Associations between Medical Conditions and Breast Cancer Risk in Asians: A Nationwide Population-Based Study in Taiwan

• Published in: PloS one Vol. 10; no. 11; p. e0143410
• Main Authors: Chuang, Shu-Chun, Wu, Guo-Jie, Lu, Yen-Shen, Lin, Ching-Hung, Hsiung, Chao Agnes
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 25.11.2015; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Analysis; Asian Continental Ancestry Group; Breast cancer; Breast Neoplasms - epidemiology; Breast Neoplasms - etiology; Cancer; Cancer screening; Care and treatment; Case-Control Studies; Chronic Disease - epidemiology; Comorbidity; Confidence intervals; Diagnosis; Digits; Diseases; Disorders; Endometriosis; Estrogens; Etiology; Female; Fibroids; Health insurance; Health risk assessment; Health risks; Health Status; Heterogeneity; Humans; Hypertension; Lipid metabolism; Literature reviews; Medical diagnosis; Medical research; Metabolism; Middle Aged; Obesity; Online databases; Population studies; Population Surveillance; Population-based studies; Regression analysis; Risk; Risk analysis; Risk factors; Statistical analysis; Studies; Taiwan - epidemiology; Thyroid cancer; Uterus; Womens health; Young Adult; Taiwan; Asia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0143410

The breast cancer incidence in Asia is rising. To explore whether the etiology of breast cancer is different from the known risk factors from studies in Western countries, we conducted a nested case-control study using data from the Taiwan National Health Insurance Research Database (NHIRD). All medical conditions based on the first three digits of the ICD-9 and a list of medical conditions based on literature review were retrieved for each case and control. The odds ratios (OR) and 95% confidence intervals (CI) of the associations between medical conditions and breast cancer risks were estimated using conditional logistic regression and adjusted for occupation, number of breast cancer screening, and the average number of outpatient visits prior the diagnosis. The associations were also estimated for younger (<50 years old) and older subjects separately. The analyses included 4,884 breast cancer cases and 19,536 age-matched controls. Prior breast diseases (OR, 95% CI: 2.47, 2.26-2.71), obesity (1.43, 1.04-1.96), endometriosis (1.44, 1.15-1.80), uterine leiomyoma (1.20, 1.03-1.40), hypertensive diseases (1.14, 1.05-1.25), and disorders in lipid metabolism (1.13, 1.04-1.24) were associated with increased breast cancer risk. No heterogeneity was observed between age groups (<50 and ≥50 years old). In addition to benign breast diseases, obesity, endometriosis, uterine leiomyoma, hypertensive diseases, and disorders of lipid metabolism were associated with a subsequent breast cancer risk. Our results suggest that estrogen related factors may play an important role in breast cancer risks in the Taiwanese female population.