RESUMEN
INTRODUCTION: Understanding the patterns of mammography use and monitoring changes in use are essential to improving national health policy for breast cancer control. We aimed to describe the use of mammography in Portugal and to identify the determinants of its nonuse and underuse by examining data from the National Health Survey 2014. METHODS: We analyzed data on 8,758 women aged 30 years or older. We defined women at an eligible age for mammography as women aged 45 to 69. Women who reported a previous mammography test were classified as ever-users and grouped according to time since the most recent test. We computed the prevalence of mammography use, and we used Poisson regression models to obtain age-adjusted and education-adjusted prevalence ratios and 95% confidence intervals. RESULTS: The overall prevalence of mammography use was 80.0%, whereas nonuse was 20.0% and underuse 27.3% among users. The prevalence of nonuse and underuse were lower and associations with sociodemographic characteristics, use of health care services, and behavioral factors were stronger among women aged 45 to 69 than among women aged 30 to 44 and women aged 70 or older. The prevalence of mammography use was generally higher in the northern areas of Portugal than in southern areas and varied by marital status, educational level, and household size. A more frequent use of health care services and healthier behaviors were associated with lower prevalences of both nonuse and underuse. CONCLUSION: This study illustrates inequalities in mammography use and provides useful information for better allocation of resources in breast cancer screening.