 47 paediatric departments. Using Cox regression, we examined the association between CD diagnosis and season of birth, region of birth and year of birth.ResultsOverall, CD risk was higher for children born during spring, summer and autumn as compared with children born during winter: adjusted HR for spring 1.08 (95% CI 1.01 to 1.16), summer 1.10 (95% CI 1.03 to 1.18) and autumn 1.10 (95% CI 1.02 to 1.18). Increased CD risk was highest if born in the south, followed by central Sweden when compared with children born in northern Sweden. Children diagnosed at <2 years had an increased CD risk if born in spring while those diagnosed at 2–14.9 years the risk was increased for summer and autumn births. The birth cohort of 1991–1996 had increased CD risk if born during spring, for the 1997–2002 birth cohort the risk increased for summer and autumn births, while for the birth cohort of 2003–2009 the risk was increased if born during autumn.ConclusionsSeason of birth and region of birth are independently and jointly associated with increased risk of developing CD during the first 15 years of life. Seasonal variation in infectious load is the likely explanation.

Exposure to the Danish Mandatory Vitamin D Fortification Policy in Prenatal Life and the Risk of Developing Coeliac Disease—The Importance of Season: A Semi Ecological Study

“…This may adversely influence the development of the fetus' immune system with consequences later in life [36]. In agreement, earlier studies have reported a lower risk of developing CD for winter-born compared to summer-born children [12][13][14][15][16]37,38].…”

“…Indeed, children born in summer/autumn often begin weaning and have their first exposure to gluten during the winter period, which is characterized by higher exposure to seasonal viruses. Viral infections influence flora and permeability of the intestine, and other studies have suggested that this may play a role in the etiology of CD [16,39]. Indeed, a recent study reported that reovirus infection may trigger CD in some patients [40].…”

“…More recently, maternal vitamin D levels have been suggested to have a role in the development of autoimmune diseases [10,11]. Other studies have shown an association between season of birth or latitude of place of living and CD [12][13][14][15][16][17]. These observations have led to a proposition known as the vitamin D deficiency-CD hypothesis [18].…”

Seasonality of birth affects paediatric coeliac disease

“…We found that 699 of 308 903 live births in one Israeli hospital were diagnosed with CD and autumn births were associated with a higher risk for developing CD, with an incidence ratio of 1.22. The autumn high season increased the incidence ratio even higher to 1.40. autumn increased the risk for future CD compared with birth during the winter (19). A study conducted in central Israel found that births during the autumn were associated with CD (20).…”

Borrelia infection and risk of celiac disease

“…In the USA, celiac disease has been found to be most prevalent in the Northeast and the Midwest regions [ 30 ], where the great majority of cases of B. burgdorferi infection also occur [ 19 ]. In Sweden, the highest incidence of celiac disease has been associated with the southern region [ 31 ], where Lyme disease is endemic [ 32 ]. Despite the similar pattern of geographic distribution and the publicized conjecture regarding a potential link between celiac disease and Lyme borreliosis, studies to assess such an association are lacking.…”