Insomnia and obstructive sleep apnea in women with breast cancer: Prevalence and associated factors in greater São Paulo

INTRODUCTION Insomnia and obstructive sleep apnea (OSA) are the most prevalent sleep disorders in adults, yet with distinct pathophysiology: insomnia involves central hyperarousal and cognitive-functional impairment, while OSA results from upper airway collapse with intermittent hypoxia and elevated sympathetic tone. In oncology patients, the coexistence of these conditions may intensify fatigue and compromise treatment adherence. In the Greater ABC region of São Paulo, data on prevalence and determinants of these disorders in women with breast cancer remain scarce.

Method

Analytical crosssectional study with 211 women in outpatient breast cancer treatment at state hospitals in the São Paulo metropolitan region. The Insomnia Severity Index (ISI; score 0–28) was used for insomnia screening and the STOP-Bang Questionnaire (score 0–8) for OSA risk, both validated for Brazilian Portuguese, alongside a structured clinical-sociodemographic form. Sample size by Wald method (n=208; 95% CI). Analyses in Stata 17.0: descriptive statistics, Wilsonmethod prevalences, Pearson correlation and logistic regression. CEP-FMABC: CAAE 90818825.2.0000.0082. RESULT Clinically significant insomnia (ISI≥15): 28.9% (95% CI: 22.7–35.6). Intermediate/high OSA risk (STOP-Bang≥3): 47.9% (95% CI: 41.0–54.8). ISI × STOP-Bang correlation was weak and non-significant (r=0.075; p=0.280), confirming independent phenomena. BMI was associated with both outcomes (p<0.05); age only with OSA risk (p<0.001). Nocturnal pain and lack of marital support were associated with insomnia.

Discussion

Insomnia and OSA showed distinct determinants: insomnia linked to socioeconomic and clinical factors; OSA to metabolic-anatomical variables and aging, reinforcing the need for independent assessment of each condition.

Conclusion

Insomnia and OSA are prevalent and independent in women with breast cancer, with specific determinants, requiring differentiated and complementary screening in outpatient oncological care.