Curvilinear incidence models for parity in the entire fertility range for cancers of the breast, ovary, and endometrium: A follow-up of the Norwegian 1960 Census.

The protective effect of parity has been demonstrated for cancer of the breast, ovary, and endometrium but no studies have estimated the effect of each subsequent birth in women with 10 or more children or grand-grand parity women, nor compared the linear relationship of the three cancers sites. Here, we aim to explore these relationships based on the Norwegian 1960 Census. The question of parity in present marriage was answered by 385,816 women born 1870-1915, a period with high fertility.

Menopausal hormone therapy and incidence, mortality, and survival of breast cancer subtypes: a prospective cohort study.

Background: Menopausal hormone therapy (MHT) is associated with an increased risk of postmenopausal breast cancer, predominantly the luminal A-like subtype. The impact of MHT on deaths from breast cancer subtypes is less understood. This study aimed to explore associations between MHT use and the incidence, mortality, and survival of intrinsic-like breast cancer subtypes.

Trajectories of body mass index in adulthood and risk of subtypes of postmenopausal breast cancer.

Background: Body fatness is a dynamic exposure throughout life. To provide more insight into the association between body mass index (BMI) and postmenopausal breast cancer, we aimed to examine the age at onset, duration, intensity, and trajectories of body fatness in adulthood in relation to risk of breast cancer subtypes.

Methods: Based on self-reported anthropometry in the prospective Norwegian Women and Cancer Study, we calculated the age at onset, duration, and intensity of overweight and obesity using linear mixed-effects models.

Cohort profile: The Clinical and Multi-omic (CAMO) cohort, part of the Norwegian Women and Cancer (NOWAC) study.

Introduction: Breast cancer is the most common cancer worldwide and the leading cause of cancer related deaths among women. The high incidence and mortality of breast cancer calls for improved prevention, diagnostics, and treatment, including identification of new prognostic and predictive biomarkers for use in precision medicine.

Material And Methods: With the aim of compiling a cohort amenable to integrative study designs, we collected detailed epidemiological and clinical data, blood samples, and tumor tissue from a subset of participants from the prospective, population-based Norwegian Women and Cancer (NOWAC) study.

Associations of breast cancer related exposures and gene expression profiles in normal breast tissue-The Norwegian Women and Cancer normal breast tissue study.

Background: Normal breast tissue is utilized in tissue-based studies of breast carcinogenesis. While gene expression in breast tumor tissue is well explored, our knowledge of transcriptomic signatures in normal breast tissue is still incomplete. The aim of this study was to investigate variability of gene expression in a large sample of normal breast tissue biopsies, according to breast cancer related exposures (obesity, smoking, alcohol, hormone therapy, and parity).

Lifetime Sunburn Trajectories and Associated Risks of Cutaneous Melanoma and Squamous Cell Carcinoma Among a Cohort of Norwegian Women.

Importance: To our knowledge, no study has prospectively investigated sunburn patterns over age periods from childhood to adulthood and their associations with skin cancer risk.

Objective: To identify lifetime trajectories of sunburns and compare the association between these trajectories and subsequent risk of cutaneous melanoma and squamous cell carcinoma (cSCC).

Design, Setting, And Participants: This population-based cohort study included participants from the Norwegian Women and Cancer Study, established in 1991, with follow-up through 2018.

Use of Selective Serotonin Reuptake Inhibitors - Validity of Self-Report versus Plasma Concentrations and Pharmacy Dispensations - A Cross-Sectional Analysis of the Norwegian Women and Cancer Study.

Purpose: To validate self-reported current use of selective serotonin reuptake inhibitors (SSRI) in the Norwegian Women and Cancer study (NOWAC) and to identify factors associated with discordance between data sources.

Material And Methods: This is a cross-sectional record-linkage study comparing SSRI-use derived from four data sources: 1) Specific SSRI questions in the main NOWAC questionnaire, 2) Open questions on medication use in the small questionnaire following blood samples, 3) plasma concentration measurements for a subsample, and 4) pharmacy dispensations from the Norwegian prescription database (NorPD) where current use of SSRI was defined by Legend Time Duration (LTD). Among 105 855 women, aged 46 to 64 years and randomly selected from the general population, 70,191 had data on SSRI-use from both NOWAC and NorPD.

Epigenetic mechanisms of lung carcinogenesis involve differentially methylated CpG sites beyond those associated with smoking.

Smoking-related epigenetic changes have been linked to lung cancer, but the contribution of epigenetic alterations unrelated to smoking remains unclear. We sought for a sparse set of CpG sites predicting lung cancer and explored the role of smoking in these associations. We analysed CpGs in relation to lung cancer in participants from two nested case-control studies, using (LASSO)-penalised regression.

Seroprevalence of antibodies against SARS-CoV-2 in the adult population during the pre-vaccination period, Norway, winter 2020/21.

BackgroundSince March 2020, 440 million people worldwide have been diagnosed with COVID-19, but the true number of infections with SARS-CoV-2 is higher. SARS-CoV-2 antibody seroprevalence can add crucial epidemiological information about population infection dynamics.AimTo provide a large population-based SARS-CoV-2 seroprevalence survey from Norway; we estimated SARS-CoV-2 seroprevalence before introduction of vaccines and described its distribution across demographic groups.

Never-smokers and the fraction of breast cancer attributable to second-hand smoke from parents during childhood: the Norwegian Women and Cancer Study 1991-2018.

Background: Second-hand smoke (SHS) is not an established risk factor for breast cancer. We examined exposure to SHS from parents during childhood and breast-cancer risk overall and by oestrogen- and progesterone-receptor status in the Norwegian Women and Cancer Study. Furthermore, we utilized our nationally representative prospective cohort study to estimate the fraction of breast cancer attributable to parental SHS during childhood.

The blood transcriptome prior to ovarian cancer diagnosis: A case-control study in the NOWAC postgenome cohort.

Epithelial ovarian cancer (EOC) has a 5-year relative survival of 50%, partly because markers of early-stage disease are not available in current clinical diagnostics. The aim of the present study was to investigate whether EOC is associated with transcriptional profiles in blood collected up to 7 years before diagnosis. For this, we used RNA-stabilized whole blood, which contains circulating immune cells, from a sample of EOC cases from the population-based Norwegian Women and Cancer (NOWAC) postgenome cohort.

Sunscreens With High Versus Low Sun Protection Factor and Cutaneous Squamous Cell Carcinoma Risk: A Population-Based Cohort Study.

Evidence on sunscreen use and cutaneous squamous cell carcinoma (cSCC) risk is limited. Most studies have not taken sun protection factor (SPF) into consideration and used nonusers of sunscreen as the reference group. Nonusers are likely a priori at lower cSCC risk than users.

Heterogeneity of Associations between Total and Types of Fish Intake and the Incidence of Type 2 Diabetes: Federated Meta-Analysis of 28 Prospective Studies Including 956,122 Participants.

The association between fish consumption and new-onset type 2 diabetes is inconsistent and differs according to geographical location. We examined the association between the total and types of fish consumption and type 2 diabetes using individual participant data from 28 prospective cohort studies from the Americas (6), Europe (15), the Western Pacific (6), and the Eastern Mediterranean (1) comprising 956,122 participants and 48,084 cases of incident type 2 diabetes. Incidence rate ratios (IRRs) for associations of total fish, shellfish, fatty, lean, fried, freshwater, and saltwater fish intake and type 2 diabetes were derived for each study, adjusting for a consistent set of confounders and combined across studies using random-effects meta-analysis.

Transcriptomic signals in blood prior to lung cancer focusing on time to diagnosis and metastasis.

Recent studies have indicated that there are functional genomic signals that can be detected in blood years before cancer diagnosis. This study aimed to assess gene expression in prospective blood samples from the Norwegian Women and Cancer cohort focusing on time to lung cancer diagnosis and metastatic cancer using a nested case-control design. We employed several approaches to statistically analyze the data and the methods indicated that the case-control differences were subtle but most distinguishable in metastatic case-control pairs in the period 0-3 years prior to diagnosis.

Global blood gene expression profiles following a breast cancer diagnosis-Clinical follow-up in the NOWAC post-genome cohort.

Objective: This explorative study aimed to assess if there are any time-dependent blood gene expression changes during the first one to eight years after breast cancer diagnosis, which can be linked to the clinical outcome of the disease.

Material And Methods: A random distribution of follow-up time from breast cancer diagnosis till blood sampling was obtained by a nested, matched case-control design in the Norwegian Women and Cancer Post-genome Cohort. From 2002-5, women were invited to donate blood samples, regardless of any cancer diagnosis.

The fraction of lung cancer attributable to smoking in the Norwegian Women and Cancer (NOWAC) Study.

Background: We examined the association between active and passive smoking and lung cancer risk and the population attributable fraction (PAF) of lung cancer due to active smoking, in the Norwegian Women and Cancer Study, a nationally representative prospective cohort study.

Methods: We followed 142,508 women, aged 31-70 years, who completed a baseline questionnaire between 1991 and 2007, through linkages to national registries through December 2015. We used Cox proportional hazards models, to estimate hazard ratios (HRs) with 95% confidence intervals (CIs).

Stochastic Epigenetic Mutations Are Associated with Risk of Breast Cancer, Lung Cancer, and Mature B-cell Neoplasms.

Background: Age-related epigenetic dysregulations are associated with several diseases, including cancer. The number of stochastic epigenetic mutations (SEM) has been suggested as a biomarker of life-course accumulation of exposure-related DNA damage; however, the predictive role of SEMs in cancer has seldom been investigated.

Methods: A SEM, at a given CpG site, was defined as an extreme outlier of DNA methylation value distribution across individuals.

Menstrual Factors, Reproductive History, Hormone Use, and Urothelial Carcinoma Risk: A Prospective Study in the EPIC Cohort.

Background: Urothelial carcinoma is the predominant (95%) bladder cancer subtype in industrialized nations. Animal and epidemiologic human studies suggest that hormonal factors may influence urothelial carcinoma risk.

Methods: We used an analytic cohort of 333,919 women from the European Prospective Investigation into Cancer and Nutrition Cohort.

Predicting breast cancer metastasis from whole-blood transcriptomic measurements.

Objective: In this exploratory work we investigate whether blood gene expression measurements predict breast cancer metastasis. Early detection of increased metastatic risk could potentially be life-saving. Our data comes from the Norwegian Women and Cancer epidemiological cohort study.

Use of skincare products and risk of cancer of the breast and endometrium: a prospective cohort study.

Background: Concerns have been raised that extensive use of personal care products that contain endocrine disrupting compounds increase the risk of hormone sensitive cancers.

Objective: To assess the effect of skincare product use on the risk of pre- and postmenopausal breast cancer, estrogen receptor positive (ER+) and negative (ER-) breast cancer and cancer of the endometrium.

Methods: We used data from 106,978 participants in the population-based Norwegian Women and Cancer cohort.

Differential expression of the miR-17-92 cluster and miR-17 family in breast cancer according to tumor type; results from the Norwegian Women and Cancer (NOWAC) study.

Background: MicroRNAs (miRNAs) are promising biomarkers due to their structural stability and distinct expression profile in various cancers. We wanted to explore the miRNA expression in benign breast tissue and breast cancer subgroups in the Norwegian Women and Cancer study.

Methods: Specimens and histopathological data from study participants in Northern Norway diagnosed with breast cancer, and benign tissue from breast reduction surgery were collected.

Association of Lifetime Indoor Tanning and Subsequent Risk of Cutaneous Squamous Cell Carcinoma.

Importance: No study, to our knowledge, has prospectively investigated a dose-response association between lifetime indoor tanning and risk of cutaneous squamous cell carcinoma (SCC).

Objective: To investigate the dose-response association between lifetime indoor tanning and SCC risk, the association between duration of use and age at initiation with SCC risk, and the association between age at initiation and age at diagnosis.

Design, Setting, And Participants: This cohort study included data from women born from 1927 to 1963 from the Norwegian Women and Cancer study, established in 1991 with follow-up through December 31, 2015.

Socioeconomic position, lifestyle habits and biomarkers of epigenetic aging: a multi-cohort analysis.

Differences in health status by socioeconomic position (SEP) tend to be more evident at older ages, suggesting the involvement of a biological mechanism responsive to the accumulation of deleterious exposures across the lifespan. DNA methylation (DNAm) has been proposed as a biomarker of biological aging that conserves memory of endogenous and exogenous stress during life.We examined the association of education level, as an indicator of SEP, and lifestyle-related variables with four biomarkers of age-dependent DNAm dysregulation: the total number of stochastic epigenetic mutations (SEMs) and three epigenetic clocks (Horvath, Hannum and Levine), in 18 cohorts spanning 12 countries.

Physical activity patterns and the risk of colorectal cancer in the Norwegian Women and Cancer study: a population-based prospective study.

Introduction: Colorectal cancer (CRC) remains the second most common cancer in women worldwide. Physical activity (PA) has been associated with reduced risk of CRC; however, this has been demonstrated more consistently in men, while results of studies in women have been largely equivocal. We aimed to further examine the relationship between PA patterns and the risk of CRC in women, using repeated measurements.