Higher recipient pre-transplant FOXP3 mRNA expression is associated with acute leukaemia relapse after HSCT.

The effect of higher FOXP3 mRNA expression by recipient pre-transplant CD4+ T cells on leukaemia relapse was analysed in a series of 106 patients who received allogeneic haematopoietic stem cell transplantation after myeloablative conditioning with or without antithymocyte globulin (ATG) due to acute leukaemia in 1st or 2nd complete remission. FOXP3 mRNA was measured by qPCR in purified CD4+ T cells from blood obtained before conditioning. Higher FOXP3 mRNA expression was associated with an increased relapse risk when conditioning included ATG (n = 43, hazard ratio [HR] 11.0 [2.50-48.4], p = 0.00001). No effect was observed in patients not receiving ATG (HR 0.95 [0.53-1.81]).

High preharvest donor Foxp3 mRNA level predicts late relapse of acute lymphoblastic leukaemia after haematopoietic stem cell transplantation.

OBJECTIVES: The curative effect of allogeneic haematopoietic stem cell transplantation (HSCT) for acute leukaemia is due in part to the donor T cell-mediated graft-versus-leukaemia immune reaction (GvL). Several studies have suggested that donor CD25+CD4+Foxp3+regulator T cells (Tregs) may decrease graft-versus-host disease (GvHD) without abrogating GVL. This notion may need modification in acute lymphoblastic leukaemia (ALL). METHODS: Foxp3 mRNA level was measured by qPCR in preharvest donor blood CD4+ T cells. The study comprised 45 patients with ALL in 1st or 2nd CR who received myeloablative HSCT using T-replete bone marrow grafts. RESULTS: Relapse occurred in 17 patients median 363 days after HSCT. The relapse risk was estimated by Cox univariate and multivariate proportional hazard regression. The proportionality assumption was met by analysing the preharvest donor Foxp3 mRNA level as a time-dependent covariate. Early relapse was not modified by the Foxp3 mRNA level. However, a higher Foxp3 mRNA level was associated with a significantly increased relapse risk after day 363 after transplantation, compatible with inhibition of GvL. In contrast, a higher preharvest donor CD4+ T-cell concentration was associated with reduced relapse risk. CONCLUSION: A higher preharvest donor Foxp3 mRNA level may be predictive of late ALL relapse after HSCT.

The influence of hormone therapies on colon and rectal cancer.

Exogenous sex hormones seem to play a role in colorectal carcinogenesis. Little is known about the influence of different types or durations of postmenopausal hormone therapy (HT) on colorectal cancer risk. A nationwide cohort of women 50-79 years old without previous cancer (n = 1,006,219) were followed 1995-2009. Information on HT exposures was from the National Prescription Register and updated daily, while information on colon (n = 8377) and rectal cancers (n = 4742) were from the National Cancer Registry. Potential confounders were obtained from other national registers. Poisson regression analyses with 5-year age bands included hormone exposures as time-dependent covariates. Use of estrogen-only therapy and combined therapy were associated with decreased risks of colon cancer (adjusted incidence rate ratio 0.77, 95 % confidence interval 0.68-0.86 and 0.88, 0.80-0.96) and rectal cancer (0.83, 0.72-0.96 and 0.89, 0.80-1.00), compared to never users. Transdermal estrogen-only therapy implied more protection than oral administration, while no significant influence was found of regimen, progestin type, nor of tibolone. The benefit of HT was stronger for long-term hormone users; and hormone users were at lower risk of advanced stage of colorectal cancer, which seems supportive for a causal association between hormone therapy and colorectal cancer.

The influence of hormone therapies on type I and II endometrial cancer: A nationwide cohort study.

The influence of hormone therapy (HT) on risk for endometrial cancer is still casting which type of HT the clinicians recommend. It is unrevealed if HT has a differential influence on Type I versus Type II endometrial tumors, and little is known about the influence of, e.g., different routes of administration and about the influence of tibolone. We followed all Danish women aged 50-79 years without previous cancer or hysterectomy (n = 914,595) during 1995-2009. From the National Prescription Register, we computed HT exposures as time-dependent covariates. Incident endometrial cancers (n = 6,202) were identified from the National Cancer Registry: 4,972 Type I tumors and 500 Type II tumors. Incidence rate ratios (RRs) and 95% confidence intervals (Cls) were estimated by Poisson regression. Compared with women never on HT, the RR of endometrial cancer was increased with conjugated estrogen: 4.27 (1.92-9.52), nonconjugated estrogen: 2.00 (1.87-2.13), long cycle combined therapy: 2.89 (2.27-3.67), cyclic combined therapy: 2.06 (1.88-2.27), tibolone 3.56 (2.94-4.32), transdermal estrogen: 2.77 (2.12-3.62) and vaginal estrogen: 1.96 (1.77-2.17), but not with continuous combined therapy: 1.02 (0.87-1.20). In contrast, the risk of Type II tumors appeared decreased with continuous combined therapy: 0.45 (0.20-1.01), and estrogen therapy implied a nonsignificantly altered risk of 1.43 (0.85-2.41). Our findings support that continuous combined therapy is risk free for Type I tumors, while all other hormone therapies increase risk. In contrast, Type II endometrial cancer was less convincingly associated with hormone use, and continuous combined therapy appeared to decrease the risk.

Risk of breast cancer in relation to combined effects of hormone therapy, body mass index, and alcohol use, by hormone-receptor status.

BACKGROUND: Alcohol consumption, increased body mass index (BMI), and hormone therapy are risk factors for postmenopausal breast cancer, but their combined effects are not well understood. Because hormone therapy is effective for the relief of menopausal symptoms, the identification of "high-risk" users is important for therapeutic reasons. We investigated interactions between hormone therapy use and alcohol-use/high BMI status in relation to invasive breast cancer risk, both overall and according to estrogen receptor (ER) status. METHODS: Two Danish prospective cohorts were pooled, including 30,789 women ages 50+ years (study period 1981 to 2009). Information on risk factors was obtained in baseline questionnaires. We performed analyses using the Aalen additive hazards model. Serum estradiol and testosterone measurements were obtained in a subsample of approximately 1000 women. RESULTS: During 392,938 person-years of follow-up, 1579 women developed invasive breast cancer. Among nonusers of hormone therapy, the risk of breast cancer was slightly increased with overweight/obesity and increasing alcohol consumption. Compared with normal-weight nonusers, the risk of breast cancer was higher in hormone therapy users across all BMI strata (P for interaction = 0.003). A markedly higher risk of breast cancer was also observed for alcohol combined with hormone therapy use compared with abstinent nonusers (P for interaction = 0.02). These effects were primarily restricted to ER-positive cases. Combined effects of hormone therapy/high BMI and hormone therapy/alcohol on serum estradiol and testosterone supported the hypothesis of a hormonal pathway linking these exposures to breast cancer. CONCLUSION: These analyses suggest an increased risk of breast cancer associated with hormone therapy use-a risk that may be particularly strong among women consuming alcohol.

Cohort profile: the Social Inequality in Cancer (SIC) cohort study.

The Social Inequality in Cancer (SIC) cohort study was established to determine pathways through which socioeconomic position affects morbidity and mortality, in particular common subtypes of cancer. Data from seven well-established cohort studies from Denmark were pooled. Combining these cohorts provided a unique opportunity to generate a large study population with long follow-up and sufficient statistical power to develop and apply new methods for quantification of the two basic mechanisms underlying social inequalities in cancer-mediation and interaction. The SIC cohort included 83 006 participants aged 20-98 years at baseline. A wide range of behavioural and biological risk factors such as smoking, physical inactivity, alcohol intake, hormone replacement therapy, body mass index, blood pressure and serum cholesterol were assessed by self-administered questionnaires, physical examinations and blood samples. All participants were followed up in nationwide demographic and healthcare registries. For those interested in collaboration, further details can be obtained by contacting the Steering Committee at the Department of Public Health, University of Copenhagen, at inan@sund.ku.dk.

Educational differences in postmenopausal breast cancer--quantifying indirect effects through health behaviors, body mass index and reproductive patterns.

Studying mechanisms underlying social inequality in postmenopausal breast cancer is important in order to develop prevention strategies. Standard methods for investigating indirect effects, by comparing crude models to adjusted, are often biased. We applied a new method enabling the decomposition of the effect of educational level on breast cancer incidence into indirect effects through reproductive patterns (parity and age at first birth), body mass index and health behavior (alcohol consumption, physical inactivity, and hormone therapy use). The study was based on a pooled cohort of 6 studies from the Copenhagen area including 33,562 women (1,733 breast cancer cases) aged 50-70 years at baseline. The crude absolute rate of breast cancer was 399 cases per 100,000 person-years. A high educational level compared to low was associated with 74 (95% CI 22-125) extra breast cancer cases per 100,000 person-years at risk. Of these, 26% (95% CI 14%-69%) could be attributed to alcohol consumption. Similar effects were observed for age at first birth (32%; 95% CI 10%-257%), parity (19%; 95%CI 10%-45%), and hormone therapy use (10%; 95% CI 6%-18%). Educational level modified the effect of physical activity on breast cancer. In conclusion, this analysis suggests that a substantial number of the excess postmenopausal breast cancer events among women with a high educational level compared to a low can be attributed to differences in alcohol consumption, use of hormone therapy, and reproductive patterns. Women of high educational level may be more vulnerable to physical inactivity compared to women of low educational level.

Thrombotic stroke and myocardial infarction with hormonal contraception.

BACKGROUND: Although several studies have assessed the risk of venous thromboembolism with newer hormonal contraception, few have examined thrombotic stroke and myocardial infarction, and results have been conflicting. METHODS: In this 15-year Danish historical cohort study, we followed nonpregnant women, 15 to 49 years old, with no history of cardiovascular disease or cancer. Data on use of hormonal contraception, clinical end points, and potential confounders were obtained from four national registries. RESULTS: A total of 1,626,158 women contributed 14,251,063 person-years of observation, during which 3311 thrombotic strokes (21.4 per 100,000 person-years) and 1725 myocardial infarctions (10.1 per 100,000 person-years) occurred. As compared with nonuse, current use of oral contraceptives that included ethinyl estradiol at a dose of 30 to 40 µg was associated with the following relative risks (and 95% confidence intervals) for thrombotic stroke and myocardial infarction, according to progestin type: norethindrone, 2.2 (1.5 to 3.2) and 2.3 (1.3 to 3.9); levonorgestrel, 1.7 (1.4 to 2.0) and 2.0 (1.6 to 2.5); norgestimate, 1.5 (1.2 to 1.9) and 1.3 (0.9 to 1.9); desogestrel, 2.2 (1.8 to 2.7) and 2.1 (1.5 to 2.8); gestodene, 1.8 (1.6 to 2.0) and 1.9 (1.6 to 2.3); and drospirenone, 1.6 (1.2 to 2.2) and 1.7 (1.0 to 2.6), respectively. With ethinyl estradiol at a dose of 20 µg, the corresponding relative risks according to progestin type were as follows: desogestrel, 1.5 (1.3 to 1.9) and 1.6 (1.1 to 2.1); gestodene, 1.7 (1.4 to 2.1) and 1.2 (0.8 to 1.9); and drospirenone, 0.9 (0.2 to 3.5) and 0.0. For transdermal patches, the corresponding relative risks were 3.2 (0.8 to 12.6) and 0.0, and for a vaginal ring, 2.5 (1.4 to 4.4) and 2.1 (0.7 to 6.5). CONCLUSIONS: Although the absolute risks of thrombotic stroke and myocardial infarction associated with the use of hormonal contraception were low, the risk was increased by a factor of 0.9 to 1.7 with oral contraceptives that included ethinyl estradiol at a dose of 20 µg and by a factor of 1.3 to 2.3 with those that included ethinyl estradiol at a dose of 30 to 40 µg, with relatively small differences in risk according to progestin type. (Funded by the Danish Heart Association.).

Quantifying mediating effects of endogenous estrogen and insulin in the relation between obesity, alcohol consumption, and breast cancer.

BACKGROUND: Increased exposure to endogenous estrogen and/or insulin may partly explain the relationship of obesity, physical inactivity, and alcohol consumption and postmenopausal breast cancer. However, these potential mediating effects have not been formally quantified in a survival analysis setting. METHODS: We combined data from two case-cohort studies based in the Women's Health Initiative-Observational Study with serum estradiol levels, one of which also had insulin levels. A total of 1,601 women (601 cases) aged 50 to 79 years who were not using hormone therapy at enrollment were included. Mediating effects were estimated by applying a new method based on the additive hazard model. RESULTS: A five-unit increase in body mass index (BMI) was associated with 50.0 [95% confidence interval (CI), 23.2-76.6] extra cases per 100,000 women at-risk per year. Of these, 23.8% (95% CI, 2.9-68.4) could be attributed to estradiol and 65.8% (95% CI, 13.6-273.3) through insulin pathways. The mediating effect of estradiol was greater (48.8%; 95% CI, 18.8-161.1) for BMI when restricted to estrogen receptor positive (ER(+)) cases. Consuming 7+ drinks/wk compared with abstinence was associated with 164.9 (95% CI, 45.8-284.9) breast cancer cases per 100,000, but no significant contribution from estradiol was found. The effect of alcohol on breast cancer was restricted to ER(+) breast cancers. CONCLUSIONS: The relation of BMI with breast cancer was partly mediated through estradiol and, to a greater extent, through insulin. IMPACT: The findings provide support for evaluation of interventions to lower insulin and estrogen levels in overweight and obese postmenopausal women to reduce breast cancer risk.

Estimating the effect of current, previous and never use of drugs in studies based on prescription registries.

PURPOSE: Many studies which investigate the effect of drugs categorize the exposure variable into never, current, and previous use of the study drug. When prescription registries are used to make this categorization, the exposure variable possibly gets misclassified since the registries do not carry any information on the time of discontinuation of treatment.In this study, we investigated the amount of misclassification of exposure (never, current, previous use) to hormone therapy (HT) when the exposure variable was based on prescription data. Furthermore, we evaluated the significance of this misclassification for analysing the risk of breast cancer. MATERIALS AND METHODS: Prescription data were obtained from Danish Registry of Medicinal Products Statistics and we applied various methods to approximate treatment episodes. We analysed the duration of HT episodes to study the ability to identify discontinuation of therapy from prescription data. Furthermore, we compared to results based on self-reported duration of HT from the Danish Nurse Cohort.Finally, we analysed the effect of HT exposure on time to breast cancer for the different prescription based exposure variables as well as for self-reported HT use. RESULTS: The results of time to discontinuation varied strongly across the different HT assessments. However, misclassification of HT exposure at baseline was limited and hence analysis of the effect of HT on time to breast cancer showed stability across the different exposure assessments with Hazard Ratios ranging from 1.68 to 1.78 for current use compared to never use. CONCLUSIONS: The findings suggest that it is possible to estimate the effect of never, current and previous use of HT on breast cancer using prescription data.

Effects of sample attrition in a longitudinal study of the association between alcohol intake and all-cause mortality.

BACKGROUND AND AIMS: Longitudinal studies show higher mortality among abstainers and heavy drinkers than among light and moderate alcohol consumers. The influence on this association of missing information on alcohol intake due to attrition (dropout) has not been examined previously. The aims of this study were to characterize participants who dropped out and to evaluate whether the missing information influenced the association between alcohol intake and all-cause mortality. DESIGN AND PARTICIPANTS: Data on the 18 974 participants in the Copenhagen City Heart Study, with four measures of alcohol intake and other life-style factors during 28 years of follow-up, were linked with nation-wide registers on socio-economic covariates, mortality and disease incidence. Logistic regression was used to describe life-style and socio-economic determinants of attrition, and Poisson regression was used to evaluate how attrition affected the association between alcohol intake and mortality. The statistical methods used for dealing with missing values were complete case analysis, carry last observation forward, simple imputations, multiple imputation and weighting. FINDINGS: Abstinence and high alcohol intake, current smoking, physical inactivity and high body mass index increased the odds of dropping out, whereas being married, more years of education, skilled occupation, high income and large residential area decreased the odds. Attrition was associated with increased mortality and incidence rates of heart disease, lung and upper digestive tract cancers and alcoholic liver diseases. Increased mortality among abstainers and heavy drinkers was observed with all methods used for handling missing data on alcohol intake. CONCLUSIONS: Attrition was non-random, and the observed association between alcohol intake and all-cause mortality did not differ by statistical method for handling missing data.

Use of baseline and updated information on alcohol intake on risk for breast cancer: importance of latency.

BACKGROUND: Alcohol intake has been shown to be associated with an increased risk for breast cancer. In the analysis of longitudinal prospective cohort studies, however, the analysis of repeated measurements of alcohol intake might not be straightforward. METHODS: In this analysis of the Copenhagen City Heart Study, in which alcohol intake was measured four times, 9318 Danish women with no previous diagnosis of cancer were followed for breast cancer for 27 years, from 1976 to 2002. During follow-up, breast cancer was diagnosed in 476 women. RESULTS: The association between alcohol intake at first measurement (baseline alcohol intake) and breast cancer was positive and approximately linear. When alcohol intake was updated during follow-up, no association was observed between breast cancer and alcohol intake. It is suggested that this difference in results may be attributable to long latency time between alcohol intake and breast cancer occurrence, because a markedly increased risk was estimated on the basis of direct lagging of risk time. CONCLUSIONS: Our results support the hypothesis that baseline alcohol intake is more strongly associated with breast cancer risk than updated intake, and we suggest that this is due to the long latency between alcohol intake and breast cancer.

Differences in stage of disease between migrant women and native Danish women diagnosed with cancer: results from a population-based cohort study.

The aim of the study is to compare differences in cancer stage at diagnosis between migrant women and native Danish women. The stage is used as a clinical indicator of access to healthcare until the point of diagnosis. Refugees and family reunited migrants who received residence permits in Denmark from 1 January 1993 to 31 December 1999 were included and matched 1 : 4 on age and sex with a Danish-born reference population. Our final female population included 24 734 migrants and 123 670 controls. Civil registration numbers of the cohort were linked to the Danish Cancer Registry whereby cases were identified in the period 1.1.1993-31.12.2002. Only women from Eastern Europe and the Middle East were included. This amounted to 269 migrants and 1608 native Danes. Data from the Danish Cancer Registry included diagnosis, time of diagnosis and disease stage at diagnosis. Our initial analyses of migrant subgroups showed that migrant women had decreased odds ratios of being diagnosed at the local stage and increased odds of having unknown stage, although these tendencies were mainly not statistically significant. A subsequent analysis of an overall migrant effect on all cancer sites emphasized these tendencies. This analysis reached borderline significance for local versus nonlocal stage and significance for unknown versus known stage. Our results indicate that migrant women may experience barriers in access to healthcare until cancer diagnosis compared with Danish women. More research is, however, needed to confirm our results and to find out if they indicate general problems concerning migrants' access to healthcare in Denmark.

Changes in alcohol intake and risk of upper digestive tract cancer.

INTRODUCTION: Alcohol intake measured at one point in time is a strong predictor for later development of cancer of the oral cavity, pharynx, larynx and esophagus. In this prospective cohort study, we examined whether changes in individual alcohol intake resulted in subsequent altered risk of these cancers. MATERIAL AND METHODS: In the Copenhagen City Heart Study we assessed alcohol intake among 4 896 men and 6 239 women who participated at both the first (1976-1978) and second (1981-1983) examination of the study. Alcohol intake changes on risk of upper digestive tract cancer 1981-2002 were examined by a Cox model adjusted for potential confounders. RESULTS: Despite a small number of cases (n = 105), alcohol intake increase > 14 drinks/week was associated with significantly elevated risk (hazard ratio = 2.5; 95% confidence interval, 1.1-5.3), while suggestively decreased risk was observed for persons lowering alcohol intake > 7 drinks/week (0.5; 0.1-2.5). The trend test was highly significant (p < 0.0001). CONCLUSIONS: These findings support public health messages of not increasing alcohol intake and lowering consumption among people with high alcohol intake.

Causes of death behind low life expectancy of Danish women.

AIMS: The authors examined causes of death contributing to the relatively high mortality of Danish women born 1915-45, and evaluated the impact of smoking related causes of death. METHODS: Age-period-cohort analysis of mortality of Danish women aged 40-89 in 1960-98. Estimate of the negative curvature in parabola patterns for 50 causes of death. RESULTS: A total of 34 causes of death contributed to the relatively high mortality for women born 1915-45. The main contribution came from smoking-related causes of death. CONCLUSION: The results indicate a high smoking prevalence to be the main explanation behind the relatively low life expectancy of Danish women born 1915-45.

Feasibility of the current-duration approach to studying human fecundity.

Approaches for monitoring time trends in couples' fecundity and for studying its sensitivity to environmental factors are needed. Two approaches rely on the inclusion of a cross-sectional sample of couples currently "at risk" of pregnancy either with follow up (prevalent cohort) or without follow up (current-duration design). To illustrate the feasibility of the current-duration design, we contacted a random sample of 1204 French women age 18 to 44 years in 2004 and recruited those who were currently having unprotected sexual intercourse. The current duration since the beginning of unprotected intercourse was defined for 69 women (5.7%). An additional 15 women (1.2%) were planning to start trying to become pregnant within the next 6 months. Parametric methods allowed, based on current duration of unprotected intercourse, estimation of fecundity as if the couples had been followed prospectively. The estimated proportion of couples not pregnant after 12 months of unprotected intercourse was 34% (95% confidence interval [CI] = 15-54%). The accelerated-failure time model allows study of the influence of environmental factors on fecundity. As an illustration, tobacco smoking by the woman was associated with a doubling in the median duration of unprotected intercourse before pregnancy (adjusted time ratio = 2.4; 95% CI = 1.1-5.2). We quantified the influence of time trends in the prevalence of smoking on this estimate. We suggest ways to quantify or avoid other potential bias. In conclusion, it is possible to recruit a sample of couples currently having unprotected intercourse. The current-duration design appears feasible with approximately 5 times as many women eligible for study as for an incident cohort design.

Studying time to pregnancy by use of a retrospective design.

Biologic fertility can be measured using time to pregnancy (TTP). Retrospective designs, although lacking detailed timed information about behavior and exposure, are useful since they have a well-defined target population, often have good response rates, and are simpler and less expensive to conduct than prospective studies. This paper reviews retrospective TTP studies from a methodological viewpoint and shows how methodological problems can be avoided or minimized by appropriate study design, conduct, and analysis. Sensitivity analyses using data from four European retrospective TTP studies are presented to explore the issues. Although the identified biases tend to have small impacts, the effects are not systematic across studies, and sensitivity analyses are recommended routinely. Planning bias can be checked by comparing propensity to report contraceptive failures in different exposure groups. Medical intervention bias can be avoided by censoring and inclusion of unsuccessful pregnancy attempts. Truncation bias can be a serious problem if unrecognized, but it is avoidable with appropriate study design and/or analysis. Behavior change bias can be minimized by assessing the covariates at the beginning of unprotected intercourse. More complete inference is possible if the study design covers the whole population, not just those who achieve a pregnancy.