General Population In Denmark Research Articles

Risk of Breast Cancer and Gynecologic Cancers in a Large Population of Nearly 50,000 Infertile Danish Women

Infertility is considered to influence the risk of breast cancer and gynecologic cancers. To assess this association, the authors used data from a large cohort of 54,362 women with a diagnosis of infertility who were referred to Danish fertility clinics between 1963 and 1998. Through 2003, 1,975 cancers were identified by linkage to the Danish Cancer Registry. Cancer risk was assessed through standardized incidence ratios (SIRs) and corresponding 95% confidence intervals, using general and parity-specific cancer incidence rates in the general population of Denmark as a reference. After adjustment for parity status, significantly increased SIRs were observed for breast (SIR = 1.08, 95% confidence interval: 1.01, 1.16) and ovarian (SIR = 1.46, 95% confidence interval: 1.24, 1.71) cancer. The risk of breast cancer increased with follow-up time. Similar risk patterns were observed for the different histologic types of breast cancer and all nonmucinous types of ovarian cancer, whereas the risk of mucinous ovarian cancers seemed not to be increased. These data thus suggest higher risks of breast and ovarian cancer among infertile women. However, since these results could not distinguish the effects of underlying infertility from the effects of fertility treatment, additional studies are needed to disentangle the effects of these two factors.

Epidemiological Survey of 214 Families With Bladder Exstrophy-Epispadias Complex

We sought to identify causative nongenetic and genetic risk factors for the bladder exstrophy-epispadias complex. A total of 237 families with the bladder exstrophy-epispadias complex were invited to participate in the study, and information was obtained from 214 families, mainly from European countries. Two families showed familial occurrence. Male predominance was found among all subgroups comprising epispadias, classic bladder exstrophy and cloacal exstrophy, with male-to-female ratios of 1.4:1, 2.8:1 and 2.0:1, respectively (p = 0.001). No association with parental age, maternal reproductive history or periconceptional maternal exposure to alcohol, drugs, chemical noxae, radiation or infections was found. However, periconceptional maternal exposure to smoking was significantly more common in patients with cloacal exstrophy than in the combined group of patients with epispadias/classic bladder exstrophy (p = 0.009). Only 16.8% of mothers followed the current recommendations of periconceptional folic acid supplementation, and 17.6% had started supplementation before 10 weeks of gestation. Interestingly, in the latter group mothers of patients with cloacal exstrophy were more compliant with folic acid supplementation than were mothers of the combined group of patients with epispadias/classic bladder exstrophy (p = 0.037). Furthermore, mothers of children with cloacal exstrophy knew significantly more often prenatally that their child would have a congenital malformation than did mothers of children with epispadias/classic bladder exstrophy (p <0.0001). Our study corroborates the hypothesis that epispadias, classic bladder exstrophy and cloacal exstrophy are causally related, representing a spectrum of the same developmental defect, with a small risk of recurrence within families. Embryonic exposure to maternal smoking appears to enforce the severity, whereas periconceptional folic acid supplementation does not seem to alleviate it. There is a disproportional prenatal ultrasound detection rate between severe and mild phenotypes, possibly due to the neglect of imaging of full bladders with a focus on neural tube defects.

Increased pain sensitivity is not a risk factor but a consequence of frequent headache: A population-based follow-up study

Altered pain sensitivity is believed to play an important role for chronification of headache. It has however mainly been evaluated in highly selected patients from headache clinics and never in longitudinal studies. The present study is a 12-year follow-up of a population-based study of primary headache disorders and pain perception, combining a diagnostic headache interview with examination of muscle tenderness and measurement of pressure pain thresholds in 1000 subjects drawn randomly from the general population in Denmark. The aim of the study was to explore the cause–effect relationship between the increased pain sensitivity and the development of headache. The pressure pain thresholds were normal at baseline but had decreased at follow-up in subjects who developed chronic tension-type headache over the 12-year period ( p = 0.025). In subjects who developed frequent episodic tension-type headache the tenderness was normal at baseline but had increased at follow-up ( p < 0.01) while the pain thresholds were normal both at baseline and at follow-up. The findings demonstrate that increased pain sensitivity is a consequence of frequent tension-type headache, not a risk factor, and support that central sensitization plays an important role for the chronification of tension-type headache.

The Burden of Genital Warts: A Study of Nearly 70,000 Women from the General Female Population in the 4 Nordic Countries

To assess the burden and correlates of genital warts in women. We conducted a population-based cross-sectional study in 69,147 women (18-45 years of age) randomly chosen from the general population in Denmark, Iceland, Norway, and Sweden. Information on clinically diagnosed genital warts and lifestyle habits was collected using a questionnaire. Overall, 10.6% reported ever having had clinically diagnosed genital warts. In addition, 1.3% reported having experienced genital warts within the past 12 months. The cumulative incidence for different birth cohorts, estimated on the basis of age at first diagnosis of genital warts, increased with each subsequent younger birth cohort (P<.01). The lifetime number of sex partners was strongly correlated with a history of genital warts (odds ratio for > or =15 partners vs. 1 partner, 9.45 [95% confidence interval, 7.89-11.30]). The likelihood of reporting genital warts also increased with a history of sexually transmitted disease, use of hormonal contraceptives, use of condoms, smoking, and higher education. The data suggest that 1 in 10 women in the Nordic countries experience genital warts before the age of 45 years, with an increasing occurrence in younger birth cohorts. These data are important for developing and evaluating strategies (e.g., human papillomavirus [HPV] vaccination) to control and prevent HPV infection and disease in the population.

10‐year prevalence of contact allergy in the general population in Denmark estimated through the CE‐DUR method

The prevalence of contact allergy in the general population has traditionally been investigated through population-based epidemiological studies. A different approach is the combination of clinical epidemiological (CE) data and the World Health Organization-defined drug utilization research (DUR) method. The CE-DUR method was applied in Denmark to estimate the prevalence of contact allergy in the general population and compare it with the prevalence estimates from the Glostrup allergy studies. Contact allergy prevalence estimates ranging from very liberal ('worst case') to conservative ('best case') assumptions were based on patch test reading data in combination with an estimate of the number of persons eligible for patch testing each year based on sales data of the 'standard series'. The estimated 10-year prevalence of contact allergy ranged between 7.3% and 12.9% for adult Danes older than 18 years. The 10-year prevalence of contact allergy measured by CE-DUR was slightly lower than previous prevalence estimates from the Glostrup allergy studies. This could probably be explained by a decrease in nickel allergy. The CE-DUR approach holds the potential of being an efficient and easy monitoring method of contact allergy prevalence.

The relation of stress and psychiatric illnesses to coronary heart disease

The relation of stress and psychiatric illnesses to coronary heart disease

Spontaneous abortion: A prospective cohort study of younger women from the general population in Denmark. Validation, occurrence and risk determinants

To assess the occurrence of spontaneous abortion, comparing two different data sources. To estimate the rate of spontaneous abortion over a 2-year period, and examine potential predictors of the risk for incident spontaneous abortion. We used interview data from a population-based prospective cohort study comprising 11,088 women and data from a linkage of the cohort with the Hospital Discharge Register to compare spontaneous abortions as reported in the interview with those identified in the register. Based on interview data, we estimated the rate of spontaneous abortion during the two-year follow-up. Finally, risk determinants for incident spontaneous abortion were analyzed by means of logistic regression. A total of 654 spontaneous abortions before enrolment in the study were reported by the women compared to 531 abortions found in the register. More than 80% of the spontaneous abortions identified from both sources were recorded in the same year. During follow-up a total of 20.9% of pregnancies intended to be carried to term ended as a spontaneous abortion. In the risk factor analysis, we found that previous spontaneous abortion, being single, never having used oral contraceptives, and use of intrauterine device were associated with increased risk of subsequent spontaneous abortion. In addition, it was indicated that a short interpregnancy interval following a spontaneous abortion may confer an increased risk of abortion in the subsequent pregnancy. We found a high rate of spontaneous abortion in the present study and an acceptable agreement between information obtained by interview and register information. More than 25% of the spontaneous abortions were only reported by the women, and this could not be explained by erroneously reported induced abortions, and may be early, nonhospitalized abortions. We confirm that number of previous spontaneous abortions is a strong determinant, and our data may also indicate a role of previous contraceptive habits. A role of the length of interpregnancy interval in the risk of spontaneous abortion cannot be ruled out.

Serum lipids of Greenland Inuit in relation to Inuit genetic heritage, westernisation and migration

Background: The reputed low prevalence of cardiovascular disease among the Inuit has recently been challenged. Studies have shown total cholesterol among the Inuit to differ little from that of western populations and the association between cholesterol and atherosclerosis to be inconsistent. Methods: We studied serum lipids in a population survey among 2114 Inuit living in Denmark or in West Greenland. Blood tests were supplemented by structured interviews, anthropometry and measurements of blood pressure. Findings: Compared with the general population of Denmark, total cholesterol was higher among Inuit women, while HDL-cholesterol was higher among Inuit men. Triglyceride was lower among Inuit of both sexes. Cholesterol and triglyceride varied according to westernisation, diet, alcohol consumption and smoking. In a multivariate analysis, serum lipids also differed significantly between pure and genetically mixed Inuit: HDL-cholesterol was higher among the genetically pure Inuit, while among men triglyceride was lower and among women total and LDL-cholesterol were higher. Interpretation: Among the Inuit, serum lipids are significantly associated with westernisation and genetic heritage. The effect of westernisation is to some extent due to dietary changes. From a cardiovascular health point of view, westernisation within Greenland is associated with unfavourable lipid changes while migration to Denmark is associated with favourable lipid changes.

Contribution of population surveys to the study of cardiovascular disease and diabetes in Greenland

Two population surveys with focus on cardiovascular disease and diabetes were carried out among the Greenland Inuit in 1993–94 and 1999–2001. The number of participants was 264 (1993–94 study) and 2056 (1999-2001 survey) Inuit living in Denmark, towns in Greenland, and villages. Compared with the general population of Denmark, the Inuit had a high consumption of marine food, but regional and demographic variation was marked. Smoking prevalence was high, being approximately 70% among adults in 1999-2001. Blood pressure was lower than in Denmark and the serum lipid profile was healthier (high HDL cholesterol and low triglyceride). The risk factor pattern is consistent with neither an increased, nor a decreased cardiovascular risk profile. Longitudinal studies are needed to determine the incidence of cardiovascular diseases and diabetes, and to establish causal links between traditional risk factors and disease in this non-European population.

Obesity and central fat pattern among Greenland Inuit and a general population of Denmark (Inter99): relationship to metabolic risk factors.

To investigate whether the obesity observed among the Inuit of Greenland and in a general Danish population was associated with the same degree of metabolic disturbances. Comparison of data from two population-based cross-sectional surveys conducted in 1999-2001. A total of 7892 individuals aged 30-60 y, 1108 Inuit participants from the Greenland Population study, and 6784 Danish participants in the Danish Inter99 study. Height, weight, waist and hip circumference were measured, and BMI and waist-to-hip ratio were calculated. The participants received a standard 75 g OGTT. s-Triglyceride, s-HDL cholesterol, fasting and 2 h p-glucose and s-insulin were analysed. Blood pressure was measured. Information on lifestyle factors was obtained by a questionnaire and interview. The Inuit had lower levels of 2-h glucose and insulin, blood pressure, triglyceride, and higher levels of HDL cholesterol than the Danish participants at any given level of obesity. Fasting glucose and fasting insulin levels within obesity categories were not different in the two populations. Adjustment for physical activity, smoking, school education, and alcohol consumption did not change these findings. The trends in the association between obesity and metabolic effects among the Inuit and a Northern European population were the same, but the levels of the risk factors were significantly different. This may be due to genetic factors and differences in body composition.

East-West gradient in semen quality in the Nordic-Baltic area: a study of men from the general population in Denmark, Norway, Estonia and Finland.

Denmark and Norway have a three-fold higher incidence of testicular cancer than Estonia and Finland. Groups of young men from Denmark, Norway, Finland and Estonia were investigated to elucidate whether semen parameters and other related parameters follow a gradient between these countries, as does the gradient in incidence of testicular cancer. In total, 968 young men from the general population in these four countries were investigated according to the same protocol. Possible confounders were evaluated, and included in the statistical analysis when appropriate. Inter-laboratory differences in assessment of sperm concentrations were controlled by an external quality control programme and morphology assessment was centralized to one person. The Finnish and Estonian men had an adjusted median sperm concentration of 54 and 57 x 10(6)/ml, respectively and the Norwegian and Danish men 41 x 10(6)/ml. The corresponding total sperm counts were 185, 174, 133 and 144 x 10(6). The frequency of normal sperm in men from Finland was 8.9%, Estonia 9.2%, Norway 6.9% and Denmark 6.4%. Within all four groups of men, a relationship between increasing levels of inhibin-B and increasing sperm counts was observed. However, inhibin-B levels were not predictive of sperm count differences between countries. It is believed that the men examined were representative of the normal population of young men in all four countries as they were recruited from groups attending a compulsory medical examination, and not selected for known fertility or semen quality. Moreover, the majority of participants had no prior knowledge of their fertility potential. It appears that an east-west gradient exists in the Nordic-Baltic area with regard to semen parameters, this being in parallel with the incidences of testicular cancer. Further investigations are required to determine whether these findings are due to genetic differences, to different environments, or perhaps to a combination of both factors.

Connective tissue disease after hip and knee implant surgery

Objective: To increase the knowledge of the long-term effects of artificial hip and knee joint implants. Methods: The study groups consisted of 24,636 patients with osteoarthritis who underwent hip implant surgery and 5,221 who received knee implants during 1977-89. The post-implant rate of hospitalization for connective tissue disease (CTD) was compared with the rate in the general population of Denmark and with that among osteoarthritis patients without implant surgery. Results: The rates of hospitalization for CTD were higher than the background level among both hip and knee implant patients with osteoarthritis, whereas the comparison with non-implanted osteoarthritis patients revealed that the hospitalization rate for CTD was reduced after hip implant surgery, but increased after knee implant surgery. Conclusion: Since the materials used in hip and knee implants in Denmark are not substantially different, these results are unlikely to reflect an implant effect but rather the selection criteria of referral for implant surgery.

Crohn's disease and cancer risk (Denmark).

The large number of studies of intestinal cancer among patients with Crohn's disease have provided inconsistent risk estimates in regard to risk of both colorectal and small intestinal cancer. We investigated incidence of cancer among Crohn's disease patients in comparison with the incidence in the general population of Denmark. From the Danish National Registry of Patients we identified 2645 patients who had been hospitalized with Crohn's disease during 1977-1989. Cancer incidence for up to 17 years was determined in the cohort and compared to an expected number derived from national cancer incidence rates. The 15 observed cases of colorectal cancer were close to the expected number of 13.1 (SIR = 1.1; 95% CI 0.6-1.9), whereas the five cases of small intestinal cancer (three adenocarcinomas and two carcinoids) observed corresponded to an 18-fold increased risk (SIR = 17.9; 95% CI 5.8-42). A potential excess of colorectal cancer among subgroups of patients with Crohn's disease was not detectable in the overall risk estimate for colorectal cancer. Only for small intestinal cancer was a significantly elevated risk found among these patients hospitalized with Crohn's disease.

Cancer risk following appendectomy for acute appendicitis (Denmark).

Epidemiologic studies have not been able definitely to exclude that appendectomy carries a cancer risk. This study was conducted to clarify whether appendectomy is associated with a subsequent increase in cancer risk, since appendectomy is frequently an elective procedure. The present study included more than 82,000 persons who underwent appendectomy for acute appendicitis during 1977-89 according to the nation-wide Danish Hospital Discharge Register. During a follow-up interval of up to 17 years, cancer incidence was assessed by linkage to the Danish Cancer Registry and compared with the incidence in the general population of Denmark. The total number of malignancies among appendectomized persons was 1.05 times higher than expected with 95 percent confidence intervals of 0.99-1.11. There was no clear significant excess of any specific cancer type. During a postsurgery period of nearly two decades, results of our study did not support the hypothesis that either appendectomy or acute appendicitis are likely to be associated with malignant neoplasms.

Cardiovascular risk factors in Inuit of Greenland.

Mortality from ischaemic heart disease (IHD) and prevalence of coronary arteriosclerosis are low in Inuit of Greenland (Greenlanders). Aetiological considerations have so far focused mostly on diet and blood lipids. The present study is a comprehensive analysis of behavioural, clinical and serological cardiovascular risk factors for IHD in Greenlanders. An interview survey from West Greenland (n = 1436) was supplemented with clinical measurements and blood sampling in selected towns and villages (n = 264). The average consumption of marine mammals and fish was 28 meals per month. In Greenland 14% of males and 30% of females were physically inactive compared with 14% and 17% in the general population of Denmark; 79% were current smokers and 22% smoked 15+ cigarettes per day compared with 42% and 21% in Denmark. High density lipoprotein (HDL) concentration was 1.6 mmol/l in Greenland (1.1 in Denmark) and triglyceride concentration 1.0 mmol/l (1.5). Obesity, blood pressure and total cholesterol were similar in Greenland and Denmark. There were significant differences between Greenlanders with a predominantly traditional childhood and those with a more westernized childhood with regard to diet, physical activity (in women) and blood lipids. In spite of an increased westernization of the Greenlanders' lifestyle and a high prevalence of several cardiovascular risk factors, mortality from IHD is still low. The change in risk factor patterns is, however, recent and an increased IHD mortality is still to be expected. Preventive measures should be initiated to reduce risk factors but they must take into consideration possible negative consequences of e.g. traditional outdoor activities and the consumption of marine mammals.

Determinants for contraceptive use in young, single, Danish women from the general population

Determinants for contraceptive use were studied in 5031, non-pregnant women aged 20–29 years from the general population in Denmark. Most women (72%) had never been pregnant, 34% had a history of a sexually transmitted disease, and 22% had ever had a legal abortion. Current contraception was most frequently condoms (60%) or oral contraceptives (33%). Among the women who used OCs or IUD, 32% reported additional condom use (double contraception). Important predictors of using one contraceptive method were lifetime number of sexual partners, parity, and age at first sexual intercourse for condoms and age for oral contraceptives. Also, women with a previous legal abortion were more likely to use condoms currently and women with a history of STDs were less likely to use condoms, but more likely to use OCs. Lifetime number of sexual partners was the only predictor of double contraception. Our data suggest a potential for reducing the number of unintended pregnancies and STDs in single women by increasing the information about the double principle in contraception.

Interactions between persons at risk for AIDS and the general population in Denmark.

A nationwide study of sexual behavior was undertaken among 4,680 randomly selected Danes aged 18-59 years. The median number of sexual partners (lifetime) was highest for men aged 30-34 years (eight partners) and for women aged 25-29 years (seven partners). After adjustment for age and sex, having had greater than or equal to 5 sexual partners in the past year was strongly associated with living in larger cities, intravenous drug use, and having sex with a prostitute, a bisexual man, an intravenous drug user, or a resident of sub-Saharan Africa. The frequency of ever having had anal intercourse was highest among women aged 20-34 years (range, 27%-36%) and was independently associated only with increasing number of sexual partners (lifetime). Overall, 2.7% of men reported any homosexual experience, among whom most (88%) had also had heterosexual intercourse. Prostitute contact (ever) was reported by 13% of all men and was associated with a high educational level, a history of travel, a greater number of sexual partners, and intravenous drug use. Overall, sexual contact with someone considered at high risk of human immunodeficiency virus (HIV) infection (a homosexual/bisexual man, intravenous drug user, prostitute, or sub-Saharan African resident) was reported by 15.9% of men and 4.8% of women. Among active blood donors (past year), 12.5% of men and 4.0% of women had engaged in potentially risky behavior. HIV testing was deliberately sought more often by respondents exposed to someone at increased risk of HIV infection (10.6%) than by those unexposed (6.5%, p less than 0.01). Exposure to persons at risk of HIV infection is considerable in Denmark. The majority of persons who have had potential exposure to HIV have not yet been tested for HIV.

Season of birth in multiple sclerosis.

The monthly distribution of births of people who were later diagnosed with multiple sclerosis differed significantly from that of the general population in Denmark. The multiple sclerosis patients had an excess of births in March, April, May, and June, and fewer in the other months. Infection was suggested as a possible explanation.

Viral hepatitis among parenteral drug addicts attending a Danish addiction clinic.

100 parenteral drug abusers attending an addiction clinic were studied for past or present infection with hepatitis A and B virus (HAV and HBV) by sensitive serological assays for hepatitis B surface and e-antigen and antibodies to HBsAg, HBeAg, HBcAg and HAV. 44% of the individuals had past HAV infection, which is 4 times as high compared to the general population in Denmark. 83% had evidence of past or present HBV infection with no difference between men and women. This is 30 times higher than in the general population in Denmark. 18% of the subjects studied were positive for HBsAg and/or anti-HBc alone, but only 3 of these were positive for HBeAg (3%). Serum transaminase values were often elevated but this finding could not differentiate between patients with or without HBV infection. Infection with HBV appeared to take place during the first year of the drug addict's career, and to eliminate this major reservoir of HBV infection the main objective will be to prevent new susceptible individuals in getting addicted.

Temporal lobe epilepsy. Social conditions and rehabilitation after surgery.

A social investigation was performed of 74 patients with temporal lobe epilepsy resistant to medication, who underwent unilateral temporal lobectomy 1960-1969. The patients were compared to their sibilings and to the general population in Denmark. Comparatively many patients were born out of wedlock. The level of schooling achieved was lower than expected, and this was most pronounced in patients with an early onset of epilepsy. The number of patients having received further education was also smaller than calculated. At the time of the operation all patients were socially incapacitated by their epilepsy; this was most pronounced in males, of whom 30 per cent were institutionalized and 32 per cent were receiving disablement pension; at follow-up the figures were 6 per cent and 52 per cent, respectively. Working capacity was markedly improved postoperatively, and at follow-up 39 per cent were in full-time employment. Relief from seizures (or almost complete relief), normal intelligence, normal psychiatric status, and operation before the age of 18 years were factors which favourably influenced the postoperative working capacity. The majority of the patients were unmarried or divorced, and few of the group had children. Their housing conditions were inferior to those of their siblings and of the general population. Parental social class distribution showed an excess in the highest and lowest social classes compared to the Danish population. The patients were subjected to downward social mobility, presumably caused by their illness, as their siblings displayed an upward mobility, which was most marked in the females.