Medically diagnosed infections and risk of childhood leukaemia: a population-based case-control study
ABSTRACT Previous studies on the association between childhood infections and childhood leukaemia have produced inconsistent results, likely due to the recall error/bias of infection data reported by the parents. The current study used a population-based and record-based case-control design to evaluate the association between childhood leukaemia and infections using the National Health Insurance Research Database of Taiwan.
In all, 846 childhood acute lymphoblastic leukaemia (ALL) and 193 acute myeloid leukaemia (AML) patients newly diagnosed between 2000 and 2008, aged >1 and <10 years, were included. Up to four controls (3374 for ALL and 766 for AML) individually matched to each case on sex, birth date and time of diagnosis (reference date for the controls) were identified. Conditional logistic regression was performed to assess the association between childhood leukaemia and infections.
Having any infection before 1 year of age was associated with an increased risk for both childhood ALL (odds ratio = 3.2, 95% confidence interval 2.2-4.7) and AML (odds ratio = 6.0, 95% confidence interval 2.0-17.8), with a stronger risk associated with more episodes of infections. Similar results were observed for infections occurring >1 year before the cases' diagnosis of childhood leukaemia.
Children with leukaemia may have a dysregulated immune function present at an early age, resulting in more episodes of symptomatic infections compared with healthy controls. However, confounding by other infectious measures such as birth order and day care attendance could not be ruled out. Finally, the results are only relevant to the medically diagnosed infections.
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ABSTRACT: The enduring suspicion that infections and immunologic response may play a role in the etiology of childhood leukemia, particularly acute lymphoblastic leukemia (ALL), is now supported, albeit still indirectly, by numerous epidemiological studies. The cumulative evidence includes, for example, descriptive observations of a peculiar peak incidence at age 2-5 years for ALL in economically developed countries, clustering of cases in situations of population mixing associated with unusual patterns of personal contacts, associations with various proxy measures for immune modulatory exposures early in life, and genetic susceptibility conferred by variation in genes involved in the immune system. In this review, our focus is the extended major histocompatibility complex (MHC), an approximately 7.6 Mb region that is well-known for its high-density of expressed genes, extensive polymorphisms exhibiting complex linkage disequilibrium patterns, and its disproportionately large number of immune-related genes, including human leukocyte antigen (HLA). First discovered through the role they play in transplant rejection, the classical HLA class I (HLA-A, -B, and -C) and class II (HLA-DR, HLA-DQ, and HLA-DP) molecules reside at the epicenter of the immune response pathways and are now the targets of many disease susceptibility studies, including those for childhood leukemia. The genes encoding the HLA molecules are only a minority of the over 250 expressed genes in the xMHC, and a growing number of studies are beginning to evaluate other loci through targeted investigations or utilizing a mapping approach with a comprehensive screen of the entire region. Here, we review the current epidemiologic evidence available to date regarding genetic variation contained within this highly unique region of the genome and its relationship with childhood ALL risk.Frontiers in Oncology 01/2013; 3:300. DOI:10.3389/fonc.2013.00300
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ABSTRACT: BACKGROUND:: Statins have been postulated to prevent infection through immunomodulatory effects. OBJECTIVES:: To compare the incidence of infections in statin users to that in nonusers within the same health care system. METHODS:: This was a retrospective cohort study of patients enrolled as Tricare Prime or Plus in the San Antonio military multimarket. Statin users were patients who received a statin for at least 3 months between October 1, 2004 and September 30, 2005. Nonusers were patients who did not receive a statin within the study period (October 1, 2003-September 30, 2009). Inpatient and outpatient International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes were used to determine the incidence of infections during the follow-up period (October 1, 2005-September 30, 2009) via multivariable regression analysis and time to infection via Cox regression analysis. RESULTS:: Of 45,247 patients who met the study criteria, 12,981 (29%) were statin users and 32,266 were nonusers. After adjustments for age, gender, Charlson Comorbidity Score, tobacco use, alcohol abuse/dependence, health care utilization and use of specific medication classes, statin use was associated with an increased incidence of common infections (odds ratio [OR]: 1.13; 95% confidence interval [CI]: 1.06-1.19) but not influenza or fungal infections (OR: 1.06, 95% CI: 0.80-1.39; OR: 0.97; 95% CI: 0.91-1.04, respectively). Time-to-first infection was similar in statin users and nonusers in all infection categories examined. CONCLUSIONS:: Statin use was associated with an increased incidence of common infections but not influenza or fungal infections. This study does not support a protective role of statins in infection prevention; however, the influence of potential confounders cannot be excluded.The American Journal of the Medical Sciences 02/2013; DOI:10.1097/MAJ.0b013e31828318e2 · 1.52 Impact Factor
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ABSTRACT: Evidence has emerged that pioglitazone may increase the risk of bladder cancer, but the association has not been confirmed. This potential risk also has not been evaluated in users of rosiglitazone. Using Taiwan's National Health Insurance Research Database (NHIRD), this large population-based nested case-control study was conducted to explore the relationship between the use of rosiglitazone or pioglitazone and risk of bladder cancer in diabetic patients. We identified 3,412 cases of newly diagnosed bladder cancer and 17,060 controls (1:5 matched by age and sex) among a diabetic patient cohort from the NHIRD. We defined an index date for each case as the date of first hospitalization for bladder cancer. Each control was assigned the index date of their corresponding case. Multivariable conditional logistic regressions were used to estimate the association between exposure (timing and duration) to rosiglitazone or pioglitazone and bladder cancer. We defined rosiglitazone or pioglitazone exposure as "current" if the prescription duration covered the index date or ended at 90 days before, as "recent" if it ended 91-180 days before the index date, or as "past" if the last prescription ended more than 180 days before. Duration of rosiglitazone or pioglitazone use was defined based on the cumulative days of exposure prior to the index date: <1, 1-2 and ≥2 years. Rosiglitazone and pioglitazone use were associated with risk of bladder cancer and the associations were stronger with a longer term of exposure (pioglitazone <1 year odds ratio [OR] 1.45 [95 % CI 1.12-1.87, p < 0.01], 1-2 years OR 1.74 [95 % CI 1.05-2.90, p = 0.03] and ≥2 years OR 2.93 [95 % CI 1.59-5.38, p < 0.01]; rosiglitazone <1 year OR 0.98 [95 % CI 0.82-1.17, p = 0.81], 1-2 years OR 1.78 [95 % CI 1.31-2.39, p < 0.01] and ≥2 years OR 2.00 [95 % CI 1.37-2.92, p < 0.01]). Long-term exposures to pioglitazone and rosiglitazone were associated with higher odds of bladder cancer, and the highest odds were seen in users with ≥2 years of exposure.Drug Safety 06/2013; DOI:10.1007/s40264-013-0080-4 · 2.62 Impact Factor