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Biomedical subjects

M Melbye

Publications and source records attributed to M Melbye.

At least 73 records · Page 4Linked to original sources
PubMed1999

Preterm delivery and risk of breast cancer.

To explore the risk of breast cancer in relation to the length of a pregnancy we tested whether a preterm delivery carries a higher risk of breast cancer than does a full-term delivery. Based on information from the Civil Registration System, and the National Birth Registry in Denmark, we established a population-based cohort of 474 156 women born since April 1935, with vital status and detailed parity information, including the gestational age of liveborn children and stillbirths. Information on spontaneous and induced abortions was obtained from the National Hospital Discharge Registry and the National Registry of Induced Abortions. Incident cases of breast cancer in the cohort (n = 1363) were identified through linkage with the Danish Cancer Registry. The period at risk started in 1978 and continued until a breast cancer diagnosis, death, emigration, or 31 December, 1992, whichever occurred first. After adjusting for attained age, parity, age at first birth and calendar period, we observed the following relative risks of breast cancer for different lengths of the pregnancy: < 29 gestational weeks = 2.11 (95% confidence interval 1.00-4.45); 29-31 weeks = 2.08 (1.20-3.60); 32-33 weeks = 1.12 (0.62-2.04); 34-35 weeks = 1.08 (0.71-1.66); 36-37 weeks = 1.04 (0.83-1.32); 38-39 weeks = 1.02 (0.89-1.17); 40 weeks = 1 (reference). Parous women who had a preterm delivery below 32 weeks gestation had a 1.72-fold (1.14-2.59) increased risk of breast cancer compared with other parous women. In conclusion, a preterm delivery of 32+ weeks gestation did not significantly increase a woman's risk of contracting breast cancer. Only for the very small group of women with preterm deliveries of less than 32 weeks gestation did we observe an increased risk.

Adult↗
PubMed1999

Maternal risk of breast cancer and birth characteristics of offspring by time since birth.

We examined the association between birth characteristics of offspring and the subsequent maternal risk of breast cancer in a population-based cohort of 998,499 women, 13 to 48 years of age at entry. There were 9,495 incident cases of breast cancer during 12.8 million person-years of follow-up among these women. Compared with mothers of singleton infants, mothers having a multiple birth had an increased risk of breast cancer in the first 5 years after a birth (relative risk (RR) = 1.8; 95% confidence interval (CI) = 1.1-2.8). The risk for mothers having a heavy-weighted child (>3.75 kg), as compared with a child of light weight (< or =3 kg), was also slightly increased (RR = 1.2; 95% CI = 0.9-1.5). This latter effect was primarily due to an increased incidence of tumors larger than 2 cm at diagnosis (RR = 1.4; 95% CI = 0.9-1.9). Our findings are compatible with the hypothesis that the hormonal level during pregnancy influences the risk of breast cancer in the early years after delivery.

Adolescent↗
PubMed1999

Salivary gland cancer in the United States.

The risk of salivary gland cancer (SGC) is increased in atomic bomb survivors and after radiotherapy, but other risk factors are not well established. Some studies have suggested an association of SGC with breast cancer and with exposure to various viruses or UVB radiation. Corroborating evidence of these associations was sought by using population-based registries to examine the demographic distribution of SGC, patterns of secondary primary cancers after SGC, and risk of SGC with AIDS. SGC incidence per 100,000 persons did not change between 1973 and 1992, averaging 1.2 in males and 0.8 in females, with a steep age gradient. To examine the relationship between UVB exposure and SGC, population-based, age-adjusted incidence rates of SGC were plotted against the UVB insolation of each registry site. Regression analysis suggested no correlation between SGC incidence and increasing UVB insolation (beta = 0.10, R2 = 0.08). SGC also did not appear to be associated with second cancers that have been linked to herpes or papilloma viruses or with AIDS [observed/expected (O/E) ratio, <2.8], but all of these conditions are so uncommon that only very large relative risks would have been statistically significant. Women with SGC before age 35 had a statistically nonsignificant elevation in breast cancer risk [O/E, 3.30; 95% confidence interval (CI), 0.66-9.65], and older women had no increased risk of breast cancer. SGC patients were at increased risk for nonsalivary, second-primary oropharyngeal cancers (O/E, 3.27; 95% CI, 2.00-5.05), thyroid cancer (O/E, 3.31; 95% CI, 1.07-7.73), and lung cancer (O/E, 1.86; 95% CI, 1.45-2.35), particularly in patients whose SGC was treated with radiotherapy (O/E, 2.83; 95% CI, 2.06-3.80). In summary, SGC remains rare and does not appear to be associated with AIDS, virally related malignancies, or UVB. Patients who have had SGC, however, should be monitored for subsequent oropharyngeal, thyroid, and lung cancers.

Acquired Immunodeficiency Syndrome↗
PubMed1998

[Sexually transmitted infection as a cause of anal cancer].

Interviews were carried out with 423 women and 93 men with invasive or in situ anal cancer in Denmark and Sweden in a search for clues to the aetiology of this neoplasm. Patients with rectal adenocarcinoma (n = 534) and persons drawn from the background population (n = 554) served as controls. Multivariate logistic regression analyses confirmed previous observations of a strong association between either male homosexual experience or a history of anogenital warts and the risk for anal cancer. Moreover, hitherto unknown, but strong and consistent associations were observed between measures of high heterosexual activity and the risk for anal cancer among both sexes. Polymerase chain reaction analysis revealed human papilloma-virus DNA in the majority (88%) of anal cancer specimens but in none of 20 examined rectal adenocarcinomas. It is concluded that most anal cancers appear to be caused by sexually transmitted types of human papillomaviruses and, consequently, that anal cancer is a potentially preventable neoplasm.

Adenocarcinoma↗
PubMed1998

Increasing Kaposi's sarcoma-associated herpesvirus seroprevalence with age in a highly Kaposi's sarcoma endemic region, Zambia in 1985.

BACKGROUND: Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is a newly discovered virus found in all forms of KS. In the United States, KSHV infection appears to be most common amongst individuals at high-risk for KS. Preliminary data from Africa suggest that KSHV infection may be much more common in the general population. OBJECTIVE: To examine the KSHV seroprevalence and age-specific patterns of infection in an African country with high rates of KS. DESIGN: Cross-sectional seroprevalence study. METHODS: Sera were taken for a hospital-based HIV seroprevalence study conducted in August 1985 in Lusaka, Zambia at a time when HIV was just becoming epidemic in this area. A total of 251 sera were randomly sampled and examined for antibodies against latent and lytic antigens to KSHV. KSHV seroprevalence was compared with demographic and clinical variables using chi2 test for linear trend and odds ratios and 95% confidence intervals. RESULTS: Overall, 58% of persons aged 14-84 years were KSHV-seropositive. KSHV seroprevalence increased linearly with age (P = 0.04) and was inversely related to years of education (P = 0.015). In contrast, HIV infection peaked in those aged 20-29 years and was positively related to years of education (P = 0.01 5). No association between KSHV and gender, marital status, or HIV serostatus was seen. CONCLUSIONS: KSHV infection was significantly more common in this region of Zambia in 1985 than it currently is in the United States. Our data are consistent with KSHV being well-established in this region prior to 1985 and that continued adult transmission of the virus was occurring. The high seroprevalence in the adolescent age-group and the relatively linear increase in prevalence with age suggest that non-sexual modes of transmission may be important for KSHV transmission in Africa.

Adolescent↗
PubMed1998

[Multiple pregnancies in Denmark 1980-1994].

The objective was to study trends in national rates of multiple pregnancies that were not explained by changes in maternal age and parity. Information on childbirths to Danish-born women were obtained from national registers. The national incidence of multiple pregnancies increased 1.7-fold during 1980-1994, the increase primarily in 1989-1994 and almost exclusively in primiparous women > or = 30 years, for whom the adjusted population-based twinning rate increased 2.7-fold and the triplet rate 9.1-fold. The proportion of multiple births among infant deaths in primiparous women > or = 30 years increased from 11.5% to 26.9%. In conclusion, the marked increase in the rate of multiple pregnancies, which in particular was observed during the 1990s and in primiparous women > or = 30 years, could not be explained by changes in maternal age or parity. Fertility-enhancing treatments are believed to have caused this increase.

Adult↗
PubMed1998

Declining HIV-2 prevalence and incidence among men in a community study from Guinea-Bissau.

OBJECTIVE: To assess the present level of HIV-2 infection in an adult population in Bissau and to evaluate sex and age-specific changes in HIV-2 prevalence and incidence between 1987 and 1996. DESIGN AND METHODS: Sex and age-specific changes in HIV-2 prevalence were evaluated comparing a survey from 1987 in a sample of 100 houses with a survey performed in 1996 in an independent sample of 212 houses from the same study area. HIV-2 incidence rates were examined in an adult population (age > or = 15 years) from 100 randomly selected houses followed with four consecutive HIV serosurveys from 1987 to 1996. RESULTS: The HIV-2 prevalence in 1996 was 6.8% (men, 4.7%; women, 8.4%). Compared with the 1987 survey there was a significant decrease in prevalence among men [age-adjusted relative risk (RR), 0.50; 95% confidence interval (CI), 0.31-0.83], whereas it remained unchanged in women (RR, 1.00; 95% CI, 0.67-1.48). The male-to-female RR decreased from 0.99 (95% CI, 0.61-1.61) in 1987 to 0.51 (95% CI, 0.34-0.76) in 1996. The overall annual incidence rate was 0.54 per 100 person-years of observation (PYO), being higher in women (0.72 per 100 PYO) than in men (0.31 per 100 PYO). With the observation time divided into an early and a late period, there was a decrease in incidence with time among men (0.66 to 0.00 per 100 PYO), but no major change among women (0.59 to 0.85 per 100 PYO). The two trends differed significantly (P = 0.03). We observed a higher annual incidence rate amongst older women aged > 44 years (1.77 per 100 PYO) than among younger women (0.55 per 100 PYO; P = 0.05). CONCLUSION: There are no signs of an epidemic spread of HIV-2 in Bissau even though the HIV-1 prevalence is increasing rapidly. A significant reduction in the male HIV-2 prevalence and incidence rates has resulted in a major shift in the pattern of spread of HIV-2, from being equally distributed to being predominantly a female infection. Currently, older women in particular seem to have a high risk of getting infected.

Adolescent↗
PubMed1998

[Induced abortion and risk of breast cancer].

It has been hypothesized that an interrupted pregnancy might increase the risk of breast cancer, because proliferation of breast cells will take place without the protective effect of subsequent differentiation. In a cohort of 1.5 million women (28.5 million person-years) we identified 370,715 induced abortions in 280,965 women (2.7 million person-years) and 10,246 women with breast cancer. After adjustment for other risk factors, induced abortion was not associated with the risk of breast cancer (relative risk: 1.00; 95 percent confidence interval 0.94 to 1.06). However, the relative risk of breast cancer increased with increasing gestational age of the most recently induced abortion: < 7 weeks: 0.81; 7 to 8 weeks; 1.01; 9 to 10 weeks: 1 (reference); 11 to 12 weeks: 1.12; 13 to 14 weeks: 1.13; 15 to 18 weeks: 1.23; > 18 weeks: 1.89; P(trend) = 0.016. On a population basis, induced abortion was not associated with an increased risk of breast cancer. An increase was only seen for the special group of late second trimester abortions, but this finding was based on small numbers.

Abortion, Induced↗
PubMed1998

Risk factors for Kaposi's-sarcoma-associated herpesvirus (KSHV/HHV-8) seropositivity in a cohort of homosexual men, 1981-1996.

A newly identified herpesvirus has been associated with Kaposi's sarcoma. We determined risk factors for Kaposi's-sarcoma-associated herpesvirus/human herpesvirus 8 (KSHV/HHV-8) seropositivity and incidence of infection over time in a cohort of Danish homosexual men followed from 1981 to 1996. Antibodies to a latent nuclear (LANA) and a structural (orf65) antigen of KSHV/HHV-8 were measured by immunofluorescence and ELISA/WB respectively. Through linkage with the national AIDS registry, all cohort members diagnosed with AIDS as of September 1996 were identified and their hospital records were scrutinized to record all diagnoses of KS. Overall, 21.1% (52/246) of the men were KSHV/HHV-8-seropositive in 1981. Among the initially seronegative, the rate of KSHV/HHV-8 seroconversion was highest between 1981 and 1982 and declined steadily thereafter. In a multivariate analysis of the status at enrollment in 1981, KSHV/HHV-8 seropositivity was not associated with age but was independently associated both with number of receptive anal intercourses (OR = 2.83; p = 0.03) and with sex with US men (OR = 2.27; p < 0.05). In a multivariate analysis of follow-up data, risk of KSHV/HHV-8 seroconversion was independently associated with having visited homosexual communities in the United States, and current HIV-positive status. More than 5 years' homosexual experience was associated with an insignificantly increased risk (RR = 2.68). KS occurred only in HIV-positive men who were KSHV/HHV-8-positive at or prior to their KS diagnosis. In conclusion, KSHV/HHV-8 appears to be sexually transmitted, probably by receptive anal intercourse, and may have been introduced to Danish homosexual men via sex with US men. The epidemic of KSHV/HHV-8 is now declining. These findings are concordant with the view that KSHV/HHV-8 may have been actively spread simultaneously with and by the same activities that lead to the spread of HIV.

Adolescent↗
PubMed1998

Differences in susceptibility to AIDS development: a cohort study of Danish and American homosexual-bisexual men, 1981 to 1995.

We estimated the annual hazard rate for progression to AIDS as defined by the 1987 case definition in HIV-infected members of a cohort of Danish and American homosexual-bisexual men who were observed from 1981 to 1995. Furthermore, we extrapolated the hazard to 25 years based on imputed future time to AIDS. Of 201 HIV-positive subjects, 112 developed AIDS before the end of follow-up. The hazard increased rapidly during the first years following infection, attained a peak of about 15% per year at year 7, and was moderately lower during years 8 through 10. In subsequent analysis, we imputed future time to AIDS in 89 subjects who had not progressed by the end of follow-up by extrapolation from subject-specific CD4 trend lines. A CD4 count of < or = 100 cells/microl was the best surrogate for clinical AIDS. Under this model, the imputed AIDS hazard stabilized at around 8% per year after 10 years. We projected that 13% (95% confidence interval [CI], 8%-19%) of the infected men may remain free from AIDS 25 years after seroconversion. Our direct data suggest that incubation times reflect a mixture of a population that is susceptible to disease progression and has short incubation periods with a group that is relatively resistant. Based on an extrapolation model, > 10% of HIV-infected persons may survive for up to 25 years without developing AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1998

HTLV-1 infection in a population-based cohort of older persons in Guinea-Bissau, West Africa: risk factors and impact on survival.

In 1989, a population-based cohort of persons aged > or = 50 years was established in an urban area of Guinea-Bissau, West Africa. Overall, 346 persons were interviewed in detail about risk behaviors and had capillary blood drawn. Among women, 12.4% were HTLV-1 seropositive, compared with 4.6% in men. No HTLV-2 was found. Seropositivity varied considerably according to place of birth and ethnic group. In women, but not in men, HTLV-1 seropositivity was strongly associated with early sexual debut (10-14 yrs, 33.3%; 15-17 yrs, 26.0%; 18-20 yrs, 6.5%; 21+ yrs, 0%; ptrend = 0.001), lifetime number of male partners (ptrend = 0.006), and the male partner's number of co-wives (ptrend = 0.006). There was also a 3.1-fold increased risk of being HTLV-1 seropositive if the woman was also HIV-2 seropositive. In a multivariate-risk-factor analysis, the strongest association with HTLV-1 was a history of having been bitten by a monkey (n = 11; combined OR adjusted = 10.1; 95% CI 2.3-44.4). Ornamental scarification was associated with a 3.3-fold increased risk. Ethnic affiliation also significantly influenced the risk of being HTLV-1 seropositive. Follow-up performed in January 1996 revealed no difference in survival between HTLV-1-seropositive and -seronegative individuals over 6 years (rate ratio = 1.4, 95% CI 0.7-2.8). In conclusion, this population, which has very high HIV-2 seroprevalence, is also highly endemic for HTLV-1. Whereas sexual behaviors are clearly important for HTLV-1 spread in women, non-sexual risk factors were the only ones of potential importance in men. HTLV-1 had no impact on survival in this older population.

Aged↗
PubMed1998

[Risk of cancer among patients with cutaneous basal cell carcinoma].

A population-based cohort of 37,674 patients diagnosed during the period 1978-1991 and registered in the Danish Cancer Registry with basal cell carcinoma of the skin (BCC) were followed for the occurrence of new malignancies. BCC patients experienced significantly increased cancer incidence rates compared with the general Danish population. The elevated cancer risk was not restricted to new cutaneous malignancies. Cancers at various sites, including lip, salivary glands, larynx, lung, breast, kidney and non-Hodgkin lymphoma occurred in significant excess. Patients diagnosed with BCC before the age of 60 years were at higher risk of developing new malignancies than patients diagnosed with BCC at an older age. This age association pertained particularly to breast cancer, testicular cancer and non-Hodgkin lymphoma.

Adult↗
PubMed1998

The role of human papillomaviruses in anogenital cancers.

There is substantial evidence to suggest that common risk factors exist for cancer of the cervix and other anogenital cancers. Cervical cancer has been etiologically linked with venereal types of human papillomavirus (HPV) and the same types of HPV are being found in other anogenital tissues. The question is to what extent these HPV types may also contribute to carcinogenesis in anogenital cancer other than cervical cancer. In this review some general aspects of the natural history of HPV are presented followed by a description of the incidence and risk factors for anal, vulvar, and penile cancer. Main focus is given to the evidence for an association between these cancers and HPV.

Anus Neoplasms↗
PubMed1998

Testicular cancer risk and maternal parity: a population-based cohort study.

The aim was to study, in a population-based cohort design, whether first-born sons run a higher risk of testicular cancer than later born sons; to investigate whether this difference in risk was affected by birth cohort, age of the son, maternal age, interval to previous delivery and other reproductive factors; and, finally, to evaluate to what extent changes in women's parity over time might explain the increasing incidence of testicular cancer. By using data from the Civil Registration System, a database was established of all women born in Denmark since 1935 and all their children alive in 1968 or born later. Sons with testicular cancer were identified in the Danish Cancer Registry. Among 1015994 sons followed for 15981 967 person-years, 626 developed testicular cancer (443 non-seminomas, 183 seminomas). Later born sons had a decreased risk of testicular cancer (RR = 0.80, 95% CI = 0.67-0.95) compared with first-born sons. The RR was 0.79 (95% CI = 0.64-0.98) for non-seminomas and 0.81 (95% CI = 0.58-1.13) for seminomas. There was no association between testicular cancer risk and overall parity of the mother, maternal or paternal age at the birth of the son, or maternal age at first birth. The decreased risk of testicular cancer among later born sons was not modified by age, birth cohort, interval to the previous birth, sex of the first-born child, or maternal age at birth of the son or at first birth. The increased proportion of first-borns from birth cohort 1946 to birth cohort 1969 only explained around 3% of an approximated two-fold increase in incidence between the cohorts. Our data document a distinctly higher risk of testicular cancer in first-born compared with later born sons and suggest that the most likely explanation should be sought among exposures in utero. The increase in the proportion of first-borns in the population has only contributed marginally to the increase in testicular cancer incidence.

Adolescent↗
PubMed1998

High incidence of classical Kaposi's sarcoma in Iceland and the Faroe Islands.

We have examined the incidence of non-AIDS-related Kaposi's sarcoma in Iceland (1955-79) and the Faroe Islands (1974-95). In Iceland, 19 cases, nine in men and ten in women, were identified, and in the Faroe Islands four cases in men and three cases in women were found. This corresponded to surprisingly high incidence rates. In men, world standardized rates (per 100000 person-years) were 0.4 and 0.6 in Iceland and the Faroe Islands, respectively, and for women, the figures were 0.3 (Iceland) and 0.5 (the Faroe Islands). These are among the highest rates ever reported. No explanation for the high rates of Kaposi's sarcoma in these two North Atlantic communities could be identified.

Aged↗
PubMed1998

Incidence rates of classical Kaposi's sarcoma and multiple myeloma do not correlate.

We compared population-based incidence rates for classical Kaposi's sarcoma and multiple myeloma. Neither for men (Spearman's rank correlation coefficient (r) = 0.01, P = 0.97, 13 pairs) nor for women (r = 0.24, P = 0.42, 13 pairs) did the incidences of the two conditions correlate. This absence of correlation does not support the hypothesis that Kaposi's sarcoma and multiple myeloma share a common aetiology, such as HHV-8.

Denmark↗