Showing papers by "Susanne K. Kjaer published in 1996"

Human papillomavirus—the most significant risk determinant of cervical intraepithelial neoplasia

Abstract: Sexual behavior has been consistently identified as a major risk factor for cervical cancer. Population-based studies have demonstrated that risk related to sexual activity is mediated by human papillomavirus (HPV) infection. We conducted a case-control study of 199 cases with low-grade squamous intraepithelial lesions or high-grade squamous intraepithelial lesions as defined by cytology and 1000 control women selected from an ongoing prospective cohort study in Copenhagen, Denmark. Furthermore, 131 women with equivocal smears (atypical squamous cells of undetermined significance) were examined as a separate borderline case group. At enrollment, all women had a personal interview and a gynecological examination including cervical swabs for HPV testing and a Pap smear. HPV testing was performed using a combination of general primer 5/6-mediated and type-specific polymerase-chain-reaction-based methods. Cervical HPV infection was by far the most significant risk factor for cervical squamous intraepithelial lesions. The relationship with HPV was observed for all grades, while strength of association was greater for more severe lesions. The importance of the previously identified epidemiological risk factors for cervical neoplasia was also demonstrated. However, most of the effect of these factors could be explained by taking HPV infection into account, except for schooling and smoking. Non-use of barrier contraceptives and smoking were the only significant risk factors in HPV-positive women. In HPV-negative women, a residual effect existed for different measures of sexual activity, and use of oral contraceptives and smoking constituted significant risk determinants Overall, 66% of cases could be attributed to HPV; however, if the results were restricted to histologically confirmed high-grade lesions, the proportion of cases that could be attributed to HPV infection increased to 80%.

Seroreactivity to HPV16 virus‐like particles as a marker for cervical cancer risk in high‐risk populations

Abstract: Sexually transmitted genital human papillomavirus (HPV) infection, most often HPV 16, is considered the major etiologic determinant of cervical cancer. However, some studies have found relatively low prevalences of genital tract HPV DNA in some geographical areas, such as Greenland, that have high rates of cervical cancer. We sought to evaluate HPV 16 infection in high-risk cohorts using a serologic assay that assesses prior exposure as well as current infection and to compare the results with those obtained using a sensitive PCR-based HPV DNA assay. An ELISA based on HPV 16 virus-like particles was used to detect IgG serum antibodies in women attending sexually transmitted disease (STD) clinics in Nuuk, Greenland and Copenhagen, Denmark. Using a preassigned cut-off, 56% of Greenlandic and 41% of Danish women were seropositive (p = 0.02). In Greenlandic women, there was a non-significant increase in seropositivity with age, and odds ratios for seropositivity were similar for women with more than 5 lifetime sex partners. Seropositivity in the Danish women, however, increased linearly with increases in these 2 factors, which are likely correlates of lifetime exposure to genital HPVs. In contrast, any genital HPV DNA (HPV16 specifically) was detected in 24% and 36% of Greenlandic and Danish women, respectively and was most frequently detected in women below 20. The finding that HPV DNA prevalences, unlike seroprevalences, tended to decrease with increased lifetime risk of infection, provides an explanation for the lack of correlation between HPV DNA prevalences and cervical cancer risk in previous studies of high-risk populations. © 1996 Wiley-Liss, Inc.

Case-control study of risk factors for cervical squamous cell neoplasia in Denmark. IV: role of smoking habits.

Abstract: The role of smoking and other risk factors for cervical neoplasia was investigated in a population-based case-control study of 586 women with histologically verified cervical squamous-cell carcinoma in situ (CIS), and 59 women with invasive squamous-cell cervical cancer from Copenhagen. Controls were randomly selected from the general female population using the computerized Danish Central Population Register. After adjustment for a variety of confounding variables, which were all significantly associated with CIS risk and included age, number of partners, proportion of sexually active life without barrier contraceptive use, years with intra-uterine devices, number of births, and age at first episode of genital warts (as a proxy measure for human papillomavirus exposure), current cigarette smoking was found to be significantly associated with CIS [adjusted relative risk (RR) = 2.4; 95% confidence interval (CI): 1.7-3.4]. Ex-smokers had a lower, but still significantly increased risk (RR = 1.6; 95% CI: 1.0-2.7). A dose-response relationship was present, especially for number of cigarettes smoked per day. In contrast, the crude estimates showed a weak association between invasive cervical cancer and smoking, which however disappeared after confounder control. The results of the present study support the hypothesis implicating smoking as a risk factor for CIS.

Childhood leukemia following phototherapy for neonatal hyperbilirubinemia (Denmark)

Abstract: To test the hypothesis that exposure to high intensity lightning (around 400 nanometers) in neonatal nurseries increases the incidence of childhood leukemia, over 55,120 newborn children treated with phototherapy for hyperbilirubinemia were identified from the Danish Hospital Discharge Register for 1977–89. Linkage of the roster with the national cancer registry through 1991 revealed 87 childhood cancers, whereas 85 were expected from the rates for the general population. The incidence of leukemia in 34 children was not unusual (standardized incidence ratio [SIR]=1.2, 95 percent confidence interval [CI]=0.8–1.7). Subgroup analyses revealed no remarkable patterns for any category of leukemia subtype, gender, or age at diagnosis. We conclude that whole-body exposure to phototherapy (420–470 nm) shortly after birth is not a significant risk factor for childhood leukemia.

Determinants of smoking behaviour in random samples of Greenlandic and Danish women 20-39 years of age.

Abstract: BACKGROUND The prevalence of smoking among young women is of particular concern in most countries as it does not decline as in men. We studied smoking behaviour in Greenlandic and Danish women over a 2 year period to provide information on the social and behavioural determinants of smoking in women. METHODS In 1986, samples of 800 women aged 20-39 years were drawn at random from Nuuk/Godthab (Greenland) and Nykobing Falster (Denmark). A total of 586 and 661 women were interviewed in Greenland and Denmark, respectively. In 1988, new random samples of 150 women were drawn from the same areas. Totally, 129 Greenlandic and 126 Danish women were included in this study. In 1987, a sample of 732 women aged 20-49 years from Copenhagen was randomly drawn from the computerized Central Population Register. Of these, 623 women completed a questionnaire. RESULTS Smoking behaviour was almost the same among women in Nykobing Falster and Copenhagen (54% smoked) while a significantly higher percentage of smokers was observed among women in Greenland (88% smoked). Heavy smoking was most prevalent among Danish women and associated with early debut of smoking. Among Danish women, smoking was associated with use of oral contraceptives, early age at first intercourse, and multiple sexual partners. In Greenland, smoking was associated with early sexual debut and multiple sexual partners. In an extended analysis on a subgroup of Danish women, smoking was also associated with low education and infrequent intake of vegetables. The study showed no development in smoking behaviour in any age group over the two year period between the two studies, neither in Nykobing Falster nor in Nuuk. CONCLUSION The high prevalence of moderate smoking among women in Greenland suggests that broad anti-smoking initiatives are urgently needed. The high prevalence of heavy smoking and a social gradient among Danish women may indicate that a strategy focusing on restrictions of smoking may be more relevant than merely continuing a pure anti-smoking information strategy.