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L Bergkvist

Publications and source records attributed to L Bergkvist.

At least 37 records · Page 2Linked to original sources
PubMed1999

Risks of breast and endometrial cancer after estrogen and estrogen-progestin replacement.

OBJECTIVE: We studied the risk of breast and endometrial cancer in a cohort of 11,231 Swedish women prescribed different replacement hormone regimens. METHODS: All 10,472 women at risk of developing breast cancer and 8,438 women at risk of endometrial cancer were followed up from the time of the questionnaire in 1987-88 through 1993, by record-linkages to the National Swedish Cancer Registry. Using data from a questionnaire we analyzed the relationships between hormone exposures and cancer risk, with non-compliers and users of less than 1 year as a reference group. RESULTS: For breast cancer, women reporting use of estrogens combined with progestins had evidence of an increased risk relative to women denying intake or taking hormones for less than 1 year; relative risk (RR) = 1.4 (95% confidence interval 0.9-2.3) after 1-6 years of intake, and RR = 1.7 (95% CI 1.1-2.6) after more than 6 years. This excess risk seemed confined to recent exposure. We found no association with intake of estrogens alone using non-compliers and short-term takers as the reference group. The risk of invasive endometrial cancer was increased four-fold in women using medium-potency estrogens alone for 6 years or longer, RR = 4.2 (95% CI 2.5-8.4). Women on such long-term progestin-combined treatment had a lower, non-significant, excess risk (RR = 1.4; 95% CI 0.6-3.3). CONCLUSIONS: We conclude that long-term recent use of estrogen-progestin combined replacement therapy may increase the risk of breast cancer. Exposure to estrogen alone substantially elevates the risk of endometrial cancer, an increase that can be reduced or perhaps avoided by adding progestins.

Breast Neoplasms↗
PubMed1998

A prospective study of association of monounsaturated fat and other types of fat with risk of breast cancer.

BACKGROUND: Animal studies suggest that monounsaturated and polyunsaturated fat may have opposite effects on the risk of breast cancer. METHODS: We performed a population-based prospective cohort study, including 61,471 women aged 40 to 76 years from 2 counties in central Sweden who did not have any previous diagnosis of cancer; 674 cases of invasive breast cancer occurred during an average follow-up of 4.2 years. All subjects answered a validated 67-item food frequency questionnaire at baseline. Cox proportional hazards models were used to obtain adjusted rate ratio (RR) estimates with 95% confidence intervals (CIs). RESULTS: After mutual adjustment of different types of fat, an inverse association with monounsaturated fat and a positive association with polyunsaturated fat were found. The RR for each 10-g increment in daily intake of monounsaturated fat was 0.45 (95% CI, 0.22-0.95), whereas the RR for a 5-g increment of polyunsaturated fat was 1.69 (95% CI, 1.02-2.78); the increments correspond to approximately 2 SDs of intake in the population. Comparing the highest quartile of intake with the lowest, we found an RR of 0.8 (95% CI, 0.5-1.2) for monounsaturated fat and 1.2 (95% CI, 0.9-1.6) for polyunsaturated fat. Saturated fat was not associated with the risk of breast cancer. CONCLUSIONS: Our results indicate that various types of fat may have specific opposite effects on the risk of breast cancer that closely resemble the corresponding effects in experimental animals. Research investigations and health policy considerations should take into account the emerging evidence that monounsaturated fat might be protective for risk of breast cancer.

Adult↗
PubMed1997

Colorectal cancer in patients over 75 years of age--determinants of outcome.

Two hundred and two consecutive patients with colorectal cancer, aged 75 years or older, diagnosed between 1980 and 1990, were followed up from the date of diagnosis until their death or until October 1994. Of these, 194 underwent some type of surgery, in 151 cases elective and in 43 emergency. The peri-operative mortality rate was 10.8% and the overall 5-year survival rate 28%. The ASA score was a predictor for both peri-operative mortality and survival. Peri-operative mortality was significantly increased among patients who had palliative operations, and those with post-operative complications and blood transfusions. Overall survival was worse for patients with absence of blood in the stools or absence of anaemia, for patients who lived in institutions pre-operatively, and for patients with advanced tumour stages. We conclude that the survival rate in elderly patients with colorectal cancer is acceptable after surgery. Old age is not a risk factor per se for peri-operative mortality or poor prognosis, and should not disqualify a person from operation.

Aged↗
PubMed1997

Hormone replacement therapy and major risk factors for reproductive cancers, osteoporosis, and cardiovascular diseases: evidence of confounding by exposure characteristics.

Observational studies have yielded reports on long-term effects of hormone replacement therapy (HRT) for cardiovascular, osteoporosis-related, and cancer diseases. There is concern that risk estimates may be confounded by complex mechanisms of selection with regard to important risk determinants. In this study, we tested the hypothesis that baseline characteristics of women vary with exposure characteristics, i.e., the choices of complying with prescriptions, using different compounds and regimens, and continuing intake long-term. We analyzed the prevalence of relevant risk factors and their relationships to characteristics of exposure among 11,211 Swedish women who had received prescription for HRT. Associations were studied through logistic regression, with comparisons of women with ever-use versus non-compliance, long-term (73+ months) versus short-term use (1-72 months), intake of conjugated estrogens versus estradiol compounds, and intake of estrogens only versus estrogens combined with progestins, respectively. We found that women denying intake of using HRT short-term had higher parity, earlier age at first birth and a lower prevalence of hysterectomy or oophorectomy than those complying or exposed long-term. A high level of education was associated with compliance and long-term exposure, and heavy physical exercise and high intake of food fibers were associated with compliance. Climacteric symptoms were associated with compliance, long-term intake and use of conjugated estrogens, whereas a history of oral contraceptive intake was associated with use of estrogens alone without progestins. We conclude that selection biases in studies of HRT effects are important and complex in that they may vary with the reported exposure. Our findings are important, as they point to the need for improved methods for measuring, in particular, factors linked to lifestyle and health behavior, in order to account more fully for confounding in the analyses of risk relationships.

Aged↗
PubMed1996

Cancer incidence and mortality in women receiving estrogen and estrogen-progestin replacement therapy--long-term follow-up of a Swedish cohort.

We analyzed cancer incidence and mortality in a cohort of 22,597 Swedish women who were prescribed replacement hormones. After 13 years of follow-up in national registries, 2,330 incident cancer cases and 848 cancer deaths were observed. Overall, our results were reassuring since incidence rate ratios (SIRs) for 16 cancer sites and mortality ratios (SMRs) for all 10 examined sites were at, or lower than, unity. However, we found that exposure to an estrogen-progestin combined brand was associated with an increasing relative risk of breast cancer with follow-up time, the SIR reaching 1.4 (95% CI 1.1-1.8) after 10 years of follow-up. The relative risk of endometrial cancer was substantially increased, with the highest SIR of 5.0 (95% CI 1.6-5.9) in women prescribed estrogens alone, whereas those given an estrogen-progestin combination showed no elevation in risk. The risk estimates for liver and biliary tract cancers and for colon cancer were reduced by about 40%, notably in women prescribed the estradiol-progestin compound. Further detailed analyses revealed no evidence of adverse or protective effects on the risk of ovarian, uterine cervical, vulvar/vaginal, rectal, pancreatic, renal, lung, thyroid and other endocrine cancers, brain tumors, malignant melanoma or other skin cancers. Hormone replacement therapy was not associated with an increase in mortality for any cancer site, at this time of follow-up. For breast and endometrial cancers, SMRs were below baseline but tended to increase with follow-up time. We conclude that hormone replacement increases the endometrial-cancer risk after unopposed estrogens and the breast-cancer risk-notably after estrogen-progestin combined therapy-and tentatively suggest that it exerts a protective effect against colon and liver cancer risks.

Aged↗
PubMed1996

Management of accidentally found pathological lymph nodes on routine screening mammography.

Normal lymph nodes in the anterior part of the axilla are readily seen on routine mammography. It is important, however, to recognize pathological lymph nodes, characterized by increased attenuation, high density, a round or irregular shape and lack of fat in the hilus, as they often indicate significant diseases. We examined the final diagnosis in 22 patients referred for clinical examination from a mammographic screening programme because of pathological lymph nodes without concomitant breast malignancy. Ten of them were found to have a malignant lesion, and one had sarcoidosis. None of the malignancies had been diagnosed before screening. Among women with abnormal but impalpable nodes, only one malignancy was found (in a woman with previous breast cancer), whereas nine of 13 women with palpable nodes had malignancies. Seven malignant lymphomas were discovered, but among all 60 women of the age group in question with newly diagnosed lymphomas in the region, only 13 had pathological axillary nodes. Mammography cannot therefore be used as a screening method for lymphoma. We conclude that mammographically pathological lymph nodes in the axilla should be examined clinically and propose a simple programme for patient management.

Adult↗
PubMed1996

A search for recall bias in a case-control study of diet and breast cancer.

BACKGROUND: In retrospective studies of dietary habits and breast cancer risk, recall bias is a concern since diet has been publicized as a cause of breast cancer. METHODS: In a case-control study of diet and breast cancer risk nested within a cohort of women screened with mammography, we contrasted answers to a retrospective dietary interview with answers to a dietary questionnaire which was filled out before any diagnostic procedures for breast cancer were undertaken. The source population was all women aged 40-74 in two counties in Sweden invited to mammographic screening and asked to fill out a questionnaire before the screening. Cases and controls were subsequently defined -- matched on age, county of residence, and time of mammography -- and approached for an interview. RESULTS: In all, 265 cases and 431 controls participated in the study. Means of frequencies differed between the agreement in the questionnaire's and the interview's classifications of study subjects into quartiles of monthly intake varied between 31 percent and 57 percent. Kappa statistics in all food groups were below 0.41. In a regression analysis, case subjects with low responses on the questionnaire about intake of meat, snacks, and coffee and tea gave higher responses on interview than did controls who had low questionnaire responses for these food groups. The reverse was also true: cases' responses that were high on the questionnaire were lower on interview for these food groups than were controls' responses. CONCLUSIONS: We found few signs of recall bias, and the few indications of a differential misclassification that we found were not in food groups that have been publicly discussed as causes of breast cancer.

Adult↗
PubMed1996

Hormone replacement therapy and breast cancer. A review of current knowledge.

More than 50 studies looking at the relationship between hormone replacement therapy and breast cancer have been published. Overall the results are reassuring. There is no evidence of an increased risk of breast cancer after ever use of exogenous estrogens. However, when long term use (i.e. use for more than 10 to 15 years) is considered the majority of data are compatible with a small increase in the risk, in the magnitude of 30 to 50%, possibly limited to women who are currently receiving hormone replacement therapy or who have recently stopped such therapy. This would translate into an increase in the absolute risk of developing breast cancer of 3 to 4% of among postmenopausal women in the Western world. No consistent evidence exists on differing risks of breast cancer with different types of estrogens, and no clear dose-relationship has been found. Risk estimates for combined estrogen-progestogen regimens have been of the same magnitude as for estrogens alone; thus, no clear evidence of a protective effect of the addition of a progestogen has been found. Investigations into a possible interaction between estrogen supplementation and other known risk factors for breast cancer have not yielded any consistent results. Cancers that develop during estrogen therapy have been found to be associated with a favourable prognosis. This could be explained in part by better medical surveillance, and early detection, but may also represent an effect of the treatment itself. Despite the increased incidence of breast cancer after long term hormone replacement therapy, no increased mortality from breast cancer among estrogen users has been found. Thus, on the whole, data seem reassuring. The small increase in the risk of breast cancer after long term hormone replacement therapy use, with no concomitant increase in mortality, is likely to be outweighed by the positive effects of estrogens on the symptoms of the menopause and osteoporosis, and the protective effects of such therapy against cardiovascular disease.

Breast Neoplasms↗
PubMed1994

Diet and breast cancer risk. Results from a population-based, case-control study in Sweden.

BACKGROUND: We describe an epidemiologic analytical study of the relationship between current diet and breast cancer risk. METHOD: The study design is a case-control analysis. Cases were recruited from a mammography screening program used within the national health care system; the control subjects were selected from subjects free of breast cancer in the same population. A total of 380 cases and 525 control subjects, frequency-matched for age, month of mammography, and county of residence, were identified. Of these, 265 cases and 432 control subjects were included in this analysis. Odds ratios for breast cancer in relation to food and nutrient intake were the main outcome measures. RESULTS: Exposure in the highest quartile of beta-carotene intake gave an odds ratio of 0.6 (95% confidence interval, 0.4 to 1.0). No increased risk was noted with high fat intake. Breast cancer risk was associated with alcohol intake only when alcohol was analyzed in quartiles: odds ratio, 1.6 (95% confidence interval, 1.0 to 2.4) for the highest quartile of intake vs the lowest. Stratified analyses showed that a high fat intake might decrease the protective effect of beta-carotene intake. Risks did not change appreciably with adjustment for total energy intake or known breast cancer risk factors. CONCLUSIONS: As in most other studies, no strong risk factors for breast cancer have been identified in the current diet. The negative association between breast cancer risk and beta-carotene intake may be supported by a plausible mechanism, but our finding concerning alcohol should be interpreted cautiously since there was no dose-response relationship and the biological mechanism for a threshold effect at very low levels of consumption is unclear.

Adult↗
PubMed1994

Self-administered food frequency questionnaire: the effect of different designs on food and nutrient intake estimates.

BACKGROUND: Our objective was to determine the possible influence that different designs of a food frequency questionnaire might have on food, energy and nutrient intake estimates. METHODS: A population-based survey included 6783 women, 40-70 years old, living in central Sweden. Using a factorial study design, we compared eight different types of questionnaire covering combinations of three factors: increasing/decreasing frequency categories; addition of portion sizes; and addition of non-dietary questions. All questionnaires included the same list of 60 food items. One of the eight questionnaires was mailed to each subject according to a random assignment. The overall response rate was 77%. RESULTS: Compared with increasing frequencies, decreasing order of frequency categories entailed 3-11% higher estimates of mean intake for 7 of 14 food groups, 4% higher estimates for energy and 3-6% higher estimates for 13 of 18 nutrients. Addition of portion sizes had heterogeneous effects, both on dietary items (e.g. from -30% decrease for eggs to +76% increase for coffee) and on calculated nutrients (from -7% for beta-carotene to +19% for vitamin C). The inclusion of some additional non-dietary questions did not influence the estimated mean intake of any food or nutrient. CONCLUSIONS: The results of this study have implications for the design of questionnaires and for pooled analyses in nutritional epidemiology, when different food questionnaires are used.

Adult↗
PubMed1993

Hormone replacement therapy and breast cancer mortality in Swedish women: results after adjustment for 'healthy drug-user' effect.

No change of breast cancer mortality has been reported previously after long-term hormone replacement therapy. A conceivable explanation for the apparent discrepancy between incidence and mortality may be selection bias due to lower prevalence of breast cancer in women who receive replacement hormones, compared with nonexposed women. We used a new approach to correct for bias due to this 'healthy drug-user effect,' by adjusting the external, population-based, mortality rates for such cases prevalent during the recruitment period of our cohort. In this cohort of some 23,000 Swedish women, who were prescribed various hormone replacement regimens, breast cancer mortality was analyzed after follow-up to 12 years. External analyses revealed overall standardized mortality ratios for breast cancer rising from 0.71 to 0.81, but not significantly different from unity, after adjustment procedures. In multivariate regression models, excluding prevalent cases in the cohort, women prescribed estradiol, conjugated estrogens, or an estrogen-progestin combination were not at a higher risk relative to those given other and weak estrogens, relative risks being 0.81 and 0.68, respectively. On the basis of the present analytical approach, we conclude that breast cancer mortality does not appear to be changed overall or in subgroups, despite increased incidence.

Aged↗
PubMed1991

Modal DNA values and estramustine-binding protein (EMBP) as prognostic markers in prostatic cancer.

In this study, we have investigated the model DNA values and the expression of estramustine-binding protein (EMBP) in formalin-fixed and paraffin-embedded TUR specimens from 76 untreated patients with prostatic cancer. In addition, specimens from 13 patients were analyzed for tumour EMBP expression only. Ploidy was measured as diploid, tetraploid and non-tetraploid aneuploid or aneuploid in the near-diploid region. All patients had been referred during 1978-1981, and were subjected to TUR due to urinary obstruction. Survival data were obtained for all patients through March 1988. Statistical analyses were performed using a Cox's regression model with respect to survival and cause specific survival and correlated to the DNA pattern and the expression of EMBP. The existence of a near-diploid aneuploid cell population as well as poor differentiation grade were both statistically significantly correlated with poor survival. Near-diploid aneuploid cell lines were seen in 9/76 (12%) of the patients and were also seen in well differentiated cancers (4/17). The expression of EMBP was most abundant in the moderately differentiated cancers. However, all prostatic cancer specimens investigated were positive for the antigen. Patients with poorly differentiated carcinomas and high EMBP expression showed a tendency towards better prognosis than those with poorly differentiated carcinomas and low EMBP expression. The present patient material was, however, too small to show a statistically significant correlation between EMBP and survival.

Aged↗