Supplementation with alpha-tocopherol or beta-carotene reduces serum concentrations of vascular endothelial growth factor-D, but Not -A or -C, in male smokers

Evidence from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study suggests that vitamin E and β-carotene supplement use may influence the risk of several cancers. Vascular endothelial growth factors (VEGF) are proteins involved in angiogenesis, an important requirement for tumor growth and metastasis. Thus, vitamin E and β-carotene may influence cancer risk through one or more VEGF. The ATBC Study was a randomized, double-blind, placebo-controlled, primary cancer prevention trial in which participants were assigned to 1 of 4 supplementation groups based on a 2 × 2 factorial design: 1) α-tocopherol (vitamin E); 2) β-carotene; 3) both; or 4) placebo. For the present study, 100 cancer-free participants with follow-up serum available were randomly selected from each intervention group. VEGF-A, -C, and -D concentrations were measured by ELISA in serum obtained at baseline and after at least 2 y of supplementation. Differences in change in VEGF levels from baseline to follow-up between intervention groups were assessed using the ANOVA test. Change in VEGF-A and VEGF-C concentrations between baseline and follow-up did not differ by intervention group (P = 0.45 and 0.29, respectively). The decrease in the serum VEGF-D concentration was greater in the men supplemented with α-tocopherol (-9.7 ± 2.5%) or β-carotene (-8.5 ± 2.7%) and tended to be greater in those supplemented with both (-6.8 ± 2.4%) compared to the placebo group, in which there was no change (-0.4 ± 3.0%) (P = 0.03). In this population of male smokers, supplementation with α-tocopherol or β-carotene was associated with a decrease in VEGF-D levels over time. Although the mechanism through which these supplements affect cancer etiolog remains unclear, our results support the hypothesis that vitamin E and β-carotene may influence cancer progression through VEGF-mediated lymphangiogenesis.

Genome-wide association study identifies new prostate cancer susceptibility loci

Prostate cancer (PrCa) is the most common non-skin cancer diagnosed among males in developed countries and the second leading cause of cancer mortality, yet little is known regarding its etiology and factors that influence clinical outcome. Genome-wide association studies (GWAS) of PrCa have identified at least 30 distinct loci associated with small differences in risk. We conducted a GWAS in 2782 advanced PrCa cases (Gleason grade ≥ 8 or tumor stage C/D) and 4458 controls with 571 243 single nucleotide polymorphisms (SNPs). Based on in silico replication of 4679 SNPs (Stage 1, P < 0.02) in two published GWAS with 7358 PrCa cases and 6732 controls, we identified a new susceptibility locus associated with overall PrCa risk at 2q37.3 (rs2292884, P= 4.3 × 10(-8)). We also confirmed a locus suggested by an earlier GWAS at 12q13 (rs902774, P= 8.6 × 10(-9)). The estimated per-allele odds ratios for these loci (1.14 for rs2292884 and 1.17 for rs902774) did not differ between advanced and non-advanced PrCa (case-only test for heterogeneity P= 0.72 and P= 0.61, respectively). Further studies will be needed to assess whether these or other loci are differentially associated with PrCa subtypes.

Genome-wide association study of circulating retinol levels

Retinol is one of the most biologically active forms of vitamin A and is hypothesized to influence a wide range of human diseases including asthma, cardiovascular disease, infectious diseases and cancer. We conducted a genome-wide association study of 5006 Caucasian individuals drawn from two cohorts of men: the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study and the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. We identified two independent single-nucleotide polymorphisms associated with circulating retinol levels, which are located near the transthyretin (TTR) and retinol binding protein 4 (RBP4) genes which encode major carrier proteins of retinol: rs1667255 (P =2.30× 10(-17)) and rs10882272 (P =6.04× 10(-12)). We replicated the association with rs10882272 in RBP4 in independent samples from the Nurses' Health Study and the Invecchiare in Chianti Study (InCHIANTI) that included 3792 women and 504 men (P =9.49× 10(-5)), but found no association for retinol with rs1667255 in TTR among women, thus suggesting evidence for gender dimorphism (P-interaction=1.31× 10(-5)). Discovery of common genetic variants associated with serum retinol levels may provide further insight into the contribution of retinol and other vitamin A compounds to the development of cancer and other complex diseases.

Serum 25-hydroxy vitamin D and prostate cancer risk in a large nested case-control study

BACKGROUND

Vitamin D compounds inhibit prostate tumorigenesis experimentally, but epidemiologic data are inconsistent with respect to prostate cancer risk, with some studies suggesting nonsignificant positive associations.

METHODS

The 25-hydroxy vitamin D [25(OH)D]-prostate cancer relation was examined in a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study of 50- to 69-year-old Finnish men. We matched 1,000 controls to 1,000 cases diagnosed during up to 20 years of follow-up on the basis of age (±1 year) and fasting blood collection date (±30 days). Conditional multivariate logistic regression models estimated ORs and 95% CIs. All statistical significance testing was 2-sided.

RESULTS

Cases had nonsignificantly 3% higher serum 25(OH)D levels (P = 0.19). ORs (95% CIs) for increasing season-specific quintiles of 25(OH)D concentrations were 1.00 (reference), 1.29 (0.95-1.74), 1.34 (1.00-1.80), 1.26 (0.93-1.72), and 1.56 (1.15-2.12), with P(trend) = 0.01. Analyses based on prespecified clinical categories and season-adjusted values yielded similar results. These findings seemed stronger for aggressive disease [OR (95% CI) for fifth quintile of serum 25(OH)D [1.70 (1.05-2.76), P(trend) = 0.02], among men with greater physical activity [1.85 (1.26-2.72), P(trend) = 0.002], higher concentrations of serum total cholesterol [2.09 (1.36-3.21), P(trend) = 0.003] or α-tocopherol [2.00 (1.30-3.07), P(trend) = 0.01] and higher intakes of total calcium [1.82 (1.20-2.76), P(trend) = 0.01] or vitamin D [1.69 (1.04-2.75), P(trend) = 0.08], or among those who had received the trial α-tocopherol supplements [1.74 (1.15-2.64), P(trend) = 0.006].

CONCLUSION

Our findings indicate that men with higher vitamin D blood levels are at increased risk of developing prostate cancer.

IMPACT

Greater caution is warranted with respect to recommendations for high-dose vitamin D supplementation and higher population target blood levels.

Cigarette smoking and prostate cancer recurrence after prostatectomy

Toward the establishment of evidence-based recommendations for the prevention of prostate cancer recurrence after treatment, we examined the association between smoking and prostate cancer recurrence in a retrospective cohort study of 1416 men who underwent radical prostatectomy. Surgeries were performed by a single surgeon at Johns Hopkins Hospital between January 1, 1993, and March 31, 2006. Smoking status at 5 years before and 1 year after surgery was assessed by survey. Prostate cancer recurrence was defined as confirmed re-elevation of prostate-specific antigen levels, local recurrence, metastasis, or prostate cancer death. The cumulative incidence of recurrence was 34.3% among current smokers, 14.8% among former smokers, and 12.1% among never smokers, with a mean follow-up time of 7.3 years. Men who were current smokers at 1 year after surgery were more likely than never smokers to have disease recurrence after adjusting for pathological characteristics, including stage and grade (hazard ratio for recurrence = 2.31, 95% confidence interval = 1.05 to 5.10). This result suggests an association between cigarette smoking and risk of prostate cancer recurrence.

Abstract 4726: Genetic determinants of serum retinol: A genome-wide association study

Background: Retinol, the most biologically active form of vitamin A, is hypothesized to influence a wide range of diseases. We recently reported results from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study suggesting that higher serum retinol is related to increased prostate cancer risk. Circulating retinol concentrations are influenced by many factors in addition to dietary and supplemental intake, including those related to intestinal absorption, transport, and cleavage of pro-vitamin A compounds to form retinol. Thus, genetic factors that influence retinol concentrations may also impact human disease risk.

Methods: We conducted a genome-wide association study (GWAS) of 4,041 Caucasian individuals drawn from two cohorts: the ATBC Study and the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Our findings were replicated in an independent sample of 2,056 individuals from the Nurses’ Health Study.

Results: We identified two independent SNPs near the genes encoding key retinol carrier proteins, transthyretin (TTR) and retinol binding protein 4 (RBP4), that were associated at the level of genome-wide significance with retinol concentrations: rs1667255 (in 18q12.1) and rs10882272 (in 10q23.33). After meta-analysis with the replication sample, these SNPs remained highly significant (rs1667255: p = 2.33 × 10-14; rs10882272: p = 1.08 × 10-13). In the two GWAS studies, mean serum retinol concentrations increased with number of risk alleles (0,1,2) for TTR from 556-578-602 μg/L in ATBC and 654-688-711 μg/L in PLCO, and decreased for 0,1,2 risk alleles in RBP4 (580-567-541 μg/L in ATBC and 697-668-653 μg/L in PLCO).

Conclusions: This is the first GWAS of circulating retinol levels to reveal novel, genome-wide significant loci, one near TTR and one near RBP4, genes that encode the two major retinol carrier proteins. Understanding the genetic and other determinants of retinol status may help shed light on the etiology of cancer and other diseases associated with vitamin A.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4726. doi:10.1158/1538-7445.AM2011-4726

Abstract LB-448: Genome-wide association study identifies new prostate cancer susceptibility loci

Prostate cancer (PrCa) is the most common non-skin cancer diagnosed among males in developed countries and the second leading cause of cancer mortality, yet little is known regarding etiology or factors influencing clinical outcome. Although PrCa genome-wide association studies (GWAS) have identified at least 30 distinct susceptibility loci for overall risk, the critical clinical question is determining who will develop advanced as opposed to indolent disease. To identify additional PrCa susceptibility loci, particularly for advanced PrCa, we conducted a GWAS of 2,782 prospectively ascertained advanced PrCa cases (Gleason grade 8+ or tumor stage C/D) and 4,458 matched controls of European ancestry from the NCI Breast & Prostate Cancer Cohort Consortium (BPC3). Case and control genotype frequencies were compared using a 1-df trend test within each cohort, and then combined using fixed effect meta-analysis for 571,243 single nucleotide polymorphisms (SNPs). In our Stage 1 GWAS, we found associations (P&lt;0.05) and consistent per-allele odds ratios (OR) with advanced PrCa for a majority of previously reported PrCa loci associated with overall risk. We did not observe associations with the proposed advanced-only region 17p12 or 22q13.1 after excluding overlapping subjects in the initial report (P=0.39). The advanced-only marker on chromosome 9q33.2 was nominally associated with advanced PrCa (rs1571801, P=1.4×10−3), but previous results in BPC3 (10,501 cases and 10,831 controls) found no evidence of difference between advanced and non-advanced PrCa (case-only test for heterogeneity P=0.50). No novel regions were detected at genome-wide significance in Stage 1 (P&lt;5×10−8). In Stage 2 we performed in silico replication for 4,679 of the most promising novel markers (P&lt;=0.02) identified in Stage 1 using data from two previous GWAS conducted in the UK and Australia (5,504 PrCa cases/5,834 controls) and the Cancer of the Prostate in Sweden Study (CAPS; 1,854 PrCa cases/898 controls). We identified a new susceptibility locus associated with overall PrCa risk at 2q37.3 (rs2292884: OR=1.14, P=4.3 × 10−8) and confirmed a suggested locus at 12q13 (rs902774: OR=1.17, P=8.6×10−9). The estimated per-allele OR between advanced and non-advanced PrCa did not differ (case-only test for heterogeneity P&gt;0.60). Furthermore, we identified several genome-wide significant markers (P&lt;5×10−8) in known PrCa loci while conditioning on the index signal, suggesting multiple risk markers may exist. Although our Stage 1 GWAS was adequately powered (&gt;90%) to detect a marker with a per-allele OR of 1.18 and minor allele frequency of 40%, we identified no loci primarily associated with advanced PrCa. This suggests that-unlike unique breast cancer markers associated with estrogen-receptor positive and negative tumors-there are very few, if any, common markers with moderate effects differentially associated with advanced or non-advanced PrCa.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-448. doi:10.1158/1538-7445.AM2011-LB-448

Serum retinol and risk of prostate cancer

Greater exposure to retinol (vitamin A) may prevent prostate cancer, although under some conditions it could promote cell growth and de-differentiation. The authors prospectively examined prostate cancer risk and serum retinol levels, measured by using high-performance liquid chromatography, at baseline (n = 29,104) and after 3 years (n = 22,843) in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study cohort. Cox proportional hazards models were used to estimate the relative risk of total (n = 2,041) and aggressive (n = 461) prostate cancer by quintiles of baseline and 3-year serum retinol concentrations and by change in serum retinol levels from baseline to 3 years. Men with higher retinol concentrations at baseline were more likely to develop prostate cancer (quintile 5 vs. quintile 1 hazard ratio = 1.19, 95% confidence interval: 1.03, 1.36; P(trend) = 0.009). The results were similar for aggressive disease. Joint categorization based on baseline and 3-year retinol levels showed that men who were in the highest quintile at both time points had the greatest increased risk (baseline/3-year quintile 5/quintile 5 vs. quintile 1/quintile 1 hazard ratio = 1.31, 95% confidence interval: 1.08, 1.59). In this largest study to date of vitamin A status and subsequent risk of prostate cancer, higher serum retinol was associated with elevated risk, with sustained high exposure conferring the greatest risk. Future studies may clarify the underlying biologic mechanisms of the retinol-prostate cancer association.

Decreased expression of Cyr61 is associated with prostate cancer recurrence after surgical treatment

PURPOSE

Cysteine-rich angiogenic inducer 61 (Cyr61) is an extracellular matrix protein involved in the transduction of growth factor and hormone signaling. Previous studies have suggested that Cyr61 may be a marker for a more aggressive phenotype. In this study, we evaluated the association between Cyr61 staining intensity and subsequent recurrence after surgical treatment of clinically localized prostate cancer.

EXPERIMENTAL DESIGN

A study of 229 men with recurrence and 229 controls matched on age, race, pathologic stage, and Gleason sum nested in a cohort of men who underwent radical prostatectomy for clinically localized prostate cancer, utilizing immunohistochemistry analysis of tissue microarray (TMA) sections, was conducted. Odds ratios (OR) of recurrence and 95% confidence intervals (CIs) were estimated using conditional logistic regression.

RESULTS

Recurrence was identified in 12.2% of cases, and in 24.0% of controls that had at least 1 TMA spot containing cancer with a staining intensity of 3 (P = 0.001). Taking into account age, pathologic stage and grade, presurgery prostate-specific antigen concentration, and calendar of surgery as a measure of tissue block storage time, men with a Cyr61 staining intensity of 3 were 56% less likely to recur than men with a lower staining intensity (OR = 0.44, 95% CI = 0.22-0.90).

CONCLUSIONS

High Cyr61 staining intensity in adenocarcinoma was associated with a lower risk of recurrence after surgical treatment of prostate cancer independent of pathologic tumor characteristics. If validated in other sample sets, Cyr61 may serve as a tissue biomarker for stratifying men for risk of recurrence and thus could inform treatment decision making.

Association of statin use with pathological tumor characteristics and prostate cancer recurrence after surgery

PURPOSE

Prospective studies suggest that statins protect against advanced stage and possibly high grade prostate cancer. However, few studies have investigated the influence of stains on outcomes in men with prostate cancer. Thus, we evaluated the association of statin use with pathological tumor characteristics and prostate cancer recurrence after prostatectomy in a retrospective cohort.

MATERIALS AND METHODS

A total of 2,399 patients of 1 surgeon at Johns Hopkins Hospital who underwent radical prostatectomy in 1993 to 2006 and had not previously received hormone or radiation therapy were followed for recurrence. The surgeon routinely asked during the preoperative consultation what medications the men were using. Additional information on statin use was obtained from a mailed survey. We estimated the association of statin use with nonorgan confined disease (pT3a/b or N1) and high grade disease (Gleason sum [4 + 3] or greater) using logistic regression (OR), and recurrence using Cox proportional hazards regression (HR).

RESULTS

The 16.1% of men who used a statin at prostatectomy were statistically significantly less likely to have nonorgan confined disease than nonusers (OR 0.66, 95% CI 0.50-0.85). Statin use was inversely associated with high grade disease only in men with preoperative PSA 10 ng/ml or greater (OR 0.35, 95% CI 0.13-0.93, p-interaction = 0.02). The HR of recurrence among men who used a statin for 1 year or greater compared to nonusers was 0.77 (95% CI 0.41-1.42).

CONCLUSIONS

Our findings support the hypothesis that statin use may protect against prostate cancer with poorer pathological characteristics. We could not rule in or out that longer term statin use may protect against recurrence after prostatectomy.

Weight gain is associated with an increased risk of prostate cancer recurrence after prostatectomy in the PSA era

Although obesity at the time of prostatectomy has been associated with prostate cancer recurrence, it is unknown whether obesity before or after surgery, or weight change from the years prior to surgery to after surgery is associated with recurrence. Thus, we examined the influence of obesity and weight change on recurrence after prostatectomy. We conducted a retrospective cohort study of 1,337 men with clinically localized prostate cancer who underwent prostatectomy performed during 1993-2006 by the same surgeon. Men self-reported weight and physical activity at 5 years before and 1 year after surgery on a survey during follow-up. Mean follow-up was 7.3 years. We estimated multivariable-adjusted HRs of prostate cancer recurrence comparing obesity at 5 years before and at 1 year after surgery with normal weight, and a gain of more than 2.2 kg from 5 years before to 1 year after surgery with stable weight. During 9,797 person years of follow-up, 102 men recurred. Compared with men who had stable weight, those whose weight increased by more than 2.2 kg had twice the recurrence risk (HR = 1.94; 95% CI, 1.14-3.32) after taking into account age, pathologic stage and grade, and other characteristics. The HR of recurrence was 1.20 (95% CI, 0.64-2.23) and 1.72 (95% CI, 0.94-3.14) comparing obesity at 5 years before and at 1 year after surgery, respectively, with normal weight. Physical activity (≥ 5 h/wk) did not attenuate risk in men who gained more than 2.2 kg. By avoiding weight gain, men with prostate cancer may both prevent recurrence and improve overall well-being.

Minimal detection bias in the inverse association between statin drug use and advanced prostate cancer risk: a simulation study

BACKGROUND

Prospective studies support that statins may protect against advanced prostate cancer. Detection bias arising from higher PSA screening rates among statin users vs. non-users could produce an inverse association for advanced disease. Thus, we conducted simulations to assess whether this source of bias is explanatory.

METHODS

3000 datasets with 100,000 men without prostate cancer were simulated for populations with high (65%) or low (15%) PSA screening. We investigated three scenarios: RR(true)=1.0, 0.75, and 0.5 for statins and advanced disease (1.0 for localized). We set the statin prevalence to 10% and varied the percentage of users who were PSA screened (0-100%). We assumed an annual total prostate cancer incidence of 1%, with risk in screened men twice that of unscreened men, and an advanced stage at diagnosis in 20% and 40% of cases in screened and unscreened men, respectively.

RESULTS

As PSA screening and statin use became more coincident, the RR(observed) for local and total prostate cancer was biased upward from the RR(true) of 1.0, especially when the prevalence of PSA screening was low. However, in all simulated scenarios, there was little downward bias for advanced disease (e.g., if RR(true)=1.0 and 70% of statin users and either 65% or 15% of the population overall was PSA screened, then RR(observed)=0.98 for both).

CONCLUSIONS

Given our assumptions, this simulation suggests that this source of detection bias is unlikely to explain the reported inverse association between statins and advanced prostate cancer, but may explain the positive association for total prostate cancer that has been reported in some studies.

Abstract B92: Serum total and HDL cholesterol and risk of prostate cancer

Background: There has been growing support for the hypothesis that low cholesterol may protect against prostate cancer with a poorer prognosis. Studies suggest a decreased risk of high-grade prostate cancer in men with lower circulating total cholesterol, and that statin drugs may protect against aggressive prostate cancer. Confirmation of these findings in additional populations and examination of lipoprotein subfractions is needed. We prospectively examined prostate cancer risk and serum total and HDL cholesterol in the ATBC Study cohort.

Methods: The ATBC Study was a randomized controlled trial conducted among male smokers in Finland to determine the effects of α-tocopherol and β-carotene supplements on cancer incidence. Fasting blood samples were collected at baseline (1985 — 1988), and total and HDL cholesterol were measured for all participants (n=29,133). Cohort follow-up continues through the Finnish Cancer Registry and the Register of Causes of Death. Cox proportional hazards models were used to estimate the relative risk of overall (n=2,041), high stage (≥ TNM stage III or AJC stage 3; n=412), high grade (Gleason sum ≥ 7; n=231), aggressive (either high stage or high grade; n=461), and non-aggressive (neither high stage nor high grade; n=829) prostate cancer by categories of total (&lt;200, 200 — &lt;240, ≥240 mg/dL) and HDL (&lt;40, 40 — &lt;60, ≥60 mg/dL) cholesterol. Multivariable models adjusted for age, serum α-tocopherol, family history of prostate cancer, education, and urban residence. Further adjustment for the following factors did not alter the results: α-tocopherol and β-carotene supplementation group, serum β-carotene, cigarettes per day, years smoked, physical activity, marital status, and intake of total energy, total fat, fruits and vegetables, red meat, alcohol, vitamin A, vitamin D, and calcium. Results: Men with high serum total cholesterol were at increased risk of prostate cancer, particularly high stage disease (≥240 vs. &lt;200 mg/dl: HR=1.26, 95% CI 0.92 — 1.71, p-trend = 0.03). Stratification by follow-up time showed that the increased risk of prostate cancer for men with higher total cholesterol was limited to cases diagnosed at least 10 years after baseline. After excluding the first 9 years of follow-up, men with higher serum total cholesterol were at an increased risk of overall (≥240 vs. &lt;200: HR=1.22, 95% CI 1.03 — 1.44, p-trend=0.01) and advanced-stage (≥240 vs. &lt;200: HR=1.85, 95% CI 1.13 — 3.03, p-trend=0.05) prostate cancer. Higher HDL cholesterol appeared related to decreased risk of prostate cancer, overall and all clinical subtypes, throughout the follow-up period.

Conclusion: In this population of male smokers with a low prevalence of PSA screening, high serum total cholesterol was associated with an increased risk of advanced prostate cancer, but only among cases diagnosed at least 10 years after baseline. Further, there was a suggestion that high HDL cholesterol reduced the risk of all clinical subtypes of prostate cancer. These results support previous studies and, indirectly, support the hypothesis that statin drugs may reduce the risk of prostate cancer with a poorer prognosis by lowering cholesterol concentrations.

Citation Information: Cancer Prev Res 2010;3(12 Suppl):B92.

Serum vitamin D and risk of bladder cancer

Vitamin D may protect against several cancers, but data about the association between circulating vitamin D and bladder cancer are limited. Within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a randomized controlled trial conducted to determine the effects of α-tocopherol and β-carotene supplements on cancer incidence in male smokers, 250 bladder cancer cases were randomly sampled by month of blood collection. Controls were matched 1:1 to cases on age at randomization and date of blood collection. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) of bladder cancer by a priori categories of baseline serum 25-hydroxyvitamin D [25(OH)D; i.e., <25, 25 to <37.5, 37.5 to <50, ≥50 nmol/L] and by season-specific quartiles. After multivariable adjustment, we found that lower 25(OH)D was associated with a statistically significantly increased risk of bladder cancer (versus ≥50 nmol/L; <25 nmol/L: OR, 1.73; 95% CI, 1.03-2.91; 25 to <37.5 nmol/L: OR, 1.81; 95% CI, 1.05-3.14; 37.5 to <50 nmol/L: OR, 1.76; 95% CI, 1.02-3.02; P trend=0.04). Similarly, increased risks for the lowest vitamin D category were observed when season-specific quartiles were used (Q1 versus Q4: OR, 1.63; 95% CI, 0.96-2.75; P trend=0.03). In this prospective study of male smokers, lower serum 25(OH)D was associated with an increased risk of bladder cancer. Future studies should examine the association in other populations, especially nonsmokers and women.

Statin drugs, serum cholesterol, and prostate-specific antigen in the National Health and Nutrition Examination Survey 2001-2004

PURPOSE

We evaluated the associations of statins and serum cholesterol with PSA to understand whether the inverse associations of statins and low cholesterol with aggressive prostate cancer are explained by detection bias.

METHODS

We analyzed data from 2,574 men aged > or =40 years without prostate cancer in The National Health and Nutrition Examination Survey 2001-2004. We estimated multivariable-adjusted geometric mean PSA by statin use and cholesterol quintiles. To limit the influence of correlates of statin use and cholesterol on PSA, we stratified by comorbidities.

RESULTS

Statin users had a non-statistically significantly lower PSA than non-users (0.90 vs. 0.95 ng/mL, p = 0.22), especially in men without comorbidities (n = 1,680; 0.86 vs. 0.99 ng/mL p = 0.02). In men with comorbidities, statin users had a non-statistically significantly higher PSA than non-users (0.91 vs. 0.83 ng/mL, p = 0.14). Men with lower cholesterol had lower PSA (bottom vs. top quintile: 0.92, 1.02 ng/mL, p-trend = 0.06).

CONCLUSION

Statin users and men with lower cholesterol may have lower PSA. If so, the probability of detecting asymptomatic prostate cancer might be lower at present, but these cases might be more likely to be diagnosed at an advanced stage in the future. Thus, PSA-associated bias is unlikely to explain the inverse association of statins with advanced prostate cancer.

Abstract 2799: Serum vitamin D and risk of bladder cancer in the ATBC Study

Background: Urinary bladder cancer is an important health concern in developed countries, particularly for men, among whom incidence is 3-5 times greater than in women. Vitamin D is thought to protect against cancer at many sites. However, to our knowledge, no studies have examined the association between serum vitamin D and bladder cancer.

Methods: Within the ATBC Study, a randomized controlled trial conducted to determine the effects of α-tocopherol and β-carotene supplements on cancer incidence, 250 bladder cancer cases were randomly sampled by month of blood collection such that there were 25 cases included from each month with 25 cases total from June - August because fewer blood collections were conducted during the summer months. Controls were sampled from ATBC study participants who were alive and cancer free at the time the case was diagnosed and were matched 1:1 with cases on age at randomization (± 1 year) and date of blood collection (± 30 days). Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals of bladder cancer by a priori categories of baseline serum 25-hydroxy vitamin D (&lt;25, 25 - &lt;37.5, 37.5 - &lt;50, ≥ 50 nmol/L).

Results: After multivariable adjustment, lower serum vitamin D was associated with a statistically significantly increased risk of bladder cancer (OR, 95% CI vs. ≥ 50 nmol/L; 37.5 - &lt;50 nmol/L: 2.04, 1.13 − 3.70; 25 - &lt;37.5 nmol/L: 1.90, 1.07 − 3.35; &lt;25 nmol/L: 1.83, 1.06 − 3.14; p-trend = 0.03), although the risk did not appear to increase with progressively lower vitamin D levels. Rather, men in any category of serum vitamin D below 50 nmol/L were at approximately two-fold risk compared to men with serum vitamin D ≥50 nmol/L (OR, 95% CI: 1.91, 1.20 − 3.04; p value = 0.006). Although the results were not statistically significant, there was a suggestion that the vitamin D - bladder cancer association was stronger among men who smoked less, were not assigned to the α-tocopherol intervention arm, or whose blood samples were obtained during the sunnier months.

Conclusion: In this population of male smokers, lower vitamin D was associated with an increased risk of bladder cancer. Future studies should examine this association in other populations, especially women and non-smokers. Replication in a larger sample may clarify possible subtle effect modification by smoking, season, and intake of other nutrients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2799.

Abstract 883: Weight gain is associated with an increased risk of prostate cancer recurrence in the PSA era

Background: Obesity measured at or near time of prostatectomy has been associated with increased risk of prostate cancer recurrence. However, it is unknown whether obesity or weight gain in the years prior to surgery is associated with recurrence. In addition, whether physical inactivity or sedentary behavior exacerbates the obesity-related risk of recurrence has not been studied. Methods: We conducted a retrospective cohort study of men with clinically-localized prostate cancer who underwent radical prostatectomy performed by one surgeon at Johns Hopkins between 1/93 − 3/06 and who previously had not had hormone or radiation therapy. The men were followed for recurrence, defined as PSA recurrence, metastasis, or prostate cancer death. A survey on dietary, lifestyle and medical factors, including weight, height, physical activity, and sedentary behavior 5 years before surgery and 1 year after, was mailed to the men residing in the U.S. as of 11/07. We classified men as normal body mass index (BMI, &lt;25 kg/m2), overweight (25-29.9), or obese (≥30); as physically active (≥5 hrs/wk leisure time activity) or inactive; and as not sedentary or sedentary (≥20 hrs/wk sitting). Men began contributing time at risk starting 1 year after surgery. We used Cox proportional hazards regression to estimate the hazard ratio (HR) of recurrence comparing a gain in BMI of ≥1 kg/m2 from 5 years before surgery to 1 year after with stable BMI, and obesity 1 year after surgery with normal weight. We adjusted for age, race, family history, preoperative PSA, surgery year, positive surgical margins, and pathologic stage and Gleason sum, and for the BMI gain analysis also for BMI 5 years before surgery. For the analysis of obesity 1 year after surgery, we stratified by physical activity and sedentary behavior. Results: At the time of prostatectomy, men who recurred (n=102) were older (58.1 vs. 56.3 yr, p=0.007), more likely to have poorer pathological tumor characteristics (all p&lt;0.0001), and were less likely to have a family history (14.7% vs. 27.7%, p=0.013) than men who did not recur (n=1235). Five years before surgery, 54% were overweight and 9% were obese. Compared with men who had stable BMI, those whose BMI increased ≥1 kg/m2 from 5 years before surgery to 1 year after had twice the recurrence risk (HR=2.18, 95% CI 1.24-3.81). Men who were obese 1 year after surgery were 1.67 times (95% CI 0.91-3.04) more likely to recur compared with men with normal BMI. Risk of recurrence associated with obesity 1 year after surgery was even stronger in men who were sedentary (HR=2.65, 95% CI 1.09-6.47) or inactive (HR=2.30, 95% CI 0.94-5.62). In contrast, in men who were not sedentary (HR=0.89, 95% CI 0.36-2.21) or who were active (HR=1.09, 95% CI 0.45-2.69), obesity 1 year after surgery was not associated with recurrence. Discussion: Weight gain and obesity, especially in sedentary or inactive men, may contribute to risk of prostate cancer recurrence after prostatectomy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 883.

Extracellular matrix associated protein CYR61 is linked to prostate cancer development

PURPOSE

The cancer cell microenvironment includes complex interactions between the cell and the extracellular matrix. Expression of the CCN family of extracellular matrix associated proteins is often modified in disease states. Depending on cancer type these changes are linked with enhanced or inhibited tumor growth. We characterized Cyr61 in prostate cancer. Cyr61 is an integrin binding matricellular protein with altered expression in many cancer types.

MATERIALS AND METHODS

Cyr61 expression in prostate cancer, benign prostatic hyperplasia and normal tissues was evaluated by microarray analysis, quantitative real-time polymerase chain reaction and tissue microarray. Immunoblots were analyzed to assess endogenous protein expression in prostate cancer cell lines.

RESULTS

On genomic analysis Cyr61 up-regulation was observed in prostate cancer tissue and in normal prostate tissue adjacent to tumor vs that in prostate donor tissue. In 174 matched tumors and normal prostate tissues adjacent to tumor tissue microarray revealed significantly up-regulated Cyr61 protein expression in cancer tissue vs normal prostate tissue adjacent to tumor. Also, increased Cyr61 expression correlated with Gleason sum 8 or greater cancer. Staining in high grade prostatic intraepithelial neoplasia was moderately up-regulated vs that in normal prostate tissue adjacent to tumor but generally less intense than in carcinoma tissue.

CONCLUSIONS

In addition to the correlation with more advanced disease, the strong association between Cyr61 expression and prostate cancer supports the potential usefulness of Cyr61 as a novel biomarker for prostate cancer. This warrants further analysis to determine the mechanisms by which Cyr61 may contribute to prostate cancer development and progression.

Abstract A108: Serum retinol and risk of prostate cancer in the alphatocopherol, beta-carotene (ATBC) cancer prevention study

Purpose: Retinol (vitamin A) may prevent prostate cancer by promoting cell differentiation and apoptosis, although under some conditions it could stimulate growth and de-differentiation. We examined serum retinol, measured at baseline and three years, in relation to prostate cancer risk in the ATBC Study.

Methods: The ATBC Study is a randomized controlled trial conducted to determine the effects of -tocopherol and s-carotene supplements on cancer incidence. 29,133 Finnish male smokers were recruited from 1985–1988 and were assigned to groups using a 2×2 factorial design: 1) -tocopherol, 2) β-scarotene, 3) both supplements, or 4) placebo. Fasting blood samples were collected at baseline and after 3 years, and as of April 30, 2006, 2,041 prostate cancer cases occurred during 417,532 person-years. Cox proportional hazards models were used to estimate the relative risk (as hazard ratio, HR) of total and aggressive (n=461) prostate cancer by quintile of baseline and 3-year serum retinol concentrations, as well as by change in serum retinol. No confounding by factors associated with either prostate cancer or retinol was observed.

Results: Men in higher quintiles of baseline retinol were more likely to develop prostate cancer compared with men in the lowest quintile (age-adjusted HR, 95%CI vs. Q1; Q2: 1.05, 0.91 – 1.21; Q3: 1.06 0.92 – 1.22; Q4: 1.13, 0.98 – 1.30; Q5: 1.19, 1.03 – 1.36; p-trend = 0.009). The association was similar for aggressive prostate cancer and when the 3-year retinol was used. Compared to men whose retinol did not differ between baseline and 3 years, men with either higher or lower retinol at follow-up were at similar risk of prostate cancer. When we jointly categorized men based on quintiles of baseline and 3-year retinol, we noted that men who were in the highest quintile of retinol at both time points had the greatest increased risk (baseline/3-year Q5/Q5 vs. Q1/Q1 HR: 1.31 95% CI: 1.08 – 1.59). Other joint categories were also at higher risk, particularly among men who did not receive the trial β-carotene supplement. Men randomized to the β-carotene arm had generally higher risk for any baseline/3-year retinol category compared to men in the no β-carotene arm, and those whose serum retinol decreased substantially from baseline Q4 or Q5 appeared to have a lower prostate cancer risk (HR, 95% CI vs. Q1/Q1; Q5 to Q1–3: 0.60, 0.35 – 1.03; Q4 to Q1–2: 0.85, 0.54 – 1.33).

Conclusion: In this largest study to date of serum retinol and prostate cancer that incorporates retinol measured at two time points three years apart, higher serum concentrations were associated with elevated risk, with sustained high exposure conferring the greatest risk. Distinct patterns of change in serum retinol over time may relate to differing risks of developing prostate cancer.

Citation Information: Cancer Prev Res 2010;3(1 Suppl):A108.

A prospective study of lower urinary tract symptoms and erectile dysfunction

PURPOSE

Several studies have shown that men with lower urinary tract symptoms are more likely to experience erectile dysfunction. All except 1 of these studies were cross-sectional, limiting inferences about whether lower urinary tract symptoms precipitate erectile dysfunction.

MATERIALS AND METHODS

The association between lower urinary tract symptoms and incident erectile dysfunction was examined prospectively in the Health Professionals Follow-Up Study. Lower urinary tract symptoms were assessed biennially by the American Urological Association symptom index, which captures symptoms of frequency, urgency and force of urinary stream. Severe lower urinary tract symptoms was defined as a symptom score of 20 points or greater and no lower urinary tract symptoms was defined as a score of 7 points or less in men not treated for lower urinary tract symptoms. In 2000 the men were asked to rate erectile function for several periods. Erectile dysfunction was defined as poor or very poor function, or erectile dysfunction medication use, while no erectile dysfunction was defined as very good or good function and no erectile dysfunction medication use. We estimated the RR using Poisson regression, adjusting for age and other potentially confounding factors.

RESULTS

We observed 3,953 incident erectile dysfunction cases among 17,086 men. Men with severe lower urinary tract symptoms in 1994 or earlier had a statistically significant 40% higher risk of erectile dysfunction subsequently than men without lower urinary tract symptoms. The risk of erectile dysfunction increased with increasing lower urinary tract symptom severity (p trend <0.0001). The positive association between lower urinary tract symptoms and erectile dysfunction was stronger in younger than in older men (p interaction = 0.03).

CONCLUSIONS

This study provides evidence that men with lower urinary tract symptoms are more likely to have erectile dysfunction subsequently.

Meat consumption among Black and White men and risk of prostate cancer in the Cancer Prevention Study II Nutrition Cohort

Previous epidemiologic studies have suggested that intake of red meat may be associated with increased risk of prostate cancer. Few studies, however, have examined these associations by race. We examined intake of red meat, processed meat, and poultry in relation to incident prostate cancer among Black and White men in the Cancer Prevention Study II Nutrition Cohort. Participants in the study completed a detailed questionnaire on diet, medical history, and lifestyle in 1992 to 1993. After excluding men with a history of cancer and incomplete dietary information, 692 Black and 64,856 White men were included in the cohort. During follow-up through August 31, 2001, we documented 85 and 5,028 cases of incident prostate cancer among Black and White men, respectively. Cox proportional hazards models were used to estimate rate ratios (RR) and 95% confidence intervals (95% CI). No measure of meat consumption was associated with risk of prostate cancer among White men. Among Black men, total red meat intake (processed plus unprocessed red meat) was associated with higher risk of prostate cancer (RR, 2.0; 95% CI, 1.0-4.2 for highest versus lowest quartile; P(trend) = 0.05); this increase in risk was mainly due to risk associated with consumption of cooked processed meats (sausages, bacon, and hot dogs; RR, 2.7; 95% CI, 1.3-5.3 for highest versus lowest quartile; P(trend) = 0.008). This study suggests that high consumption of cooked processed meats may contribute to prostate cancer risk among Black men in the United States.

Age at natural menopause and cause-specific mortality

Several studies have suggested that a young age at menopause may be associated with increased risk of all-cause mortality. Few studies have examined the influence of age at menopause on specific causes of death other than coronary heart disease. Data from a prospective cohort study of US adults were used to examine the relation between age at natural menopause and all-cause and cause-specific mortality among women who never used hormone replacement therapy, who never smoked, and who experienced natural menopause between the ages of 40 and 54 years. After 20 years of follow-up between 1982 and 2002, 23,067 deaths had occurred among 68,154 women. Results from Cox proportional hazards models showed that all-cause mortality rates were higher among women who reported that menopause occurred at age 40-44 years compared with women who reported that menopause occurred at age 50-54 years (rate ratio (RR) = 1.04, 95% confidence interval (CI): 1.00, 1.08). This increased risk was largely due to higher mortality rates from coronary heart disease (RR = 1.09, 95% CI: 1.00, 1.18), respiratory disease (RR = 1.19, 95% CI: 1.02, 1.39), genitourinary disease (RR = 1.39, 95% CI: 1.07, 1.82), and external causes (RR = 1.56, 95% CI: 1.21, 2.02). These findings suggest that mortality from other diseases, as well as coronary heart disease, may contribute to the increased mortality associated with a younger age at menopause.

A large cohort study of aspirin and other nonsteroidal anti-inflammatory drugs and prostate cancer incidence

BACKGROUND

Use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) has consistently been associated with a reduced risk of colon cancer. Recent epidemiologic studies have suggested that the use of NSAIDs, particularly aspirin, may also be associated with a reduced risk of prostate cancer, but the evidence remains limited.

METHODS

We examined the association between NSAID use and prostate cancer incidence among 70 144 men in the American Cancer Society's Cancer Prevention Study II Nutrition Cohort. Information on NSAID use was obtained from a questionnaire completed at study enrollment in 1992-1993 and was updated using follow-up questionnaires in 1997 and 1999. We calculated rate ratios (RRs) and 95% confidence intervals (CIs) for prostate cancer incidence associated with NSAID use, adjusting for age and potential prostate cancer risk factors.

RESULTS

During follow-up from 1992-1993 through August 31, 2001, 4853 cases of incident prostate cancer were identified. Neither current aspirin use nor current use of NSAIDs (aspirin and other NSAIDs combined) was associated with prostate cancer risk, even at the highest usage level (60 or more pills per month). However, long-duration regular use (30 or more pills per month for 5 or more years) of NSAIDs was associated with reduced risk of prostate cancer (RR = 0.82, 95% CI = 0.71 to 0.94). Long-duration regular use of aspirin was also associated with reduced risk of prostate cancer (RR = 0.85, 95% CI = 0.73 to 0.99). The absolute rate of prostate cancer (standardized to the age distribution of study participants using 5-year age categories) was 1013 per 100,000 person-years among men who had never reported NSAID use, and 847 per 100,000 person-years among long duration regular NSAID users.

CONCLUSIONS

These results support the hypothesis that long duration regular NSAID use is associated with modestly reduced risk of prostate cancer.

Diabetes and risk of prostate cancer in a prospective cohort of US men

One previous study has suggested that diabetes may decrease risk of prostate cancer but only several years after diagnosis of diabetes. The authors examined the role of timing of diabetes diagnosis in relation to risk of prostate cancer among men in the Cancer Prevention Study II Nutrition Cohort. Participants in the study completed a mailed questionnaire including information on diabetes at enrollment in 1992 and at follow-up questionnaires in 1997 and 1999. Historical information on diabetes was also available from a previous study in 1982. The authors documented 5,318 cases of incident prostate cancer through August 31, 2001, among 72,670 men. Results from Cox proportional hazards models showed that diabetes was associated with a lower incidence of prostate cancer (rate ratio (RR) = 0.67, 95% confidence interval (CI): 0.60, 0.75). This association differed significantly by time since diagnosis of diabetes (p < 0.0002); risk of prostate cancer was slightly increased during the first 3 years after diagnosis of diabetes (RR = 1.23, 95% CI: 0.92, 1.65) but was reduced among men diagnosed 4 or more years before (RR = 0.63, 95% CI: 0.56, 0.71). Study results are consistent with the hypothesis that diabetes is associated with reduced risk of prostate cancer but only several years after diagnosis of diabetes.

Vitamin E supplements and risk of prostate cancer in U.S. men

Supplementation with alpha-tocopherol (a form of vitamin E) was associated with decreased risk of prostate cancer in a randomized trial among Finnish smokers. We examined the association between vitamin E supplement use and prostate cancer incidence in the Cancer Prevention Study II Nutrition Cohort. Participants in the study completed a detailed questionnaire at enrollment in 1992-1993. Historical information was also available from a questionnaire completed in 1982 at enrollment in a previous cohort. Through August 31, 1999, we documented 4,281 cases of incident prostate cancer among 72,704 men. Multivariate-adjusted rate ratios (RRs) were calculated using Cox Proportional Hazards models. Regular vitamin E supplement use (>/=4 times per week) was not associated with overall risk of prostate cancer or with risk of advanced prostate cancer at diagnosis. No trend was seen with increasing dose of vitamin E. Men who reported regular vitamin E use in both 1982 and in 1992-1993 were not at lower risk of prostate cancer. Among current smokers, there was a suggestion of slightly reduced risk with regular vitamin E supplement use [RR = 0.87, 95% confidence interval (CI) = 0.67-1.11]. Our results do not support an important role for vitamin E supplements in prostate cancer prevention.

Vitamin E Supplements and Risk of Prostate Cancer in U.S. Men

Supplementation with α-tocopherol (a form of vitamin E) was associated with decreased risk of prostate cancer in a randomized trial among Finnish smokers. We examined the association between vitamin E supplement use and prostate cancer incidence in the Cancer Prevention Study II Nutrition Cohort. Participants in the study completed a detailed questionnaire at enrollment in 1992–1993. Historical information was also available from a questionnaire completed in 1982 at enrollment in a previous cohort. Through August 31, 1999, we documented 4,281 cases of incident prostate cancer among 72,704 men. Multivariate-adjusted rate ratios (RRs) were calculated using Cox Proportional Hazards models. Regular vitamin E supplement use (≥4 times per week) was not associated with overall risk of prostate cancer or with risk of advanced prostate cancer at diagnosis. No trend was seen with increasing dose of vitamin E. Men who reported regular vitamin E use in both 1982 and in 1992–1993 were not at lower risk of prostate cancer. Among current smokers, there was a suggestion of slightly reduced risk with regular vitamin E supplement use [RR = 0.87, 95% confidence interval (CI) = 0.67–1.11]. Our results do not support an important role for vitamin E supplements in prostate cancer prevention.

Cigarette tar yields in relation to mortality from lung cancer in the cancer prevention study II prospective cohort, 1982-8

OBJECTIVE

To assess the risk of lung cancer in smokers of medium tar filter cigarettes compared with smokers of low tar and very low tar filter cigarettes.

DESIGN

Analysis of the association between the tar rating of the brand of cigarette smoked in 1982 and mortality from lung cancer over the next six years. Multivariate proportional hazards analyses used to assess hazard ratios, with adjustment for age at enrollment, race, educational level, marital status, blue collar employment, occupational exposure to asbestos, intake of vegetables, citrus fruits, and vitamins, and, in analyses of current and former smokers, for age when they started to smoke and number of cigarettes smoked per day.

SETTING

Cancer prevention study II (CPS-II).

PARTICIPANTS

364 239 men and 576 535 women, aged > or = 30 years, who had either never smoked, were former smokers, or were currently smoking a specific brand of cigarette when they were enrolled in the cancer prevention study.

MAIN OUTCOME MEASURE

Death from primary cancer of the lung among participants who had never smoked, former smokers, smokers of very low tar (< or = 7 mg tar/cigarette) filter, low tar (8-14 mg) filter, high tar (> or = 22 mg) non-filter brands and medium tar conventional filter brands (15-21 mg).

RESULTS

Irrespective of the tar level of their current brand, all current smokers had a far greater risk of lung cancer than people who had stopped smoking or had never smoked. Compared with smokers of medium tar (15-21 mg) filter cigarettes, risk was higher among men and women who smoked high tar (> or = 22 mg) non-filter brands (hazard ratio 1.44, 95% confidence interval 1.20 to 1.73, and 1.64, 1.26 to 2.15, respectively). There was no difference in risk among men who smoked brands rated as very low tar (1.17, 0.95 to 1.45) or low tar (1.02, 0.90 to 1.16) compared with those who smoked medium tar brands. The same was seen for women (0.98, 0.80 to 1.21, and 0.95, 0.82 to 1.11, respectively).

CONCLUSION

The increase in lung cancer risk is similar in people who smoke medium tar cigarettes (15-21 mg), low tar cigarettes (8-14 mg), or very low tar cigarettes (< or = 7 mg). Men and women who smoke non-filtered cigarettes with tar ratings > or = 22 mg have an even higher risk of lung cancer.

Calcium, dairy products, and risk of prostate cancer in a prospective cohort of United States men

Intake of calcium and/or dairy products has been associated with increased risk of prostate cancer in some epidemiological studies. One potential biological mechanism is that high calcium intake down-regulates 1,25 dihydroxy vitamin D(3), which may increase cell proliferation in the prostate. We examined the association between calcium, dairy intake, and prostate cancer incidence in the Cancer Prevention Study II Nutrition Cohort, a prospective cohort of elderly United States adults. Participants in the study completed a detailed questionnaire on diet, medical history, and lifestyle at enrollment in 1992-1993. After excluding men with a history of cancer or incomplete dietary information, 65,321 men remained for analysis. During follow-up through August 31, 1999, we documented 3811 cases of incident prostate cancer. Multivariate-adjusted rate ratios (RRs) were calculated using Cox proportional hazards models. Total calcium intake (from diet and supplements) was associated with modestly increased risk of prostate cancer [RR = 1.2, 95% confidence interval (CI) = 1.0-1.6 for >or=2000 versus <700 mg/day, P trend = 0.02). High dietary calcium intake (>or=2000 versus <700 mg/day) was also associated with increased risk of prostate cancer (RR = 1.6, 95% CI = 1.1-2.3, P trend = 0.10), although moderate levels of dietary calcium were not associated with increased risk. Dairy intake was not associated with prostate cancer risk. The association between prostate cancer and total calcium intake was strongest for men who reported not having prostate-specific antigen testing before 1992 (RR = 1.5, 95% CI = 1.1-2.0, P trend < 0.01 for >or= 2000 mg/day of total calcium; RR = 2.1, 95% CI = 1.3-3.4 >or=2000 mg/day of dietary calcium, P trend = 0.04). Our results support the hypothesis that very high calcium intake, above the recommended intake for men, may modestly increase risk of prostate cancer.

Trends in national surveillance for rabies among bats in the United States (1993-2000)

OBJECTIVE

To describe surveillance trends and epidemiologic features of rabies in bats in the United States, focusing on 3 bat species primarily associated with variants of the rabies virus that affect humans.

DESIGN

Retrospective study.

ANIMALS

31,380 bats.

PROCEDURE

Data on rabies for bats identified to species and reported by state laboratories from 1993 to 2000 were analyzed, focusing on silver-haired, eastern pipistrelle, and Brazilian free-tailed bats. Categoric variables were derived from other provided information.

RESULTS

Data were reported from 37 states during the study interval; complete species-specific data were not reported by any state for the entire interval. Bats primarily associated with rabies virus variants affecting humans were more likely to yield positive test results for rabies (22.7%), compared with all other bats (5.5%) in most seasons and from most regions of the United States. However, certain other bat species had higher percentages of positive results. Risk of positive results was highest in the fall and highest among bats originating in the southwestern United States.

CONCLUSIONS AND CLINICAL RELEVANCE

Increased risk of rabies among certain groups of bat species was consistently found across seasons and most geographic regions of the United States. Results were in general agreement with those of previous studies conducted within smaller geographic regions. There are ongoing efforts to improve surveillance of rabies in bats, although surveillance is incomplete in some regions.

Rabies surveillance in the United States during 2000

During 2000, 49 states, the District of Columbia, and Puerto Rico reported 7,364 cases of rabies in nonhuman animals and 5 cases in human beings to the Centers for Disease Control and Prevention, an increase of 4.3% from 7,067 cases in nonhuman animals reported in 1999. Ninety-three percent (6,855 cases) were in wild animals, whereas 6.9% (509 cases) were in domestic species (compared wth 91.5% in wild animals and 8.5% in domestic species in 1999). Compared with cases reported in 1999, the number of cases reported in 2000 increased among bats, dogs, foxes, skunks, and sheep/goats and decreased among cats, cattle, horses/mules, raccoons, and swine. The relative contributions of the major groups of animals were as follows: raccoons (37.7%; 2,778 cases), skunks (30.2%; 2,223), bats (16.8%; 1,240), foxes (6.2%; 453), cats (3.4%; 249), dogs (1.6%; 114), and cattle (1.1%; 83). Ten of the 19 states where the raccoon-associated variant of the rabies virus has been enzootic reported increases in the numbers of cases of rabies during 2000. Among those states that have engaged in extensive wildlife rabies control programs, no cases of rabies associated with the epizootic of rabies in raccoons (or in any other terrestrial species) were reported in Ohio, compared with 6 cases reported in 1999. No rabies cases associated with the dog/coyote variant (compared with 10 cases in 1999, including 5 in dogs) were reported in Texas, and cases associated with the gray fox variant of the virus decreased (58 cases in 2000, including 38 among foxes). Reports of rabid skunks exceeded those of rabid raccoons in Massachusetts and Rhode Island, states with enzootic raccoon rabies, for the fourth consecutive year. Nationally, the number of rabies cases in skunks increased by 7.1% from that reported in 1999. The greatest numerical increase in rabid skunks (550 cases in 2000, compared with 192 in 1999) was reported in Texas. The number of cases of rabies reported in bats (1,240) during 2000 increased 25.4% over the number reported during 1999 (989) and represented the greatest contribution (16.8% of the total number of rabid animals) ever recorded for this group of mammals. Cases of rabies reported in cattle (83) and cats (249) decreased by 38.5% and 10.4%, respectively, whereas cases in dogs (114) increased by 2.7% over those reported in 1999. Reported cases of rabies among horses and mules declined 20% from 65 cases in 1999 to 52 cases in 2000. Four indigenously acquired cases of rabies reported in human beings were caused by variants of the rabies virus associated with bats. One case of human rabies acquired outside the United States that resulted from a dog bite was caused by the canine variant of the rabies virus.