THU0669 GESTATIONAL AGE AT BIRTH AND THE RISK OF AUTOIMMUNE DISEASE

Background A preterm newborn has an immature immune system. Although preterm birth is associated with autoimmune hypothyreosis, it is unclear, whether it also could lead to an overall increased risk of autoimmune disease. Objective We assessed whether a shorter gestation increases the risk of special reimbursement for medication for hypothyreosis, rheumatic disease, or ulcerative colitis/Crohn’s disease Design/Methods A total of 235 622 children were born in Finland from Jan 1987 to Sep 1990, according to the Medical birth register, which provided also gestational age (GA) at birth. Data were linked by help of the personal identity number. A register held by the Social Insurance Institution provided the data on special reimbursements. We calculated cumulative incidences within gestational age groups until December 2014 and tested statistical significance by the chi-squared –test. Results At the end of the follow-up, 1354 men and 2200 women had at least one of the specified autoimmune diseases. The cumulative incidences differed by gestational age only regarding a 50% higher incidence for hypothyreosis among all subgroups of preterm wome (P=0.05). No other clear patterns were seen regarding autoimmune diseases among preterm born or early term born subgroups. Conclusion(s) Those born preterm develop hypothyreosis more often. However, the two other composite categories of autoimmune diseases were unrelated to gestational age pointing against an overall tendency toward autoimmune disease in preterm born young adults. Cumulative incidence (1/100,000) of four groups of autoimmune diseases 202 Disseminated connective tissue disorders, rheumatoid arthritis and other rheumatic diseases (A04.6, A39.8, A50.5, D76.0, D76.3, H20.1, H30, I33.0, I40.8, J84, K50.9, K51.9, K73.2, K74.3, K83.0, L40.5, M02, M05, M06, M08, M13.9, M30–M35, M45, M46.1, M46.9, M94.1, N03, N04, Q44.2). 104 Hypothyreosis 208 Ulcerative colitis or Crohn’s disease Disclosure of Interests:   Petteri Hovi Consultant for: Pfizer, Paid instructor for: Pfizer, Suvi Alenius: None declared, Pieta Nasanen-Gilmore: None declared, Mika Gissler: None declared, Eero Kajantie: None declared