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Diabetes and breast cancer in T aiwanese women: a detection bias?
Author(s) -
Tseng ChinHsiao
Publication year - 2014
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/eci.12323
Subject(s) - medicine , diabetes mellitus , breast cancer , confounding , confidence interval , odds ratio , logistic regression , incidence (geometry) , cancer , gynecology , endocrinology , physics , optics
Purpose To evaluate whether diabetes is a risk factor for breast cancer considering confounders and potential detection examinations. Methods National Health Insurance data on 501 747 women without breast cancer were retrieved. Three‐year cumulative incidence (2003–2005) and risk ratios ( RR s) between diabetic and nondiabetic women were calculated. Potential detection examinations were compared between diabetic and nondiabetic women by chi‐square test. Odds ratios ( OR s) were estimated by logistic regression for diabetes status/duration with and without adjustment for potential detection examinations and confounders. Results The crude RR (95% confidence interval [ CI ]) for all ages, and age groups < 50, 50–64 and ≥ 65 years, was 2·62 (2·31–2·91), 2·69 (2·11–3·44), 1·39 (1·15–1·68) and 1·37 (1·03–1·84), respectively. Patients with diabetes more frequently received potential detection examinations than nondiabetes (17·5% vs. 7·4%, P ‐value < 0·001). The unadjusted OR (95% CI ) for breast cancer for diabetes status (yes vs. no) was 2·63 (2·31–2·98) and was significant for any diabetes duration. The OR for diabetes status was 1·81 (95% CI : 1·59–2·06) after adjustment for potential detection examinations. In models adjusted for potential detection examinations, age, living region, occupation, comorbidities and used medications, OR for diabetes status attenuated to 1·13 (95% CI 0·96–1·32, P ‐value = 0·14) and none was significant for any diabetes duration. Potential detection examinations were associated with a fivefold to sevenfold higher risk in various models, indicating a strong impact of detection bias. Conclusions An association between diabetes and breast cancer is observed, but this can be due to potential detection bias and confounders.