Assessing knowledge and confidence of surgical residents in inguinal hernia repair using a low-cost synthetic model

PURPOSE

Open repair of groin hernia is an essential skill for the general surgeon. This study aimed to develop a low-cost hernia model based on a validated high-fidelity model and assess its effectiveness in teaching inguinal hernia repair to surgical trainees from many institutions throughout Africa.

METHODS

Using inexpensive, locally available materials, a low-cost hernia model was created. Six models were constructed, and a workshop was conducted for surgical residents. Pre- and post-workshop surveys were administered to assess knowledge, confidence, and understanding. Statistical analyses were performed using paired t tests and the Wilcoxon signed-rank test.

RESULTS

The low-cost hernia model consisted of various readily available materials and cost an average of $5.07. Sixty-eight trainees participated in the workshop, and 59 completed the post-workshop survey. Participants reported a significant increase in confidence for both mesh and non-mesh repairs and an improved understanding of hernia anatomy after the workshop. Trainees scored an average of 5.6 (SD 1.9) out of 10 questions on the pre-workshop quiz and 7.9 (SD 1.4) out of 10 on the post-workshop quiz (p < 0.001), indicating improved knowledge. All trainees supported the use of the model for education.

CONCLUSION

The low-cost hernia model demonstrated its effectiveness in enhancing trainees' understanding of hernia anatomy and increasing their confidence in hernia repair. Integrating low-cost hernia models into training programs can help improve trainees' knowledge and confidence in a safe and affordable environment.

An Analysis of Factors Related to Care Engagement along the Cancer Survivorship Care Continuum for Cancer Survivors in Florida

PURPOSE

This study identifies factors associated with care engagement along the cancer survivorship care continuum for Floridians.

METHODS

We identified patients from the OneFlorida Data Trust with a cancer diagnosis at any age and encounters from 2012-2020. Multivariable logistic regression models produced odds ratios (OR) predicting 1) any outpatient non-acute care visit, 2) cancer-related visit with any provider, 3) cancer-related visit with a cancer provider, and 4) survivorship visit with a cancer provider. Encounter-based independent variables were insurance, Social Deprivation Index quartile, and Rural Urban Continuum Area (adjusted for age, sex, race, ethnicity, and treatment).

RESULTS

662,489 survivors were included in the sample. Those with Medicaid and dual eligible status (Medicare and Medicaid) were more likely to have an outpatient visit (Medicaid OR 2.02, 95%CI 1.93-2.12; dual eligible 3.06, 2.91-3.22) or a cancer-related visit with a cancer provider (Medicaid 1.82, 1.77-1.86; dual eligible 1.32, 1.28-1.35), and less likely to have a survivorship visit (Medicaid 0.27, 0.26-0.28; dual eligible 0.20, 0.19-0.21). Uninsured survivors were less likely to have all visit types, while those with Medicare were more likely. Those from the most socially deprived areas were more likely to have an outpatient visit (1.09, 1.03-1.14) and less likely to have a cancer-related visit with any provider (0.90, 0.88-0.92) or a cancer provider (0.93, 0.91-0.95). Survivors from non-metropolitan areas were more likely to have an outpatient visit (1.38, 1.22-1.56), cancer-related visit (1.22, 1.16-1.28), cancer-related visit with a cancer provider (1.45, 1.39-1.52), and a survivorship visit (1.34, 1.22-1.48).

CONCLUSIONS

Survivors who have public insurance are more likely to have outpatient visits, and those with Medicaid or dual eligible status are less likely to have survivorship visits. Uninsured status is consistently associated with lack of engagement across the care continuum. Those from areas with higher social deprivation are more likely to have outpatient visits, but less likely to have a cancer-related visit with or without a cancer provider. Survivors from non-metropolitan areas are more likely to engage in all visit types along the care continuum.

The role of surface energy heterogeneity on crystal morphology during solid-state crystallization at the amorphous atazanavir–water interface

Solid-state crystallization at the amorphous atazanavir/water interface was studied via a lattice Monte Carlo model and atomic force microscopy.

Biomechanical Comparison of 3 Syndesmosis Repair Techniques With Suture Button Implants

Background:

Suture button fixation of syndesmotic injury is growing in popularity, as it has been shown to provide adequate stability in a more cost-effective manner than screw fixation while allowing more physiologic distal tibiofibular joint motion. However, the optimal repair technique and implant orientation have yet to be determined.

Purpose/Hypothesis:

The purpose of this study was to biomechanically compare 3 suture button construct configurations/orientations for syndesmosis fixation: single, parallel, and divergent. The authors hypothesized that all 3 methods would provide adequate stabilization but that the divergent technique would be the most stable.

Study Design:

Controlled laboratory study.

Methods:

The fixation strengths of 3 stabilization techniques with suture button devices were compared with 10 cadaveric legs each (N = 30). Ankle motion under cyclic loading was measured in multiple planes: first in the intact state, then following simulated syndesmosis injury, and then following fixation with 1 of 3 randomly assigned constructs—1 suture button, 2 suture buttons in parallel, and 2 divergent suture buttons. Finally, axial loading with external rotation was applied to failure.

Results:

All syndesmotic fixation methods provided stability to the torn state. There was no statistically significant difference among the 3 fixation techniques in biomechanical stability. Failure most commonly occurred through fibular fracture at supraphysiologic loads.

Conclusion:

Suture button implant fixation for syndesmotic injury appears to provide stability to the torn syndesmosis, and the configuration of the fixation does not appear to affect the strength or security of the stabilization.

Clinical Relevance:

This study provides further insight into the biomechanics and optimal configuration of suture button fixation of the torn syndesmosis. Based on these results, the addition of a second suture button may not significantly contribute to immediate postoperative stability.

Differential gene expression profiling of matched primary renal cell carcinoma and metastases reveals upregulation of extracellular matrix genes

Background

The majority of renal cell carcinoma (RCC) studies analyze primary tumors, and the corresponding results are extrapolated to metastatic RCC tumors. However, it is unknown if gene expression profiles from primary RCC tumors differs from patient-matched metastatic tumors. Thus, we sought to identify differentially expressed genes between patient-matched primary and metastatic RCC tumors in order to understand the molecular mechanisms underlying the development of RCC metastases.

Patients and methods

We compared gene expression profiles between patient-matched primary and metastatic RCC tumors using a two-stage design. First, we used Affymetrix microarrays on 15 pairs of primary RCC [14 clear cell RCC (ccRCC), 1 papillary] tumors and patient-matched pulmonary metastases. Second, we used a custom NanoString panel to validate seven candidate genes in an independent cohort of 114 ccRCC patients. Differential gene expression was evaluated using a mixed effect linear model; a random effect denoting patient was included to account for the paired data. Third, The Cancer Genome Atlas (TCGA) data were used to evaluate associations with metastasis-free and overall survival in primary ccRCC tumors.

Results

We identified and validated up regulation of seven genes functionally involved in the formation of the extracellular matrix (ECM): DCN, SLIT2, LUM, LAMA2, ADAMTS12, CEACAM6 and LMO3. In primary ccRCC, CEACAM6 and LUM were significantly associated with metastasis-free and overall survival (P < 0.01).

Conclusions

We evaluated gene expression profiles using the largest set to date, to our knowledge, of patient-matched primary and metastatic ccRCC tumors and identified up regulation of ECM genes in metastases. Our study implicates up regulation of ECM genes as a critical molecular event leading to visceral, bone and soft tissue metastases in ccRCC.

High-resolution profiling of histone h3 lysine 36 trimethylation in metastatic renal cell carcinoma

Mutations in SETD2, a histone H3 lysine trimethyltransferase, have been identified in clear cell renal cell carcinoma (ccRCC); however it is unclear if loss of SETD2 function alters the genomic distribution of histone 3 lysine 36 trimethylation (H3K36me3) in ccRCC. Furthermore, published epigenomic profiles are not specific to H3K36me3 or metastatic tumors. To determine if progressive SETD2 and H3K36me3 dysregulation occurs in metastatic tumors, H3K36me3, SETD2 copy number (CN) or SETD2 mRNA abundance was assessed in two independent cohorts: metastatic ccRCC (n=71) and the Cancer Genome Atlas Kidney Renal Clear Cell Carcinoma data set (n=413). Although SETD2 CN loss occurs with high frequency (>90%), H3K36me3 is not significantly impacted by monoallelic loss of SETD2. H3K36me3-positive nuclei were reduced an average of ~20% in primary ccRCC (90% positive nuclei in uninvolved vs 70% positive nuclei in ccRCC) and reduced by ~60% in metastases (90% positive in uninvolved kidney vs 30% positive in metastases) (P<0.001). To define a kidney-specific H3K36me3 profile, we generated genome-wide H3K36me3 profiles from four cytoreductive nephrectomies and SETD2 isogenic renal cell carcinoma (RCC) cell lines using chromatin immunoprecipitation coupled with high-throughput DNA sequencing and RNA sequencing. SETD2 loss of methyltransferase activity leads to regional alterations of H3K36me3 associated with aberrant RNA splicing in a SETD2 mutant RCC and SETD2 knockout cell line. These data suggest that during progression of ccRCC, a decline in H3K36me3 is observed in distant metastases, and regional H3K36me3 alterations influence alternative splicing in ccRCC.

Mapping the Pareto optimal design space for a functionally deimmunized biotherapeutic candidate

The immunogenicity of biotherapeutics can bottleneck development pipelines and poses a barrier to widespread clinical application. As a result, there is a growing need for improved deimmunization technologies. We have recently described algorithms that simultaneously optimize proteins for both reduced T cell epitope content and high-level function. In silico analysis of this dual objective design space reveals that there is no single global optimum with respect to protein deimmunization. Instead, mutagenic epitope deletion yields a spectrum of designs that exhibit tradeoffs between immunogenic potential and molecular function. The leading edge of this design space is the Pareto frontier, i.e. the undominated variants for which no other single design exhibits better performance in both criteria. Here, the Pareto frontier of a therapeutic enzyme has been designed, constructed, and evaluated experimentally. Various measures of protein performance were found to map a functional sequence space that correlated well with computational predictions. These results represent the first systematic and rigorous assessment of the functional penalty that must be paid for pursuing progressively more deimmunized biotherapeutic candidates. Given this capacity to rapidly assess and design for tradeoffs between protein immunogenicity and functionality, these algorithms may prove useful in augmenting, accelerating, and de-risking experimental deimmunization efforts.

Protein therapeutics have created a revolution in disease therapy, providing improved outcomes for prevalent illnesses and conditions while at the same time yielding treatments for diseases that were previously intractable. However, this powerful class of drugs is subject to their own unique challenges and risk factors. In particular, the biological origins of therapeutic proteins predispose them towards eliciting a detrimental immune response from the patient's own body. Therefore, fully capitalizing on the medicinal reservoir of natural and engineered proteins will require efficient, effective, and broadly applicable deimmunization technologies. We have developed deimmunization algorithms that simultaneously optimize therapeutic candidates for both low immunogenicity and high-level activity and stability. Here, we combine computational modeling and experimental analysis to show that the process of protein deimmunization manifests inherent tradeoffs between immunogenic potential and biomolecular function. Our experimental results demonstrate that dual objective optimization allows us to assess and design for these tradeoffs, thereby enabling facile construction of deimmunized variants that span a broad range of immunogenicity and functionality performance parameters. Thus, we can rapidly map the design space for deimmunized drug candidates, and we can use this information to guide selection of engineered proteins that are most likely to meet performance benchmarks for a given clinical application.

Measurement of ulnar variance from the lateral radiograph: a comparison of techniques

PURPOSE

To determine the reliability of measuring ulnar variance on lateral wrist radiographs and to compare this technique with previously described methods.

METHODS

Ulnar variance was measured in 100 normal wrist radiographs using the methods of perpendiculars, central reference point, and the lateral radiograph by 3 surgeons on 2 occasions. Intraobserver repeatability and agreement between raters and methods were assessed and compared.

RESULTS

Intra- and interobserver reliability and agreement were both excellent using all 3 methods within a ± 1.0-mm cutoff. However, there was substantial pairwise disagreement in measures of ulnar variance between all 3 methods.

CONCLUSIONS

This study demonstrates that, for measurement of ulnar variance, the methods of perpendiculars, central reference point, and lateral radiographic measurement each have clinically acceptable intraobserver repeatability and interobserver agreement. Despite their independent reliability, each method of radiographic determination of ulnar variance had considerable disagreement with the other methods, indicative of inherent inaccuracies in the techniques. The lateral radiograph uniquely allows for visualization of the amount of ulnar head protruding proximal or distal to the concave lunate facet and allows for a rapid estimation of pronosupination, which is known to affect ulnar variance.

CLINICAL RELEVANCE

Determination of ulnar variance can be an important component of surgical decision making in various pathological conditions of the hand and wrist. Traditionally, it has been measured through methods using the posteroanterior wrist radiograph, but there are potential shortcomings with these methods, and use of the lateral radiograph may provide a more clinically relevant picture of ulnar variance. This study shows that measurement from the lateral radiograph provides similar reliability to previously accepted techniques.

Structure-guided deimmunization of therapeutic proteins

Therapeutic proteins continue to yield revolutionary new treatments for a growing spectrum of human disease, but the development of these powerful drugs requires solving a unique set of challenges. For instance, it is increasingly apparent that mitigating potential anti-therapeutic immune responses, driven by molecular recognition of a therapeutic protein's peptide fragments, may be best accomplished early in the drug development process. One may eliminate immunogenic peptide fragments by mutating the cognate amino acid sequences, but deimmunizing mutations are constrained by the need for a folded, stable, and functional protein structure. These two concerns may be competing, as the mutations that are best at reducing immunogenicity often involve amino acids that are substantially different physicochemically. We develop a novel approach, called EpiSweep, that simultaneously optimizes both concerns. Our algorithm identifies sets of mutations making such Pareto optimal trade-offs between structure and immunogenicity, embodied by a molecular mechanics energy function and a T-cell epitope predictor, respectively. EpiSweep integrates structure-based protein design, sequence-based protein deimmunization, and algorithms for finding the Pareto frontier of a design space. While structure-based protein design is NP-hard, we employ integer programming techniques that are efficient in practice. Furthermore, EpiSweep only invokes the optimizer once per identified Pareto optimal design. We show that EpiSweep designs of regions of the therapeutics erythropoietin and staphylokinase are predicted to outperform previous experimental efforts. We also demonstrate EpiSweep's capacity for deimmunization of the entire proteins, case analyses involving dozens of predicted epitopes, and tens of thousands of unique side-chain interactions. Ultimately, Epi-Sweep is a powerful protein design tool that guides the protein engineer toward the most promising immunotolerant biotherapeutic candidates.

Experimental designs for array comparative genomic hybridization technology

Array comparative genomic hybridization (aCGH) technology is commonly used to estimate genome-wide copy-number variation and to evaluate associations between copy number and disease. Although aCGH technology is well developed and there are numerous algorithms available for estimating copy number, little attention has been paid to the important issue of the statistical experimental design. Herein, we review classical statistical experimental designs and discuss their relevance to aCGH technology as well as their importance for downstream statistical analyses. Furthermore, we provide experimental design guidance for various study objectives.

Design and analysis of immune-evading enzymes for ADEPT therapy

The unparalleled specificity and activity of therapeutic proteins has reshaped many aspects of modern clinical practice, and aggressive development of new protein drugs promises a continued revolution in disease therapy. As a result of their biological origins, however, therapeutic proteins present unique design challenges for the biomolecular engineer. For example, protein drugs are subject to immune surveillance within the patient's body; this anti-drug immune response can compromise therapeutic efficacy and even threaten patient safety. Thus, there is a growing demand for broadly applicable protein deimmunization strategies. We have recently developed optimization algorithms that integrate computational prediction of T-cell epitopes and bioinformatics-based assessment of the structural and functional consequences of epitope-deleting mutations. Here, we describe the first experimental validation of our deimmunization algorithms using Enterobacter cloacae P99 β-lactamase, a component of antibody-directed enzyme prodrug cancer therapies. Compared with wild-type or a previously deimmunized variant, our computationally optimized sequences exhibited significantly less in vitro binding to human type II major histocompatibility complex immune molecules. At the same time, our globally optimal design exhibited wild-type catalytic proficiency. We conclude that our deimmunization algorithms guide the protein engineer towards promising immunoevasive candidates and thereby have the potential to streamline biotherapeutic development.

Optimization of combinatorial mutagenesis

Protein engineering by combinatorial site-directed mutagenesis evaluates a portion of the sequence space near a target protein, seeking variants with improved properties (e.g., stability, activity, immunogenicity). In order to improve the hit-rate of beneficial variants in such mutagenesis libraries, we develop methods to select optimal positions and corresponding sets of the mutations that will be used, in all combinations, in constructing a library for experimental evaluation. Our approach, OCoM (Optimization of Combinatorial Mutagenesis), encompasses both degenerate oligonucleotides and specified point mutations, and can be directed accordingly by requirements of experimental cost and library size. It evaluates the quality of the resulting library by one- and two-body sequence potentials, averaged over the variants. To ensure that it is not simply recapitulating extant sequences, it balances the quality of a library with an explicit evaluation of the novelty of its members. We show that, despite dealing with a combinatorial set of variants, in our approach the resulting library optimization problem is actually isomorphic to single-variant optimization. By the same token, this means that the two-body sequence potential results in an NP-hard optimization problem. We present an efficient dynamic programming algorithm for the one-body case and a practically-efficient integer programming approach for the general two-body case. We demonstrate the effectiveness of our approach in designing libraries for three different case study proteins targeted by previous combinatorial libraries--a green fluorescent protein, a cytochrome P450, and a beta lactamase. We found that OCoM worked quite efficiently in practice, requiring only 1 hour even for the massive design problem of selecting 18 mutations to generate 10⁷ variants of a 443-residue P450. We demonstrate the general ability of OCoM in enabling the protein engineer to explore and evaluate trade-offs between quality and novelty as well as library construction technique, and identify optimal libraries for experimental evaluation.

Optimization of therapeutic proteins to delete T-cell epitopes while maintaining beneficial residue interactions

Exogenous enzymes, signaling peptides, and other classes of nonhuman proteins represent a potentially massive but largely untapped pool of biotherapeutic agents. Adapting a foreign protein for therapeutic use poses numerous design challenges. We focus here on one significant problem: modifying the protein to mitigate the immune response mounted against "non-self" proteins, while not adversely affecting the protein's stability or therapeutic activity. In order to propose such variants suitable for experimental evaluation, this paper develops a computational method to select sets of mutations predicted to delete immunogenic T-cell epitopes, as evaluated by a 9-mer potential, while simultaneously maintaining important residues and residue interactions, as evaluated by one- and two-body potentials. While this design problem is NP-hard, we develop an integer programming approach that works very well in practice. We demonstrate the effectiveness of our approach by developing plans for biotherapeutic proteins that, in previous studies, have been partially deimmunized via extensive experimental characterization and modification of limited segments. In contrast, our global optimization technique considers an entire protein and accounts for all residues, residue interactions, and epitopes in proposing candidates worth subjecting to experimental evaluation.

Optimization algorithms for functional deimmunization of therapeutic proteins

Background

To develop protein therapeutics from exogenous sources, it is necessary to mitigate the risks of eliciting an anti-biotherapeutic immune response. A key aspect of the response is the recognition and surface display by antigen-presenting cells of epitopes, short peptide fragments derived from the foreign protein. Thus, developing minimal-epitope variants represents a powerful approach to deimmunizing protein therapeutics. Critically, mutations selected to reduce immunogenicity must not interfere with the protein's therapeutic activity.

Results

This paper develops methods to improve the likelihood of simultaneously reducing the anti-biotherapeutic immune response while maintaining therapeutic activity. A dynamic programming approach identifies optimal and near-optimal sets of conservative point mutations to minimize the occurrence of predicted T-cell epitopes in a target protein. In contrast with existing methods, those described here integrate analysis of immunogenicity and stability/activity, are broadly applicable to any protein class, guarantee global optimality, and provide sufficient flexibility for users to limit the total number of mutations and target MHC alleles of interest. The input is simply the primary amino acid sequence of the therapeutic candidate, although crystal structures and protein family sequence alignments may also be input when available. The output is a scored list of sets of point mutations predicted to reduce the protein's immunogenicity while maintaining structure and function. We demonstrate the effectiveness of our approach in a number of case study applications, showing that, in general, our best variants are predicted to be better than those produced by previous deimmunization efforts in terms of either immunogenicity or stability, or both factors.

Conclusions

By developing global optimization algorithms leveraging well-established immunogenicity and stability prediction techniques, we provide the protein engineer with a mechanism for exploring the favorable sequence space near a targeted protein therapeutic. Our mechanism not only helps identify designs more likely to be effective, but also provides insights into the interrelated implications of design choices.

Tea consumption and risk of cancer of the colon and rectum

The association between tea consumption and risk of colon and rectal cancers was investigated in a population-based case-control study conducted in Iowa (United States). Colon (n = 685) and rectal (n = 655) cancer cases age 40-85 yr were identified through the Iowa Surveillance, Epidemiology, and End Results (SEER) Cancer Registry (86% response rate); controls (n = 2,434) were frequency matched by sex and 5-yr age group (80% response rate). The usual adult consumption of tea (hot and iced), along with other information including dietary data, was self-reported using a mailed questionnaire. Total tea consumption (cups/day) was categorized as none (reference category), low (< 3.1), medium (3.1-5.0), and high (> 5.0), with cut points for tea consumers based on the 75th and 90th percentiles of use among controls. Unconditional logistic regression was used to estimate the odds ratios (ORs) and 95% confidence intervals. There was no association between total tea consumption and colon cancer (ORs = 1.0, 1.1, 1.3, and 0.7) or rectal cancer (ORs = 1.0, 0.9, 1.4, and 1.0) after adjustment for age, sex, education, physical activity, smoking history, and intake of coffee, fiber, and fruits and vegetables. Results were similar when hot tea and iced tea were evaluated individually. Further adjustment for other colorectal cancer risk factors did not alter these results. There was no association with proximal or distal colon cancer. There was also no interaction between tea consumption and any of the dietary variables or total fluid on risk of colon or rectal cancer, with the exception of a suggestive positive association between an increasing frequency of tea consumption and colon cancer risk among current smokers (multivariate ORs = 1.0, 1.4, 2.0, and 1.8; P for trend = 0.1), but not among never smokers (multivariate ORs = 1.0, 1.0, 1.1, and 0.4; P for trend = 0.3). These data do not support an overall association, either positive or negative, between tea consumption and risk of colon or rectal cancer in this Mid-western US population.

Adenocarcinoma of the lung is strongly associated with cigarette smoking: further evidence from a prospective study of women

In a prospective cohort of 41,836 Iowa women aged 55-69 years with 13 years of follow-up from 1986 through 1998, the authors examined the association between cigarette smoking history and three common histologic subtypes of lung cancer (123 small cell, 115 squamous cell, and 234 adenocarcinoma). Using Cox proportional hazards and additive Poisson regression analysis, they estimated four epidemiologic measures of effect: age-adjusted incidence rate, relative risk, excess risk (or risk difference), and population attributable risk. Of the three major lung cancer subtypes, the excess risk for heavy smokers compared with never smokers was higher for adenocarcinoma (excess risk = 206) than for squamous cell (excess risk = 122) and small cell (excess risk = 104) carcinomas. Adenocarcinoma of the lung is more strongly associated with tobacco smoke exposure than previously recognized.

Blood transfusions and risk of non-Hodgkin's lymphoma subtypes and chronic lymphocytic leukemia

Allogeneic blood transfusion has been suggested as a risk factor for non-Hodgkin's lymphoma (NHL), possibly specific to certain NHL subtypes, or chronic lymphocytic leukemia (CLL). Self-reported transfusion history and risk of NHL subtypes and CLL were examined in a cohort of 37,934 older Iowa women, using data from a questionnaire mailed in 1986. Through 1997, 229 cases of NHL and 57 cases of CLL in the cohort were identified through linkage to the Iowa Surveillance, Epidemiology and End Results Cancer

REGISTRY

Women who reported ever receiving a blood transfusion were at increased risk for all NHLs [age adjusted relative risk (RR), 1.6; 95% confidence interval (CI), 1.2-2.1). On the basis of the Working Formulation classification, blood transfusion was positively associated with low-grade NHL (RR, 2.7; 95% CI, 1.7-4.5) but not with intermediate-grade NHL (RR, 1.1; 95% CI, 0.7-1.6); there were only 8 cases of high-grade NHL. Blood transfusion was positively associated with follicular (RR, 2.8; 95% CI, 1.6-5.1) and small lymphocytic (RR, 3.4; 95% CI, 1.5-7.9) NHL subtypes but not with diffuse NHL (RR, 1.0; 95% CI, 0.7-1.5). There was also a positive association with CLL (RR, 1.7; 95% CI, 1.0-3.0). Finally, transfusion was associated with nodal (RR, 1.8; 95% CI, 1.3-2.5) but not extranodal (RR, 1.2; 95% CI, 0.7-2.1) NHL. Further adjustment for marital status, farm residence, diabetes, alcohol use, smoking, and red meat and fruit consumption did not alter these associations. In conclusion, prior blood transfusion was associated with NHL and CLL, and the strongest associations were seen for low-grade NHL, particularly follicular and small lymphocytic NHL.

Lifestyle and anthropometric risk factors for prostate cancer in a cohort of Iowa men

PURPOSE

Several lines of evidence suggest that prostate cancer has a hormonal etiology. We evaluated factors known to modulate the endocrine system, including alcohol and tobacco use, physical activity, and obesity as risk factors for prostate cancer.

METHODS

Cancer-free controls who participated in a population-based case-control study from 1986-1989 (81% response rate) were followed through 1995 for cancer incidence by linkage to the Iowa Cancer Registry; 101 incident prostate cancers were identified.

RESULTS

Compared with non-users of alcohol, men who consumed <22 grams alcohol per week (relative risk [RR] = 1.1; 95% Confidence Interval [CI] 0.6-2.1), 22-96 grams alcohol per week (RR = 2.6; 95% CI 1.4-4. 6) and >96 grams alcohol per week (RR = 3.1; 95% CI 1.5-6.3) were at increased risk of prostate cancer after adjustment for age, family history of prostate cancer, body mass index, total energy, and intake of carbohydrate, linoleic acid, lycopene, retinol, and red meat (p for trend < 0.0001). The respective RRs were similar when assessing type of alcohol consumed (beer, wine or liquor) or when well-differentiated, localized tumors were excluded. Body mass index was only weakly and positively associated with prostate cancer after adjustment for age, but this association strengthened after multivariate adjustment and exclusion of well-differentiated, localized tumors. For the latter tumors, men with a BMI of 24.1-26.6 kg/m(2) and >26.6 kg/m(2) were at elevated risk compared to men with a BMI <24.1 kg/m(2). Tobacco use (cigarettes, cigar/pipe, chewing tobacco and snuff use), height, weight, and both leisure and occupational physical activity were not associated with risk of prostate cancer in this cohort.

CONCLUSIONS

These data suggest that in white men obesity is a risk factor for more clinically significant prostate cancer and confirm limited previous reports showing that alcohol consumption is positively associated with prostate cancer and that this risk is not limited to any specific type of alcohol.

Smoking and risk of non-Hodgkin lymphoma subtypes in a cohort of older women

Although non-Hodgkin lymphoma (NHL) has not been considered to be a smoking-related malignancy, recent investigations suggest otherwise. We evaluated this association in a cohort of 37,336 women, aged 55-69 years, who reported in a mailed questionnaire in 1986 information regarding smoking history as well as demographic, medical history and dietary factors. Cancer and mortality experience through 1996 was determined by linkage to the Iowa Cancer Registry and other databases; there were 200 incident cases of NHL during the 380,231 total person-years of follow-up. Compared to never smokers, former (age-adjusted RR = 1.0; 95% CI 0.8-1.5) and current smokers (age-adjusted RR = 1.0; 95% CI 0.7-1.5) were not at elevated risk of NHL, and there was no trend with pack-years smoked (Ptrend = 0.3). Multivariate adjustment for other NHL risk factors did not alter these findings. Age-adjusted analysis by NHL subtype revealed a suggestive positive association of smoking with follicular NHL [(RRformer = 1.3; 95% CI 0.6-2.8), (RRcurrent = 1.8; 95% CI 0.8-3.8)], which strengthened after multivariate adjustment [(RRformer = 1.6; 95% CI 0.7-3.4), (RRcurrent = 2.3; 95% CI 1.0-5.0)]; there was no association for diffuse or small cleaved-cell NHL. Our study findings, which are consistent with other recent investigations, suggest that smoking may be associated with an increased risk of follicular NHL.

Tea consumption and risk of bladder and kidney cancers in a population-based case-control study

Recent epidemiologic studies have suggested that tea may be protective against cancers of the urinary tract. The authors examined the association between usual adult tea consumption and risk of bladder and kidney cancers in a population-based case-control study that included 1,452 bladder cancer cases, 406 kidney cancer cases, and 2,434 controls. For bladder cancer, the age- and sex-adjusted odds ratios (OR) (95% confidence intervals (CI)) referent to nonusers of tea were 0.9 (0.7, 1.1) for <1.0 cup/day, 1.0 (0.8, 1.2) for 1.0-2.6 cups/day, and 0.9 (0.7, 1.1) for >2.6 cups/day (cutpoints for users based on the tertile distribution among controls). When more extreme cutpoints were used, persons who consumed >5 cups/day (>90th percentile) had a suggestive decreased risk (OR = 0.7; 95% CI 0.5, 1.0), but there was no evidence of a dose-response relation. In analyses stratified by median total beverage intake (2.6 liters/day), there was an inverse association with tea use among persons who consumed less than the median (OR = 0.5; 95% CI 0.3, 0.8) but no association for persons who consumed at or above the median. In contrast, for kidney cancer, there was no association with tea use. Adjustment for site-specific risk factors did not alter these results. This study offers only minimal support for an inverse association between tea consumption and bladder or kidney cancer risk.

A cohort study of farming and risk of prostate cancer in Iowa

Although farming has been linked to prostate cancer mortality, few investigations have addressed its association with prostate cancer incidence. We followed a population-based cohort of 1,177 cancer-free men for up to 9 years and identified 81 incident prostate cancers. Men whose usual occupation was farmer were at an increased risk of prostate cancer after adjustment for age, smoking, alcohol, and dietary factors (RR = 1.7; 95% CI = 1.0-2.7). Exclusion of well-differentiated, localized tumors slightly strengthened the association (RR = 2.0; 95% CI = 1.1-3.6). Risk was confined to older (age 70+ years) farmers (RR = 2.2; 95% CI = 1.1-4.3); we found no evidence of an effect among younger farmers (RR = 1.0; 95% CI = 0.4-2.1).

Family history and prostate cancer risk in a population-based cohort of Iowa men

A family history of prostate cancer has been associated with prostate cancer risk in most prior studies, and more limited data suggest that a family history of breast cancer may also be important; however, there are no data from a population-based cohort study of prostate cancer incidence that adjusts for major confounders. We conducted follow-up through 1995 on 1557 men, ages 40-86 years, who were randomly selected (81% response rate) as cancer-free controls for a population-based case-control study conducted in Iowa from 1987-1989. Family history of cancer in parents and siblings was obtained using a mailed questionnaire. Incident cancers and deaths were ascertained through linkages to state and national databases; 101 incident cases of prostate cancer were identified. At baseline, 4.6% of the cohort reported a family history of prostate cancer in a brother or father, and this was positively associated with prostate cancer risk after adjustment for age [relative risk (RR) = 3.2; 95% confidence interval (CI), 1.8-5.7] or after multivariate adjustment for age, alcohol, and dietary factors (RR = 3.7; 95% CI, 1.9-7.2). Risk was greater if a brother had prostate cancer (RR = 4.5; 95% CI, 2.1-9.7) than if a father had prostate cancer (RR = 2.3; 95% CI, 1.0-5.3). Also at baseline, 9.6% of the cohort had a family history of breast and/or ovarian cancer in a mother or sister, and this was positively associated with prostate cancer risk (age-adjusted RR = 1.7; 95% CI, 1.0-3.0; multivariate RR = 1.7; 95% CI, 0.9-3.2). Men with a family history of both prostate and breast/ovarian cancer were also at increased risk of prostate cancer (RR = 5.8; 95% CI, 2.4-14). There was no association with a family history of colon cancer. Exclusion of well-differentiated, localized tumors did not alter these findings. These data from an incidence study confirm that a family history of prostate cancer is a strong prostate cancer risk factor after adjustment for dietary and other risk factors, and suggest that selection and recall bias have not had an important influence on most case-control study results. These data also support the idea that a family history of breast cancer may also be a prostate cancer risk factor.

Economics of dialysis

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