Abstract P1-08-04: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Trabert B, Bauer DC, Brinton LA, Buist DS, Cauley JA, Dallal CM, Gierach GL, Falk RT, Hue TF, Lacey, Jr. JV, LaCroix AZ, Tice JA, Xu X. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-08-04.

Abstract OT2-08-01: Personalized breast cancer screening in a population based study: Women Informed to Screen Depending On Measures of risk (WISDOM)

Background: WISDOM is a 100,000 healthy women preference-tolerant, pragmatic study comparing annual to personalized risk-based breast screening. The novelty of WISDOM personalized screening is the integration of previously validated genetic and clinical risk factors (age, family history, breast biopsy results, ethnicity, mammographic density) into a single risk assessment model that directs the starting age, timing, and frequency of screening. The goal of WISDOM is to determine if personalized screening, compared to annual screening, is as safe, less morbid, enables prevention, and is preferred by women. The study is registered on ClinicalTrials.gov, NCT02620852.

Methods: Women aged 40-74 years with no history of breast cancer or DCIS, and no previous double mastectomy can join the study online at wisdomstudy.org. Participants can elect randomization or self-select a study arm, and provide electronic consent and Release for Medical Information using DocuSign. For all participants, 5-year risk of developing breast cancer is calculated according to the Breast Cancer Screening Consortium (BCSC) model. Participants in the personalized arm undergo panel-based mutation testing, and their 5-year risk is calculated using the BCSC score combined with a Polygenic Risk Score (BCSC-PRS) that includes 75 single nucleotide polymorphisms (SNPs, increase to 229) known to increase breast cancer risk. SNPs and mutations (BRCA1, BRCA2, TP53, PTEN, STK11, CDH1, ATM, PALB2, and CHEK2) are assessed by saliva-based testing through Color Genomics. 5-year risk level thresholds are used to stratify for low-, moderate- and high risk. Risk stratification determines age to start, stop, and frequency of screening.

Enrollment: As of July 2018, the WISDOM study is open to all eligible women in California, North Dakota, South Dakota, Minnesota and Iowa. To date, 23,329 eligible women have registered and 14,393 women have consented to participate in the trial. We analyzed 3,255 participants who have completed risk assessment in the personalized arm. The median age was 56 years. 82% were Caucasian, 1% African-American, and 6% Asian. 9% self-reported as Hispanic. We are partnering with health insurers and self-insured companies using coverage with evidence progression. To strengthen generalizability, we are expanding to other states. WISDOM enrollment will continue past 2019.

Feasibility: To evaluate the addition of PRS, we used paired statistical tests (McNemar) to compare the distributions of BCSC, and BCSC-PRS risk estimates around low-risk (<1.3%), and very-high risk (>6%) thresholds, the latter corresponding to 5-year risk of a BRCA mutation carrier. The median 5-year risk was 1.5% (IQR 1.0-2.1%) using the BCSC model, and 1.4% (IQR 0.8-2.5%) using the BCSC-PRS model. The BCSC-PRS model classified more women into the low (<1%) and very high (≥6%) risk categories compared to the BCSC model (p < 0.001).

Conclusions: Our findings demonstrate that incorporating genetic variants into a validated clinical model is feasible and impacts risk classification compared to a model without genetic risk factors. Results at 5 years will reveal if this classification improves healthcare value by reducing screen volumes and costs without jeopardizing outcomes.

Citation Format: Acerbi I, Shieh Y, Madlensky L, Tice J, Ziv E, Eklund M, Blanco A, DeRosa D, Tong B, Goodman D, Nassereddine L, Anderson N, Harvey H, Layton T, Park HL, Petruse A, Stewart S, Wernisch J, Risty L, Koenig B, Sarrafan S, Firouzian R, Kaplan C, Hiatt R, Parker BA, Wenger N, Lee V, Heditsian D, Brain S, Stover Fiscalini A, Borowsky AD, Anton-Culver H, Naeim A, Kaster A, Talley M, van 't Veer LJ, LaCroix A, Wisdom Study and Athena Breast Health Network Investigators and Advocate Partners, Esserman LJ. Personalized breast cancer screening in a population based study: Women Informed to Screen Depending On Measures of risk (WISDOM) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-08-01.

Breast Density and Risk of Invasive Breast Cancer among Older Women Undergoing Mammography: The Breast Cancer Surveillance Consortium Cohort Study

This study examined whether breast density is associated with risk of breast cancer in women age ≥65 years undergoing screening mammography in community practice. Methods: We used prospective cohort data between 1996 and 2012 from the Breast Cancer Surveillance Consortium (BCSC). We calculated separate cumulative incidence models for breast cancer incidence according to Breast Imaging Reporting and Data System (BI-RADS) breast density for women ages 65–74 and ages ≥75. Multivariable Cox proportional hazards regression models were fitted to determine the risk of invasive breast cancer adjusted for BCSC registry, race/ethnicity, BMI, hormone therapy use and benign breast disease. Results: Among the 403,268 women included in the study, approximately 40% were ages ≥75. The annual incidence rate of invasive breast cancer increased with increasing breast density among women ages 65–74 [BI- RADS fatty breasts: 2.2% (95% CI, 2.1%–2.4%) vs. heterogeneously or extremely dense breasts: 4.7% (95% CI, 4.6%–4.9%)] and women ages 75+ [BI-RADS fatty breasts: 2.3% (95% CI, 2.1%–2.5%) vs. heterogeneously or extremely dense: 4.3% (95% CI, 4.1%–4.5%)]. Women with BI-RADS fatty breasts had a decreased risk of breast cancer among women ages 65–74 [HR: 0.66 (95% CI: 0.58%–0.78%) and women ages ≥75 [HR: 0.73 (95% CI: 0.62%–0.87%). Women with BI-RADS heterogeneously or extremely dense breasts were found to have increased risk of breast cancer among women ages 65–74 [HR: 1.39 (95% CI: 1.28%–1.51%)] and women ages ≥75 [HR: 1.23 (95% CI: 1.10%–1.37%)]. Conclusions: Older women with higher BI-RADS density had a significantly increased risk of breast cancer. These findings add further evidence that breast density continues to be associated with an increased risk of breast cancer, even among women age ≥75 years.

Abstract OT3-03-01: Preference-Tolerant randomized trial of risk-based vs. annual breast cancer screening: WISDOM study in progress

Purpose: Women Informed to Screen Depending on Measures of risk (WISDOM) trial is a pragmatic study comparing two real world approaches to clinical care for breast screening: annual screening versus personalized screening. The novelty of the personalized arm of the study is that we are combining known risk factors (age, family history, history of breast disease, ethnicity, BIRADS breast density, and genetics) into a single risk assessment model. All components of the model have been tested and established, but have never been used jointly.

The goal of the WISDOM study is to examine the effectiveness of personalized breast cancer screening and to bring objective recommendations to the current mammography screening debate.

Methods: The WISDOM trial will enroll 100,000 women with a preference-tolerant design that will determine if risk-based screening vs. annual screening, is as safe, less morbid, enables prevention, and is preferred by women. Women 40 - 74 years of age with no history of breast cancer or DCIS, and no previous double mastectomy can join the study from the WISDOM Study website (wisdomstudy.org). All participants sign up, elect randomization or self-select the study arm, provide electronic consent using DocuSign (eConsent), and sign a Medical Release Form. For all participants, 5-year risk of developing breast cancer is calculated according to the Breast Cancer Screening Consortium (BCSC) model. For participants in the personalized arm, the overall 5-year risk BCSC score is combined with a Polygenic Risk Score, based on a genetic test including mutations in 9 genes (BRCA1, BRCA2, TP53, PTEN, STK11, CDH1, ATM, PALB2, and CHEK2) and a panel of 75 common single nucleotide polymorphisms known to increase breast cancer risk. Risk stratification will determine frequency of screening. The study is registered on ClinicalTrials.gov as NCT02620852.

Results: As of June 12th 2017, the WISDOM study is live at all UC medical centers and recruitment is open to all eligible women in California. Up to date 4,769 eligible women registered at all sites. 2,823 women have consented in the trial. 64% were randomized and 36% chose their screening arm. A pilot was conducted to test the logistics of online participation and examine the acceptance of the study design and approach. We are partnering with health insurance companies and self-insured companies to reach our recruitment goal.

Conclusions: Enrollment will be completed by end of 2018.

Acknowledgment: support by the Patient-Centered Outcomes Research Institute (PCORI), PCS-1402-10749 to L.J.E.

(*) Authors equally contributed to this work.

Citation Format: Acerbi I, Abihider K, Ling J, Layton T, DeRosa D, Madlensky L, Tice J, Shieh Y, Ziv E, Sarrafan S, Firouzian R, Tong B, Blanco A, Lee V, Heditsian D, Brain S, Kaplan C, Borowsky A, Anton-Culver H, Naeim A, Cink T, Stover Fiscalini A, Parker B, van 't Veer L, Wisdom Study and Athena Breast Health Network Investigators and Advocate Partners, LaCroix A, Esserman L. Preference-Tolerant randomized trial of risk-based vs. annual breast cancer screening: WISDOM study in progress [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-03-01.

Abstract P3-09-02: Risk stratification using clinical risk factors and genetic variants in a personalized screening trial

Introduction: Tailoring breast cancer screening according to individual risk may represent an improvement over the current practice of age-based screening. WISDOM (Women Informed to Screen Depending on Measures of Risk) is an ongoing randomized trial comparing the safety, efficacy, cost, and patient acceptability of personalized versus annual screening. Women in the personalized arm receive screening recommendations based on sequencing of 9 genes associated with hereditary breast cancer and a 5-year risk estimate from the Breast Cancer Surveillance Consortium (BCSC) risk model modified by a polygenic risk score (PRS) comprised of 75 single nucleotide polymorphisms. WISDOM represents the first-ever use of a PRS to prospectively modify risk estimates and allows comparison of risk model performance in a population-based setting. Thus, we evaluated the risk estimates generated by: 1) the Breast Cancer Risk Assessment Tool (BCRAT) based on the Gail model, 2) the BCSC model, and 3) the BCSC model modified by the PRS (BCSC-PRS).

Methods: We analyzed participants in the personalized screening arm of the WISDOM Study (NCT02620852). The trial opened in October 2016 and is enrolling participants aged 40-74 years. Participants' self-reported demographic and risk factor information were collected through an online portal. Genotyping of participants in the personalized arm was done using a custom panel from Color Genomics. 5-year risk estimates were generated using the BCRAT (2011 version), BCSC, and BCSC-PRS models. In the latter, the PRS was used as a Bayesian likelihood ratio to modify the BCSC 5-year risk estimate. We compared the distributions of BCRAT, BCSC, and BCSC-PRS risk estimates around a low-risk (<1%) and moderately high-risk (≥3%) threshold using a paired statistical test (McNemar).

Results: To date, WISDOM has enrolled 2,065 participants, of whom 1,157 are in the personalized arm and 830 have completed risk assessment. The median age was 57 years (interquartile range, IQR 49-64). 83% were Caucasian, 2% African-American, and 7% Asian. 8% self-reported as Hispanic. The median 5-year risk was 1.7% (IQR 1.1-2.3%) using the BCRAT, 1.6% (IQR 1.1-2.3%) using the BCSC model, and 1.5% (IQR 0.9-2.7%) using the BCSC-PRS model. The BCSC-PRS model classified more women into the low (<1%) and moderately high (≥3%) risk categories compared with the BCRAT (p < 0.001) and BCSC model (p < 0.001), Table.

5-year risk classification according to the BCRAT, BCSC and BCSC-PRS models <1%1-3%≥3% n (%)n (%)n (%)Gail161 (19)556 (67)113 (14)BCSC159 (19)568 (68)103 (12)BCSC-PRS275 (33)379 (46)176 (21)

Discussion: Adding a PRS to the BCSC model categorized significantly more women below the low-risk threshold and above the moderately high-risk threshold compared with the BCSC model and BCRAT. Furthermore, the BCSC and BCRAT generated similar distributions of risk estimates. Follow-up with incident breast cancer data is needed to determine whether the reclassification provided by the PRS improves risk stratification and clinical outcomes. However, our preliminary findings suggest that incorporating genetic variants into a validated clinical model is feasible and could enhance risk prediction.

Citation Format: Shieh Y, Ziv E, Eklund M, Sabacan L, Firouzian R, Madlensky L, Anton-Culver H, Borowsky A, LaCroix A, Naeim A, Parker B, van't Veer L, Esserman L, Tice J, WISDOM Study and Athena Network Investigators WS. Risk stratification using clinical risk factors and genetic variants in a personalized screening trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-09-02.

Abstract P5-09-05: A model with polygenic risk score and mammographic density predicts interval cancers

Introduction:

Interval breast cancers present with clinical symptoms following a normal screening mammogram. They are associated with unfavorable biological features and with dense breasts. Models predictive of aggressive phenotypes may facilitate tailored screening for women at elevated risk of interval cancers. Polygenic risk scores (PRS) represent the cumulative effects of multiple single nucleotide polymorphisms (SNPs) and can be used to risk-stratify women. In prior reports, PRS is preferentially associated with screen-detected rather than interval cancers. We investigated methods to refine the PRS to preferentially predict interval cancers, and tested the performance of the PRS in joint models with mammographic breast density (MBD).

Methods:

We used data from 1058 breast cancer cases from The Cancer Genome Atlas (TCGA) as the discovery set for our PRS. We selected 107 SNPs from genomewide association studies of breast cancer risk for testing against tumor status at last follow-up in TCGA. Presence of tumor indicated recurrence, progression, or positive margins after resection. Women with tumor present at <100 days of follow-up were excluded. Suggestive associations (p<0.2) were used to construct a PRS, calculated as the sum across all SNPs of the per-allele log-odds ratio multiplied by the number of risk alleles for each SNP. We tested the performance of the PRS in a nested case-control dataset with 471 cases (102 interval cancers, 369 screen detected) and 496 controls from the California Pacific Medical Center Research Institute cohort. Logistic regression was used to evaluate the association between PRS, MBD and interval cancers. Area under the receiver operating characteristic (AUROC) curve was used to measure discrimination.

Results:

Of 107 SNPs, 23 had suggestive associations with presence of tumor at last follow-up in TCGA. The 23-SNP PRS discriminated between women with interval cancers and controls, with AUROC 0.57 (95% CI 0.51-0.63). With the inclusion of MBD in the model, the AUROC was 0.68 (95% CI 0.62-0.74). Women in the highest PRS quintile had an unadjusted 2.07-fold odds (95% CI 1.05-4.07) of developing interval cancers compared with women in the lowest quintile; adjustment for MBD did not change the point estimate. The PRS also discriminated between women with interval and screen-detected cancers, although the findings did not reach statistical significance (AUROC 0.55, 95% CI 0.48-0.61). With the inclusion of MBD in the model, the AUROC was 0.63 (95% CI 0.57-0.69).

Discussion:

A PRS associated with presence of tumor at last follow-up was independently predictive of interval cancers relative to controls. Models with PRS and MBD discriminated between interval and screen-detected cancers, although MBD provided most of the predictive power. Our findings are limited by the size and low number of recurrences in TCGA. It is possible that tumor status largely reflects treatment received, and may only partially represent the biological pathways of interval cancers. Our results suggest that SNPs may potentially identify women at risk for developing interval breast cancer, although further validation is required.

Citation Format: Shieh Y, Hu D, Huntsman S, Ma L, Gard CC, Leung JWT, Tice JA, Cummings SR, Kerlikowske K, Ziv E. A model with polygenic risk score and mammographic density predicts interval cancers [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-09-05.

Abstract P2-06-05: Development and validation of a new non-parametric breast cancer risk assessment model on US and European screening populations

Background: Stratified breast cancer (BC) prevention is a major option for the future but requires clinically meaningful internationally validated risk models. Non parametric models may be alternate methods for modeling in very large cohorts. We have previously shown that a non-parametric similarity-based k-nearest neighbors' (kNN) model performs better than the BCRAT/Gail model to on 65 000 women of the E3N French national cohort (Dartois et al 2015). We used this method to develop and validate a mammographic density-based model in larger general screening populations (pops).

Methods: A modified version of a data-mining based algorithm, the kNN method, was implemented and adapted as previously described [ref Dartois]. Core concept of kNN algorithm is to gather similar profiles using a distance computation.

We developed a BC risk prediction model on 629 229 women (wn) from the US Breast Cancer Research Consortium (BCSC), with 5 times random selection of learning and validation sets (75/25 %) within the cohort. 5 parameters were included: age, family history, previous breast biopsy, mammographic density and race. The model's performances (discrimination using c-stat (AUC) and calibration using E/0 ratio) were evaluated and compared to the parametric model developed on the same pop (param/BCSC)(Tice et al 2008). This kNN/BCSC model was then tested on two French screening pops after adjustment on French BC incidence: an urban area (Paris suburbs, N=316 775) and a rural area (Côte d'Or, N=32 930). Its performances were compared to those of a model directly developed (same methods) on the Paris cohort (kNN/Paris). Levels of individual risks assessed by the models were assigned into 4 risk categories. The sensitivity of the models was defined as the number of wn who had BC whose 5 yrs-risk category was intermediate (median risk at 50-yrs - 1.66%), high (> 1.66%) or very high (> 20% lifetime) divided by the total number of wn who had BC.

Results: The performances of the different models are shown in Table 1. The kNN model developed on BCSC performed well (c-stat 0.653 and E/0 1.001). It had equivalent performances as the parametric model developed previously on the same pop. This kNN/BCSC had a good discrimination on French pops, although slightly lower than that on US pops. This is expected since French screening starts at 50 (vs 40 in BCSC) and French parameters do not include race. The calibration of such model was excellent on Paris, while it overestimated the risk on Côte d'Or, in which BC incidence is lower. It performed as well as the kNN/Paris model directly developed on Paris' pop. The sensitivity of the kNN/BCSC on US and French pops was good.

Conclusions: A new non parametric kNN breast cancer risk model developed on an American screening cohort (BCSC) was successfully validated on two French screening cohorts. This new international model could allow stratified prevention.

Performances of the models Param/BCSC on BCSCParam/BCSC on PariskNN/BCSC on BCSCkNN/BCSC on PariskNN/BCSC on Cote d'OrkNN/Paris on ParisN629 229313 817629 229313 81732 930313 817c-statistic0.6580.6020.6530.6020.5930.605E/0 global1.031.071.0011.061.521.00Sensitivity--76.18%72.87%72.58%-

Citation Format: Ragusa S, Gauthier E, Dartois L, Tice J, Dancourt V, Arveux P, Brixi Z, Bernoux A, Soyer P, Delattre H, Brechenade S, Catajar N, Kaufmanis A, Hélin VM, Clavel F, Kerlikowske K, Miglioretti D, Delaloge S. Development and validation of a new non-parametric breast cancer risk assessment model on US and European screening populations [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-06-05.

Abstract P6-02-08: Breast cancer screening in the precision medicine era

We are entering the era of precision medicine in which cancer screening, prevention and treatment will be tailored to each individual. The progress made in this field is due, in part, to advances in our understanding of cancer risk and tumor biology. The challenge before us is to harness this knowledge and apply it in the clinical setting. Breast cancer screening provides an excellent opportunity to test the value of precision medicine in the real world. In this report we describe the process of designing a model of personalized breast cancer screening.

Methods

Risk factors were selected that have the greatest impact, have been validated and can be measured across a population. A risk model was selected that is highly calibrated, has been validated in a large screening cohort and is easy to apply in a large population of women. An expert committee was convened that set risk thresholds for stratifying women into groups that will be recommended to undergo biennial, annual or every six month screening. Risk thresholds and screening schedules are in accordance with the United States Preventive Services Task Force breast cancer screening recommendations.

Results

Risk factors: Age, race/ethnicity, personal history of breast biopsies and benign breast disease, family history, breast density and breast cancer-associated genetic mutations and single nucleotide polymorphisms (SNPs) were chosen as the risk factors that will be used to determine breast cancer risk. Risk model: The Breast Cancer Surveillance Consortium risk model will be used to calculate a woman's 5-year risk and will be modified by a polygenic risk score based on 81 SNPs. Risk thresholds: Women will be recommended to undergo biennial screening mammography when they reach the age of 50 or have the risk of an average 50 year-old woman (1.3% 5-year risk). Women will be advised to undergo annual screening if they are at increased risk of developing an interval cancer (women in their forties with extremely dense breasts and women at increased risk of developing estrogen receptor negative breast cancer based on their SNPs). Women will be recommended to undergo annual mammography and annual MRI if they are found to be gene mutation positive, have the risk of a BRCA1 mutation carrier (6% 5-year risk) or have a history of mantle radiation.

Discussion

Selecting the appropriate risk factors and risk model and determining risk thresholds are key components of designing a personalized breast cancer screening model. Personalized screening may be the way forward, but this can only be determined within the setting of a randomized controlled trial. We will conduct such a trial to determine if personalized screening is as safe as, less morbid than, more preferred by women than and enables prevention when compared to annual screening. The WISDOM (Women Informed to Screen Depending on Measures of risk) study will compare risk-based screening to annual screening within the Athena Breast Health Network with support from the Patient-Centered Outcomes Research Institute. Our intent is that this trial will provide us with the data that we need to determine the safest and most effective way to screen women for breast cancer in the era of precision medicine.

Citation Format: Thompson CK, Fiscalini AS, Donnellan P, Kaplan CP, Madlensky L, Eklund M, Ziv E, van't Veer LJ, Tice JA, Esserman LJ. Breast cancer screening in the precision medicine era. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-02-08.

The Effect of Weight Change on Volumetric Measures of Mammographic Density

The association between changing body mass index (BMI) and mammographic breast density is important to better evaluate how to adjust for BMI gain/loss in longitudinal studies of density and breast cancer risk. Increasing BMI has been associated with decreasing percent dense area but the effect on absolute dense area is unclear. No studies have explored a longitudinal association using volumetric density measurement. Methods: We examined the association between change in BMI and change in volumetric breast density among 24,556 women who received breast imaging at the San Francisco Mammography Registry from 2007–2013. Height and weight were self-reported at the time of mammography. Breast density was assessed using single x-ray absorptiometry (SXA) volumetric measurement. The cross-sectional and longitudinal associations between BMI and absolute dense volume (DV) and percent dense volume (PDV) were assessed using multivariable adjusted regression. Results: Women were primarily Caucasian (66%) or Asian (25%) and most were postmenopausal (64%) at time of first mammogram. In cross-sectional analysis, BMI was positively associated with DV (β = 2.95 cm3, 95% CI, 2.69–3.21) and inversely associated with PDV (β = −2.03%, 95% CI, −2.09–−1.98). In longitudinal analysis, an annual increase in BMI was associated with an annual decrease in both DV (β = −1.01 cm3/year, 95% CI, −1.59–−0.42) and PDV (β = −1.17%/year, 95% CI, −1.31–−1.04). Findings were consistent between pre- and postmenopausal women. The annual decrease in DV was strongest among premenopausal women who were initially overweight or obese (P < 0.01 for interaction by initial BMI). Conclusion: Our findings support an inverse association between change in BMI and change in PDV. Longitudinal studies of PDV and breast cancer risk, or those using PDV as an indicator of breast cancer risk, should consider adjusting for change in BMI. The association between increasing BMI and decreasing DV is unexpected and will require confirmation using volumetric methods.

Pathophysiology of acute small bowel disease with CT correlation

The objective of this article is to review the pathophysiology of acute small bowel diseases, and to correlate the mechanisms of disease with computed tomography (CT) findings. Disease entities will be classified into the following: immune mediated and infectious causes, vascular causes, mechanical causes, trauma, and others. Having an understanding of acute small bowel pathophysiology is a useful teaching tool, and can lead to imaging clues to the most likely diagnosis of acute small bowel disorders.

Phytoestrogens and healthy aging: gaps in knowledge. A workshop report

There is an increasing public interest in foods and dietary supplements containing phytoestrogens for the maintenance of health. A workshop was convened to assess evidence for the potential benefits of phytoestrogen-containing foods or supplements on diseases or conditions affecting older populations. Preclinical, clinical, and epidemiologic data on the cardiovascular system, various cancers, bone diseases, and menopausal symptoms were the focus of the discussions. Research on the basis of consumer food choices as well as a presentation from the FDA regarding approval of the use of soy foods to reduce the risk of cardiovascular disease were also presented. Based on the information presented, isoflavone-containing soy foods may have favorable effects on the cardiovascular system, but major knowledge gaps still exist regarding effects ofphytoestrogen supplements on bone diseases, various cancers, menopausal symptoms, and cognitive function.

Cost-effectiveness of vitamin therapy to lower plasma homocysteine levels for the prevention of coronary heart disease: effect of grain fortification and beyond

CONTEXT

A high homocysteine level has been identified as an independent modifiable risk factor for coronary heart disease (CHD) events and death. Since January 1998, the US Food and Drug Administration has required that all enriched grain products contain 140 microg of folic acid per 100 g, a level considered to decrease homocysteine levels.

OBJECTIVES

To examine the potential effect of grain fortification with folic acid on CHD events and to estimate the cost-effectiveness of additional vitamin supplementation (folic acid and cyanocobalamin) for CHD prevention.

DESIGN AND SETTING

Cost-effectiveness analysis using the Coronary Heart Disease Policy Model, a validated, state-transition model of CHD events in adults aged 35 through 84 years. Data from the third National Health and Nutrition Examination Survey (NHANES III) were used to estimate age- and sex-specific differences in homocysteine levels.

INTERVENTION

Hypothetical comparison between a diet that includes enriched grain products projected to increase folic acid intake by 100 microg/d with the same diet without folic acid fortification; and a comparison between vitamin therapy that consists of 1 mg of folic acid and 0.5 mg of cyanocobalamin and the diet that includes grains fortified with folic acid.

MAIN OUTCOME MEASURES

Incidence of myocardial infarction and death from CHD, quality-adjusted life-years (QALYs) saved, and medical costs.

RESULTS

Grain fortification with folic acid was predicted to decrease CHD events by 8% in women and 13% in men, with comparable reductions in CHD mortality. The model projected that, compared with grain fortification alone, treating all patients with known CHD with folic acid and cyanocobalamin over a 10-year period would result in 310 000 fewer deaths and lower costs. Over the same 10-year period, providing vitamin supplementation in addition to grain fortification to all men aged 45 years or older without known CHD was projected to save more than 300 000 QALYs, to save more than US $2 billion, and to be the preferred strategy. For women without CHD, the preferred vitamin supplementation strategy would be to treat all women older than 55 years, a strategy projected to save more than 140 000 QALYs over 10 years.

CONCLUSIONS

Folic acid and cyanocobalamin supplementation may be cost-effective among many population subgroups and could have a major epidemiologic benefit for primary and secondary prevention of CHD if ongoing clinical trials confirm that homocysteine-lowering therapy decreases CHD event rates.

Relation of serum ascorbic acid to mortality among US adults

PURPOSE

To examine the relation between serum ascorbic acid (SAA), a marker of dietary intake (including supplements), and cause-specific mortality.

SUBJECTS AND METHODS

We analyzed data from a probability sample of 8,453 Americans age > or = 30 years at baseline enrolled in the Second National Health and Nutrition Examination Survey (NHANES II), who were followed for mortality endpoints. We calculated relative hazard ratios as measures of disease association comparing the mortality rates in three biologically relevant SAA categories.

RESULTS

Participants with normal to high SAA levels had a marginally significant 21% to 25% decreased risk of fatal cardiovascular disease (CVD) (p for trend = 0.09) and a 25% to 29% decreased risk of all-cause mortality (p for trend <0.001) compared to participants with low levels. Because we determined that gender modified the association between SAA levels and cancer death, we analyzed these associations stratified by gender. Among men, normal to high SAA levels were associated with an approximately 30% decreased risk of cancer deaths, whereas such SAA levels were associated with an approximately two-fold increased risk of cancer deaths among women. This association among women persisted even after adjustment for baseline prevalent cancer and exclusion for early cancer death or exclusion for prevalent cancer.

CONCLUSIONS

Low SAA levels were marginally associated with an increased risk of fatal CVD and significantly associated with an increased risk for all-cause mortality. Low SAA levels were also a risk factor for cancer death in men, but unexpectedly were associated with a decreased risk of cancer death in women. If the association between low SAA levels and all-cause mortality is causal, increasing the consumption of ascorbic acid, and thereby SAA levels, could decrease the risk of death among Americans with low ascorbic acid intakes.

Double crystals

The lowest-energy way to enclose and separate two planar regions of prescribed areas is found, where the energy is given by the l1 norm ('Manhattan metric'), in which horizontal and vertical directions use less energy than other directions, as in some crystals. With the assumption that interfaces carry a fraction lambda of the energy of exterior faces, it is proved that there are three possible types of energy-minimizing double crystals. The dependence of these three types of lambda as well as the ratio of the areas of the two regions is discussed, and some paths for further study are suggested.

Effect of serotesting with counselling on condom use and seroconversion among HIV discordant couples in Africa

OBJECTIVE

To determine whether HIV testing and counselling increased condom use and decreased heterosexual transmission of HIV in discordant couples.

DESIGN

Prospective study.

SETTING

Kigali, the capital of Rwanda.

SUBJECTS

Cohabiting couples with discordant HIV serology results.

MAIN OUTCOME MEASURES

Condom use in the couple and HIV seroconversion in the negative partners.

RESULTS

60 HIV discordant couples were identified, of whom 53 were followed for an average of 2.2 years. The proportion of discordant couples using condoms increased from 4% to 57% after one year of follow up. During follow up two of the 23 HIV negative men and six of the 30 HIV negative women seroconverted (seroconversion rates of 4 and 9 per 100 person years). The rate among women was less than half that estimated for similar women in discordant couples whose partners had not been serotested. Condom use was less common among those who seroconverted (100% v 5%, p = 0.01 in men; 67% v 25%, p = 0.14 in women).

CONCLUSIONS

Roughly one in seven cohabiting couples in Kigali have discordant HIV serological results. Confidential HIV serotesting with counselling caused a large increase in condom use and was associated with a lower rate of new HIV infections. HIV testing is a promising intervention for preventing the spread of HIV in African cities.

Knowledge, attitudes, and perceived risk of AIDS among urban Rwandan women: relationship to HIV infection and behavior change

We examined factors associated with perceived risk of AIDS, behavior change, and HIV infection in a representative sample of 1458 child-bearing urban women in Rwanda, central Africa. Although 68% of women reported only one lifetime partner, and the majority (87%) lived with a husband or steady partner, the prevalence of HIV antibodies was still high (32%). Before receiving their HIV test results, the women completed a questionnaire about AIDS knowledge, attitudes, and practices. Knowledge about HIV transmission was high, with 96-98% of women correctly identifying the three primary routes of infection. However, only 16% of women reported taking any action to avoid AIDS in the previous year, and most (11%) had done so merely by asking their male partners to change their behavior. Only 7% of women had ever tried condoms, and many (68%) thought they could be dangerous to use. Women who perceived themselves at risk of AIDS (57%) were more likely to report changing behavior; they were also more likely to be infected with HIV. Other factors associated with behavior change included having known someone with AIDS, having discussed AIDS with a male partner, and believing that condoms are not dangerous. Future interventions should enhance perception of risk, encourage male sexual partners to reduce risky behavior, and increase familiarity with condoms.

Human immunodeficiency virus and malaria in a representative sample of childbearing women in Kigali, Rwanda

In 1986-1987 a consecutive sample of 3702 women presenting to prenatal and pediatric clinics at the only hospital in Kigali, Rwanda, was screened for human immunodeficiency virus (HIV) and malaria infection. The prevalence of HIV antibodies was 29%, and that of malaria parasites was 9%. HIV antibodies were more prevalent in women from the urban center than in those from the outskirts (31% vs. 20%, P less than .001), and malaria parasites showed the opposite prevalence pattern (8% vs. 15%, P less than .001); after stratifying by location, there was no association between HIV and the presence or degree of malaria parasitemia. HIV prevalence was 45% in women who had received a blood transfusion between 1980-1985 (before screening of donated blood began), and 28% among the great majority (94%) who had never been transfused. HIV prevalence was 44% in single mothers. 34% in women in common law unions, and 20% in those in legal marriages. These high rates of infection in the general population of Kigali highlight the need to develop effective programs for preventing further spread of sexually transmitted HIV.

What if Americans ate less fat? A quantitative estimate of the effect on mortality

Americans consume an average of 37% of their energy intake as fat. Many authorities recommend restricting fat intake to 30% of energy intake to reduce the rates of coronary heart disease and perhaps of cancers of the breast, colon, and prostate. Based on the assumptions that underlie those recommendations, we estimated the effect of this dietary change on mortality. If all Americans restricted their intake of dietary fat by reducing consumption of saturated fat and accompanying dietary cholesterol, the corresponding reductions in serum cholesterol levels could reduce coronary heart disease mortality rates by 5% to 20%, depending on age. If the relationship between dietary fat and cancer is as strong as has been observed in some studies, the proportional effects on mortality from fat-related cancers could be even greater, although the absolute effects--given the lower mortality rates--would be smaller. Overall, if the assumptions are correct, about 42,000 of the 2.3 million deaths that would have occurred in adults each year in the United States could be deferred. This 2% benefit, equivalent to an increase in average life expectancy of 3 to 4 months, would accrue chiefly to people over the age of 65 years. If recent concerns about the possibly harmful effects of cholesterol lowering on mortality from noncardiovascular causes--which mainly affect younger persons--are valid, these relatively modest benefits would be overestimates of the actual effect.