Correlation between allostatic load index and cumulative mortality: a register-based study of Danish municipalities

OBJECTIVES

The aim of this study was to examine population-based allostatic load (AL) indices as an indicator of community health across 14 municipalities in Denmark.

DESIGN

Register-based study.

SETTING

Data derived from: the Lolland-Falster Health Study, the Copenhagen General Population Study and the Danish General Suburban Population Study. Nine biomarkers (systolic blood pressure, diastolic blood pressure, pulse rate, total serum cholesterol, high-density lipoprotein cholesterol, waist-to-hip ratio, triglycerides, C-reactive protein and serum albumin) were divided into high-risk and low-risk values based on clinically accepted criteria, and the AL index was defined as the average between the nine values. All-cause mortality data were obtained from Statistics Denmark.

PARTICIPANTS

We examined a total of 106 808 individuals aged 40-79 years.

PRIMARY OUTCOME MEASURE

Linear regression models were performed to investigate the association between mean AL index and cumulative mortality risk.

RESULTS

Mean AL index was higher in men (range 2.3-3.3) than in women (range 1.7-2.6). We found AL index to be strongly correlated with the cumulative mortality rate, correlation coefficient of 0.82. A unit increase in mean AL index corresponded to an increase in the cumulative mortality rate of 19% (95% CI 13% to 25%) for men, and 16% (95% CI 8% to 23%) for women but this difference was not statistically significant. The overall mean increase in cumulative mortality rate for both men and women was 17% (95% CI 14% to 20%).

CONCLUSIONS

Our findings indicate the population-based AL index to be a strong indicator of community health, and suggest identification of targets for reducing AL.

Self-Reported Health as Predictor of Allostatic Load and All-Cause Mortality: Findings From the Lolland-Falster Health Study

Objectives: The aim was to determine the association between self-reported health (SRH), allostatic load (AL) and mortality. Methods: Data derived from the Lolland-Falster Health Study undertaken in Denmark from 2016-2020 (n = 14,104). Median follow-up time for death was 4.6 years where 456 participants died. SRH was assessed with a single question and AL by an index of ten biomarkers. Multinomial regression analysis were used to examine the association between SRH and AL, and Cox regression to explore the association between SRH, AL and mortality. Results: The risk of high AL increased by decreasing level of SRH. The ratio of relative risk (RRR) of having medium vs. low AL was 1.58 (1.11-2.23) in women reporting poor/very poor SRH as compared with very good SRH. For men it was 1.84 (1.20-2.81). For high vs. low AL, the RRR was 2.43 (1.66-3.56) in women and 2.96 (1.87-4.70) in men. The hazard ratio (HR) for all-cause mortality increased by decreasing SRH. For poor/very poor vs. very good SRH, the HR was 6.31 (2.84-13.99) in women and 3.92 (2.12-7.25) in men. Conclusion: Single-item SRH was able to predict risk of high AL and all-cause mortality.

Occupational variation in incidence of oropharyngeal cancer in the Nordic countries

PURPOSE

Evaluate the occupational variation in incidence of oropharyngeal cancer (OPC).

METHODS

We calculated standardized incidence ratios (SIRs) of OPC in occupational categories in the Nordic countries relative to the entire national populations. The data covered 6155 OPC cases.

RESULTS

Among men high risk of OPC was observed, among else, in waiters (SIR 6.28, 95% CI 4.68-8.26), beverage workers (SIR 3.00, 95% CI 1.72-4.88), and artistic workers (SIR 2.97, 95% CI 2.31-3.76). Among women high risk of OPC was observed in waiters (SIR 2.02, 95% CI 1.41-2.81) and packers (SIR 1.73, 95% CI 1.07-2.64). The lowest SIRs were observed in female gardeners (SIR 0.27, 95% CI 0.12-0.51) and male farmers (SIR 0.30, 95% CI 0.25-0.35).

CONCLUSION

The 20-fold variation in incidence of OPC between occupations needs further investigation in studies with detailed information on occupational and non-occupational risk factors.

Non-participation in a health examination survey in a rural-provincial area of Denmark - results from the Lolland-Falster Health Study (LOFUS)

BACKGROUND

Lolland-Falster Health Study (LOFUS) was a health examination survey that included self-administered questionnaires, clinical examinations, and the collection of biological samples, undertaken in 2016-2020 in a rural, socioeconomically deprived area with the lowest life expectancy in Denmark. The aim of this study was to examine the determinants of non-participation in LOFUS to evaluate the extent to which LOFUS data reflected the general population of the area.

METHODS

LOFUS invited randomly selected subjects together with their entire household. As determinants of non-participation, we analyzed age, sex, municipality of residency, citizenship, residency status, socioeconomic status, invitation type, and year of invitation. Relative risk regression was used to estimate the association between determinants and non-participation rate, mutually adjusted for other determinants.

RESULTS

In total, 53,313 subjects were invited of whom 18,949 (36%) participated. In the multivariable analysis, men had a 3% higher non-participation rate than women; subjects with citizenship other than Danish had a 3% higher non-participation rate than Danes. In-migrants had 6% higher non-participation than long-term residents. Compared with self-supported subjects aged 30-64, both publicly supported subjects of this age and younger and older subjects had higher non-participation rates: 16%, 16%, and 13%, respectively. Compared with self-supported, long-term residents, publicly supported in-migrants had 23% higher non-participation.

CONCLUSIONS

Only about one third of subjects invited to LOFUS participated. Yet, this is a relatively high participation rate compared with other recent health examination surveys in Denmark. Furthermore, there was a relatively flat social gradient in the non-participation rate across the studied determinants.

Robust cross-vendor mammographic texture models using augmentation-based domain adaptation for long-term breast cancer risk

Purpose

Risk-stratified breast cancer screening might improve early detection and efficiency without comprising quality. However, modern mammography-based risk models do not ensure adaptation across vendor-domains and rely on cancer precursors, associated with short-term risk, which might limit long-term risk assessment. We report a cross-vendor mammographic texture model for long-term risk.

Approach

The texture model was robustly trained using two systematically designed case-control datasets. Textural features, indicative of future breast cancer, were learned by excluding samples with diagnosed/potential malignancies from training. An augmentation-based domain adaption technique, based on flavorization of mammographic views, ensured generalization across vendor-domains. The model was validated in 66,607 consecutively screened Danish women with flavorized Siemens views and 25,706 Dutch women with Hologic-processed views. Performances were evaluated for interval cancers (IC) within 2 years from screening and long-term cancers (LTC) from 2 years after screening. The texture model was combined with established risk factors to flag 10% of women with the highest risk.

Results

In Danish women, the texture model achieved an area under the receiver operating characteristic curve (AUC) of 0.71 and 0.65 for ICs and LTCs, respectively. In Dutch women with Hologic-processed views, the AUCs were not different from AUCs in Danish women with flavorized views. The AUC for texture combined with established risk factors increased to 0.68 for LTCs. The 10% of women flagged as high-risk accounted for 25.5% of ICs and 24.8% of LTCs.

Conclusions

The texture model robustly estimated long-term breast cancer risk while adapting to an unseen processed vendor-domain and identified a clinically relevant high-risk subgroup.

No Excess Cancer Risk among Veterinarians in Denmark, Finland, Iceland, Norway, and Sweden after the 1980s

The cancer profile of veterinarians has received little research attention, despite the profession potentially being exposed to a wide range of known and suspected carcinogens. In this large-scale cohort study, we assessed cancer incidence in veterinarians in Denmark, Finland, Iceland, Norway, and Sweden, across more than 40 years (1961-2005). The cohort comprised 4708 veterinarians and 119,503 person-years at follow-up. The overall cancer incidence in veterinarians was close to the incidence in the total population in all countries and in all age groups. In male veterinarians, the standardized incidence ratios (SIR) in 1961-1990 were elevated for colon cancer (1.86, 95% confidence interval (CI) 1.39-2.44), prostate cancer (1.35, 95% CI 1.07-1.67), and especially skin melanoma (3.62, 95% CI 2.78-2.84), while there was no longer any statistically significant excess in the more recent follow-up period. Decreased SIRs were observed for lip cancer (0.11, 95% CI 0.00-0.62), laryngeal cancer (0.38, 95% CI 0.12-0.89), lung cancer (0.59, 95% CI 0.47-0.74), and stomach cancer (0.58, 95% CI 0.38-0.86), without a marked change in SIR over time. Non-significant excesses among male veterinarians were also observed in Hodgkin lymphoma (1961-1990 only), and leukaemia. This multi-country study indicates that there was an elevated incidence of several cancer types among male veterinarians before the 1990s but not after that. Some of the findings might rather be attributed to lifestyle factors and not directly to work conditions, but the excess risk of cancers of kidney and bladder, for example, might be related to work exposures.

Socioeconomic, lifestyle and biological determinants of cervical screening coverage: Lolland-Falster Health Study, Denmark

BACKGROUND

Cervical cancer is preventable. Screening is important for early detection. However, even in high-income countries, coverage is sub-optimal. We identified socioeconomic, lifestyle and biological determinants of cervical screening coverage.

METHODS

In Denmark, women aged 23-64 are free of charge personally invited to screening. All cervical cell samples are registered centrally in the Patobank. We linked data from the Lolland-Falster Health Study (LOFUS) with Patobank data. LOFUS was a population-based health survey undertaken in 2016-2020. With logistic regression, coverage defined as ≥1 cervical sample registered within a 6-year period from 2015 to 2020 was compared across levels of risk factors expressed as adjusted odds ratios (aOR) with 95% confidence intervals (CI).

RESULTS

Among 13 406 women of screening aged 23-64 and invited to LOFUS, 72% had ≥1 cervical sample registered. Non-participation in LOFUS was a strong predictor of low coverage; aOR 0.32; 95% CI 0.31-0.36. Among LOFUS participants, education was a strong predictor of coverage in univariate analysis, OR 0.58; 95% CI 0.48-0.71, but this association disappeared in multi-variate analysis, aOR 0.86; 95% CI 0.66-1.10. In multi-variate analysis, predictors of low coverage were high age, living without a partner, retired, current smoker, poor self-rated health, elevated blood pressure and elevated glycated haemoglobin.

CONCLUSIONS

Women with low cervical screening coverage had limited contact to healthcare, exemplified by non-participation in LOFUS, and pertinent health and social problems, exemplified by elevated blood pressure and glycated haemoglobin, poor self-rated health, and retirement already in screening age. Structural changes in screening are needed to reach non-screened women.

Assessing Breast Cancer Risk by Combining AI for Lesion Detection and Mammographic Texture

Background Recent mammography-based risk models can estimate short-term or long-term breast cancer risk, but whether risk assessment may improve by combining these models has not been evaluated. Purpose To determine whether breast cancer risk assessment improves when combining a diagnostic artificial intelligence (AI) system for lesion detection and a mammographic texture model. Materials and Methods This retrospective study included Danish women consecutively screened for breast cancer at mammography from November 2012 to December 2015 who had at least 5 years of follow-up data. Examinations were evaluated for short-term risk using a commercially available diagnostic AI system for lesion detection, which produced a score to indicate the probability of cancer. A mammographic texture model, trained on a separate data set, assessed textures associated with long-term cancer risk. Area under the receiver operating characteristic curve (AUC) analysis was used to evaluate both the individual and combined performance of the AI and texture models for the prediction of future cancers in women with a negative screening mammogram, including those with interval cancers diagnosed within 2 years of screening and long-term cancers diagnosed 2 years or more after screening. AUCs were compared using the DeLong test. Results The Danish screening cohort included 119 650 women (median age, 59 years [IQR, 53-64 years]), of whom 320 developed interval cancers and 1401 developed long-term cancers. The combination model achieved a higher AUC for interval and long-term cancers grouped together than either the diagnostic AI (AUC, 0.73 vs 0.70; P < .001) or the texture risk (AUC, 0.73 vs 0.66; P < .001) models. The 10% of women with the highest combined risk identified by the combination model accounted for 44.1% (141 of 320) of interval cancers and 33.7% (472 of 1401) of long-term cancers. Conclusion Combining a diagnostic AI system and mammographic texture model resulted in improved risk assessment for interval cancers and long-term cancers and enabled identification of women at high risk. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Poynton and Slanetz in this issue.

Occupational variation in the incidence of lip cancer in the Nordic countries

INTRODUCTION

While certain occupations, such as agriculture and fishery, have been associated with an increased risk of lip cancer, the occupational risk profile of lip cancer and its change over time remain poorly known. This study aims to evaluate the incidence of lip cancer across different occupations in the Nordic countries.

METHODS

The Nordic Occupational Cancer Study (NOCCA) covers 14.9 million people and includes 45 years of cancer incidence data, from 1961 to 2005, linked to occupational categories for all the five Nordic populations. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) were used to quantify the risk of lip cancer across occupational categories relative to the entire national populations.

RESULTS

There were a total of 14,477 male and 3008 female lip cancer patients identified during follow up. The highest SIRs were observed among male fishermen (SIR 2.26, 95% CI: 2.04-2.50), gardeners (SIR 1.60, 95% CI: 1.48-1.72), and farmers (SIR 1.60, 95% CI: 1.55-1.66). A significantly reduced risk of lip cancer (SIR < 0.50) was observed among male physicians, teachers, religious workers, artistic workers, journalists, administrators, printers, waiters, and hairdressers. Among women, no occupations were associated with an increased risk of lip cancer.

CONCLUSIONS

The incidence of lip cancer varies widely between outdoor and indoor occupations. Occupations involving outdoor activity and exposure to sunlight show the most elevated SIRs.

Predicting diabetes-related conditions in need of intervention: Lolland-Falster Health Study, Denmark

In the Danish population, about one-in-ten adults have prediabetes, undiagnosed, poorly or potentially sub-regulated diabetes, for short DMRC. It is important to offer these citizens relevant healthcare intervention. We therefore built a model for prediction of prevalent DMRC. Data were derived from the Lolland-Falster Health Study undertaken in a rural-provincial area of Denmark with disadvantaged health. We included variables from public registers (age, sex, age, citizenship, marital status, socioeconomic status, residency status); from self-administered questionnaires (smoking status, alcohol use, education, self-rated health, dietary habits, physical activity); and from clinical examinations (body mass index (BMI), pulse rate, blood pressure, waist-to-hip ratio). Data were divided into training/testing datasets for development and testing of the prediction model. The study included 15,801 adults; of whom 1,575 with DMRC. Statistically significant variables in the final model included age, self-rated health, smoking status, BMI, waist-to-hip ratio, and pulse rate. In the testing dataset this model had an area under the curve (AUC) = 0.77 and a sensitivity of 50% corresponding to a specificity of 84%. In a health disadvantaged Danish population, presence of prediabetes, undiagnosed, or poorly or potentially sub-regulated diabetes could be predicted from age, self-rated health, smoking status, BMI, waist-to-hip ratio, and pulse rate. Age is known from the Danish personal identification number, self-rated health and smoking status can be obtained from simple questions, and BMI, waist-to-hip ratio, and pulse rate can be measured by any person in health care and potentially by the person him/her-self. Our model might therefore be useful as a screening tool.

Mammographic density and interval cancers in mammographic screening: Moving towards more personalized screening

PURPOSE

The European Society on Breast Imaging has recommended supplemental magnetic resonance imaging (MRI) every two to four years for women with mammographically dense breasts. This may not be feasible in many screening programs. Also, the European Commission Initiative on Breast Cancer suggests not implementing screening with MRI. By analyzing interval cancers and time from screening to diagnosis by density, we present alternative screening strategies for women with dense breasts.

METHODS

Our BreastScreen Norway cohort included 508 536 screening examinations, including 3125 screen-detected and 945 interval breast cancers. Time from screening to interval cancer was stratified by density measured by an automated software and classified into Volpara Density Grades (VDGs) 1-4. Examinations with volumetric density ≤3.4% were categorized as VDG1, 3.5%-7.4% as VDG2, 7.5%-15.4% as VDG3, and ≥15.5% as VDG4. Interval cancer rates were also determined by continuous density measures.

RESULTS

Median time from screening to interval cancer was 496 (IQR: 391-587) days for VDG1, 500 (IQR: 350-616) for VDG2, 482 (IQR: 309-595) for VDG3 and 427 (IQR: 266-577) for VDG4. A total of 35.9% of the interval cancers among VDG4 were detected within the first year of the biennial screening interval. For VDG2, 26.3% were detected within the first year. The highest annual interval cancer rate (2.7 per 1000 examinations) was observed for VDG4 in the second year of the biennial interval.

CONCLUSIONS

Annual screening of women with extremely dense breasts may reduce the interval cancer rate and increase program-wide sensitivity, especially in settings where supplemental MRI screening is not feasible.

A cervical screening initiative for elderly women in Denmark

INTRODUCTION

To assess outcome of a one-time human papillomavirus (HPV)-screening in 2017 of Danish women aged 70+.

MATERIAL AND METHODS

Women born 1947 or before were personally invited to have a cell-sample collected by their general practitioner. Screening- and follow-up samples were analyzed in hospital laboratories in the five Danish regions and registered centrally. Follow-up procedures varied slightly across regions. Cervical intraepithelial neoplasia 2 (CIN2) was recommended treatment threshold. Data were retrieved from the Danish Quality Database for Cervical Cancer Screening. We calculated CIN2+ and CIN3+ detection rates per 1000 screened women, and number of biopsies and conizations per detected CIN2+ case. We tabulated annual number of incident cervical cancer cases in Denmark for the years 2009-2020.

RESULTS

In total, 359 763 women were invited of whom 108 585 (30% of invited) were screened; 4479 (4.1% of screened, and 4.3% of screened 70-74 years) tested HPV-positive; of whom 2419 (54% of HPV-positive) were recommended follow-up with colposcopy, biopsy and cervical sampling, and 2060 with cell-sample follow-up. In total, 2888 women had histology; of whom 1237 cone specimen and 1651 biopsy only. Out of 1000 screened women 11 (95% confidence interval [CI]: 11-12) had conization. In total, 579 women had CIN2+; 209 CIN2, 314 CIN3, and 56 cancer. Out of 1000 screened women five (95% CI: 5-6) had CIN2+. Detection rate of CIN2+ was highest in regions where conization was used as part of first-line follow-up. In 2009-2016, number of incident cervical cancers in women aged 70+ in Denmark fluctuated around 64; in 2017 it reached 83 cases; and by 2021 the number had decreased to 50.

CONCLUSIONS

The prevalence of high-risk HPV of 4.3% in women aged 70-74 is in agreement with data from Australia, and the detection of five CIN+2 cases per 1000 screened women is in agreement with data for 65-69 year old women in Norway. Data are thus starting to accumulate on primary HPV-screening of elderly women. The screening resulted in a prevalence peak in incident cervical cancers, and it will therefore take some years before the cancer preventive effect of the screening can be evaluated.

Impact of COVID-19 pandemic on breast and cervical cancer screening in Denmark: A register-based study

Background

Denmark was one of the few countries where it was politically decided to continue cancer screening during the COVID-19 pandemic. We assessed the actual population uptake of mammography and cervical screening during this period.

Methods

The first COVID-19 lockdown in Denmark was announced on 11 March 2020. To investigate possible changes in cancer screening activity due to the COVID-19 pandemic, we analysed data from the beginning of 2017 until the end of 2021. A time series analysis was carried out to discover possible trends and outliers in the screening activities in the period 2017-2021. Data on mammography screening and cervical screening were retrieved from governmental pandemic-specific monitoring of health care activities.

Results

A brief drop was seen in screening activity right after the first COVID-19 lockdown, but the activity quickly returned to its previous level. A short-term deficit of 43% [CI -49 to -37] was found for mammography screening. A short-term deficit of 62% [CI -65 to -58] was found for cervical screening. Furthermore, a slight, statistically significant downward trend in cervical screening from 2018 to 2021 was probably unrelated to the pandemic. Other changes, for example, a marked drop in mammography screening towards the end of 2021, also seem unrelated to the pandemic.

Conclusions

Denmark continued cancer screening during the pandemic, but following the first lockdown a temporary drop was seen in breast and cervical screening activity.

Funding

Region Zealand (R22-A597).

Breast density and risk of breast cancer

Early studies reported a 4- to 6-fold risk of breast cancer between women with extremely dense and fatty breasts. As most early studies were case-control studies, we took advantage of a population-based screening program to study density and breast cancer incidence in a cohort design. In the Capital Region, Denmark, women aged 50 to 69 are invited to screening biennially. Women screened November 2012 to December 2017 were included, and classified by BI-RADS density code, version 4, at first screen after recruitment. Women were followed up for incident breast cancer, including ductal carcinoma in situ (DCIS), to 2020 in nationwide pathology data. Rate ratios (RRs) and 95% confidence intervals (CI) were compared across density groups using Poisson-regression. We included 189 609 women; 1 067 282 person-years; and 4110 incident breast cancers/DCIS. Thirty-three percent of women had BI-RADS density code 1; 38% code 2; 24% code 3; 4.7% code 4; and missing 0.3%. Using women with BI-RADS density code 1 as baseline; women with code 2 had RR 1.69 (95% CI 1.56-1.84); women with code 3, RR 2.06 (95% CI 1.89-2.25); and women with code 4, RR 2.37 (95% CI 1.05-2.74). Results differed between observations accumulated during screening and above screening age. Our results indicated less difference in breast cancer risk across level of breast density than normally stated. Translated into absolute risk of breast cancer after age 50, we found a 6.2% risk for the one-third of women with lowest density, and 14.7% for the 5% of women with highest density.

Incidence of cancer among Nordic police officers

Police work may expose officers to various circumstances that have potential for increasing their risk of cancer, including traffic-related air pollution, night shift work and radiation from radars. In this study, we examined the incidence of cancer among Nordic male and female police officers. We utilize data from the Nordic Occupational Cancer (NOCCA) project, which linked census data on occupations from Finland, Iceland, Norway and Sweden to national cancer registries for the period 1961 to 2005. We report standardized incidence ratios (SIR) and 95% confidence intervals (CI) of selected cancers for each country by sex, age and calendar period. The cohort included 38 523 male and 1998 female police officers. As compared with the general population, male police officers had a 7% (95% CI: 4-9%) excess cancer risk, with elevated SIRs for various cancer sites, including prostate (SIR 1.19, 1.14-1.25), breast (SIR 1.77, 1.05-2.80), colon (SIR 1.22, 1.12-1.32) and skin melanoma (SIR 1.44, 1.28-1.60). Conversely, male police officers had a lower risk of lung cancer than the general population (SIR 0.72, 0.66-0.77). In female police officers, the SIR for cancer overall was 1.15 (0.98-1.34), and there was a slight excess of cancers of the breast (SIR 1.25, 0.97-1.59) and colon (SIR 1.21, 0.55-2.30). In conclusion, cancer incidence among the police officers was slightly higher than in the general population. Notably, SIRs were elevated for cancer sites potentially related to night shift work, namely colon, breast and prostate cancer.

Abstract P4-03-10: BREAST DENSITY AND RISK OF BREAST CANCER

Background: Early studies reported a 4-6-fold risk of breast cancer between women with extremely dense and fatty breasts. As most early studies were case-control studies, we took advantage of a population-based screening program to study density and breast cancer incidence in a cohort design. Methods: In the Capital Region, Denmark, woman aged 50-69 are invited to screening biennially. Women screened November 2012 - December 2017 were included, and classified by BI-RADS density code, version 4, at first screen after recruitment. Women were followed up for incident breast cancer, including ductal carcinoma in situ (DCIS), to 2020 in nationwide pathology data. Rate ratios (RR) and 95% confidence intervals (CI) were compared across density groups using Poisson-regression. Results: We included 189,609 women; 1,067,293 person-years; and 4110 incident breast cancers/DCIS. Thirty-three percent of women had BI-RADS density code 1; 38% code 2; 24% code 3; 4.7% code 4; and missing 0.3%. Using women with BI-RADS density code 1 as baseline; women with code 2 had RR 1.69 (95% CI 1.56-1.84); women with code 3, RR 2.06 (95% CI 1.89-2.25); and women with code 4, RR 2.37 (95% CI 1.05-2.74). Results differed between observations accumulated during screening and above screening age. Conclusions: This cohort study showed a 2.37-fold difference in breast cancer risk between women with highest and lowest breast density. Translated into absolute risk of breast cancer after age 50, this was a 6.2% risk for the one-third of women with lowest density, and 14.7% for the five percent of women highest density.

Citation Format: Elsebeth Lynge, Ilse Vejborg, Martin Lillholm, Mads Nielsen, George Napolitano, My von Euler-Chelpin. BREAST DENSITY AND RISK OF BREAST CANCER [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-10.

Selective migration and mortality by economic status in Lolland-Falster, Denmark, 1992-2018

During the past 30 years, a mortality gap developed between Lolland-Falster (the rural-provincial southeastern part) and the rest of Denmark. A main driver was selective in-migration of Danes with a high risk of death, especially of working-ages. In the present study, we determined the role of economic status in this selective in-migration. We used individual-level data from the Central Population Register and data on income source; self- or publicly supported. The study population included people aged 30-64 and living in Denmark at any time between 1992 and 2018. Mortality rate ratios (MRR) were calculated using Poisson regression for three time-periods: 1992-1999, 2000-2009 and 2010-2018. Two in five in-migrants to Lolland-Falster were people on public support. In 2010-2018, they had an MRR of 8.71 (95% confidence interval (CI): 8.05-9.42) compared with self-supported people, and an MRR of 1.49 (95% CI: 1.38-1.61) compared with publicly supported people elsewhere in Denmark. In-migration of working-aged people on public support was a main contributor to the excess mortality in Lolland-Falster as compared with the rest of Denmark. To understand urban-rural differences in health, population movements and national income patterns are important to take into account.

Occupational risk variation of nasopharyngeal cancer in the Nordic countries

Background

The aim of this study was to estimate occupational risk variation in the incidence of nasopharyngeal cancer (NPC) in a large population-based cohort of the Nordic Occupational Cancer (NOCCA) study.

Methods

This study is based on a cohort of almost 15 million persons from Denmark, Finland, Iceland, Norway and Sweden, with 2898 nasopharyngeal cancer cases diagnosed in 1961–2005. The data on occupations were gathered from population censuses and cancer data from the national cancer registries. Standardized incidence ratios (SIR) with 95% confidence intervals (CI) were estimated using the national NPC incidence rates as the reference.

Results

There were 1980 male and 918 female NPC patients. The highest SIRs of NPC were observed among male waiters (SIR 3.69, 95% CI 1.91–6.45) and cooks and stewards (SIR 2.24, 95% CI 1.16–3.91). Among women, launderers had the highest SIR of NPC (2.04, 95% CI 1.02–3.65). Significantly decreased SIRs were found among male farmers (SIR 0.79, 95% CI 0.68–0.92) and male textile workers (SIR 0.49, 95% CI 0.22–0.93).

Conclusions

This study suggests that NPC may be associated with several work-related exposure agents such as smoking, kitchen air pollution and solvents. In future, occupational exposure-risk relations should be studied to understand more about causality and to assess effective prevention strategies.

Lifetime Exposure to Welding Fumes and Risk of Some Rare Cancers

We investigated the association between exposure to welding fumes and the risk of biliary tract, male breast, bone, and thymus cancer, as well as cancer of the small intestine, eye melanoma, and mycosis fungoides, among men in a European, multicenter case-control study. From 1995-1997, 644 cases and 1,959 control subjects from 7 countries were studied with respect to information on welding and potential confounders. We linked the welding histories of the participants with a measurement-based exposure matrix to calculate lifetime exposure to welding fumes. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models, conditional on country and 5-year age groups, and adjusted for education and relevant confounders. Regular welding was associated with an increased risk of cancer of the small intestine (OR = 2.30, 95% CI: 1.17, 4.50). Lifetime exposure to welding fumes above the median of exposed controls was associated with an increased risk of cancer of the small intestine (OR = 2.00, 95% CI: 1.07, 3.72) and male breast (OR = 2.07, 95% CI: 1.14, 3.77), and some elevation in risk was apparent for bone cancer (OR = 1.92, 95% CI: 0.85, 4.34) with increasing lifetime exposure to welding fumes. Welding fumes could contribute to an increased risk of some rare cancers.

Long-Term Follow-Up on Morbidity Among Women With a History of Gestational Diabetes Mellitus: A Systematic Review

BACKGROUND

Gestational diabetes mellitus (GDM) complicates up to 10% of pregnancies and is a well-known risk factor for type 2 diabetes mellitus (T2DM) and cardiovascular disease. Little is known about possible long-term risks of other diseases.

BACKGROUND

The aim was to review the literature for evidence of associations with morbidity other than T2DM and cardiovascular disease and with long-term mortality.

METHODS

A systematic review based on searches in Medline, Embase, and Cochrane Library until March 31, 2021, using a broad range of keywords. We extracted study characteristics and results on associations between GDM and disease occurrence at least 10 years postpartum, excluding studies on women with diabetes prior to pregnancy or only diabetes prior to outcome. The results are reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Newcastle-Ottawa Scale was used to assess risk of bias.

RESULTS

We screened 3084 titles, 81 articles were assessed full-text, and 15 included in the review. The strongest evidence for an association was for kidney diseases, particularly in Black women. We found indication of an association with liver disease, possibly restricted to women with T2DM postpartum. The association between GDM and breast cancer had been studied extensively, but in most cases based on self-reported diagnosis and with conflicting results. Only sparse and inconsistent results were found for other cancers. No study on thyroid diseases was found, and no study reported on short-term or long-term mortality in women with a history of GDM.

CONCLUSION

Given the frequency of GDM, there is a need for better evidence on possible long-term health consequences, in particular, studies based on comprehensive records of diagnosis of GDM and long-term health outcomes.

An Artificial Intelligence-based Mammography Screening Protocol for Breast Cancer: Outcome and Radiologist Workload

Background Developments in artificial intelligence (AI) systems to assist radiologists in reading mammograms could improve breast cancer screening efficiency. Purpose To investigate whether an AI system could detect normal, moderate-risk, and suspicious mammograms in a screening sample to safely reduce radiologist workload and evaluate across Breast Imaging Reporting and Data System (BI-RADS) densities. Materials and Methods This retrospective simulation study analyzed mammographic examination data consecutively collected from January 2014 to December 2015 in the Danish Capital Region breast cancer screening program. All mammograms were scored from 0 to 10, representing the risk of malignancy, using an AI tool. During simulation, normal mammograms (score < 5) would be excluded from radiologist reading and suspicious mammograms (score > recall threshold [RT]) would be recalled. Two radiologists read the remaining mammograms. The RT was fitted using another independent cohort (same institution) by matching to the radiologist sensitivity. This protocol was further applied to each BI-RADS density. Screening outcomes were measured using the sensitivity, specificity, workload, and false-positive rate. The AI-based screening was tested for noninferiority sensitivity compared with radiologist screening using the Farrington-Manning test. Specificities were compared using the McNemar test. Results The study sample comprised 114 421 screenings for breast cancer in 114 421 women, resulting in 791 screen-detected, 327 interval, and 1473 long-term cancers and 2107 false-positive screenings. The mean age of the women was 59 years ± 6 (SD). The AI-based screening sensitivity was 69.7% (779 of 1118; 95% CI: 66.9, 72.4) and was noninferior (P = .02) to the radiologist screening sensitivity of 70.8% (791 of 1118; 95% CI: 68.0, 73.5). The AI-based screening specificity was 98.6% (111 725 of 113 303; 95% CI: 98.5, 98.7), which was higher (P < .001) than the radiologist specificity of 98.1% (111 196 of 113 303; 95% CI: 98.1, 98.2). The radiologist workload was reduced by 62.6% (71 585 of 114 421), and 25.1% (529 of 2107) of false-positive screenings were avoided. Screening results were consistent across BI-RADS densities, although not significantly so for sensitivity. Conclusion Artificial intelligence (AI)-based screening could detect normal, moderate-risk, and suspicious mammograms in a breast cancer screening program, which may reduce the radiologist workload. AI-based screening performed consistently across breast densities. © RSNA, 2022 Online supplemental material is available for this article.

Allostatic load as predictor of mortality: a cohort study from Lolland-Falster, Denmark

OBJECTIVES

The purposes of the present study were to determine the association between (1) 10 individual biomarkers and all-cause mortality; and between (2) allostatic load (AL), across three physiological systems (cardiovascular, inflammatory, metabolic) and all-cause mortality.

DESIGN

Prospective cohort study.

SETTING

We used data from the Lolland-Falster Health Study undertaken in Denmark in 2016-2020 and used data on systolic blood pressure (SBP) and diastolic blood pressure (DBP), pulse rate (PR), waist-hip ratio (WHR) and levels of low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), triglycerides, glycated haemoglobin A1c (HbA1c), C-reactive protein (CRP) and serum albumin. All biomarkers were divided into quartiles with high-risk values defined as those in the highest (PR, WHR, triglycerides, HbA1c, CRP) or lowest (HDL-c, albumin) quartile, or a combination hereof (LDL-c, SBP, DBP). The 10 biomarkers were combined into a summary measure of AL index. Participants were followed-up for death for an average of 2.6 years.

PARTICIPANTS

We examined a total of 13 725 individuals aged 18+ years.

PRIMARY OUTCOME MEASURE

Cox proportional hazard regression (HR) analysis were performed to examine the association between AL index and mortality in men and women.

RESULTS

All-cause mortality increased with increasing AL index. With low AL index as reference, the HR was 1.33 (95% CI: 0.89 to 1.98) for mid AL, and HR 2.37 (95% CI: 1.58 to 3.54) for high AL.

CONCLUSIONS

Elevated physiological burden measured by mid and high AL index was associated with a steeper increase of mortality than individual biomarkers.

An Artificial Intelligence-based Mammography Screening Protocol for Breast Cancer: Outcome and Radiologist Workload

Background Developments in artificial intelligence (AI) systems to assist radiologists in reading mammograms could improve breast cancer screening efficiency. Purpose To investigate whether an AI system could detect normal, moderate-risk, and suspicious mammograms in a screening sample to safely reduce radiologist workload and evaluate across Breast Imaging Reporting and Data System (BI-RADS) densities. Materials and Methods This retrospective simulation study analyzed mammographic examination data consecutively collected from January 2014 to December 2015 in the Danish Capital Region breast cancer screening program. All mammograms were scored from 0 to 10, representing the risk of malignancy, using an AI tool. During simulation, normal mammograms (score < 5) would be excluded from radiologist reading and suspicious mammograms (score > recall threshold [RT]) would be recalled. Two radiologists read the remaining mammograms. The RT was fitted using another independent cohort (same institution) by matching to the radiologist sensitivity. This protocol was further applied to each BI-RADS density. Screening outcomes were measured using the sensitivity, specificity, workload, and false-positive rate. The AI-based screening was tested for noninferiority sensitivity compared with radiologist screening using the Farrington-Manning test. Specificities were compared using the McNemar test. Results The study sample comprised 114 421 screenings for breast cancer in 114 421 women, resulting in 791 screen-detected, 327 interval, and 1473 long-term cancers and 2107 false-positive screenings. The mean age of the women was 59 years ± 6 (SD). The AI-based screening sensitivity was 69.7% (779 of 1118; 95% CI: 66.9, 72.4) and was noninferior (P = .02) to the radiologist screening sensitivity of 70.8% (791 of 1118; 95% CI: 68.0, 73.5). The AI-based screening specificity was 98.6% (111 725 of 113 303; 95% CI: 98.5, 98.7), which was higher (P < .001) than the radiologist specificity of 98.1% (111 196 of 113 303; 95% CI: 98.1, 98.2). The radiologist workload was reduced by 62.6% (71 585 of 114 421), and 25.1% (529 of 2107) of false-positive screenings were avoided. Screening results were consistent across BI-RADS densities, although not significantly so for sensitivity. Conclusion Artificial intelligence (AI)-based screening could detect normal, moderate-risk, and suspicious mammograms in a breast cancer screening program, which may reduce the radiologist workload. AI-based screening performed consistently across breast densities. © RSNA, 2022 Online supplemental material is available for this article.

Socioeconomic status and risk of lung cancer by histological subtype in the Nordic countries

BACKGROUND

While the excess in lung cancer risk among lower socioeconomic status individuals has been widely described, the magnitude of this association across lung cancer subtypes, as well as histotype-related long-term incidence trends, are inconclusively reported.

AIMS

We explored the variation in the incidence of the three main lung cancer histotypes (i.e. squamous cell carcinoma, small cell carcinoma and adenocarcinoma) by socioeconomic status (SES, i.e. upper and lower white collar, upper and lower blue collar, and farming/forestry/fishing) in the adult population of four Nordic countries (i.e. Sweden, Norway, Finland and Denmark).

MATERIALS & METHODS

We have used data from the Nordic Occupational Cancer Study (NOCCA), computing age-standardized incidence rates per 100,000 person-years truncated at ages 50-69 years, by sex, histotype, country and SES, for the period 1971-2005. We estimated relative risks and the corresponding 95% confidence intervals through Poisson regression models, including terms for SES, age, sex and country, as indicated.

RESULTS

A clear socioeconomic gradient, with a progressive increase in lung cancer risk as SES level decreases, was observed in all subtypes and in both sexes. Favourable lung cancer incidence trends were seen among men for squamous cell and small cell carcinomas, although for adenocarcinomas rates were increasing everywhere except for Finland. Among women, upward temporal trends were seen in all SES groups and for all subtypes, although rates increased to a greater extent for low, compared to high, SES, especially in Denmark and Norway. Farmers showed comparatively lower risks compared to other SES categories.

DISCUSSION

This prospective cohort study shows that substantial socioeconomic inequalities in the incidence of the most important lung cancer histotypes exist in the Nordic Countries, and that these inequalities are on the rise, especially among women.

CONCLUSION

Smoking habits are likely to largely explain the observed social gradient for lung cancer histotypes in both sexes.

[Phased implementation of HPV-based cervical cancer screening in Denmark]

Studies have shown, that HPV-based screening is more sensitive than cytology-based screening, but local factors will influence the performance. From January 2021 phased implementation of HPV-based screening was introduced in the Danish cervical cancer screening programme to women between 30 and 59 years. Women with even birth dates will remain on the current cytology-based screening, whereas women with odd birth dates will receive HPV-based screening. The aim of the implementation is to provide guidance to the National Health Authority on the future Danish cervical screening, as argued in this review.

Temporal trends in cause-specific mortality in a rural-provincial area of Denmark, Lolland-Falster, 1970-2018

AIM

In Denmark, rural-provincial Lolland-Falster currently has the highest mortality, caused mainly by the high mortality of in-migrating people. To identify possible preventive measures to combat this excess mortality insight into the underlying diseases is needed.

METHODS

We used data from Danish registers to calculate cause-specific mortality for 1970-1979, 1980-1989, 1990-1999, 2000-2009 and 2010-2018 divided into cancer, cardiovascular diseases, respiratory diseases, external causes and other causes (all remaining causes). We calculated age-standardised mortality rates for Lolland-Falster and the rest of Denmark: mortality rate ratios and excess number of deaths per 100,000 person-years for Lolland-Falster distinguishing between long-term residents (10+ years) and in-migrants.

RESULTS

In 1970-1979, the age-standardised mortality rates for Lolland-Falster resembled those for rest of Denmark. Over time, age-standardised mortality rates for cardiovascular diseases decreased but more so for the rest of Denmark than for Lolland-Falster. Age-standardised mortality rates for other diseases increased but more so for Lolland-Falster than for the rest of Denmark. The excess mortality in Lolland-Falster derived in particular from in-migrants: in 2010-2018 the mortality rate ratios for this population reached 2.29 (95% confidence interval 1.96-2.69) for external causes and 2.12 (95% confidence interval 1.97-2.29) for other diseases. In-migrants had in total 411 excess deaths per 100,000 person-years. Of these 27% came from tobacco smoking-related causes of death. However, another 25% came from ill-defined, unspecified and a broad range of other, minor causes of deaths.

CONCLUSIONS

The excess mortality of in-migrants to Lolland-Falster was attributable to all main causes of deaths, which stresses the complexity in combatting geographical disparities in mortality.

Microscopic Colitis in Denmark: Regional Variations in Risk Factors and Frequency of Endoscopic Procedures

OBJECTIVE

Microscopic colitis [MC], encompassing collagenous colitis [CC] and lymphocytic colitis [LC], is an increasingly prevalent gastrointestinal disease with an unknown aetiology. Previous research has reported significant differences in the incidence of MC within Denmark, with the lowest incidence found in the most populated region [Capital Region of Denmark]. Our aim was to elucidate the causes of these regional differences.

DESIGN

All incident MC patients [n = 14 302] with a recorded diagnosis of CC [n = 8437] or LC [n = 5865] entered in The Danish Pathology Register between 2001 and 2016 were matched to 10 reference individuals [n = 142 481]. Information regarding drug exposure, including proton pump inhibitors [PPIs], selective serotonin reuptake inhibitors [SSRIs], statins, and nonsteroidal anti-inflammatory drugs [NSAIDs], were retrieved from The Danish National Prescription Registry. Information regarding endoscopy rate, smoking-related diseases, and immune-mediated inflammatory diseases were acquired from The Danish National Patient Registry.

RESULTS

Smoking, immune-mediated inflammatory diseases, exposure to PPIs, SSRIs, statins, and NSAIDs were significantly associated with MC in all Danish regions. The association between drug exposure and MC was weakest in the Capital Region of Denmark with an odds ratio of 1.8 (95% confidence interval [CI]: 1.61-2.01). The relative risk of undergoing a colonoscopy with biopsy was significantly increased in sex- and age-matched controls in all regions compared with controls from the Capital Region of Denmark, with the greatest risk found in the Region of Southern Denmark, 1.37 [95% CI: 1.26-1.50].

CONCLUSIONS

The cause of the regional differences in MC incidence in Denmark seems to be multifactorial, including variations in disease awareness and distribution of risk factors.

[Excess mortality in the Lolland-Falster region in Denmark is associated with migration]

At present, Lolland-Falster, a provincial-rural area in south-eastern Denmark, has the lowest life expectancy nationwide; about 78.6 years. This review summarises the development in mortality in this region. Mortality data from 1968 to 2017 showed this to be a new phenomenon. Until 1990, mortality in Lolland-Falster resembled the of Denmark as a whole. In the period 2013-2017, however, men in Lolland-Falster had a 15-25% excess mortality. In-migration contributed substantially to this development, since in-migrating people of working age in 2008-2017 had a 134% excess mortality. Prevention of excess mortality in Lolland-Falster requires a national effort.

Risk of precancerous cervical lesions in women using a hormone-containing intrauterine device and other contraceptives: a register-based cohort study from Denmark

STUDY QUESTION

Is the risk of high-grade precancerous cervical lesions and/or is the risk of lesion progression increased in users of a hormone-containing intrauterine device (HIUD) compared with users of other contraceptive methods.

SUMMARY ANSWER

Women starting use of HIUD had the same subsequent risk of cervical intraepithelial neoplasia 3+ (CIN3+) as copper IUD (CIUD) users, and both groups tended to have lower risks than oral contraceptives (OC) users.

WHAT IS KNOWN ALREADY

HIUDs may cause inflammatory and immunosuppressive changes that may potentially affect the risk of persistent human papillomavirus infection and precancerous cervical lesions.

STUDY DESIGN, SIZE, DURATION

A Danish population-based cohort study was conducted using register data from 2008 to 2011 on 26–50-year-old users of HIUD (n = 60 551), CIUD (n = 30 303), or OC (n = 165 627).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Within each user group, women were divided into two groups; normal cytology or abnormal diagnosis before start of contraceptive use (baseline). Follow-up histology and cytology diagnoses were registered during the 5 years after baseline. Adjusted relative risks (aRR) and 95% CI were calculated for precancerous cervical lesions in HIUD users compared with CIUD and OC users.

MAIN RESULTS AND THE ROLE OF CHANCE

Women with normal cytology at baseline: at follow-up HIUD users had the same risk of CIN3 or higher (3+) as CIUD users; aRR 1.08 (95% CI 0.94–1.22). For the HIUD and CIUD groups compared with OCs, the risks of CIN3+ were lower: aRR 0.63 (95% CI 0.57–0.69) and aRR 0.58 (95% CI 0.52–0.65), respectively. The same was observed for CIN2 risks: aRR 0.86 (95% CI 0.76–0.96) and aRR 0.68 (95% CI 0.58–0.79) for HIUD and CIUD groups, respectively. Women with abnormal diagnosis at baseline: a lower progression risk, except for CIN2+ at baseline, was observed in HIUD users compared with OC users. Similar progression risks were found in HIUD and CIUD users. There were no differences between the three contraceptive groups in persistence or regression of present lesions.

LIMITATIONS, REASONS FOR CAUTION

We adjusted for age, education, and region of residence as a proxy for socio-economic factors. Data on smoking and sexual behavior were not available thus we cannot exclude some differences between the three user groups.

WIDER IMPLICATIONS OF THE FINDINGS

These findings suggest that women may safely use HIUDs.

STUDY FUNDING/COMPETING INTEREST(S)

A.P. Møller Foundation for the Advancement of Medical Science, Else and Mogens Wedell-Wedellborgs Fund, Direktør Emil C. Hertz og Hustru Inger Hertz Fund, and the Fund for Development of Evidence Based Medicine in Private Specialized Practices. EL is principle investigator for a study with HPV-test-kits provided by Roche. The other authors have nothing to declare.

TRIAL REGISTRATION NUMBER

N/A.

Cancer incidence in Thyborøn-Harboøre, Denmark: a cohort study from an industrially contaminated site

In a fishing community Thyborøn-Harboøre on the Danish West coast, a chemical factory polluted air, sea, and ground with > 100 xenobiotic compounds. We investigated cancer incidence in the community. A historical cohort was identified from the Central Population Register and followed for cancer incidence in the Danish Cancer Register including inhabitants from 1968-1970 at height of pollution, and newcomers in 1990-2006 after pollution control. Two fishing communities without pollution, Holmsland and Hanstholm, were referent cohorts. We calculated rate ratios (RR) and 95% confidence intervals (CI). In 1968-1970, 4914 persons lived in Thyborøn-Harboøre, and 9537 persons in Holmsland-Hanstholm. Thyborøn-Harboøre had a statistically significant excess cancer incidence compared with Holmsland-Hanstholm; RR 1.20 (95% CI 1.11-1.29) deriving from kidney and bladder cancer; stomach and lung cancer in men, and colorectal cancer in women. In 1990-2006, 2933 persons came to live in Thyborøn-Harboøre. Their cancer incidence was the same as for newcomers to Holmsland-Hanstholm; RR 1.07 (95% CI 0.88-1.30). Persons in Thyborøn-Harboøre at height of chemical pollution had a cancer risk 20% above persons living in non-polluted fishing communities with a pattern unlikely to be attributable to life style. The study suggested that chemical pollution may have affected cancer risk.

Mortality, Reoperation, and Hospital Stay Within 90 Days of Primary and Secondary Antireflux Surgery in a Population-Based Multinational Study

BACKGROUND & AIMS

Absolute rates and risk factors of short-term outcomes after antireflux surgery remain largely unknown. We aimed to clarify absolute risks and risk factors for poor 90-day outcomes of primary laparoscopic and secondary antireflux surgery.

METHODS

This population-based cohort study included patients who had primary laparoscopic or secondary antireflux surgery in the 5 Nordic countries in 2000-2018. In addition to absolute rates, we analyzed age, sex, comorbidity, hospital volume, and calendar period in relation to all-cause 90-day mortality (main outcome), 90-day reoperation, and prolonged hospital stay (≥2 days over median stay). Multivariable logistic regression provided odds ratios (ORs) with 95% confidence intervals (95% CI), adjusted for confounders.

RESULTS

Among 26,193 patients who underwent primary laparoscopic antireflux surgery, postoperative 90-day mortality and 90-day reoperation rates were 0.13% (n = 35) and 3.0% (n = 750), respectively. The corresponding rates after secondary antireflux surgery (n = 1 618) were 0.19% (n = 3) and 6.2% (n = 94). Higher age (56-80 years vs 18-42 years: OR, 2.66; 95% CI 1.03-6.85) and comorbidity (Charlson Comorbidity Index ≥2 vs 0: OR, 6.25; 95% CI 2.42-16.14) increased risk of 90-day mortality after primary surgery, and higher hospital volume suggested a decreased risk (highest vs lowest tertile: OR, 0.58; 95% CI, 0.22-1.57). Comorbidity increased the risk of 90-day reoperation. Higher age and comorbidity increased risk of prolonged hospital stay after both primary and secondary surgery. Higher annual hospital volume decreased the risk of prolonged hospital stay after primary surgery (highest vs lowest tertile: OR, 0.74; 95% CI, 0.67-0.80).

CONCLUSION

These findings suggest that laparoscopic antireflux surgery has an overall favorable safety profile in the treatment of gastroesophageal reflux disease, particularly in younger patients without severe comorbidity who undergo surgery at high-volume centers.

Breast cancer screening and overdiagnosis

Overdiagnosis is a harmful consequence of screening which is particularly challenging to estimate. An unbiased setting to measure overdiagnosis in breast cancer screening requires comparative data from a screened and an unscreened cohort for at least 30 years. Such randomised data will not become available, leaving us with observational data over shorter time periods and outcomes of modelling. This collaborative effort of the International Cancer Screening Network quantified the variation in estimated breast cancer overdiagnosis in organised programmes with evaluation of both observed and simulated data, and presented examples of how modelling can provide additional insights. Reliable observational data, analysed with study design accounting for methodological pitfalls, and modelling studies with different approaches, indicate that overdiagnosis accounts for less than 10% of invasive breast cancer cases in a screening target population of women aged 50 to 69. Estimates above this level are likely to derive from inaccuracies in study design. The widely discrepant estimates of overdiagnosis reported from observational data could substantially be reduced by use of a cohort study design with at least 10 years of follow-up after screening stops. In contexts where concomitant opportunistic screening or gradual implementation of screening occurs, and data on valid comparison groups are not readily available, modelling of screening intervention becomes an advantageous option to obtain reliable estimates of breast cancer overdiagnosis.

Does Lolland-Falster make people sick, or do sick people move to Lolland-Falster? An example of selective migration and mortality in Denmark, 1968-2017

INTRODUCTION

Lolland-Falster is a rural area in south-eastern Denmark that scores unfavourable in health surveys and has the lowest life expectancy in the country. To determine the origin of poor health in Lolland-Falster, we investigated impact on mortality of long-term population movements.

METHODS

We used data from the Danish Central Population Register 1968-2017 to track movements in and out of Lolland-Falster. This enabled us to calculate mortality based on tenure of residence. Poisson regression adjusted for sex, 5-year age-groups, and calendar year; separately for men and women; and ages <30, 30-64 and ≥ 65 years; was reported as mortality rate ratios (MRR) with 95% confidence intervals (95% CI).

RESULTS

Until 1988, mortality in Lolland-Falster was fairly similar to that in the rest of Denmark. Hereafter, mortality rates drifted apart. In 2008-2017, MRR of the total Lolland-Falster population was 1.21 (95% CI: 1.19-1.23). In each 10-year calendar period, people recently in-migrating constituted about one fourth of the population. MRRs of the in-migrating population increased over time from 1.17 (95% CI: 1.08-1.26) in 1968-1977, to 1.82 (95% CI: 1.75-1.89) in 2008-2017. Persons aged 30-64 constituted the largest in-migrating group and had highest excess mortality, MRR 2.34 (95% CI: 2.19-2.50) in 2008-2017.

CONCLUSION

Long-term selective in-migration of vulnerable persons was behind the gradual build-up of the currently high mortality in Lolland-Falster compared to the rest of Denmark. In particular, people of working age in-migrating to Lolland-Falster contributed to this disparity.

Occupation and cutaneous melanoma: a 45-year historical cohort study of 14·9 million people in five Nordic countries

BACKGROUND

The age-adjusted incidence of cutaneous melanoma (CM) in the Nordic countries has increased during the last 60 years. Few prospective population-based studies have estimated the occupational variation in CM risk over time.

OBJECTIVES

To determine occupational variation in CM risk.

METHODS

A historical prospective cohort study with a 45-year follow-up from 1961 to 2005 (Nordic Occupational Cancer Study, NOCCA) based on record linkages between census and cancer registry data for Nordic residents aged 30-64 years in Denmark, Finland, Iceland, Norway and Sweden. National occupational codes were converted to 53 occupational categories, and stratified into indoor, outdoor and mixed work, and into socioeconomic status. The standardized incidence ratios (SIRs) were estimated as observed number of CM cases divided by the expected number calculated from stratum-specific person-years and national CM incidence rates.

RESULTS

During a follow-up of 385 million person-years, 83 898 incident cases of CM were identified. In all countries combined, men with outdoor work had a low SIR of 0·79 [95% confidence interval (CI) 0·77-0·81] and men with indoor work had a high SIR of 1·09 (95% CI 1·07-1·11). Differences in women pointed in the same direction. High socioeconomic status was associated with an excess risk: SIR 1·34 (95% CI 1·28-1·40) in men and SIR 1·31 (95% CI 1·26-1·36) in women. Technical, transport, military and public safety workers with potential skin exposure to carcinogens had excess risks.

CONCLUSIONS

Occupational variation in CM risk may be partly explained by host, socioeconomic and skin exposure factors. Differences in CM risk across socioeconomic groups attenuated slightly over time.

Management of low-grade cervical cytology in young women. Cohort study from Denmark

OBJECTIVE

Cytology findings of atypical squamous cells of unknown significance (ASCUS) or low-grade squamous intraepithelial lesion (LSIL) are common among women under 30, but evidence on best management strategy is insufficient. We therefore investigated how different management strategies used in Denmark influenced biopsy rates and detection of cervical intraepithelial neoplasia (CIN).

METHODS

Register-based cohort study including Danish women aged less than 30 years and born 1980-95, with ASCUS/LSIL as their first abnormal cervical cytology in 2008-16. Rates and relative risks (RR) of biopsy and detection of CIN3+, CIN2 and < CIN2 during two years follow-up were compared between women referred directly to colposcopy after ASCUS/LSIL or undergoing additional testing, including mRNA or DNA test for high risk HPV or repeat cytology.

RESULTS

19,946 women with ASCUS and 19,825 with LSIL were included in the study of whom 92% had adequate information about follow-up. Among women referred directly to biopsy, CIN3+ was detected among 21%, CIN2 in 17%, while 62% had < CIN2. Repeating cytology after 6 months reduced the biopsy rate to 44% of which 53% had < CIN2. Biopsy rates with HPV test were 67% for DNA test, 77% with 14-type mRNA test and 58% with 5-type mRNA test. The detection of CIN3+ was somewhat higher, between 13% and 14% for the three HPV tests vs. 11% with repeat cytology. However, the detection of < CIN2 (not indicating treatment) also increased with RR 2.11 (95% CI 2.01-2.21) for 14-type mRNA test, 1.35 (95% CI 1.29-1.41) for 5-type mRNA test, and 1.86 (95% CI 1.76-1.97) with HPV DNA test.

CONCLUSIONS

The choice of management strategy influences both the detection rate for severe lesions (CIN3+) and the proportion of women followed up for potentially insignificant findings.

Survival after antireflux surgery versus medication in patients with reflux oesophagitis or Barrett's oesophagus: multinational cohort study

BACKGROUND

The aim was to examine the hypothesis that antireflux surgery with fundoplication improves long-term survival compared with antireflux medication in patients with reflux oesophagitis or Barrett's oesophagus.

METHOD

Individuals aged between 18 and 70 years with reflux oesophagitis or Barrett's oesophagus (intestinal metaplasia) documented from in-hospital and specialized outpatient care were selected from national patient registries in Denmark, Finland, Iceland, and Sweden from 1980 to 2014. The study investigated all-cause mortality and disease-specific mortality, comparing patients who had undergone open or laparoscopic antireflux surgery with fundoplication versus those using antireflux medication. Multivariable Cox regression analysis was used to estimate hazard ratios (HRs) with 95 per cent confidence intervals for all-cause mortality and disease-specific mortality, adjusted for sex, age, calendar period, country, and co-morbidity.

RESULTS

Some 240 226 patients with reflux oesophagitis or Barrett's oesophagus were included, of whom 33 904 (14.1 per cent) underwent antireflux surgery. The risk of all-cause mortality was lower after antireflux surgery than with use of medication (HR 0.61, 95 per cent c.i. 0.58 to 0.63), and lower after laparoscopic (HR 0.56, 0.52 to 0.60) than open (HR 0.80, 0.70 to 0.91) surgery. After antireflux surgery, mortality was decreased from cardiovascular disease (HR 0.58, 0.55 to 0.61), respiratory disease (HR 0.62, 0.57 to 0.66), laryngeal or pharyngeal cancer (HR 0.35, 0.19 to 0.65), and lung cancer (HR 0.67, 0.58 to 0.80), but not from oesophageal cancer (HR 1.05, 0.87 to 1.28), compared with medication, The decreased mortality rates generally remained over time.

CONCLUSION

In patients with reflux oesophagitis or Barrett's oesophagus, antireflux surgery is associated with lower mortality from all causes, cardiovascular disease, respiratory disease, laryngeal or pharyngeal cancer, and lung cancer, but not from oesophageal cancer, compared with antireflux medication.

Cervical cancer survivors and health care use: A Danish population-based register study

OBJECTIVE

To evaluate the impact of a cervical cancer (CC) diagnosis on use of health care and prescription drugs.

METHODS

This population-based register-study included Danish women aged 23-59 years and diagnosed with CC in 2001-2005. Women with a cervical screening outcome were used as comparison group. We obtained number of contacts to general practitioners (GPs), hospitals, psychologists/psychiatrists and defined daily doses (DDD) of analgesic/psychotropic prescription drugs. A difference-in-differences-design was used to estimate effect of a CC diagnosis on health-care use from five-year periods before and after the diagnosis/screening outcome.

RESULTS

In total, 926 women with CC and 1,004,759 women without cancer were included. In five years following the date of CC diagnosis, CC patients had increased their use of GPs with 8.6 (95% CI 4.8-12.4) contacts more than women in the comparison group, and with 4.12 (95% CI 3.99-4.25) more hospital contacts. In contrast, use of psychologists/psychiatrists was low and largely unaffected by the CC diagnosis. For use of prescription drugs, analgesics increased with 80 (95% CI 60-100) DDD more in CC patients than in comparison women, and for psychotropics with 304 (95% CI 261-347) DDD more.

CONCLUSIONS

A CC diagnosis was followed by an increase in use of GPs, hospitals, and analgesic/psychotropic prescription drugs, while use of psychologist/psychiatrist was largely unaffected. This pattern may indicate that pain/mental health concerns after CC either persisted or were alleviated by other means only.

Histological outcomes in HPV-screened elderly women in Denmark

Introduction

Danish women exit cervical cancer screening at age 65 years, but 23% of cervical cancer cases occur beyond this age. In addition, due to gradual implementation of cervical cancer screening, older women are underscreened by today´s standards. A one-time screening with HPV test was therefore offered to Danish women born before 1948.

Methods

Register based study reporting histology diagnoses and conizations in women found HPV positive in the one-time screening. Number and proportion of women with severe or non-severe histology results were calculated for screened and HPV-positive women by age group or region of residence. Number of women with biopsy and/or conization per case of cervical intraepithelial neoplasia (CIN) grade 2 or worse (CIN2+) or CIN3+ were also calculated by age groups and region.

Results

4,479 (4.1% of screened women) had positive HPV test. 94% of these had one or more additional tests. 2,785 (62%) of HPV-positive women had histology results, and conization was performed in 1,076 (24% of HPV-positive and 1% of all screened women). HPV positivity and CIN3+ detection varied little between regions, but the proportions of HPV positive women undergoing histology varied between regions from 40% to 86% and the proportion with conization from 13% to 36%. Correspondingly, the number of histologies and conizations per CIN3+ detected varied from 5.9 to 11.2 and 1.8 to 4.7, respectively. In total, 514 CIN2+ (0.47% of screened women, 11% of HPV-positive) and 337 CIN3+ (0.31% of screened women, 7.5% of HPV-positive) were diagnosed, including 37 cervical cancer cases.

Discussion

HPV screening of insufficiently screened birth cohorts can potentially prevent morbidity and mortality from cervical cancer but longer follow-up is needed to see if cancer incidence declines in the screened women in the coming years. Management strategies differed among regions which influenced the proportions undergoing biopsy/conization.

Reference intervals for 12 clinical laboratory tests in a Danish population: The Lolland-Falster Health Study

Reference intervals (RIs), developed as part of the Nordic Reference Interval Project 2000 (NORIP) are widely used in most European laboratories. We aimed to examine the validity of the NORIP RIs by establishing RIs for 12 frequently used laboratory tests based on data from a local Danish population and compare these local RIs with the NORIP RIs. Using an a posteriori direct sampling approach, blood sample data were assessed from 11,138 participants aged 18+ years in the Lolland-Falster Health Study (LOFUS), of whom 2154 turned out to meet criteria for being healthy for inclusion in establishing RIs according to the NORIP methodology. The 2.5th and 97.5th percentiles were calculated for alanine aminotransferase (ALAT), albumin, alkaline phosphatase, bilirubin, creatinine, hemoglobin, high-density lipoprotein cholesterol, iron, low-density lipoprotein cholesterol, thrombocytes, total cholesterol, and triglycerides. When comparing our estimates with the NORIP, the lower reference limits (RLs) for bilirubin and iron were lower, and higher for ALAT, thrombocytes and triglycerides. Upper RLs were lower for albumin (males and females ≥70 years), bilirubin and iron, but higher for alkaline phosphatase, triglycerides and for creatinine in men. In LOFUS, approximately 20% of the participants were healthy and qualified for inclusion in the establishment of RIs. Several of the local RIs differed from the NORIP RIs.

Emergence of a mortality disparity between a marginal rural area and the rest of Denmark, 1968-2017

BACKGROUND

Lolland-Falster is a rural area of Denmark, where the life expectancy is presently almost six years lower than in the rich capital suburbs. To determine the origin of this disparity, we analysed changes in mortality during 50 years in Lolland-Falster.

METHODS

Annual population number and number of deaths at municipality level were retrieved from StatBank Denmark and from Statistics Denmark publications, 1968-2017. For 1974-2017, life expectancy at birth by sex and 5-year calendar period was calculated. From 1968 to 2017, standardised mortality ratio (SMR) for all-cause mortality was calculated by sex, 5-year calendar period and municipality, with Denmark as standard and including 95% confidence intervals (CI).

RESULTS

In 1968-2017, life expectancy in Lolland-Falster increased, but less so than in the rest of Denmark. Fifty years ago, Lolland-Falster had a mortality similar to the rest of Denmark. The increasing mortality disparity developed gradually starting in the late 1980s, earlier in Lolland municipality (western part) than in Guldborgsund municipality (eastern part), and earlier for men than for women. By 2013-2017, the SMR had reached 1.25 (95% CI 1.19-1.31) for men in the western part, and 1.11 (95% CI 1.08-1.16) for women in the eastern part. Increasing mortality disparity was particularly seen in people aged 20-69 years.

CONCLUSIONS

This study is the first to report on increasing geographical segregation in all-cause mortality in a Nordic welfare state. Development of the mortality disparity between Lolland-Falster and the rest of Denmark followed changes in agriculture, industrial company closure, a shipyard close-down, administrative centralisation, and a decreasing population size.

Geography of COVID-19 in Denmark

Aim: To investigate the COVID-19 situation across geographical areas of Denmark over time. Methods: We used COVID-19 data from the Danish State Serum Institute on national, regional and municipality level. Cumulative number of tests, incidence, hospitalizations and deaths per 100,000 inhabitants were analysed for the five Danish regions and for all of Denmark. The cumulative number of tested and incidence of COVID-19 per 100,000 was compared for the two municipalities, Lolland and Gentofte. A sensitivity analysis of the COVID-19 indicators on a regional level was performed using number of tested as the denominator. Results: The Capital Region ranked highest on all analysed COVID-19 indicators with 10,849 tested, 365 cases, 63 hospitalized and 18 deaths per 100,000 by 2 June 2020. The three regions in western Denmark all had low levels, while Region Zealand ranked second highest. Despite general low health status in Lolland municipality, the cumulative incidence of COVID-19 was consistently below that of Gentofte. Sensitivity analysis showed that the Capital Region had the highest number of COVID-19 cases per 100,000 tested, but Region Zealand had a higher number of hospitalized and similar number of deaths per 100,000 tested as the Capital Region over time. Conclusion: COVID-19 had affected eastern Denmark, especially the Capital Region, considerably more than western Denmark. The difference may relate to population density and housing conditions.

Burden of prediabetes, undiagnosed, and poorly or potentially sub-controlled diabetes: Lolland-Falster health study

BACKGROUND

This study aimed to investigate prevalence and risk factors for prediabetes, undiagnosed diabetes mellitus, poorly and potentially sub-controlled diabetes in a rural-provincial general adult population in Denmark.

METHODS

Using cross-sectional data from the Lolland-Falster Health Study, we examined a total of 10,895 individuals aged 20 years and above.

RESULTS

Prevalence of prediabetes was 5.8% (men: 6.1%; women: 5.5%); of undiagnosed diabetes 0.8% (men: 1.0%; women: 0.5%); of poorly controlled diabetes 1.2% (men: 1.5%; women: 0.8%); and of potentially sub-controlled diabetes 2% (men: 3.0%; women: 1.3%). In total, 9.8% of all participants had a diabetes-related condition in need of intervention; men at a higher risk than women; RR 1.41 (95% CI 1.26-1.58); person aged + 60 years more than younger; RR 2.66 (95% CI 2.34-3.01); obese more than normal weight person, RR 4.51 (95% CI 3.79-5.38); smokers more than non-smokers, RR 1.38 (95% CI 1.19-1.62); persons with self-reported poor health perception more than those with good, RR 2.59 (95% CI 2.13-3.15); low leisure time physical activity more than those with high, RR 2.64 (95% CI 2.17-3.22); and persons with self-reported hypertension more than those without, RR 3.28 (95% CI 2.93-3.68).

CONCLUSIONS

In the Lolland-Falster Health Study, nearly 10% of participants had prediabetes, undiagnosed diabetes, poorly controlled, or potentially sub-controlled diabetes. The risk of these conditions was more than doubled in persons with self-reported poor health perception, self-reported hypertension, low leisure time physical activity, or measured obesity, and a large proportion of people with diabetes-related conditions in need of intervention can therefore be identified relatively easily.

Stronger responders-uptake and decline of HPV-vaccination in Denmark

Background

The purpose of this study was to identify the stronger responders behind the fluctuating coverage with the HPV-vaccine in Denmark in order to facilitate information campaigns targeted at specific subgroups.

Methods

Newspaper articles published from 2006 to 2009 with information about coverage with the HPV-vaccine in Denmark were identified from the database Infomedia.dk. Vaccination coverage of recent years was retrieved from the publically accessible statistics from the State’s Serum Institute. Data on average disposable income nationally and for each municipality was retrieved from Statistics Denmark.

Results

According to numbers published in newspapers, girls residing in municipalities with a high disposable income were the first ones to secure the HPV-vaccine in Denmark. Years later, at the start of the debate about possible side effects of the HPV-vaccine, the decline in vaccination coverage was slightly steeper for girls from high income municipalities than for girls from low income municipalities.

Conclusions

Girls from municipalities with a high disposable income seem to be the stronger responders of the fluctuating coverage with the HPV-vaccine in Denmark. This was the case both during the initial surge in coverage after the vaccine’s introduction on the market, and during the later decline following the debate on possible side effects. Identification of this dispersion pattern enables health authorities to initiate targeted information campaigns.

Cancer incidence among seafarers and fishermen in the Nordic countries

Objectives:

Maritime workers may be exposed to several occupational hazards at sea. The aim of this study was to assess cancer incidence among seafarers and fishermen in the Nordic countries and identify patterns in morbidity in the context of existing studies in this field.

Methods:

A cohort of 81 740 male seafarers and 66 926 male fishermen was established from census data on 15 million citizens in the five Nordic countries. Using personal identity codes, information on vital status and cancer was linked to members of the cohort from the national population and cancer registries for the follow-up period 1961–2005. Standardized incidence ratios (SIR) were calculated applying national cancer incidence rates for each country and pooling results.

Results:

The overall incidence of cancer was increased among the male seafarers [SIR 1.22, 95% confidence interval (CI) 1.19–1.23]. Significant excesses were observed for multiple cancer sites among the seafarers, while results for the fishermen were mixed. Lip cancer incidence was increased among both maritime populations. For mesothelioma (SIR 2.17, 95% CI 1.83–2.56 seafarers) and non-melanoma skin cancer (SIR 1.23, 95% CI 1.14–1.32 seafarers), incidence was increased among the seafarers.

Conclusion:

In our cohort, seafaring was associated with a higher overall incidence of cancer compared to the general population. While the majority of cancers could not be linked to specific occupational factors, increases in mesothelioma, lip and non-melanoma-skin cancer indicate previous exposure to asbestos, ultraviolet radiation and potentially also chemicals with dermal carcinogenic properties at sea.

High-grade cervical lesions after vaccination against human papillomavirus: A Danish cohort study

Introduction

It is pertinent to evaluate the impact of vaccination against human papillomavirus (HPV) in real life. The aim of the study was to evaluate the real‐life impact of HPV vaccination in the first birth cohort of Danish women offered free HPV vaccination as girls and invited to screening at the age of 23 years.

Material and methods

Women born in 1993 were offered free HPV vaccination at the age of 15 years but women born in 1983 have never been offered free HPV vaccination. We followed these two birth cohorts for 10 years from the age of 15 to after their first invitation to screening, and compared the risk of high‐grade cervical intraepithelial neoplasia (CIN). Data were obtained from Danish national health registers.

Results

Vaccination coverage was 91% in the 1993 birth cohort and <0.1% in the 1983 cohort. Screening coverage was close to 80% in both cohorts. CIN2+ was detected in 4% of the 15 748 screened women born in 1983 and in 3% of the 19 951 screened women born in 1993. The risk of high‐grade CIN was reduced by about 30% in the 1993 cohort compared with the 1983 cohort; for CIN2+ relative risk 0.74 (95% CI 0.66‐0.82) and for CIN3+ relative risk 0.68 (95% CI 0.58‐0.79).

Conclusions

This study investigated the real‐life impact of quadrivalent HPV vaccination by comparing a cohort of women offered HPV vaccination with a cohort of women not offered HPV vaccination. The observed decrease in the detection of high‐grade cervical lesions following HPV vaccination is in line with results from the randomized trials and has important implications for future cervical screening of HPV vaccinated cohorts.

Rare cancers of unknown etiology: lessons learned from a European multi-center case-control study

Rare cancers together constitute one fourth of cancers. As some rare cancers are caused by occupational exposures, a systematic search for further associations might contribute to future prevention. We undertook a European, multi-center case–control study of occupational risks for cancers of small intestine, bone sarcoma, uveal melanoma, mycosis fungoides, thymus, male biliary tract and breast. Incident cases aged 35–69 years and sex-and age-matched population/colon cancer controls were interviewed, including a complete list of jobs. Associations between occupational exposure and cancer were assessed with unconditional logistic regression controlled for sex, age, country, and known confounders, and reported as odds ratios (OR) with 95% confidence intervals (CI). Interviewed were 1053 cases, 2062 population, and 1084 colon cancer controls. Male biliary tract cancer was associated with exposure to oils with polychlorinated biphenyls; OR 2.8 (95% CI 1.3–5.9); male breast cancer with exposure to trichloroethylene; OR 1.9 (95% CI 1.1–3.3); bone sarcoma with job as a carpenter/joiner; OR 4.3 (95% CI 1.7–10.5); and uveal melanoma with job as a welder/sheet metal worker; OR 1.95 (95% CI 1.08–3.52); and cook; OR 2.4 (95% CI 1.4–4.3). A confirmatory study of printers enhanced suspicion of 1,2-dichloropropane as a risk for biliary tract cancer. Results contributed to evidence for classification of welding and 1,2-dichloropronane as human carcinogens. However, despite efforts across nine countries, for some cancer sites only about 100 cases were interviewed. The Rare Cancer Study illustrated both the strengths and limitations of explorative studies for identification of etiological leads.

Prevalence of high-risk human papillomavirus after HPV-vaccination in Denmark

Vaccination against human papillomavirus (HPV) has been introduced as a public health initiative in many countries, including Denmark since October 2008. It is important to monitor postimplementation effectiveness of HPV‐vaccination at the population‐level. We studied HPV‐prevalence after first invitation to screening at age 23 years in women offered the quadrivalent HPV‐vaccine at the age of 14 years. Randomly selected screening samples from women born in 1994 in four out of five Danish regions were subjected to analysis for HPV in addition to routine cytology. Cobas4800 was used in all participating pathology departments. Data from a Danish prevaccination cross‐sectional study using Hybrid Capture 2, and a Danish split‐sample study using Cobas4800 were used for comparison. In the period from February 2017 to April 2019, 6233 screening samples from women born in 1994 were selected for HPV‐analysis; 27 samples had no HPV‐test and 3 samples had no HPV‐diagnosis, leaving 6203 samples with an HPV‐diagnosis. Prevalence of any high‐risk (HR) HPV was 35%; only 0.9% were positive for vaccine HPV types 16/18 while the remaining 34% were positive for other HR HPV. When comparing with prevaccination prevalence data, HPV‐16/18 decreased by 95%; RR = 0.05 (95% CI 0.04‐0.06), while other HR HPV remained fairly constant; RR = 0.88 (95% CI 0.82‐0.94) and RR = 0.95 (95% CI 0.88‐1.03), respectively. One‐third of women vaccinated as girls with the quadrivalent HPV‐vaccine were HR HPV‐positive at time of first invitation to screening. Vaccine HPV‐types 16 and 18 were almost eliminated, while the prevalence of nonvaccine HR HPV‐types remained constant.

What's new?

Vaccination against human papillomavirus (HPV) has been introduced as a public health initiative in many countries. However, data on HPV infection prevalence at screening age in HPV‐vaccinated birth cohorts remain scarce. This study found that HPV‐16 and 18 were almost eliminated in a population aged 23‐24 years where 92% of women received quadrivalent HPV vaccination at age 14. Prevalence of HPV 16 and 18 was lower in non‐vaccinated women than in previous birth cohorts not offered HPV‐vaccination. Nonetheless, one third of vaccinated women were positive for high‐risk HPV other than 16/18, with potential implications for cervical cancer prevention and screening programs.