RE: The Association of Dyslipidemia With Chronic Lymphocytic Leukemia: A Population-Based Study
Year: 2017
Type: letter
Abstract: We read with interest the recent paper by Mozessohn et al. regarding an association between dyslipidemia and chronic lymphocytic leukemia (CLL) (1). They report an adjusted odds ratio of 1.26 (95% confidence interval [CI] = 1.11 to 1.44) and conclude that dyslipidemia may increase risk of CLL. In contrast, our recent case-control study of multiple medical conditions and non-Hodgkin lymphoma in the United States found an inverse association between hyperlipidemia and risk of CLL/small lymphocytic lymphoma (SLL; adjusted odds ratio = 0.86, 95% CI = 0.83 to 0.90) (2). Our study and the Mozessohn study had very similar designs. Both identified cancer cases from cancer registries, included general population control subjects, and ascertained the presence of medical conditions before case diagnosis/control selection using administrative databases (Medicare in our study). Both studies were limited to elderly adults (age 66 years or older), but our study was much larger (18 236 vs 2124 cases) and covered a wider range of calendar years (cases diagnosed 1992–2009 vs 2000–2005). We have considered several possible explanations for differing results in the two studies. First, Mozessohn et al. assessed only CLL as the outcome (International Classification of Diseases [ICD] for Oncology, version 3, morphology code 9823), whereas we assessed CLL/SLL combined because SLL (code 9670) is now considered to be the same entity (3,4). Nonetheless, our results were similar for CLL and SLL separately (Table 1). Also, we assessed hyperlipidemia (ICD version 9 code 272.4). We reran our analyses considering the broader group of “disorders of lipoid metabolism” (ie, dyslipidemia, ICD9 272.X), and we still observed an inverse association (Table 1). Our cases and control subjects were not perfectly matched by age, but the inverse association persisted even with fine adjustment for age (Table 1). Our results were similar after we included additional adjustment for hypertension and diabetes mellitus, as was done by Mozessohn et al. in one set of analyses. Finally, the inverse association was present when we restricted cases and control subjects to those selected during 2000 to 2005, to match Mozessohn et al. Associations of hyperlipidemia and dyslipidemia with CLL/SLL among elderly adults in the United states Dyslipidemia was present in 98359 controls (49.2%), 6503 CLL cases (45.8%), and 1866 SLL cases (46.3%), as determined by the presence of 1 MEDPAR claim or 2 NCH/OUTPAITENT claims at least 30 days apart. The base model is adjusted for sex, age in 5 categories, race (white, black, other), calendar year of selection, and average number of provider visits per year (excluding the 12 months immediately preceding selection). Abbreviations: CLL chronic lymphocytic leukemia, SLL small lymphocytic lymphoma Associations of hyperlipidemia and dyslipidemia with CLL/SLL among elderly adults in the United states Dyslipidemia was present in 98359 controls (49.2%), 6503 CLL cases (45.8%), and 1866 SLL cases (46.3%), as determined by the presence of 1 MEDPAR claim or 2 NCH/OUTPAITENT claims at least 30 days apart. The base model is adjusted for sex, age in 5 categories, race (white, black, other), calendar year of selection, and average number of provider visits per year (excluding the 12 months immediately preceding selection). Abbreviations: CLL chronic lymphocytic leukemia, SLL small lymphocytic lymphoma We do not know the explanation for the different results in the two studies, but if the association were driven by a direct biological mechanism, one would expect similar findings. CLL/SLL can be detected at an asymptomatic stage, which makes it difficult to determine whether associations of CLL/SLLL with medical risk factors reflect differential access to or utilization of medical care. Given the conflicting findings in these two studies, we urge caution in making etiologic conclusions and point to a need for further assessment.
DOI: 10.1093/jnci/djx026
Authors: Eric A. Engels, Ruth Parsons, Caroline Besson, Lindsay M. Morton, Elizabeth L. Yanik, Hannah Arem, Ruth M. Pfeiffer
Language: English
Subfield: Genetics
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2606540596