Potential preventive properties of GLP-1 receptor agonists against prostate cancer: a nationwide cohort study.

AIMS/HYPOTHESIS: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been suggested to possess antineoplastic properties against prostate cancer. We examined the association between GLP-1RA use and prostate cancer risk in a real-world setting. METHODS: We performed a nationwide register-based cohort study using an active-comparator, new-user design. We included all men in Denmark aged ≥50 years who commenced use of GLP-1RAs or basal insulin during 2007-2019. HRs and 95% CIs for incident prostate cancer were estimated using multivariable Cox regression in 'intention-to-treat' (ITT)- and 'per-protocol'-like analyses. RESULTS: Among 14,206 initiators of GLP-1RAs and 21,756 initiators of basal insulin, we identified 697 patients with prostate cancer during a mean follow-up period of about 5 years from initiation of the study drugs. In comparison with basal insulin use, GLP-1RA use was associated with an adjusted HR of 0.91 (95% CI 0.73, 1.14) in the 'ITT' analysis and 0.80 (95% CI 0.64, 1.01) in the 'per-protocol' analysis. Stronger inverse associations were seen among older men (≥70 years) ('ITT' HR 0.56; 95% CI 0.38, 0.82; 'per-protocol' HR 0.47; 95% CI 0.30, 0.74), and in patients with CVD ('ITT' HR 0.75; 95% CI 0.53, 1.06; 'per-protocol' HR 0.60; 95% CI 0.39, 0.91). CONCLUSIONS/INTERPRETATION: GLP-1RA use was inversely associated with prostate cancer risk compared with use of basal insulin in the 'per-protocol' analysis. Older men and patients with CVD exhibited stronger inverse associations in both the 'ITT' and 'per-protocol' analyses. Our results may indicate that GLP-1RA use could protect against prostate cancer.

Are education and cohabitation associated with health-related quality of life and self-management during breast cancer follow-up? A longitudinal study.

BACKGROUND: Oncologist-led follow-up after breast cancer (BC) is increasingly replaced with less intensive follow-up based on higher self-management, which may overburden the less resourceful patients. We examined whether socioeconomic factors measured recently after the implementation of a new follow-up program for BC patients were associated with health-related quality of life (HRQoL) and self-management 12 months later. METHODOLOGY: Between January and August 2017, we invited 1773 patients in Region Zealand, Denmark, to participate in baseline and 12 months follow-up questionnaires. The patients had surgery for low- and intermediate risk BC 1-10 years prior to the survey, and they had recently been allocated to the new follow-up program of either patient-initiated follow-up, or in-person or telephone follow-up with a nurse, based on patients' preferences. We examined associations between socioeconomic factors (education and cohabitation) at baseline and two outcomes: HRQoL (EORTC QLQ-C30 and QLQ-BR23) and self-management factors (health care provider, confidence in follow-up, contact at symptoms of concern, and self-efficacy) at 12 months follow-up. Sensitivity analyses were performed according to time since diagnosis (≤ 5 > 5 years). Furthermore, we investigated whether treatment and self-management factors modified the associations. RESULTS: A total of 987 patients were included in the analyses. We found no statistically significant associations between socioeconomic factors and HRQoL, except in patients ≤ 5 years from diagnosis. For self-management patients with short education were more likely to report that they had not experience relevant symptoms of concern compared to those with medium/long education (OR 1.75 95% CI: 1.04; 2.95). We found no clear patterns indicating that treatment or self-management factors modified the associations between socioeconomics' and HRQoL. CONCLUSION: Overall socioeconomic factors did not influence HRQoL and self-management factors except for experiencing and reporting relevant symptoms of concern. Socioeconomic factors may, however, influence HRQoL in patients within five years of diagnosis.

Long-term survival of nonlocalized epithelial ovarian cancer among women using menopausal hormone therapy prior to diagnosis: The extreme study.

Prediagnostic use of menopausal hormone therapy (MHT) has been suggested to be associated with improved survival of epithelial ovarian cancer (EOC). We investigated the potential long-term survival benefit of prediagnostic MHT use in women ≥50 years with nonlocalized EOC using the Extreme study including all women in Denmark registered with nonlocalized EOC during 2000 to 2014 (N = 3776). We obtained individual-level information on prediagnostic use of systemic estrogen therapy (ET) and estrogen plus progestin therapy (EPT) from the National Prescription Registry and estimated absolute and relative 5- and 10-year survival probabilities with 95% confidence intervals (CIs) using pseudo-values, taking into account histology, comorbidity, income and residual disease. Among women not having used prediagnostic MHT, 5- and 10-year absolute survival probabilities were 19% and 11%, respectively. Compared to MHT nonusers, prediagnostic systemic ET use for 3 to 4 years and ≥ 5 years was associated with 1.43 (95% CI: 1.01-2.02) and 1.22 (95% CI: 0.96-1.55) times higher 5-year survival probabilities, respectively. Ten-year survival probabilities were also increased but not statistically significantly. Among prediagnostic EPT users, increased 5-year (1.14, 95% CI: 0.85-1.53) and 10-year (1.38, 95% CI: 0.91-2.08) survival probabilities were observed after use for 3 to 4 years compared to MHT nonuse, whereas EPT use for ≥5 years was not associated with long-term survival of nonlocalized EOC. Our findings may suggest a better long-term survival of nonlocalized EOC in women having used long-term prediagnostic ET. However, the statistical precision of our results did not allow firm conclusions and more studies are needed.

Low-dose aspirin use and mortality risk in patients with head and neck cancer: A nationwide cohort study of 10 770 patients.

Several recent observational studies have linked low-dose aspirin use to improved survival in patients with head and neck cancer. However, studies of patterns of aspirin use and risk of cancer-specific mortality are lacking. This nationwide cohort study included all patients in the Danish Cancer Registry with a primary diagnosis of head and neck squamous cell cancer (HNSCC) during 2000 to 2016, aged 30 to 84 years, without prior cancer (except nonmelanoma skin cancer) and alive 1 year after diagnosis. Nationwide registries provided information on filled prescriptions, mortality and potential confounding factors. For a subpopulation, a clinical database provided additional information, including human papillomavirus (HPV) tumor status. We used Cox proportional hazards regression models to estimate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for the association between postdiagnostic low-dose aspirin use (≥1 prescription within first year after diagnosis) and risk of cancer-specific mortality. We identified 10 770 patients with HNSCC during a median follow-up of 3.9 years. Of these, 1799 (16.7%) were low-dose aspirin users. Postdiagnostic use of low-dose aspirin was associated with a HR of 0.97 (95% CI 0.82-1.15) for cancer-specific mortality. Similar neutral associations were found according to patterns of aspirin use. No apparent trends emerged according to age, sex, topography or stage. A tendency towards a decreased cancer-specific mortality risk with low-dose aspirin use was observed among HPV-positive patients; however, the statistical precision was low. In conclusion, we did not observe an association between postdiagnostic low-dose aspirin use and cancer-specific mortality in a nationwide cohort of patients with HNSCC.

Bilateral oophorectomy and rate of colorectal cancer: A prospective cohort study.

Worldwide, colorectal cancer is the second most common cancer and third cause of cancer death in women. Estrogen exposure has been inversely associated with colorectal cancer. Oophorectomy reduces circulating estrogen, but the effect on colorectal cancer remains uncertain. The aim of this study was to examine the association between unilateral and bilateral oophorectomy and subsequent risk of colorectal cancer, and whether this association varied by menopausal status at time of oophorectomy, use of hormone replacement therapy (HRT) at baseline, hysterectomy and baseline body mass index (BMI). The study included 25 698 female nurses (aged ≥45 years) participating in the Danish Nurse Cohort. Nurses were followed from baseline until date of colorectal cancer, death, emigration or end of follow-up at December 31, 2018, whichever came first. We examined the association between oophorectomy and colorectal cancer (all ages and stratified by menopausal status). The potential modifying effects of hysterectomy, HRT use at baseline and BMI were investigated. During 542 140 person-years of follow-up, 863 (3.4%) nurses were diagnosed with colorectal cancer. Bilateral oophorectomy was associated with a 79% increased colorectal cancer rate, adjusted rate ratio (aRR) (95% confidence interval [CI]): 1.79 (1.33-2.42). Effect estimates following unilateral oophorectomy also showed higher rate of colorectal cancer, although less pronounced and nonstatistically significant (aRR) (95% CI): 1.25 (0.86-1.82). Similar results were seen when stratifying by menopausal status. The association was not modified by baseline HRT use, hysterectomy or BMI. Oophorectomy was associated with increased rate of colorectal cancer, with highest rates among women with bilateral oophorectomy.

Prescription rates for commonly used drugs before and after a prostate cancer diagnosis.

PURPOSE: To investigate differences in prescription rates of commonly used drugs among prostate cancer patients and cancer-free comparisons and between patients diagnosed with localized and non-localized disease. METHODS: We conducted a register-based study including all men aged 50-85 years diagnosed with prostate cancer in Denmark from 1998 to 2015 and an age-matched cancer-free comparison cohort. We calculated the number of new and total prescriptions from three years before to three years after the date of diagnosis of the case for selected drug classes divided by the number of person-months and stratified by stage at diagnosis. RESULTS: We included 54,286 prostate cancer patients and 249,645 matched comparisons. 30,712 patients were diagnosed with localized disease and 12,884 with non-localized disease. The rates of new prescriptions increased considerably among patients within the year before the diagnosis. Hereafter the rates varied between drug classes. For most drug classes, total prescription rates for patients and comparisons increased similarly in the study period. Total prescription rates varied between men with localized and non-localized disease for all drug classes apart from statins. CONCLUSION: Our findings indicate that a large proportion of prostate cancer cases are likely diagnosed during medical work-up for other reasons than prostate cancer. Increased rates occur within the last year before diagnosis and future studies on the interaction between drug use and prostate cancer should at least include a one year pre-diagnostic lag-time. Post-diagnostic prescription rates demonstrated an increased use of drugs most likely associated with the consequences of the disease.

Prescription rates for drugs used in treatment of benign prostatic hyperplasia and erectile dysfunction before and after prostate cancer diagnosis.

BACKGROUND: Symptoms and treatment of benign prostatic hyperplasia (BPH) or erectile dysfunction (ED) may lead to prostate cancer workup, and patterns of prescriptions before diagnosis may affect findings of pharmacoepidemiological studies. Usage of BPH and ED drugs after diagnosis may be related to prostate cancer treatment. We investigated differences in prescription rates of BPH and ED drugs among prostate cancer patients and cancer-free comparisons and between patients with localized and non-localized disease. MATERIAL AND METHODS: A nationwide register-based study, including all Danish men aged 50-85 years diagnosed with prostate cancer during 1998-2015 and an age-matched comparison cohort without cancer. We calculated rates of new and total prescriptions in 1-month intervals from 3 years before to 3 years after cancer diagnosis for drugs used to treat BPH and ED, overall and stratified by clinical stage. RESULTS: We identified 54,286 men with prostate cancer and a comparison cohort of 249,645 age-matched men. The new prescription rate for BPH drugs increased for men with prostate cancer in the year before diagnosis and peaked 1 month before diagnosis with an 18-fold higher rate. Men with prostate cancer had a higher total prescription rate of BPH drugs 3 years before diagnosis, notably among men with localized disease. Before diagnosis, the new prescription rates for ED drugs were similar among men with prostate cancer and comparisons. After diagnosis, men with prostate cancer had a 7-fold higher rate of new prescriptions for ED drugs. Among men with localized disease, the total prescription rate of ED drugs increased in the months following diagnosis. CONCLUSION: Differences in prescription rates suggest increased prostate cancer surveillance among men receiving BPH drugs, whereas the post-diagnostic increase in ED drugs among men with localized disease is compatible with the increased risk of ED following prostate cancer treatment.

Hormonal contraception use before and after breast cancer diagnosis: A nationwide drug utilization study.

PURPOSE: To describe the use of hormonal contraceptives in Danish breast cancer patients. METHODS: Nationwide drug utilization study in Danish women diagnosed with breast cancer at ages 13-50 years during 2000-2015. User proportions were estimated in 6-months intervals from 2 years before to 2 years after diagnosis. RESULTS: Use of hormonal contraceptives declined sharply after breast cancer diagnosis. Still, 7% of patients aged 13-39 years filled hormonal contraceptive prescriptions within 6 months after the diagnosis. CONCLUSIONS: The majority of premenopausal breast cancer patients discontinues hormonal contraception at diagnosis. All prescribers of hormonal contraceptives should acknowledge that hormonal contraception is contraindicated for breast cancer patients. PLAIN LANGUAGE SUMMARY: Use of hormonal contraception is contraindicated among women with breast cancer. In this nationwide study, we assessed the use of hormonal contraceptives among all Danish premenopausal women diagnosed with breast cancer during 2000-2015. Hormonal contraceptive use was assessed within 2 years before and 2 years after breast cancer diagnosis. The majority of patients discontinued hormonal contraception at breast cancer diagnosis. However, 7% of patients aged 13-39 years filled hormonal contraceptive prescriptions within 6 months after the diagnosis.

One-Dose Human Papillomavirus Vaccination and the Risk of Genital Warts: A Danish Nationwide Population-based Study.

BACKGROUND: Increasing evidence suggests that 1-dose human papillomavirus (HPV) vaccination may protect significantly against HPV-related disease. We provide nationwide, real-world data on the risk of genital warts (GWs) after <3 vaccine doses. METHODS: All Danish women born in 1985-2003 were identified, and individual-level vaccination data were retrieved. The cohort was followed up for first occurrence of GWs until 31 December 2016. Using Poisson regression, we calculated incidence rates (IRs) of GWs per 100 000 person-years and IR ratios (IRRs) with corresponding 95% confidence intervals (CIs) for GWs, according to vaccination status, age at first dose, and calendar time. RESULTS: The cohort comprised 1 076 945 girls and women, of whom 485 408 were vaccinated. For girls initiating vaccination at age 12-14 years and 15-16 years, 1-dose vaccine effectiveness (VE) was 71% (IRR = 0.29; 95% CI, .22-.38) and 62% (0.38; .29-.49), respectively, compared with unvaccinated girls. In the same age groups, 2-dose VE was 78% (IRR, 0.22; 95% CI, .18-.26) and 68% (0.32; .26-.38), respectively. After 2009, the IRRs for 3 versus 1 dose and 2 versus 1 dose increased towards unity over calendar time, being 0.69 (95% CI, .57-.84) and 0.86 (.68-1.08) in 2016, respectively. CONCLUSIONS: In this study, 1 or 2 doses of quadrivalent HPV vaccine was associated with substantial protection against GWs in girls vaccinated at age ≤16 years. The 1-dose VE approached that of 3 or 2 doses over calendar time, probably reflecting the impact of herd protection.

Incidence of human papillomavirus-related anogenital precancer and cancer in women with diabetes: A nationwide registry-based cohort study.

In this register-based cohort study, we estimated the incidence of human papillomavirus (HPV)-related anogenital precancer and cancer in women with diabetes compared with women without diabetes. We followed all women living in Denmark born 1916 to 2001 (n = 2 508 321) for individual-level information on diabetes (Type 1 or 2 [T1D or T2D]), diagnoses of cervical, vaginal, vulvar and anal intraepithelial neoplasia Grade 2 or 3 (IN2/3) and cancer and other covariates from nationwide registries. We used Poisson regression to model the incidence rates of anogenital IN2/3 and cancer as a function of diabetes status, age, HPV vaccination, education, calendar year, and cervical cancer screening status. Incidence rate ratios (IRRs) were estimated for diabetes overall, and separately for T1D and T2D, compared with women without diabetes. Women with diabetes had higher rates of vulvar IN2/3 (IRR = 1.63; 95% confidence interval [CI]: 1.41-1.88), vulvar cancer (IRR = 1.61; 95% CI: 1.36-1.91) and vaginal cancer (IRR = 1.79; 95% CI: 1.27-1.91) than women without diabetes. Similar patterns were observed for anal IN2/3, anal cancer and cervical cancer, although not statistically significant. In contrast, women with diabetes had lower rates of cervical IN2/3 (IRR = 0.74; 95% CI: 0.69-0.79) than women without diabetes. Patterns were generally similar in women with T1D and T2D, although cancer rates were higher in women with T2D. In conclusion, the incidence of most anogenital precancers and cancers were increased in women with diabetes. However, women with diabetes had lower incidence of cervical precancer. Our findings could be explained by biological mechanisms and/or behavioral factors, such as smoking and less frequent cervical screening participation.

Breast cancer rate after oophorectomy: A Prospective Danish Cohort Study.

The association between oophorectomy and risk of breast cancer in the general population is uncertain. The aim of our study was to determine the breast cancer rate in women from the general population after oophorectomy (performed before/after menopause), and whether this varies by use of hormone replacement therapy (HRT), hysterectomy, body mass index (BMI) and shift work. The study included 24 409 female nurses (aged ≥45 years) participating in the Danish Nurse Cohort. Nurses were followed from cohort entry until date of breast cancer, death, emigration or end of follow-up at 31 December 2018, whichever came first. Poisson regression with log-transformed person-years as the offset examined the association between oophorectomy and breast cancer (all ages and stratified by menopausal status at time of oophorectomy). The potential modifying effect of HRT use, hysterectomy, BMI and shift work on the associations was estimated. During 502 463 person-years of follow-up, 1975 (8.1%) nurses were diagnosed with breast cancer. Bilateral oophorectomy was associated with a reduced breast cancer rate compared to nurses with preserved ovaries, adjusted rate ratio (95% confidence interval): 0.79 (0.64; 0.99). Similar associations (magnitude and direction) were detected for unilateral oophorectomy and when stratifying according to menopausal status at time of oophorectomy, but without statistical significance. Unilateral and bilateral oophorectomy is associated with a reduced breast cancer rate in women from the general population. This association is not modified by use of HRT, hysterectomy, BMI or shift work.

Non-aspirin NSAID use and mortality of endometrial cancer. A nationwide cohort study.

PURPOSE: Laboratory studies have shown anti-neoplastic properties of non-aspirin NSAID; however, no studies have examined the influence of non-aspirin NSAIDs as potential adjuvant cancer therapy in women with endometrial cancer. We therefore examined the association between post-diagnostic use of non-aspirin NSAIDs and endometrial cancer mortality in Denmark. METHODS: We identified all women with a primary endometrial cancer diagnosis between 2000 and 2012, who were alive one year after the diagnosis. Information on drug use, cause-specific mortality and potential confounders was obtained from nationwide health- and demographic registries. Cox regression models were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between post-diagnostic non-aspirin NSAID use and endometrial cancer mortality. RESULTS: Among 6 694 endometrial cancer patients with a maximum follow-up of 13 years, 753 women died from endometrial cancer. Post-diagnostic non-aspirin NSAID use (≥ 1 filled prescription) was associated with an overall HR of 1.15 (95% CI; 0.97-1.36) for endometrial cancer mortality, with higher HRs for the highest intensity of use (HR; 1.40, 95% CI; 1.11-1.77) and largest cumulative amount (HR; 1.56, 95% CI; 1.14-2.14). CONCLUSION: Our findings yielded no evidence that use of non-aspirin NSAIDs was associated with reduced endometrial cancer. Rather, we observed that high-intensity and large cumulative amount of non-aspirin NSAID use may be associated with increased endometrial cancer mortality.

Incidence of HPV-related Anogenital Intraepithelial Neoplasia and Cancer in Men With Diabetes Compared With the General Population.

BACKGROUND: Diabetes may increase risk of human papillomavirus (HPV)-related precancer and cancer. We estimated incidence of penile and anal high-grade intraepithelial neoplasia (hgPeIN, hgAIN) and squamous cell carcinoma (SCC) in men with diabetes compared with the entire Danish male population without diabetes. METHODS: In this registry-based cohort study, we included all men born 1916-2001 and residing in Denmark (n = 2,528,756). From nationwide registries, we retrieved individual-level information on diabetes, educational level, and diagnoses of hgPeIN, hgAIN, penile SCC, and anal SCC. We used Poisson regression models to estimate incidence of hgPeIN, hgAIN, penile SCC, and anal SCC as a function of diabetes status, attained age, calendar period, and education. We estimated incidence rate ratios (IRRs) of each outcome in men with diabetes compared with nondiabetic men, both for diabetes overall and separately for type 1 (T1D) and type 2 diabetes (T2D). RESULTS: Men with diabetes had increased incidence rate of penile SCC compared with nondiabetic men (IRR = 1.5, 95% CI = 1.2, 1.9). We saw similar trends for anal SCC, hgPeIN, and hgAIN. The combined incidence rate of penile and anal SCC was increased in men with T2D (IRR = 1.5, 95% CI = 1.3, 1.8), but not with T1D (IRR = 0.53, 95% CI = 0.20, 1.4) compared with men without diabetes. CONCLUSION: The incidence of penile and anal high-grade intraepithelial neoplasia and SCC in men with diabetes was increased compared with men without diabetes. For penile and anal SCCs, this was primarily due to an increased risk in men with T2D.

The association of reproductive factors with risk of non-epithelial ovarian cancer and comparison with serous ovarian cancer.

OBJECTIVE: To examine the association between reproductive factors and risk of non-epithelial ovarian cancer and to compare the associations with those in serous ovarian cancer. METHODS: From the Danish Cancer Registry, we identified all ovarian cancer cases (≥20 years old at diagnosis) of germ cell (n = 188), sex cord-stromal (n = 116), or serous (n = 4854) histology during 1982-2016. For each case, 15 age-matched female controls were selected with risk set sampling. Reproductive history was obtained from nationwide registries. Conditional logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between reproductive factors and the three ovarian cancer types. RESULTS: Compared with nulliparity, ever giving birth was associated with increased odds for germ cell tumors (OR = 1.28, 95% CI: 0.85-1.93) and decreased odds for sex cord-stromal (OR = 0.74, 95% CI: 0.44-1.26) and serous tumors (OR = 0.70, 95% CI: 0.64-0.76). Infertility decreased odds for germ cell tumors (OR = 0.63, 95% CI: 0.23-1.76) but increased odds for sex cord-stromal tumors (OR = 2.20, 95% CI: 0.89-5.43) and serous tumors (OR = 1.97, 95% CI: 1.69-2.30). Finally, use of oral contraceptives decreased the odds for all three tumor types (germ cell: OR = 0.50, 95% CI: 0.29-0.87; sex cord-stromal: OR = 0.40, 95% CI: 0.13-1.22; serous: OR = 0.50, 95% CI: 0.40-0.62). CONCLUSIONS: Reproductive factors affected the risk of sex cord-stromal and serous ovarian cancer similarly with decreased risk associated with parity and use of oral contraceptives. Oral contraceptives also seemed to decrease the risk of germ cell tumors, whereas parity was associated with increased risk.

Prognostic impact of socioeconomic status on long-term survival of non-localized epithelial ovarian cancer ꟷ The Extreme study.

OBJECTIVE: To examine the influence of socioeconomic status (SES) on long-term survival of non-localized ovarian cancer. METHODS: All women in Denmark with a first diagnosis of non-localized epithelial ovarian cancer 1982-2007 were identified in the Cancer Registry and/or the Pathology Registry and followed up until December 2017. The survival probability was estimated after respectively 5 and 10 years, using so-called pseudo observations, and analyzed according to education, income, and marital status defined from nationwide registries. RESULTS: The study cohort included 6486 women, and the estimated 5- and 10-year survival probabilities were 21.4% and 12.7%, respectively. Compared to women with short education, the 5-year survival probability was 7% higher for women with medium (relative survival probability = 1.07, 95% CI: 0.97, 1.19) and long education (relative survival probability = 1.07, 95% CI: 0.93, 1.24). Compared with married women, the 5-year survival probability for divorced women/widower was slightly lower (0.85, 95% CI: 0.69, 1.04) and for unmarried women slightly higher (1.08, 95% CI: 0.94, 1.23). Finally, the probability of being alive 5 years after diagnosis was 1.09 times higher (95% CI: 0.95, 1.24) for medium-income women and 1.23 times higher (95% CI: 1.08, 1.41) for high-income women compared with low-income women. Similar patterns were observed for 10-year survival. CONCLUSIONS: Non-localized ovarian cancer patients have a poor prognosis. Our data suggest that among Danish women with advanced ovarian cancer, higher personal income is associated with slightly higher probability of long-term survival, whereas education and marital status did not affect the probability of long-term survival.

Low-dose aspirin use and risk of head and neck cancer-A Danish nationwide case-control study.

Results concerning a potential preventive effect of aspirin on head and neck cancer (HNC) are conflicting. We examined the association between low-dose aspirin use and HNC risk overall and by degree of human papillomavirus association in a nested case-control study using nationwide registries. Cases (n = 12 389) were all Danish residents diagnosed with primary HNC (2000-2015). Age- and sex-matched population controls (n = 185 835) were selected by risk-set-sampling. Using conditional logistic regression, we estimated multivariable-adjusted odds ratios and 95% confidence intervals for HNC associated with low-dose aspirin use (≥2 prescriptions). No association was observed between low-dose aspirin ever-use and overall HNC (odds ratio: 1.03, 95% confidence interval: 0.97-1.10). Estimates remained neutral according to patterns of use. Low-dose aspirin use appeared to slightly decrease HNC risk among the eldest (71-84 y), independently of human papillomavirus association, while slightly increase HNC risk among younger age groups (30-60, 61-70 y), driven by an increased risk of oral cancer. However, no consistent patterns in risk estimates were found according to duration and consistency of low-dose aspirin use in the age-stratified analyses.

Factors influencing participation rates in clinical late-effect studies of childhood cancer survivors.

To ensure external validation of a study population in clinical late-effect studies of childhood cancer, the participation rate must be high. This study investigated demographic data in Nordic late-effect studies and potential factors impacting participation rates such as cancer type, time since diagnosis, and duration of clinical examinations. We found 80 published studies originating from 16 cohorts, with median follow-up of 6.0 years (range 3-14). The overall participation rates ranged from 27% to 100%. The highest participation rates were seen in studies of survivors with solid tumors (92%) and the lowest in hematologic malignancies (67%) and central nervous system tumors (73%). The clinical examination in 10 studies (62.5%) lasted for more than 3 hours. Neither duration of the clinical examination nor time since diagnosis seemed to affect the participation rate. We encourage future studies to describe the recruitment process more thoroughly to improve understanding of the factors influencing participation rates.

Long-term exposure to road traffic noise and stroke incidence: a Danish Nurse Cohort study.

BACKGROUND: Road traffic noise has been linked to increased risk of ischemic heart disease, yet evidence on stroke shows mixed results. We examine the association between long-term exposure to road traffic noise and incidence of stroke, overall and by subtype (ischemic or hemorrhagic), after adjustment for air pollution. METHODS: Twenty-five thousand six hundred and sixty female nurses from the Danish Nurse Cohort recruited in 1993 or 1999 were followed for stroke-related first-ever hospital contact until December 31st, 2014. Full residential address histories since 1970 were obtained and annual means of road traffic noise (Lden [dB]) and air pollutants (particulate matter with diameter < 2.5 µm and < 10 µm [PM2.5 and PM10], nitrogen dioxide [NO2], nitrogen oxides [NOx]) were determined using validated models. Time-varying Cox regression models were used to estimate hazard ratios (HR) (95% confidence intervals [CI]) for the associations of one-, three-, and 23-year running means of Lden preceding stroke (all, ischemic or hemorrhagic), adjusting for stroke risk factors and air pollutants. The World Health Organization and the Danish government's maximum exposure recommendations of 53 and 58 dB, respectively, were explored as potential Lden thresholds. RESULTS: Of 25,660 nurses, 1237 developed their first stroke (1089 ischemic, 148 hemorrhagic) during 16 years mean follow-up. For associations between a 1-year mean of Lden and overall stroke incidence, the estimated HR (95% CI) in the fully adjusted model was 1.06 (0.98-1.14) per 10 dB, which attenuated to 1.01 (0.93-1.09) and 1.00 (0.91-1.09) in models further adjusted for PM2.5 or NO2, respectively. Associations for other exposure periods or separately for ischemic or hemorrhagic stroke were similar. There was no evidence of a threshold association between Lden and stroke. CONCLUSIONS: Long-term exposure to road traffic noise was suggestively positively associated with the risk of overall stroke, although not after adjusting for air pollution.

Dose-related Effectiveness of Quadrivalent Human Papillomavirus Vaccine Against Cervical Intraepithelial Neoplasia: A Danish Nationwide Cohort Study.

BACKGROUND: A reduced, 2-dose schedule of human papillomavirus (HPV) vaccination has been endorsed for preadolescent women on the basis of immunogenicity data from randomized trials, and limited data suggest that even 1 dose may provide sufficient protection. Surveillance of the impact of <3 vaccine doses on clinical endpoints in the targeted age group is warranted. METHODS: We conducted a nationwide cohort study of all women aged 17-25 years, living in Denmark between 2006 and 2016. From nationwide registries, we extracted individual-level data on vaccination with the quadrivalent HPV (qHPV) vaccine at 16 years or younger, number of doses administered, diagnoses of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) or grade 3 or worse (CIN3+), and potential confounders. Using Poisson regression, we estimated incidence rate ratios (IRRs) with 95% confidence intervals (CIs) for CIN2+ and CIN3+, according to vaccination status. RESULTS: The cohort comprised 590 083 women, of which 215 309 (36%) women were vaccinated at ≤16 years, and among these, 40 742 (19%) received <3 vaccine doses. A total of 5561 women had a diagnosis of CIN3+. We found considerable vaccine effectiveness against CIN3+ after 1 (IRR, 0.38 [95% CI, .14-.98]), 2 (IRR, 0.38 [95% CI, .22-.66]), or 3 (IRR, 0.37 [95% CI, .30-.45]) vaccine doses, compared to unvaccinated women. Results were similar for CIN2+. CONCLUSIONS: We find substantial effectiveness of qHPV vaccination against high-grade cervical precancerous lesions, among women vaccinated with 1, 2, or 3 doses at ≤16 years of age. One-dose vaccination appeared to provide similar protection as 3-dose vaccination.

Risk of cervical intraepithelial neoplasia grade 2 or worse after conization in relation to HPV vaccination status.

Human papillomavirus (HPV) is essential for developing cervical cancer and precancerous lesions. Currently, three vaccines are available, which are effective as prophylaxis against HPV infection, however, limited knowledge exists about the possible effect of vaccinating women treated with conization to prevent recurrence. The aim of our study was to examine the risk of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) after conization according to HPV vaccination status. Using Danish nationwide registries, we identified women diagnosed with CIN3 on the cone (2006-2012) and their HPV vaccination status. Vaccinees were defined as women vaccinated between 3 months before until 1 year after conization. The women were followed from 1 year after conization until diagnosis of CIN2+, conization, death, emigration or end of follow-up. Cox proportional hazard regression was used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of CIN2+ comparing vaccinees with nonvaccinees. The HR was adjusted for age, histology on cone, education, year of conization, repeat conizations and CIN2+ lesions between conization and start of follow-up. Altogether 17,128 women were included (2,074 vaccinees). There was a statistically nonsignificant lower risk of CIN2+ among vaccinees (HRadjusted = 0.86, 95% CI: 0.67-1.09). Women vaccinated 0-3 months before tended to have a slightly lower HR of CIN2+ (HRadjusted = 0.77, 95% CI: 0.45-1.32) than women vaccinated 0-12 months after conization (HRadjusted = 0.88, 95% CI: 0.67-1.14), although not statistically significantly different. Our results add to the current knowledge about the potential clinical effect of vaccination as an adjunct to conization of high-grade cervical neoplasia to decrease risk of recurrence.