Some studies have argued that obstructive sleep apnoea (OSA) increases the risk of breast cancer. However, the results are often conflicting. This study aimed to investigate associations between OSA and breast cancer incidence using the Korea National Health Insurance Service (KNHIS) database. This retrospective cohort study analyzed data from the KNHIS database. A total of 45,699 women (≥20 years of age) newly diagnosed with OSA between 2007 and 2014 were included. The control groups were a 5-fold, age-matched women who had not been diagnosed with OSA. Mean follow-up duration was 3.7 ± 2.3 years. The primary endpoint was newly diagnosed breast cancer. The breast cancer hazard ratio (95% confidence interval) was calculated for patients with OSA and compared with that of the control group. The incidence of breast cancer among patients with OSA was significantly higher than that among the controls (1.20 [1.04–1.39]). In particular, the incidence of breast cancer was higher among patients aged ≥65 years (1.72 [1.10–2.71]). The result suggests that OSA may be a risk factor for breast cancer in women.

Objective: To perform a meta‐analysis on the distribution and characteristics of the obstructive site in patients with obstructive sleep apnea (OSA) using data from a variety of published studies that evaluated the obstruction with drug‐induced sleep endoscopy (DISE).Methods: A literature search was performed to identify studies in which DISE was used to identify the obstruction site in adult patients with OSA, and the obstruction site was described in sufficient detail. Four items were evaluated in the meta‐analysis: the obstruction site, closing direction of the soft palate, degree of closure, and percentage of single‐level obstructions.Results: A total of 2,950 patients from 19 studies were included. In the two‐level classification system, the rate of obstruction was 91.6% for the soft palate and 58.0% for the tongue base. In the four‐level classification system, the rate of obstruction was 84.1% for soft palate, 32.8% for the tonsil, 51.6% for the tongue base, and 34.3% for the epiglottis. The soft palate closed in the anteroposterior direction at a rate of 44.4% and in the concentric direction at a rate of 46.5%. The rate of a closure of 75% or more was 69.3% for the soft palate and 56.8% for the hypopharynx. The percentage of single‐level obstructions was 42.5%.Conclusion: The soft palate is obstructed in most patients with OSA, and the tongue base is obstructed in half of the patients. In addition, multilevel obstructions including the tonsil, lateral pharyngeal wall, or epiglottis are common; thus, these areas must be checked carefully.Level of Evidence: NA Laryngoscope, 129:1235–1243, 2019

Population-adjusted ratio=average cancer incidence number from 2009–2011/average incidence number from 1999–2001×1.053