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Purpose: To explore the risk of infections in individuals with IgA deficiency compared to general population controls. Methods: In this nationwide prospective population-based cohort study, we used data on IgA levels (<0.07 g/L) from six university hospitals in Sweden to identify 2100 individuals with IgA deficiency. Individuals were diagnosed between 1980 and 2010. For each patient with IgA deficiency we identified 10 controls from the general population, matched on age, sex, and place of residence ( n = 18,653). Data on infections were obtained from the Swedish National Patient Register (including inpatient and hospital-based outpatient care) between 2001 and 2010. We defined infections as having a record of a relevant international classification of disease (ICD) code. Prevalences and prevalence ratios (PRs) were calculated. Results: Individuals with IgA deficiency were more likely to have a record of any infection (36.1 vs. 18.8 % in controls) corresponding to a PR of 2.4 (95%CI 2.2-2.6). We also noted statistically significant associations with IgA deficiency (all P-values <0.05) and respiratory tract infections (17.8 vs. 6.3 % in controls; PR = 3.2), gastrointestinal infections (6.0 vs. 1.8 % in controls; PR = 3.5), skin infections (4.1 vs. 2.2 % in controls; PR = 1.9), joint infections (0.48 vs. 0.24 % in controls; PR = 2.0; P = 0.052), sepsis (1.5 vs. 0.45 % in controls; PR = 3.4), meningitis (0.38 vs. 0.12 %, PR = 3.2), mastoiditis/otitis (2.1 vs. 1.1 % in controls; PR = 2.0), and urinary tract infections (6.1 vs. 3.4 % in controls; PR = 1.8). Conclusions: Individuals with IgA deficiency are at an increased risk of infections requiring hospital care. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the risk of cancer in individuals with IgA deficiency compared with the general population. Methods: Prospective nationwide population-based cohort study. We identified 2320 individuals with IgA deficiency (IgA levels < 0.07 g/L) diagnosed between 1980 and 2010 in six Swedish university hospitals. Individuals with IgA deficiency were then matched on age, sex, place of residence, and year of diagnosis with up to 10 general population controls ( n = 23,130). Through linkage with the Swedish Cancer Register we calculated conditional hazard ratios (HRs) for cancer diagnosed after IgA deficiency diagnosis in patients without a previous cancer diagnosis. Results: During follow-up, 125 individuals with IgA deficiency (61/10,000 person-years) and 984 controls (47/10,000 person-years) developed cancer (HR 1.31; 95%CI = 1.09-1.58). In cause-specific analyses, we found an increased risk of any gastrointestinal cancer (HR = 1.64; 95%CI = 1.07-2.50), but not for lymphoproliferative malignancy (HR 1.68; 95%CI = 0.89-3.19). Relative risk estimates for overall cancer were very high in the first year of follow-up (overall: HR = 2.80; 95%CI = 1.74-4.49), but failed to reach statistical significance thereafter. IgA deficiency diagnosed in childhood ( n = 487) was not associated with overall cancer (HR = 3.26; 0.88-12.03). Conclusions: Individuals with IgA deficiency are at a moderately increased risk of cancer, with excess risks of gastrointestinal cancer. This excess risk is highest just after diagnosis suggesting a degree of surveillance bias. Children with IgA deficiency were at no increased risk of cancer but the statistical power was limited in subanalyses. [ABSTRACT FROM AUTHOR]

Background: Several autoimmune disorders have been linked to adverse pregnancy outcome. IgA deficiency shares many autoimmune traits, but its association with pregnancy outcome is unknown. Methods: Prospective population-based cohort study in Sweden of 613 mothers with IgA deficiency (IgA levels < .07 g/L) diagnosed in 1980-2010 in six university hospitals. In 1973-2010, these women delivered 1,172 singleton infants registered in the Swedish Medical Birth Register. Each delivery to a woman with IgA deficiency was matched on maternal age, parity, early pregnancy smoking status, education level, and delivery year with up to 5 control births ( n = 5,758). Results: Offspring to women with IgA deficiency had 79 g lower birth weight than controls (mean ± SD: 3,457 ± 559 vs 3,537 ± 553 g, P < 0.001), and 1.4 days shorter gestational age (mean ± SD: 278 ± 13 vs 280 ± 14 days, P = 0.001). No difference in preterm birth (<37 weeks) could be detected in deliveries to women with IgA deficiency vs control deliveries (5.8 % vs 5.2 %; odds ratio (OR) = 1.13, 95%CI = 0.85-1.49), but small for gestational age birth was more common (4.3 % vs 2.8 %; OR = 1.48, 95%CI = 1.04-2.10). Women with IgA deficiency also delivered more often by caesarean section (16.9 % vs 11.9 %; OR = 1.51, 95%CI = 1.26-1.82), while no difference was observed regarding low Apgar score (<7 at 5 min; 1.1 % vs 1.0 %; OR = 1.18; 95%CI = 0.62-2.27). When excluding women with autoimmune diseases, the excess risks of adverse pregnancy outcome diminished. Conclusion: There is a small excess risk of certain adverse delivery and perinatal outcomes among offspring to women with IgA deficiency. These excess risks are attenuated when considering the presence of autoimmune diseases. [ABSTRACT FROM AUTHOR]

Purpose: To examine autoimmune disorders in patients with IgA deficiency compared with the general population. Methods: Nationwide prospective population-based cohort study. Through six university hospitals in Sweden we identified 2100 individuals with IgA deficiency (IgA levels < .07 g/L) diagnosed between 1980 and 2011. Each patient with IgA deficiency was matched on age, sex, place of residence, and year of diagnosis with up to 10 general population controls ( n = 18,653). Data on nine autoimmune disorders were retrieved from the Swedish National Patient Register (including inpatient and non-primary outpatient care). Autoimmune disorders were defined as having at least two visits listing the relevant international classification of disease (ICD) code as main diagnosis. Prevalences and prevalence ratios (PRs) were calculated. Results: Individuals with IgA deficiency more often had celiac disease (6.7 % vs. 0.19 % in controls) and type 1 diabetes (5.9 % vs. 0.57 %) corresponding to a 35-fold higher PR for celiac disease and 10-fold higher for type 1 diabetes. Also for the other autoimmune diseases did we see statistically significantly elevated prevalences and PRs (juvenile idiopathic arthritis (0.76 % vs. 0.09 % in controls, PR = 8.9), systemic lupus erythematosus (0.57 % vs. 0.06 %; PR = 8.9), inflammatory bowel disease (3.9 % vs. 0.81 %; PR = 5.0; specifically Crohn's disease (2.4 % vs. 0.42 %; PR = 5.7) and ulcerative colitis (1.7 % vs. 0.46 %; PR = 3.9)), hypothyreosis (0.76 % vs. 0.16 %; PR = 4.6), rheumatoid arthritis (2.2 % vs. 0.50 %; PR = 4.5), and hyperthyreosis (1.7 % vs. 0.43 %; PR = 3.9), but not with myasthenia gravis (0.05 % vs. 0.02 %; PR = 3.0). Conclusions: Individuals with IgA deficiency have a higher prevalence of several other autoimmune disorders. [ABSTRACT FROM AUTHOR]