Yrsa Andersen Hundrup

Glostrup Hospital, København, Capital Region, Denmark

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Publications (31)111.5 Total impact

  • International Journal of Epidemiology 03/2011; 41(5):1241-7. · 6.98 Impact Factor
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    ABSTRACT: To investigate the validity of self-reported birthweight among middle-aged and elderly women and to identify possible determinants of reporting accuracy. The Danish Nurse Cohort Study (DNCS), a prospective risk factor and hormone therapy study. Participants in the 1999 DNCS. Self-reported exact and categorical birthweight data from the DNCS was compared with data from the Copenhagen School Health Records Register (CSHRR), which contains birthweight data. Accuracy of self-reported birthweight expressed as mean difference with limits of agreement, sensitivity, specificity, and positive and negative predictive values (PPV and NPV). Exact birthweight was available for 441 participants. The correlation coefficient was 0.83. The mean difference was -21 g and limits of agreement were -843 to 818 g. A total of 74% answered correctly within 250 g while 7% were more than 500 g in error. Categorical birthweight was available for 925 participants. A total of 87% reported the correct birthweight. Sensitivity and PPV were high for normal birthweight, whereas specificity and NPV were better for high and low birthweight (HBW and LBW). Multiple logistic regression analyses showed that HBW, LBW and being the daughter of a young mother decreased the accuracy of self-reported birthweight. Self-reported birthweight is a valid measure of actual birthweight among middle-aged and elderly women. Due to the lower accuracy of HBW and LBW, studies of the association between birthweight and chronic disease may underestimate the true effect of these weights.
    Acta Obstetricia Et Gynecologica Scandinavica 09/2010; 89(9):1134-9. · 1.85 Impact Factor
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    ABSTRACT: We evaluated the Women's Health Initiative (WHI) hip fracture risk score in 15,648 postmenopausal Danish nurses. The algorithm was well calibrated for Denmark. However, the sensitivity was poor at common decision making thresholds. Obtaining sensitivity better than 80% led to a low specificity of 61.4%. A new score based on data from the WHI has been designed to predict 5-year risk of hip fracture in postmenopausal women. The performance of the algorithm has not been validated in populations with different lifestyle characteristics and ethnicity. The aim of this study was to test the clinical performance of the algorithm in a large Danish cohort of postmenopausal Caucasian women against hip fracture. The Danish Nurse Cohort is a prospective risk factor and hormone therapy (HT) study established in 1993. Participants in the present analysis were 15,648 postmenopausal nurses. The calibration and diagnostic performance of the WHI algorithm was evaluated using fracture events captured in the Danish National Hospital Registry. During 5 years of follow-up, 122 participants suffered a hip fracture (1.8/1,000 person years). The WHI algorithm predicted that 107 hip fractures would occur, indicating an underestimation of the number of fractures by 12%. To obtain sensitivity better than 80%, the cut-off value for 5-year risk was set to 0.5%, which was accompanied by a low positive predictive value of 1.9% and a low specificity of 61.4%. The algorithm predicted too many fractures in HT-users (12 observed, 22 expected) and too few in non HT-users (107 observed, 81 expected). While the WHI algorithm was well calibrated on the Danish population, the clinical utility of the WHI algorithm in Danish postmenopausal women was limited by poor sensitivity at common decision-making thresholds and suboptimal in non-HT-users.
    Osteoporosis International 02/2010; 21(12):2135-42. · 4.04 Impact Factor
  • Bone 06/2009; 44. · 4.46 Impact Factor
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    ABSTRACT: Many studies which investigate the effect of drugs categorize the exposure variable into never, current, and previous use of the study drug. When prescription registries are used to make this categorization, the exposure variable possibly gets misclassified since the registries do not carry any information on the time of discontinuation of treatment.In this study, we investigated the amount of misclassification of exposure (never, current, previous use) to hormone therapy (HT) when the exposure variable was based on prescription data. Furthermore, we evaluated the significance of this misclassification for analysing the risk of breast cancer. Prescription data were obtained from Danish Registry of Medicinal Products Statistics and we applied various methods to approximate treatment episodes. We analysed the duration of HT episodes to study the ability to identify discontinuation of therapy from prescription data. Furthermore, we compared to results based on self-reported duration of HT from the Danish Nurse Cohort.Finally, we analysed the effect of HT exposure on time to breast cancer for the different prescription based exposure variables as well as for self-reported HT use. The results of time to discontinuation varied strongly across the different HT assessments. However, misclassification of HT exposure at baseline was limited and hence analysis of the effect of HT on time to breast cancer showed stability across the different exposure assessments with Hazard Ratios ranging from 1.68 to 1.78 for current use compared to never use. The findings suggest that it is possible to estimate the effect of never, current and previous use of HT on breast cancer using prescription data.
    Pharmacoepidemiology and Drug Safety 12/2008; 18(2):147-53. · 2.90 Impact Factor
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    ABSTRACT: Most prospective observational studies suggest that weight loss increases the risk of premature death among obese individuals. This is surprising because clinical studies show that weight loss generally leads to overall improvements in cardiovascular risk factors. It is sometimes argued that the increased mortality observed with weight loss must depend on confounding or poor study designs. This review was conducted to summarize results from studies on intentional weight loss and mortality among healthy individuals, while carefully considering the designs and problems in these studies. Evaluation criteria with a rating scale were developed. Of the studies evaluated, two found decreased mortality with intentional weight loss, three found increased mortality, and four found no significant associations between intentional weight loss and total mortality. Thus, it is still not possible for health authorities to make secure recommendations on intentional weight loss. More studies designed to specifically address this issue are warranted.
    Nutrition Reviews 08/2008; 66(7):375-86. · 4.60 Impact Factor
  • A Bjørn, Y A Hundrup, L Wagner
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    ABSTRACT: Nursing research in Denmark has evolved over the last 30 years. By 2005, 48 Danish nurses had earned a doctoral degree. The Danish Nurses Organization formalized a strategy for development of nursing research for the period 1999-2002. The strategy was evaluated in 2004. One point in the evaluation was that the nurses' publication of peer-reviewed articles in journals with an Impact Factor did not show in the bibliographic measure used in health sciences. The purpose of this study is to identify the number of Danish nurses holding a doctoral degree by the end of 2005 and to document their scientific production. A descriptive design based on a national register of all nurses in Denmark holding doctoral degrees was used to explore the curricula vitae and publication lists of 38 out of 48 (79%) nurses on the register. Authorship of all 48 graduated nurses was sought in the databases: PubMed and CINAHL. A pattern of growing engagement in publishing peer-reviewed articles was identified among the Danish nurses holding a doctoral degree. Fifty per cent of these doctoral prepared nurses published peer-reviewed papers. The majority apparently pursued a career in health sciences. Nursing as an academic discipline is evolving in Denmark but, with its roots in clinical nursing, scientists may have to be aware of the necessity to prevail as a discipline through scientific production.
    International Nursing Review 07/2008; 55(2):227-33. · 0.94 Impact Factor
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    ABSTRACT: Moderate alcohol consumption has beneficial effects on survival. Sex differences, however, have been suggested implying less beneficial effect among women. We examined the impact of alcohol consumed on weekdays and at weekends, respectively, on risk of death among women. At baseline in 1993, a total of 17 772 female members of the Danish Nurse Association completed questionnaires on alcohol intake and other lifestyle factors. The influence of alcohol intake on risk of death was analyzed using Cox proportional hazard model. Alcohol intake of 1-3 drinks per week was associated with the lowest risk of death. Intake above six drinks per weekend (Friday through Sunday) increased risk of death from all causes by 3% for each additional drink consumed per weekend (corresponding to an increased risk by 9% per drink per weekend day). Consumption of one or more drinks per weekday (Monday, Tuesday, Wednesday or Thursday) increased risk by 4% for each additional drink consumed per day. The results indicated an increasing risk of death for intake above six drinks per weekend and of one or more drinks per weekday.
    European Journal of Clinical Nutrition 07/2008; 62(6):817-22. · 2.76 Impact Factor
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    ABSTRACT: Background:  Denmark is facing a shortage of nurses and this trend is anticipated to worsen within the next decades. The major reason for this shortage is that only very few nurses remain employed until the general retirement age. Every year several nurses are expelled from the labour market prematurely which causes a problem not only for the disabled nurses but also because it can affect the morale and productivity among the remaining personnel while new staff members are hired and trained.Aim:  The aim of the study was to analyse the relationship between lifestyle, working environment, socio-demographic factors and disability pension (DP) among nurses.Methods:  The study was based on 12 028 nurses above the age of 44 who in 1993 completed a questionnaire. The survey information was combined with longitudinal data from a register compiled by Statistics Denmark. The follow-up period was from 1993 to 2002.Results:  Nurses with relatively low gross incomes were more likely to become disability pensioners compared to nurses with high incomes (hazard ratio, HR 1.33 and HR 2.17). Also, nurses who were singles had a higher probability of entering DP (HR 1.63). Nurses who worked fixed evening or night shifts had higher risks of DP than nurses who worked daytime exclusively (HR 1.51 and HR 1.45). Smoking, obesity and having a sedentary lifestyle were also risk indicators for DP (HR 1.42, HR 1.63 and HR 1.50). Furthermore, low influence and high physical demands at work increased the probability of entering DP (HR 1.39 and HR 1.22).Conclusion:  DP among nurses is influenced by a number of factors. Nurses who have poor working environments and/or unhealthy lifestyles have higher risks of becoming disability pensioners. Also, nurses who are singles and/or have low gross incomes have higher probability of entering DP.
    Scandinavian Journal of Caring Sciences 05/2008; 22(2):241 - 248. · 0.89 Impact Factor
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    ABSTRACT: To assess the relation between work-related stressors and breast cancer incidence and prognostic characteristics (estrogen receptor status, grade, lymph node status, size, stage) at the time of diagnosis. The 18,932 women included in the Danish Nurse Cohort reported work-related stressors in 1993 and again in 1999 and were followed until the end of 2003 in national registries. Prognostic characteristics were obtained from a clinical database and fewer than 0.1% were lost to follow up. During follow-up, 455 women were diagnosed with breast cancer. Neither women with high work pressure (HR = 1.17; 95% CI: 0.79, 1.73) nor women with self-reported low influence on work organization (0.98; 0.69, 1.39) or long working hours (0.93; 0.54, 1.58) were at higher risk of breast cancer than women with no such stressors. Women with high work tempo had a slightly higher risk of breast cancer (1.25; 1.02, 1.54) than women with a suitable work tempo, but there was no dose-response effect. There were no clear differences in the prognostic characteristics of breast tumors diagnosed in women with and without work-related stressors. Work-related stressors do not affect breast cancer risk or the prognostic characteristics of incident breast cancers at the time of diagnosis. These results may be a comfort to working women and can hopefully prevent self-blaming among women who develop breast cancer.
    Cancer Causes and Control 05/2008; 19(3):297-303. · 3.20 Impact Factor
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    ABSTRACT: Obesity and self-rated health (SRH) are strong predictors of morbidity and mortality but their interrelation is sparsely studied. The aim of this study was to analyse the association between weight changes and changes in SRH among women. We also examined if poor SRH at baseline was associated with later weight gain. The Danish Nurse Cohort Study is a prospective population study (1993-1999) and comprises 13,684 female nurses aged 44 to 69 years. Logistic regression analyses were used to examine the association between weight changes and changes in SRH. Women who gained weight during the study period had higher odds of reporting poorer self-rated health (Odds Ratio (OR): 1.18, 95% CI: 1.04-1.35). Weight loss among overweight women, did not result in an increase in self-rated health ratings, in fully adjusted analyses (0.96 (95% CI: 0.76-1.23). Poor self-rated health combined with normal weight at first examination was associated with higher odds of later weight gain (OR: 1.29, 95% CI: 1.10-1.51). Weight changes may result in lower SRH. Further, poor self-rated health at baseline seems to predict an increase in weight, among women without any longstanding chronic diseases. Future obesity prevention may focus on normal weight individuals with poor SRH.
    BMC Women's Health 02/2008; 8:13. · 1.66 Impact Factor
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    ABSTRACT: In this study, we compared the response rates of blood, saliva, and buccal cell samples in a pilot study on the Danish nurse cohort and examined the quantity and quality of the purified genomic DNA. Our data show that only 31% of the requested participants delivered a blood sample, whereas 72%, 80%, and 76% delivered a saliva sample, buccal cell sample via mouth swabs, or buccal cell sample on FTA card, respectively. Analysis of purified genomic DNA by NanoDrop and agarose gel electrophoresis revealed that blood and saliva samples resulted in DNA with the best quality, whereas the DNA quality from buccal cells was low. Genotype and PCR analysis showed that DNA from 100% of the blood samples and 72% to 84% of the saliva samples could be genotyped or amplified, whereas none of the DNA from FTA cards and only 23% of the DNA from mouth swabs could be amplified and none of the DNA from swabs and 94% of the DNA from FTA cards could be genotyped. Our study shows that the response rate of self-collection saliva samples and buccal cell samples were much higher than the response rate of blood samples in our group of Danish nurses. However, only the quality of genomic DNA from saliva samples was comparable with blood samples as accessed by purity, genotyping, and PCR amplification. We conclude that the use of saliva samples is a good alternative to blood samples to obtain genomic DNA of high quality and it will increase the response rate considerably in epidemiologic studies.
    Cancer Epidemiology Biomarkers &amp Prevention 11/2007; 16(10):2072-6. · 4.56 Impact Factor
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    ABSTRACT: Background/Objective: Moderate alcohol consumption has beneficial effects on survival. Sex differences, however, have been suggested implying less beneficial effect among women. We examined the impact of alcohol consumed on weekdays and at weekends, respectively, on risk of death among women.
    European Journal of Clinical Nutrition 05/2007; 62(6):817-822. · 2.76 Impact Factor
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    ABSTRACT: The aim of the study was to analyze the relationship between health, lifestyle, work-related and sociodemographic factors, and older nurses' exit from the labor market to Post-Employment Wage (PEW). PEW is an early retirement scheme to make it possible for workers to retire at the age of 60. The study was based on 5,538 nurses in the age of 51-59 who in 1993 completed a questionnaire on health, lifestyle, working environment, and sociodemographic factors. The survey information was combined with longitudinal data from the Danish Integrated Database for Labor Market Research compiled by Statistics Denmark. The follow-up period was from 1993 to 2002. Nurses who had poor self-rated health were more likely to join PEW compared with nurses who considered their health as good (HR 1.28, 95% CI 1.16-1.41). Low job influence, high workload, and physical job demands only marginally increased the probability of retiring. Nurses who have relatively low gross incomes had an increased probability of entering PEW compared with nurses with relatively high gross incomes (HR 1.60, CI 1.43-1.79). Having a spouse increased the probability of joining PEW, especially having a spouse who had retired or was unemployed. The retirement age among nurses is influenced by a number of sociodemographic, work-related, and health-related factors. Poor health, low income, living outside the Copenhagen area, being married, having a spouse who is outside the labor force, and working in the daytime are all predictors of early retirement among nurses. Poor working environment only marginally increased the probability of retiring early.
    Scandinavian Journal of Public Health 02/2007; 35(1):23-30. · 1.97 Impact Factor
  • Karina Friis, Ola Ekholm, Yrsa A Hundrup
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    ABSTRACT: To generalize findings from a nursing population to the general female population, the aim of this study was to compare lifestyle and health among Danish female nurses with that among Danish women. Furthermore, the aim was to compare lifestyle and health among Danish female nurses with women belonging to the same socio-economic group as nurses. Danish females above the age of 44 in 1999 (n = 22,715) were compared with a group of women from the Danish Health and Morbidity Survey conducted in 2000 (n = 4,445). Age standardized risk ratios (SRR) with 95% confidence intervals were calculated to compare the two groups. Nurses smoke less (SRR 0.74, CI: 0.70-0.78) and are more physically active (SRR 2.53, CI: 2.31-2.77) when compared with the general female population. A higher percentage of nurses consume five drinks or more on a weekday compared with the general female population (SRR 2.68, CI: 2.25-3.19). When comparing nurses with women belonging to the same socio-economic group, these differences are also found to be statistically significant, but no differences are found according to overweight/obesity, self-reported health and limitations in daily activities when nurses are compared with women belonging to the same socio-economic group. In general, Danish nurses have a healthier lifestyle than other Danish women. In future studies, differences and similarities in lifestyle and health between nurses and other women should be considered when generalizing findings from Danish nurses to the Danish female population.
    Scandinavian Journal of Caring Sciences 01/2006; 19(4):361-7. · 0.89 Impact Factor
  • International Journal of Epidemiology 09/2005; 34(4):931-5. · 6.98 Impact Factor
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    ABSTRACT: To identify risk factors for hip fracture and to examine whether hormone replacement therapy (HRT) modifies the effect of these risk factors. Prospective cohort study. Setting: The Danish Nurse Cohort Study. 14,015 female nurses aged 50 years and above who in 1993 completed a questionnaire on general health and lifestyle issues, reproductive history including information on HRT, and family history of osteoporosis and personal history of a wrist fracture. End-point was the first-ever hip fracture registered in the Danish National Hospital Register during the period from 1993 to 1999. During the follow-up period 245 hip fractures were identified. Ever users of HRT had a lower risk of hip fracture (hazard ratio 0.69; 0.50-0.94). Women reporting a poor health (hazard ratio 2.01; 1.30-3.11), restrictions in daily activities (hazard ratio 1.52; 1.05-2.21), low body mass index (hazard ratio 1.65; 0.98-2.77), and leisure time sedentary physical activity (hazard ratio 1.88; 1.30-2.70) were main identified risk factors for hip fracture. HRT did not modify the effect of risk factors on the risk of hip fracture. This study confirms that women with a frail health are at increased hip fracture risk and that ever use of HRT decreases the risk of hip fracture. HRT did not modify the effect of these risk factors, indicating that the preventive effect of this therapy is independent of risk factors.
    European Journal of Epidemiology 02/2005; 20(10):871-7. · 5.12 Impact Factor
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    ABSTRACT: The purpose of this study was to examine the influence of lifestyle, health, and work environment on smoking cessation among Danish nurses age 45-66 years over a 6-year period from 1993-1999. Data derive from the Danish Nurse Cohort Study; a prospective cohort established in 1993 when all Danish female nurses 45+ years old and members of the Danish Nurses Association were mailed a questionnaire. The cohort was followed up 6 years later in 1999. In total, 12,980 responded to questions concerning smoking status in both the 1993 and 1999 surveys. This study deals with the 4713 women (36%) who reported smoking at baseline. Smoking cessation was based on self-report. At follow-up in 1999, 24% reported that they no longer smoked. Low prior tobacco consumption at baseline, high fresh fruit consumption, high blood pressure, working day shifts, having low physical job strain, perceiving influence on one's own work, and partner's socio-economic status (as measured by most recent occupation) were associated with successful smoking cessation. The findings from this study highlight the importance of various factors, including lifestyle, health status, and aspects of one's work environment, on successful efforts at smoking cessation.
    Preventive Medicine 01/2005; 41(3-4):757-60. · 3.50 Impact Factor
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    ABSTRACT: The aim of this study is to investigate the risk of developing prognostic different types of breast cancer in women using hormone replacement therapy (HRT). A total of 10 874 postmenopausal Danish Nurses were followed since 1993. Incident breast cancer cases and histopathological information were retrieved through the National Danish registries. The follow-up ended on 31 December 1999. Breast cancer developed in 244 women, of whom 172 were invasive ductal carcinomas. Compared to never users, current users of HRT had an increased risk of a hormone receptor-positive breast cancer, but a neutral risk of receptor-negative breast cancer, relative risk (RR) 3.29 (95% confidence interval (CI): 2.27-4.77) and RR 0.99 (95% CI: 0.42-2.36), respectively (P for difference=0.013). The risk of being diagnosed with low histological malignancy grade was higher than high malignancy grade with RR 4.13 (95% CI: 2.43-7.01) and RR 2.17 (95% CI: 1.42-3.30), respectively (P=0.063). For breast cancers with other prognostic characteristics, the risk was increased equally for the favourable and non favourable types. Current users of HRT experience a two- to four-fold increased risk of breast cancer with various prognostic characteristics, both the favourable and non favourable types. For receptor status, the risk with HRT was statistically significantly higher for hormone receptor-positive breast cancer compared to receptor-negative breast cancer.
    British Journal of Cancer 09/2004; 91(4):644-50. · 5.08 Impact Factor
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    ABSTRACT: Epidemiologic studies have shown an increased risk of breast cancer following hormone replacement therapy (HRT). The aim of this study was to investigate whether different treatment regimens or the androgenecity of progestins influence the risk of breast cancer differently. The Danish Nurse Cohort was established in 1993, where all female nurses aged 45 years and above received a mailed questionnaire (n = 23,178). A total of 19,898 women returned the questionnaire (86%). The questionnaire included information on HRT types and regimens, reproductive history and lifestyle-related factors. Breast cancer cases were ascertained using nationwide registries. The follow-up ended on 31 December 1999. Women with former cancer diagnoses, women with missing information on HRT, surgical menopause, premenopausal, as well as hysterectomized women were excluded, leaving 10,874 for analyses. Statistical analyses were performed using Cox proportional hazards model. A total of 244 women developed breast cancer during follow-up. After adjustment for confounding factors, an increased risk of breast cancer was found for the current use of estrogen only (RR = 1.96; 95% CI = 1.16-3.35), for the combined use of estrogen and progestin (RR = 2.70; 95% CI = 1.96-3.73) and for current users of tibolone (RR = 4.27; 95% CI = 1.74-10.51) compared to the never use of HRT. In current users of combined HRT with testosterone-like progestins, the continuous combined regimens were associated with a statistically significant higher risk of breast cancer than the cyclical combined regimens (RR = 4.16, 95% CI = 2.56-6.75, and RR = 1.94, 95% CI = 1.26-3.00, respectively). An increased risk of breast cancer was noted with longer durations of use for the continuous combined regimens (p for trend = 0.048). The European traditional HRT regimens were associated with an increased risk of breast cancer. The highest risk was found for the use of continuous combined estrogen and progestin.
    International Journal of Cancer 06/2004; 109(5):721-7. · 6.20 Impact Factor

Publication Stats

424 Citations
111.50 Total Impact Points

Institutions

  • 2010–2011
    • Glostrup Hospital
      • Research Centre for Prevention and Health
      København, Capital Region, Denmark
  • 2003–2008
    • National Institute of Public Health
      København, Capital Region, Denmark
  • 2002–2007
    • National Institute of Public Health, Denmark
      København, Capital Region, Denmark
  • 2000
    • Danish Institute for Health Services Research
      København, Capital Region, Denmark