[Case-control study of female breast cancer and occupational risk factors based on lasso logistic regression in Beijing].

Objective: To understand the relationship between female breast cancer and occupational risk factors in Beijing, and provide scientific basis for the formulation of prevention strategies and measures. Methods: From June to December 2019, A 1: 1 case-control study was adopted, eight medical institutions in Beijing were selected as the research objects. Patients with breast cancer diagnosed by medical institutions were selected as case group and non breast cancer patients in the same medical institution as control group. A total of 973 subjects were included, including 495 in the case group and 478 in the control group. A one-to-one survey was conducted using a questionnaire uniformly compiled by the Beijing Centers for Disease Control and Prevention. The survey content mainly includes basic demographic characteristics and occupational risk factors. The Trait Coping Style Questionnaire (TCSQ) was used to investigate the corresponding methods, including two aspects: positive coping and negative coping. First, chi square test or Wilcoxon rank sum test were used for univariate analysis. Then Lasso regression was used to screen the risk factors of breast cancer. Finally, the risk factors were screened by multivariate logistic regression analysis. Results: Education lovel was 49.64%, body mass index (BMI) was 18.4~23.9 kg/m(2), accounting for 48.82%, marital status ws 84.48%. Compared with no night shift history, there was a significant increase in risk of breast cancer at night shift history (OR=1.70, 95% CI: 1.25~2.30, P<0.05) . Compared with most of the sitting posture and sometimes standing, the risk of breast cancer was increased, and the difference was statistically significant (OR=2.01, 95%CI: 1.40~2.90, P<0.05) . Conclusion: In the occupation risk factors, night shift work and working posture are related to the incidence of breast cancer in women, establishing a good schedule and avoiding long standing can effectively prevent and reduce the occurrence of breast cancer.

[Relationship between intrauterine device and intrauterine pressure and levels of PGs in uterine fluid].

PIP: 73 healthy, parous nonpregnant women were examined for intrauterine pressure (IUP) and levels of 6-keto-prostaglandin Flalpha (PGF1alpha) and TXB2 in uterine fluid were examined before and after insertion of an IUD and then 1 month after insertion. The authors wanted to see the relationship between IUP, IUD expulsion, and relative factors affecting IUP. Results were as follows: 1. The IUP of healthy parous women during days 8-14 of the menstrual cycle was 1.91 +or- 1.18 kPa (95% confidence limits: 1.64, 2.18 kPa) and frequency was 2.68 +or- 1.25 times/minute. 2. In spite of IUD insertion, IUP rose significantly. But IUD insertion did not produce any longterm effects of IUP (p0.05). IUP had some effects on IUD expulsion. Prior to IUD insertion, the higher the IUP was, the easier was the IUD expulsion (p0.05). 3. Disparity in laxity degree of internal cervical orifice and gravida/parity had no effects on IUP (p,0.05). Insertion of different types of IUD had no effects on IUP either (p0.01). 4. 1 month after IUD use, the levels of 6-keto-PGF1alpha and TXB2 in uterine fluid could rise significantly, but the rate of P/T had not remarkable changes. The results indicate that a linear negative correlation exists between IUP and ratio of P/T (r=0/264, p0.05). (Author's modified)^ieng