Objective To analyze the relationship between passive smoking and breast diseases in primary-level ultrasound screening in Liaoning province, China, and to provide a basis for women's breast screening and tobacco control.

Methods From May to August 2021, women in urban and rural areas in Shenyang, Donggang, Fengcheng and other places in Liaoning Province were screened for breast diseases with a handheld ultrasound machine. 1 973 people who were effectively screened were included. The effects of demographic characteristics and passive smoking-related factors on breast diseases were analyzed. Associations between diseases, passive smoking-related factors and BI-RADS classification, and analysis of risk factors for breast diseases.

Results There were significant differences in the age group, BMI, family history of breast cancer and amenorrhea between the two groups of subjects (χ² were 24.56, 14.35, 26.38, 7.19, respectively, P<0.05); passive smoking exposure, exposure to passive smoking There were statistically significant differences between the main place, the environment, the number of people who were in close contact with them, the number of times, and the age of the breast disease at the time of the study (χ² were 11.94, 20.98, 12.81, 12.41, 35.17, 47.50, P<0.05); Multivariate Logistic regression showed that passive smoking exposure was a risk factor for breast disease (OR=5.414, 95%CI: 2.745-10.680); grass-roots women in the province who were exposed to passive smoking in an open environment had a higher risk of developing breast disease (OR=1.780, 95%CI: 1.191-2.660); among the people who are in close contact with smokers, the risk of breast disease is highest when they are in contact with 2-3 people (OR=1.947, 95%CI: 1.339-2.831); women who were exposed to passive smoking 4-6 times or more than 6 times a week had a higher risk of breast disease (OR=2.656, 95%CI: 1.465-4.815), (OR=2.114, 95%CI: 1.153-3.877); women's exposure to passive smoking for more than 30 years was a risk factor for breast disease (OR=71.090, 95%CI: 33.517-150.785). There were statistically significant differences between the passive smoking exposure, the main places when exposed to passive smoking, the environment, the number of people who were in close contact with smokers, the number of times, and the composition ratio of years between cases with different BI-RADS classifications (χ² were 12.69, 27.08, 20.60, 15.50, 16.26, 13.95, respectively, P<0.05). Passive smoking exposure was an independent risk factor for BI-RADS classification (OR=2.789, 95%CI: 1.277-6.094).

Conclusion Exposure to passive smoking may increase the risk of breast disease in women, among which the passive smoking environment, the number, frequency and years of close contact with smoking are the influencing factors.