Notes
Oral contraceptive use has been suggested to influence the risk of breast, ovarian, and endometrial cancer. The purpose of this study is to clarify the time-dependent effects between long-term oral contraceptive use and cancer risk. We performed an observational study in 256,661 women from UK Biobank, born between 1939 and 1970. Information on cancer diagnoses were collected from self-reported data and from national registers until March 2019. Cumulative risk of cancer over the timespan of the study, as measured by the OR, and instantaneous risk, as measured by the HR, were assessed using Logistic and Cox regression analyses, respectively. The odds were lower among ever users, compared with never users, for ovarian cancer [OR = 0.72; 95% confidence interval (CI), 0.65-0.81] and endometrial cancer (OR = 0.68; 95% CI, 0.62-0.75), an association that was stronger with longer use (P < 0.001). Increased odds were seen for breast cancer in women when limiting the follow-up to 55 years of age (OR = 1.10; 95% CI, 1.03-1.17), but not for the full timespan. We only found a higher HR for breast cancer in former users immediately (≤2 years) after discontinued oral contraceptive use (HR = 1.55; 95% CI, 1.06-2.28), whereas the protective association for ovarian and endometrial cancer remained significant up to 35 years after last use of oral contraceptives. Given the body of evidence presented in our study, we argue that oral contraceptives can dramatically reduce women's risk of ovarian and endometrial cancer, whereas their effect on lifetime risk of breast cancer is limited.
SIGNIFICANCE: These results enable women and physicians to make more informed decisions considering oral contraceptive use, thus constituting an important step toward personalized medicine.
Application 41143
Effects of diet and lifestyle, and their interactions with genetic variants, on our health
In this project, we will evaluate the health-related effects of three common exposures on population health. The aims are to:
1) to determine the optimal level of oily fish consumption in order to maximize the bifacial effects, to investigate if omega-3 supplement can replace oily fish intake, and to compare to the effects seen in individuals carrying genetic variants that allow for faster biosynthesis of the fatty acids that are present in oily fish.
2) investigate the relative risk of disease in women taking contraceptive pills compared to women not taking contraceptive pills and how this risk differs in women carrying a genetic variant associated with increased risk for venous thrombosis
3) investigate the relative risk of disease in persons that have been breastfeed in compared to persons that not have been breastfeed.
Oily fish intake and omega-3 supplements as well as use of contraceptive pills and weather a person has been breastfeed or not, are common factors that have been associated with many health effects. We will therefore investigate a wide spectrum of diseases and disease-traits as health outcomes including: cardiovascular diseases (acute myocardial infarction, cerebral infarction, intra cerebral haemorrhage, hypertension, atherosclerosis, deep vein thrombosis, pulmonary embolism), some of the most common cancers (breast, cervical, ovarian, colorectal, endometrial, kidney), benign breast disease, inflammatory diseases (rheumatoid arthritis, osteoarthritis, irritable bowel syndrome, inflammatory bowel disease), atopic diseases (asthma, allergy, allergic rhinitis, eczema), mental health issues (depression, anxiety, panic attacks), diabetes (type I and II), osteoporosis, fluid intelligence and educational attainment.
Many common exposures have been associated with variable risk for disease risk. However, we also know that exposures have variable effects in different groups of individuals depending on for example sex, age, socioeconomic status or on genetic factors. Using data from UK biobank, will allow for more precise results which can lead to a better understanding of the causal effect of different exposures on disease risk. The main rationale for this project is that the society needs clear recommendations for diet, lifestyle and use of different pharmaceuticals which will help the individuals as well as the healthcare system to make more qualified choices/recommendations which will result in better population health.
The data analyses will take place during 2018 and writing of manuscripts and presentation results during 2019. We expect the results from the project to be published in late 2019.
Lead investigator: | Professor Asa Johansson |
Lead institution: | Uppsala University |