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Season of birth affects risk for Addison’s disease

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September 6, 2016

British and Polish adults born in winter months are more likely to develop Addison’s disease vs. those born in summer months, according to recent findings.

Agnieszka Pazderska, MD, of the Institute of Genetic Medicine at Newcastle University, United Kingdom, and colleagues analyzed data from two independent cohorts of adults with Addison’s disease. Using the Cosinor test, researchers compared the monthly distribution of birth for 415 British patients with Addison’s disease (312 women) with the pattern of total live births in England and Wales between 1963 and 1972 (n = 8,180,180) based on demographic information from the Office for National Statistics. They conducted a similar comparison with 231 Polish patients with Addison’s disease (167 women) vs. total live births in Poland for 1980, 1990, 2010 and 2012, based on data from the Polish Statistical Annals (n = 2,421,384). Within the two cohorts, 46% of British patients and 27% of Polish patients had isolated Addison’s disease; the remainder had at least one other autoimmune condition.

Researchers observed a signal for periodicity after adjusting for sex and country of origin (P = .028), but when analyzing the cohorts separately, the signal persisted only in the Polish cohort (P = .042). Patients with Addison’s disease showed a peak of births in December, with a nadir in June.

In the British cohort, the OR for developing Addison’s disease was highest among those born in December (OR = 1.41; 95% CI, 1.035-1.92) and lowest among those born in May (OR = 0.61; 95% CI, 0.4-0.93) vs. the general population. In the Polish cohort, the OR was highest among those born in January (OR = 1.5; 95% CI, 1.02-2.1) and lowest among those born in July (OR = 0.56; 95% CI, 0.31-0.99) vs. the general population.

The researchers noted that the findings mirror observations suggesting a peak incidence of type 1 diabetes among those born in autumn and winter months, possibly linked to the increase in viral infections observed during this period of the year.

“Our study demonstrates that month of birth exerts an effect on the risk for developing [Addison’s disease], with excess risk in individuals born in winter months and a protective effect when born in the summer,” the researchers wrote. “Exposure to seasonal viral infections in the perinatal period, coupled with vitamin D deficiency leading to dysregulation of innate immunity, could be the potential initial triggers for the eventual development of [Addison’s disease], although this requires further exploration.” – by Regina Schaffer

Disclosure: The researchers report no relevant financial disclosures.