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J Wohlfahrt

Publications and source records attributed to J Wohlfahrt.

45 records · Page 3Linked to original sources
PubMed1997

Time since childbirth and prognosis in primary breast cancer: population based study.

OBJECTIVE: To investigate whether time since birth of last child was of prognostic importance in women with primary breast cancer. DESIGN: Retrospective cohort study based on a population based database of breast cancer diagnoses with detailed information on tumour characteristics, treatment regimens, reproductive factors, and vital status. SETTING: Denmark. SUBJECTS: 5652 women with primary breast cancer aged 45 years or less at the time of diagnosis. MAIN OUTCOME MEASURES: 5 and 10 year survival; relative risk of dying. RESULTS: Women diagnosed in the first 2 years after last childbirth had a crude 5 year survival of 58.7% and 10 year survival of 46.1% compared with 78.4% and 66.0% for women whose last childbirth was more than 2 years before their diagnosis. After adjustment for age, reproductive factors, and stage of disease (tumour size, axillary nodal status, and histological grading), a diagnosis sooner than 2 years since last childbirth was significantly associated with a poor survival (relative risk 1.58, 95% confidence interval 1.24 to 2.02) compared with women who gave birth more than 5 years previously. Further analyses showed that the effect was not modified by age at diagnosis, tumour size, and nodal status. CONCLUSIONS: A diagnosis of breast cancer less than 2 years after having given birth is associated with a particularly poor survival irrespective of the stage of disease at debut. Therefore, a recent pregnancy should be regarded as a negative prognostic factor and should be considered in counselling these patients and in the decisions regarding adjuvant treatment.

Adult↗
PubMed1997

Should women be advised against pregnancy after breast-cancer treatment?

BACKGROUND: Oestrogen is an established growth factor in breast cancer. There has, therefore, been much discussion about whether women should be advised against becoming pregnant after breast-cancer treatment because of a possible negative prognostic effect from the high oestrogen concentrations associated with pregnancy. METHODS: We studied 5725 women with primary breast cancer. Information on these women was obtained from the Danish Breast Cancer Cooperative Group. Since 1977 this group has collected population-based data on tumour characteristics, treatment regimens, and follow-up status of Danish women with breast cancer. Details of reproductive history were obtained from The Danish Civil Registration System, the National Birth Registry, and the National induced Abortion registry. We estimated the relative risk of death among women who became pregnant after breast-cancer treatment compared with women who had not become pregnant. FINDINGS: 5725 women with primary breast cancer aged 45 years of younger at the time of diagnosis were followed up for 35,067 patient-years. Among these, 173 women became pregnant after treatment of breast cancer. Women who had a full-term pregnancy after breast-cancer treatment had a non-significantly reduced risk of death (relative risk 0.55 [95% CI 0.28-1.06]) compared with women who had had no full-term pregnancy after adjustment for age at diagnosis, stage of disease (tumour size, axillary nodal status, and histological grading), and reproductive history before diagnosis. The effect was also not significantly modified by age at diagnosis, tumour size, nodal status, or reproductive history before diagnosis of breast cancer. Neither miscarriages nor induced abortions after breast-cancer treatment influenced the prognosis. INTERPRETATION: We found no evidence that a pregnancy after breast-cancer treatment increased the risk of a poor outcome.

Abortion, Induced↗
PubMed1997

Birth characteristics, sibling patterns, and acute leukemia risk in childhood: a population-based cohort study.

BACKGROUND: The occurrence of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) during childhood may be influenced by factors operating in fetal life. Furthermore, childhood ALL has been suggested to be linked to patterns of infection during infancy. PURPOSE: To explore these hypotheses and other associations, we studied the impact of sibling patterns (e.g., birth order) and birth characteristics (e.g., birth weight) on the risk of childhood ALL and AML. METHODS: By linkage of records of population-based registries, a cohort of all children whose mothers were born in Denmark from April 1935 through March 1978 was established. Children who developed ALL or AML during the period from April 1968 through December 1992 were identified by linkage with the Danish Cancer Registry. Birth weights were obtained for children born during the period from January 1973 through December 1992 by linkage with the Medical Birth Registry. RESULTS: The cohort of approximately 2.0 million children was followed for the diagnosis of ALL or AML for 20.9 million person-years. A total of 704 cases of childhood ALL were identified. Among 0-4 year olds, the relative risks (RRs) of ALL for birth order positions 1, 2, 3, and 4+ were 1.00 (reference), 0.85 (95% confidence interval [CI] = 0.68-1.07), 0.91 (95% CI = 0.66-1.25), and 0.57 (95% CI = 0.30-1.06), respectively (P for trend = .09). A decreasing trend was not observed among 5-14 year olds. A significant log-linear association between birth weight and the risk of ALL was observed for both age groups. Overall, the RR of ALL increased by a factor of 1.46 (95% CI = 1.18-1.81) (P = .0005) for each kilogram of increase in birth weight. A total of 114 cases of childhood AML were identified. Children born second or later in the birth order had an increased risk of AML (RR = 1.53; 95% CI = 1.01-2.32) compared with firstborns. A particularly high risk of AML at ages 2 (RR = 2.53; 95% CI = 1.46-4.40) and 3 years was associated with having siblings compared with being an only child at those ages. Similar to the findings for ALL risk, there was a significant association between birth weight and AML risk. The relative increase in AML risk per 1-kg increase in birth weight was 2.14 (95% CI = 1.19-3.85; P = .009). CONCLUSION AND IMPLICATIONS: The association between birth weight and childhood leukemia suggests the importance of intrauterine factors. A plausible explanation may be that increasing birth weight is associated with a higher rate of cell proliferation and/or a larger number of precursor cells being at risk of malignant transformation. The inverse association between birth order and ALL risk among 0-4 year olds was weak, but it was compatible with the hypothesis that delayed exposure to infection may increase the risk of ALL in this age group. The association of childhood AML with birth order and sibship size at young ages deserves further attention in the search for environmental factors that affect childhood AML risk.

Acute Disease↗
PubMed1997

Population based study of rates of multiple pregnancies in Denmark, 1980-94.

OBJECTIVE: To study trends in multiple pregnancies not explained by changes in maternal age and parity patterns. DESIGN: Trends in population based figures for multiple pregnancies in Denmark studied from complete national records on parity history and vital status. POPULATION: 497,979 Danish women and 803,019 pregnancies, 1980-94. MAIN OUTCOME MEASURES: National rates of multiple pregnancies, infant mortality, and stillbirths controlled for maternal age and parity. Special emphasis on primiparous women > or = 30 years of age, who are most likely to undergo fertility treatment. RESULTS: The national incidence of multiple pregnancies increased 1.7-fold during 1980-94, the increase primarily in 1989-94 and almost exclusively in primiparous women aged > or = 30 years, for whom the adjusted population based twinning rate increased 2.7-fold and the triplet rate 9.1-fold. During 1989-94, the adjusted yearly increase in multiple pregnancies for these women was 19% (95% confidence interval 16% to 21%) and in dizygotic twin pregnancies 25% (21% to 28%). The proportion of multiple births among infant deaths in primiparous women > or = 30 years increased from 11.5% to 26.9% during the study period. The total infant mortality, however, did not increase for these women because of a simultaneous significant decrease in infant mortality among singletons. CONCLUSIONS: A relatively small group of women has drastically changed the overall national rates of multiple pregnancies. The introduction of new treatments to enhance fertility has probably caused these changes and has also affected the otherwise decreasing trend in infant mortality. Consequently, the resources, both economical and otherwise, associated with these treatments go well beyond those invested in specific fertility enhancing treatments.

Adult↗
PubMed1997

Induced abortion and the risk of breast cancer.

BACKGROUND: It has been hypothesized that an interrupted pregnancy might increase a woman's risk of breast cancer because breast cells could proliferate without the later protective effect of differentiation. METHODS: We established a population-based cohort with information on parity and vital status consisting of all Danish women born from April 1, 1935, through March 31, 1978. Through linkage with the National Registry of Induced Abortions, information on the number and dates of induced abortions among those women was combined with information on the gestational age of each aborted fetus. All new cases of breast cancer were identified through linkage with the Danish Cancer Registry. RESULTS: In the cohort of 1.5 million women (28.5 million person-years), we identified 370,715 induced abortions among 280,965 women (2.7 million person-years) and 10,246 women with breast cancer. After adjustment for known risk factors, induced abortion was not associated with an increased risk of breast cancer (relative risk, 1.00; 95 percent confidence interval, 0.94 to 1.06). No increases in risk were found in subgroups defined according to age at abortion, parity, time since abortion, or age at diagnosis of breast cancer. The relative risk of breast cancer increased with increasing gestational age of the fetus at the time of the most recent induced abortion: <7 weeks, 0.81 (95 percent confidence interval, 0.58 to 1.13); 7 to 8 weeks, 1.01 (0.89 to 1.14); 9 to 10 weeks, 1.00 >12 weeks, 1.38 (1.00 to 1.90) (reference category, 9 to 10 weeks). CONCLUSIONS: Induced abortions have no overall effect on the risk of breast cancer.

Abortion, Induced↗
PubMed1996

Anal and cervical abnormality in women--prediction by human papillomavirus tests.

A total of 151 women at risk of human immunodeficiency virus infection were investigated, to study the strength of the association between cervix and anus regarding the presence of HPV and cytological abnormality. An equal percentage of women had abnormal cervical (12.2%) and anal (12.1%) Papanicolaou smears. HPV measured by PCR was detected in 93.3% of cervical squamous intraepithelial lesions (SIL) compared to 49.1% of normal cervical cytologies, and in 100% of anal SIL and 67.4% of normal anal cytologies, respectively. After controlling for HPV-PCR status, immunodeficiency, as measured by a low CD4+ count and HIV positivity, increased the detection of cervical and to some extent anal squamous intraepithelial lesions (SIL). We evaluated how precisely an HPV test could predict cervical disease and found that the HPV-PCR test was slightly more sensitive than the HPV-hybrid capture (HC) test (PCR: 93.3% vs. HC: 88.9%), whereas the HC test was significantly more specific (83.6% vs. 50.9%), and with a much higher positive predictive value (43.2% vs. 20.6%). Similar results were obtained for anal SIL. HIV positivity increased sensitivity, lowered specificity and increased the positive predictive value of the tests. A diagnosis of cervical SIL was associated with a more than 3-fold increased risk of a simultaneous abnormal anal smear (p < 0.05). In conclusion, cervical and anal disease were significantly associated and almost exclusively seen in the presence of HPV. Immunodeficiency and HIV positivity increased the risk of disease in HPV-positive subjects. Hybrid capture, which requires a higher viral load than PCR to detect HPV, was clearly superior in predicting cervical and anal disease. Altogether, these findings suggest that a high level of HPV infection may be important for the development of SIL in the population studied.

Adult↗