Validation of Assisted Reproductive Technology in the Medical Birth Registry of Norway Versus the Norwegian Prescription Database.

BACKGROUND: Increasing attention has been given to the long-term effects of assisted reproductive technology (ART). This study assessed the validity and completeness of ART as registered in the Medical Birth Registry of Norway (MBRN) using drug prescription data from the Norwegian Prescription Database (NorPD) as reference. METHODS: In this nationwide registry validation study, we included all pregnancies recorded in the MBRN between 2005 and 2017. We estimated sensitivity, specificity, and positive and negative predictive value (PPV and NPV) of the MBRN, using data from the NorPD as reference. We obtained the total percentage of ART pregnancies that could be identified (completeness) from both registries using the capture-recapture method. We analyzed subgroups by maternal age, gestational length, mode of ART treatment, health region, and mode of registration of ART (ART institution or birth notification form). RESULTS: Twenty-three thousand seven hundred eighteen of a total 765,789 pregnancies were registered as ART pregnancies through the MBRN and 20,807 as ART pregnancies through the NorPD. The sensitivity of the MBRN was 85.1% (95% confidence interval [CI] = 84.7, 85.6) and the PPV was 74.7% (74.1-75.2). Sensitivity declined with increasing maternal age: 71.5% (69.4-73.7) in the age group 40-44 years, and 40.7% (22.2-59.3) in the ages above 45 years. Completeness when combining data was 96.2% (96.0-96.5). CONCLUSIONS: Our analysis shows that, when identifying women pregnant through ART, NorPD data complemented MBRN data to obtain a more complete count of all women giving birth after ART in Norway.

Distribution of allele frequencies for genes associated with physical activity and/or physical capacity in a homogenous Norwegian cohort- a cross-sectional study.

BACKGROUND: There are large individual differences in physical activity (PA) behavior as well as trainability of physical capacity. Heritability studies have shown that genes may have as much impact on exercise participation behavior as environmental factors. Genes that favor both trainability and participation may increase the levels of PA. The present study aimed to assess the allele frequencies in genes associated with PA and/or physical capacity, and to see if there is any association between these polymorphisms and self-reported PA levels in a cohort of middle-aged Norwegians of Scandinavian descent (n = 831; mean age mean age (± SD) 55.5 ± 3.8 years). RESULTS: The genotype distributions of the ACTN3 R577X, ACE I/D and MAOA uVNTR polymorphisms were similar to other populations of European descent. When comparing the genotype distribution between the low/medium level PA group (LMPA) and high level PA groups (HPA), a significant difference in ACTN3 577X allele distribution was found. The X allele frequency was 10% lower in the HPA level group (P = 0.006). There were no differences in the genotype distribution of the ACE I/D or MAOA uVNTR polymorphism. Education and previous participation in sports or outdoor activities was positively associated with the self-reported PA levels (P ≤ 0.001). CONCLUSIONS: To the best of our knowledge, this is the first study to report association between ACTN3 R577X genotype and PA level in middle-aged Scandinavians. Nevertheless, the contribution of a single polymorphism to a complex trait, like PA level, is likely small. Socioeconomic variables, as education and previous participation in sports or outdoor activities, are positively associated with the self-reported PA levels.

Education, income and risk of cancer: results from a Norwegian registry-based study.

INTRODUCTION: Several studies have shown an association between socioeconomic status and incidence of cancer. In this study, we have examined the association between socioeconomic factors, using income and education as proxies, and cancer incidence in Norway, a country known to be egalitarian, with universal access to health care and scoring high on the human development index. METHODS: We linked individual data for the total Norwegian population with information on all cancer patients registered in the Cancer Registry of Norway (CRN) with any cancer diagnosed between 2012 and 2016. Data on education, and individual income, were provided from Statistics Norway. We used Poisson regression to obtain incidence rate ratios (IRR) across education and income levels for 23 cancer sites. RESULTS: A total of 9 cancers among men and 13 cancers among women were observed to have significantly higher incidence rates in cases with the lowest level of education. Melanoma for both sexes, testis and prostate cancer in men, and breast cancer in women were found to have a higher incidence rate among those with the highest level of education. The largest differences in IRR were found for lung cancer, where men and women with college or university education as their highest completed education had a two- to threefold decreased risk, compared to those with primary school (IRR men; 0.40 [0.37-0.43], women 0.34 [0.31-0.37]). The results for income mirrored the results for education among men, while for women we did not observe many differences in cancer risk across income groups. CONCLUSION: Our findings were consistent with findings from other studies showing that the incidence rate of cancer differs across levels of socioeconomic status. We may need behavioral change campaigns focused on lifestyle changes that lower the risk of cancer and target perhaps to those with lower socioeconomic status.

Waiting times and treatment following cancer diagnosis: comparison between immigrants and the Norwegian host population.

Background: There are concerns about timely access to appropriate cancer treatment for the growing immigrant population in Norway. This study aims to compare waiting times between cancer diagnosis and start of cancer treatment, as well as treatment patterns between immigrants in Norway and the host population.Material and methods: We performed a nationwide, registry-based study with individual-level data, including 213,320 Norwegians and 8324 immigrants diagnosed with breast, colorectal, lung or prostate cancer in 1990-2014. Differences in time from diagnosis to treatment and in treatment patterns were described for the selected cancer sites. The Cox and logistic regressions were used to adjust for patient and tumour characteristics.Results: After adjustment for covariates, hazard ratios for time from diagnosis to treatment for non-Western immigrants compared to Norwegians were 0.88 (95% confidence interval (CI): 0.82-0.95) for breast cancer and 0.84 (95% CI: 0.75-0.95) for lung cancer, indicating longer waiting times. Treatment patterns in the four major cancer sites were similar among immigrants and the Norwegian host population, except for breast cancer, where women from East and South Asia received less breast-conserving surgery than the Norwegian host population (adjusted odds ratios 0.65 (95% CI: 0.46-0.93) for East Asians and 0.75 (95% CI: 0.50-1.13) for South Asians).Conclusions: The present study reports delayed treatment for lung and breast cancer among immigrants from non-Western countries in Norway. Systematic differences in cancer treatment were not detected. However, less breast-conserving surgery among breast cancer patients from Asia compared to Norwegians was observed.

Underlying conditions in adults with COVID-19. / Underliggende tilstander hos voksne med covid-19.

BACKGROUND: Cardiovascular diseases, cancer, type-2 diabetes and chronic obstructive pulmonary disease (COPD) were initially noted as the most common diseases among individuals who were hospitalised for COVID-19. However, the evidence base is weak. The objective of this study is to describe how selected diseases were distributed among adults with confirmed COVID-19 (COVID-19 positive tests) and among those hospitalised for COVID-19 compared to the general population. MATERIAL AND METHOD: We used data from the Norwegian Patient Registry, the Norwegian Registry for Primary Health Care and the Norwegian Surveillance System for Communicable Diseases for adults from the age of 20 and older for the period 1 March 2020-13 May 2020. RESULTS: Of all those who tested positive for COVID-19, 7 632 (94 %) were aged 20 years or older, and 1 025 (13.4 %) of these had been hospitalised. Among those hospitalised with COVID-19, there was a higher proportion of individuals with cardiovascular diseases (18.3 % versus 15.6 %), cancer (6.9 % versus 5.4 %), type-2 diabetes (8.6 % versus 5.2 %) and COPD (3.8 % versus 2.7 %) than in the general population as a whole after adjusting for age. The proportion of hospitalised patients with asthma, other chronic respiratory disease, cardiovascular disease, ongoing cancer treatment, complications related to hypertension, obesity and overweight, neurological disorders and cardiac and renal failure was also higher than in the general population. There were few differences between persons who had tested positive for COVID-19 and the general population in terms of underlying conditions. INTERPRETATION: Among those hospitalised for COVID-19, there was a higher proportion of patients with underlying illnesses than in the general population. This may indicate that these patients tend to have a more severe course of disease or that they are more likely to be hospitalised compared to healthy individuals. The results must be interpreted with caution, since the sample of COVID-19 individuals is non-random.

Differences in cancer survival between immigrants in Norway and the host population.

Cancer survival is an important indicator for quality of cancer care. We sought to determine if there are differences in cancer survival between immigrants and the host population in Norway. We performed a nationwide registry-based study comprising subjects diagnosed with cancer between 1990 and 2014, and followed until the end of 2016. Survival was estimated for 13 cancer sites with cause-specific survival. Adjustments were made for common confounders (age, sex, year of diagnosis and place of residence) and defined mediators (stage at diagnosis, comorbidity and socioeconomic factors). A total of 500,255 subjects were available for analysis, of which 11,252 were Western and 8,701 non-Western immigrants. We did not find differences in cancer survival between Western immigrants and Norwegians, while non-Western immigrants, with some exceptions, had similar or better survival. Better lung cancer survival in non-Western immigrants than Norwegians was notable (hazard ratio (95% confidence interval): 0.78 (0.71-0.85)), and not explained by defined mediators. Immigrants from Eastern Europe and Balkan with melanoma (hazard ratio: 1.54 (1.12-2.12)) and prostate cancer (hazard ratio: 1.34 (1.08-1.67)), and possibly from sub-Saharan Africa with breast cancer (hazard ratio: 1.41 (0.94-2.12)) had worse survival than Norwegians. The results suggest that immigrants in Norway have good cancer survival relative to the host population. Poor survival in immigrants from Eastern Europe and Balkan with melanoma and prostate cancer, and sub-Saharan Africa with breast cancer might be a concern.

Cancer trends and population structure in Norway 1990-2016. / Kreftutvikling og befolkningssammensetning i Norge 1990­2016.

BAKGRUNN: Befolkningssammensetningen i Norge har endret seg, og innvandrere utgjør nå nær 14 % av befolkningen. Vi vet ikke hvordan dette påvirker kreftbildet. I denne studien presenterer vi forekomst av kreft for den norskfødte delen av befolkningen for å kunne få et bilde på hvordan forekomsten har endret seg, sett bort fra effekten av innvandring. MATERIALE OG METODE: Data fra Kreftregisteret og populasjonsdata fra Statistisk sentralbyrå ble benyttet for å beregne aldersstandardiserte insidensrater av kreft i Norge i perioden 1990-2016. RESULTATER: Studiepopulasjonen besto av 6 703 675 personer, hvorav 82,3 % ble definert som norskfødte. Ratene for alle kreftformer samlet hos norskfødte og totalbefolkningen fulgte hverandre mer eller mindre jevnt. I siste femårsperiode (2012-16) var ratene for den norskfødte delen av befolkningen 2 % høyere enn de nasjonale ratene, og føflekk- og livmorhalskreft hadde den største prosentvise forskjellen med 6-8 % høyere rater. Raten for leverkreft var 3-4 % lavere for norskfødte sammenlignet med totalbefolkningen. FORTOLKNING: De nasjonale ratene har så langt gitt et godt bilde på kreftutviklingen i den norskfødte delen av befolkningen. Siden forskjellen mellom ratene økte mot slutten av tidsperioden, kan fødeland være en viktig faktor å ta hensyn til i presentasjonen av kreftforekomst.

Cancer risk in mother and child after fertility treatment. / Kreftrisiko hos mor og barn etter fertilitetsbehandling.

BAKGRUNN: I Norge fødes nå om lag 2 500 barn årlig etter fertilitetsbehandling. Hvorvidt behandlingen er forbundet med økt kreftrisiko, er fremdeles usikkert. KUNNSKAPSGRUNNLAG: Oversikten inkluderer kohortstudier om kreftrisiko hos kvinner behandlet med fertilitetsbehandling og barn unnfanget etter slik behandling. Et systematisk søk etter artikler ble gjort i EMBASE og Medline for perioden 2006-17. RESULTATER: Resultatene viser ingen generell økning i kreft hos kvinner som har fått fertilitetsbehandling. Hos barn antyder resultatene en tendens til økt risiko for hematologisk kreft, men ingen generell økt kreftrisiko. FORTOLKNING: Det er ingen entydige funn av forhøyet risiko for kreft hos kvinner som har gjennomgått fertilitetsbehandling, eller hos barn unnfanget etter slik behandling. Oppfølgingstiden er foreløpig kort, og det er behov for store befolkningsbaserte kohortstudier med lengre oppfølgingsperioder.

Comparison of cancer stage distribution in the immigrant and host populations of Norway, 1990-2014.

Cancer stage at diagnosis is the most important prognostic factor for survival. We conducted a nationwide, population-based cohort study to investigate cancer stage distribution in immigrants compared to the host population of Norway. All patients recorded in the Cancer Registry of Norway in 1990-2014 were included (17,709 immigrants and 431,936 Norwegians). Individual level sociodemographic data was obtained from Statistics Norway. Ordered logistic regression was used to estimate if immigrants were diagnosed with cancer at a more advanced stage than Norwegians. Seven cancer sites were analyzed (breast, cervix, colorectal, liver, lung and trachea, prostate and stomach). With exception of breast cancer, we did not observe a clear pattern of more advanced cancer stage distribution in immigrants compared to Norwegians. Odds ratios and corresponding 95% confidence intervals for being diagnosed with a more advanced stage of breast cancer for non-Western immigrant groups compared to Norwegians were: Eastern Europe: 1.41 (1.20-1.65), Middle East: 1.58 (1.19-2.10), sub-Saharan Africa: 1.44 (0.99-2.08), South Asia: 1.40 (1.07-1.83) and East Asia: 0.90 (0.72-1.13). Sub-analyses showed that late detection of breast cancer in young non-Western immigrants might be of particular concern. Young (<50 years) non-Western immigrants had an odds ratio of 1.40 (1.21-1.62) for more advanced stage breast cancer compared to young Norwegians.

Long-term lifestyle changes after colorectal cancer screening: randomised controlled trial.

OBJECTIVE: There is uncertainty whether cancer screening affects participant incentives for favourable lifestyle. The present study investigates long-term effects of colorectal cancer (CRC) screening on lifestyle changes. DESIGN: In 1999-2001, men and women drawn from the population registry were randomised to screening for CRC by flexible sigmoidoscopy ('invited-to-screening' arm) or to no-screening (control arm) in the Norwegian Colorectal Cancer Prevention trial. A subgroup of 3043 individuals in the 'invited-to-screening' and 2819 in the control arm, aged 50-55 years, randomised during 2001 had their lifestyle assessed by a questionnaire at inclusion and after 11 years (42% of cohort). The outcome was 11-year changes in lifestyle factors (body weight, smoking status, physical exercise, selected dietary habits) and in total lifestyle score (0-4 points, translating to the number of lifestyle recommendations adhered to). We compared outcomes in the two randomisation arms and attendees with positive versus negative findings. RESULTS: Total lifestyle scores improved in both arms. The improvement was smaller in the 'invited-to-screening' arm (score 1.43 at inclusion; 1.58 after 11 years) compared with the control arm (score 1.49 at inclusion; 1.67 after 11 years); adjusted difference -0.05 (95% CI -0.09 to -0.01; p=0.03). The change in the score was less favourable in screening attendees with a positive compared with negative screening result; adjusted difference -0.16 (95% CI -0.25 to -0.08; p<0.001). CONCLUSIONS: The present study suggests that possible unfavourable lifestyle changes after CRC screening are modest. Lifestyle counselling may be considered as part of cancer screening programmes. TRIAL REGISTRATION NUMBER: NCT00119912.

Risk of breast cancer following fertility treatment--a registry based cohort study of parous women in Norway.

Despite increasing numbers of women availing themselves of assisted reproductive technology (ART), effects on cancer risk remain unresolved. Given hormonal exposures, breast cancer risk is of particular concern. The aim of this study is to investigate breast cancer risk amongst women giving birth following ART as compared to that amongst women who gave birth without ART. Data on all women who gave birth in Norway with or without ART, between 1984 and 2010 were obtained from the Medical Birth Registry of Norway (MBRN). 808,834 women eligible for study were linked to the Cancer Registry of Norway. Cox proportional models computed hazard ratios (HR) and 95% confidence intervals (CI) of breast cancer between the two groups, adjusting for age, parity, age at first birth, calendar period and region of residence. In total, 8,037 women were diagnosed with breast cancer during the study period, 138 ART women and 7,899 unexposed. Total follow-up time was 12,401,121 person-years (median 16.0); median age at entry was 32.5 years (range 18.6-49.9) for ART women and 26.3 (range 10.5-54.6) for unexposed. Women exposed to ART had an elevated risk of breast cancer (adjusted HR 1.20, 95% CI 1.01-1.42). Subgroup analyses gave an HR of 1.30 (95% CI 1.07-1.57) for women treated with IVF and 1.35 (95 % CI 1.07-1.71) for women with follow-up >10 years, compared with controls. Our findings of increased risk in the study population warrant continued monitoring of women treated with ART as this population advances into more typical cancer age ranges.

Colon cancer trends in Norway and Denmark by socio-economic group: A cohort study.

AIMS: Norway has experienced an unprecedented rapid and so far unexplained increase in colon cancer incidence. Norwegian rates passed Danish rates for men in 1985 and for women in 1990. This study aimed to unravel clues to the development in colon cancer incidence by investigating changes over time in incidence by socio-economic group. METHODS: Persons participating in the 1970 censuses in Norway and Denmark were aged 55-75 years in 1971-1980 (called pre-crossing period) and in 1991-2000 (called post-crossing period), respectively. Country, sex, age and socio-economic group-specific colon cancer incidence rates. Percent change in the average rate from the pre- to the post-crossing period. RESULTS: In the pre-crossing period, Norwegian male managers/administrators had the highest colon cancer incidence, but the largest increase in incidence from the pre-to the post-crossing period was seen for unskilled workers, skilled workers and farmers. The rate for unskilled workers almost doubled and in the post-crossing period this rate had bypassed that of managers/administrators. A similar development was seen for Norwegian women and was less dramatic in Denmark. CONCLUSIONS: The change in the risk of manual workers has been the driving force behind the dramatic increase in the Norwegian incidence of colon cancer. This development resulted in a reversal of the socio-economic gradient from the classic European pattern with the highest incidence in the upper socio-economic groups to an American pattern with the highest incidence in the lower socio-economic groups. This 'Americanization' of the disease pattern followed the rapid growth in the Norwegian gross domestic product.

Lung cancer ­ changes in incidence by gender, age and county of residence 1984-2013.

BACKGROUND: The Cancer Registry of Norway has reported a decline in age-standardised lung cancer rates for men and an unconfirmed levelling-off in the rate for women. This study describes the development in trends according to gender and age, nationwide as well as by county. MATERIAL AND METHOD: Data on lung cancer from the Cancer Registry of Norway and the NORDCAN website are presented as age-specific and age-standardised rates by gender and place of residence, with a main emphasis on the period 1984-2013. RESULTS: Out of 62,937 Norwegian lung cancer patients (1984-2013), altogether 63% were men. Nationally there was a decline in the rate for middle-aged men (50-69 years), but only a levelling-off in the oldest age group (≥ 70 years). For women, the rates increased in both age groups, most markedly in the oldest one. The rates for older men in the Agder, Vestfold and Finnmark counties have remained above the national average for a prolonged period, and there are only modest signs of a decline among the middle-aged. Oslo is a clear exception, with a clear and sustained decline among men in both age groups. Vest-Agder county had the highest rate for women during the last five-year period, while the rates in Oslo are now at the national average. The national rates for middle-aged women and middle-aged men are converging, intersecting each other in Akershus county. INTERPRETATION: The large differences between genders, age groups, counties and nations in terms of trends in lung cancer indicate that through preventive efforts, we might have achieved much more in a shorter time.

Educational disparities in cancer incidence, stage, and survival in Oslo.

OBJECTIVES: This study aimed to examine disparities in cancer incidence, stage at diagnosis, and survival rates across districts with differences in education levels in Oslo, Norway. METHODS: Aggregated data from the Cancer Registry of Norway in the period 2013-2021 were used to describe the distribution of cancer incidence and survival across Oslo's 15 administrative districts, subsequently grouped into three areas based on the population's level of education. Age-standardised incidence rates and five-year relative survival were calculated for colon, rectal, lung, melanoma, breast, and prostate cancer. The stage at the time of diagnosis was categorised as localised, regional, distant, and unknown for all cancer types except breast cancer, which was categorised into stage I-IV and unknown. RESULTS: Mid- and high-education areas had higher incidences of breast, melanoma, and prostate cancer, while the low-education area had higher incidence rates for lung cancer. The low-education area had a higher proportion diagnosed at a distant stage than the other groups for all cancer types studied, except breast cancer. The mid- and high-education areas had higher five-year relative survival rates overall. CONCLUSIONS: Incidence, stage at diagnosis, and survival varied between education areas. The variation indicates disparities in healthcare access, quality of care, and health behaviours. Addressing these disparities can help improve overall health outcomes and promote health equity.

Hospital surgical volume and colorectal cancer survival in Norway: A nationwide cohort study.

BACKGROUND: Studies of hospital surgical volume and colorectal cancer survival are inconclusive. We investigated whether surgical volume was associated with survival of patients operated for colorectal cancer in Norway. METHODS: Using Cancer Registry of Norway data, we compared excess mortality from colorectal cancer by hospital surgical volume among 26,989 colon and 9779 rectal cancer patients diagnosed 2009-2020 and followed-up to 31.12.2021. Hospitals were divided into terciles according to their three-year average annual surgical volume; colon: low (< 22), middle (22-73), high (> 73); rectal: low (< 17), middle (17-38), high (> 38). We estimated excess hazard ratios (EHR) with flexible parametric models adjusted for age, year, stage, surgical urgency and surgery location (within/outside patient's residential health trust). RESULTS: Low-volume hospitals had the highest proportion of late-stage or acutely operated colon cancer patients. Colon cancer patients operated at low- versus high-volume hospitals had significantly increased crude excess mortality (EHR = 1.30; 95 % CI = 1.14-1.48) but no difference after adjustment for age, year, and stage (EHR = 0.97; 0.85-1.11). High-volume hospitals had the highest proportion of late-stage rectal cancer patients and patients operated outside their residential area. Rectal cancer patients operated at low- versus high-volume hospitals did not have significantly different excess mortality before (EHR = 0.84; 0.64-1.10) or after (EHR = 1.03; 0.79-1.35) adjustment for age, year, stage, surgical urgency and surgery location. After accounting for case-mix, hospital surgical volume was not associated with excess mortality from colon (P = 0.40) or rectal cancer (P = 0.22). CONCLUSION: Low hospital surgical volume was not associated with poorer colorectal cancer survival.