Introduction Mammographic density (MD) which refers to the percentage of the radiologically dense fibroglandular tissue in the breast, is one of the most important risk factors for breast cancer. Although highly hereditary, MD is also influenced by other factors.

Objectives To study the influence of socio-demographic characteristics, lifestyle, gyneco-obstetrical conditions and occupational factors on the degree of MD among Tunisian women.

Methods A 04-months cross-sectional study was carried out on women aged between 25 and 68 years presenting to the Department of Radiology in the Centre of Maternity and Neonatology of Monastir, for the practice of mammography. Data collection was carried out through a survey on socio-demographic, medical and occupational characteristics of the participants. The study population was divided into two groups: professionally ‘active’ women and ‘inactive’ women. Density assessment was based on the BIRADS 2013 classification.

Results A total of 220 women were included in this study, with an average age of 45.2± 9.7 years. At the moment of the study, 63% of participants had a paid job. Mammographic density was significantly associated with level of education (p=0.009), type of diet (p=0.032), BMI (p=0.003), the period of the menstrual cycle when the mammography was realized (p=0.008). According to the multivariate analysis, determinants of MD were: level of education (p=0.011; OR=1.9 ; 95% CI = [1,15–3,12]), BMI (p=0,001; OR=2,67; 95% CI = [1,46–4,88]), occupational status (p=0.002; OR= 0.26; 95% CI = [0.11–0.62]) and number of weekly working hours (p=0.002; OR=4.4; 95% CI = [1.76–11.16]).

Conclusion Mammographic density is an established risk factor for breast cancer. It is dependent on several individual, hormonal and occupational factors. Its modifiable character justifies the information and sensibilization of concerned women, as well as the implementation of adequate preventive measures in workplaces.