L. Joseph Su

Tea consumption and the reduced risk of colon cancer – results from a national prospective cohort study

OBJECTIVE This study examines the relationship between tea consumption and colon cancer risk in the US population. DESIGN Data from the NHANES I Epidemiologic Follow-up study (NHEFS) were used to examine the hypothesis. Cox proportional hazard models were used to examine the hypothesis of a protective effect of frequent tea consumption on colon cancer occurrence. SETTING Due to differences in the precision of the exposure data, we analysed two cohort periods based on the NHEFS. Cohort I was based on the survey conducted at the NHEFS baseline and Cohort II began at the first follow-up. SUBJECTS After excluding non-incidence cases and cases lost to follow-ups, there were 2359 tea users and 6498 non-tea users at baseline and 7656 tea users and 4514 non-tea users at the first follow-up. RESULTS : After adjusting for confounders, the relative risks of colon cancer are 0.57 (95% confidence interval (CI) 0.42, 0.78) and 0.59 (95% 1.00) for subjects who consumed <or=1.5 cups and >1.5 cups per day, respectively, compared with non-tea users in Cohort II. Although more women consumed tea and the mean intake was higher, the preventive effect of tea consumption on colon cancer was found predominantly in men. The relative risks of colon cancer are 0.41 (95% 0.66) for men who consumed <or=1.5 cups day-1 and 0.30 (95% 0.98) for >1.5 cups day-1 of tea consumption (P-value for trend <0.01). No significant results were found in Cohort I. CONCLUSIONS This study suggests an inverse association between colon cancer risk and habitual tea consumption.

How does health literacy affect quality of life among men with newly diagnosed clinically localized prostate cancer? Findings from the North Carolina-Louisiana Prostate Cancer Project (PCaP).

Health literacy deficits affect half of the US overall patient population, especially the elderly, and are linked to poor health outcomes among noncancer patients. Yet little is known about how health literacy affects cancer populations. The authors examined the relation between health‐related quality of life (HRQOL) and health literacy among men with prostate cancer.

Obesity and Prostate Cancer Aggressiveness among African and Caucasian Americans in a Population-based Study

Background: This study evaluated obesity and prostate cancer aggressiveness relationship in a population-based incident prostate cancer study. Methods: The North Carolina–Louisiana Prostate Cancer Project includes medical records data for classification of prostate cancer aggressiveness at diagnosis by using clinical criteria for 1,049 African American (AA) and 1,083 Caucasian American (CA) participants. An association between prostate cancer aggressiveness and obesity, measured using body mass indices (BMI) and waist-to-hip ratio (WHR), was assessed using ORs and 95% CIs adjusted for confounders. Results: A significantly positive association was found between prostate cancer aggressiveness and obesity. The ORs for high aggressive prostate cancer among prediagnosis obese and severely obese were 1.48 (95% CI = 1.02–2.16) and 1.98 (95% CI = 1.31–2.97), respectively, compared with normal weight research subjects. Race-stratified results suggested the association is stronger among CAs. Interaction model showed that normal weight AAs had more aggressive prostate cancer than normal weight CAs (OR = 2.69, 95% CI = 1.36–5.30); severe obesity was associated with aggressive disease in AAs (OR = 3.90, 95% CI = 1.97–7.75). WHR > 0.98 among all research subjects adjusted for race was significantly associated with high aggressive prostate cancer (OR = 1.42, 95% CI = 1.00–2.00) when compared with WHR < 0.90. The stratified result is less clear among AAs. Conclusions: This study shows a positive association between obesity and aggressive prostate cancer. AAs have more aggressive prostate cancer in general than CAs even at normal weight. Therefore, the association between obesity and aggressiveness is not as evident in AAs as in CAs. Impact: This study provides a unique opportunity to examine impact of race on obesity and high aggressive prostate cancer relationship. Cancer Epidemiol Biomarkers Prev; 20(5); 844–53. ©2011 AACR.

Cadmium Exposure and Pancreatic Cancer in South Louisiana

Cadmium has been hypothesized to be a pancreatic carcinogen. We test the hypothesis that cadmium exposure is a risk factor for pancreatic cancer with a population-based case-control study sampled from a population with persistently high rates of pancreatic cancer (south Louisiana). We tested potential dietary and nondietary sources of cadmium for their association with urinary cadmium concentrations which reflect long-term exposure to cadmium due to the accumulation of cadmium in the kidney cortex. Increasing urinary cadmium concentrations were significantly associated with an increasing risk of pancreatic cancer (2nd quartile OR = 3.34, 3rd = 5.58, 4th = 7.70; test for trend P ≤ 0.0001). Potential sources of cadmium exposure, as documented in the scientific literature, found to be statistically significantly associated with increased risk of pancreatic cancer included working as a plumber, pipefitter or welder (OR = 5.88) and high consumption levels of red meat (4th quartile OR = 6.18) and grains (4th quartile OR = 3.38). Current cigarette smoking, at least 80 pack years of smoking, occupational exposure to cadmium and paints, working in a shipyard, and high consumption of grains were found to be statistically significantly associated with increased concentrations of urinary cadmium. This study provides epidemiologic evidence that cadmium is a potential human pancreatic carcinogen.

Genetic Ancestry, Self-Reported Race and Ethnicity in African Americans and European Americans in the PCaP Cohort

Background Family history and African-American race are important risk factors for both prostate cancer (CaP) incidence and aggressiveness. When studying complex diseases such as CaP that have a heritable component, chances of finding true disease susceptibility alleles can be increased by accounting for genetic ancestry within the population investigated. Race, ethnicity and ancestry were studied in a geographically diverse cohort of men with newly diagnosed CaP. Methods Individual ancestry (IA) was estimated in the population-based North Carolina and Louisiana Prostate Cancer Project (PCaP), a cohort of 2,106 incident CaP cases (2063 with complete ethnicity information) comprising roughly equal numbers of research subjects reporting as Black/African American (AA) or European American/Caucasian/Caucasian American/White (EA) from North Carolina or Louisiana. Mean genome wide individual ancestry estimates of percent African, European and Asian were obtained and tested for differences by state and ethnicity (Cajun and/or Creole and Hispanic/Latino) using multivariate analysis of variance models. Principal components (PC) were compared to assess differences in genetic composition by self-reported race and ethnicity between and within states. Results Mean individual ancestries differed by state for self-reporting AA (p = 0.03) and EA (p = 0.001). This geographic difference attenuated for AAs who answered “no” to all ethnicity membership questions (non-ethnic research subjects; p = 0.78) but not EA research subjects, p = 0.002. Mean ancestry estimates of self-identified AA Louisiana research subjects for each ethnic group; Cajun only, Creole only and both Cajun and Creole differed significantly from self-identified non-ethnic AA Louisiana research subjects. These ethnicity differences were not seen in those who self-identified as EA. Conclusions Mean IA differed by race between states, elucidating a potential contributing factor to these differences in AA research participants: self-reported ethnicity. Accurately accounting for genetic admixture in this cohort is essential for future analyses of the genetic and environmental contributions to CaP.

Environmental Exposure to Emissions from Petrochemical Sites and Lung Cancer: The Lower Mississippi Interagency Cancer Study

To investigate potential links between environmental exposure to petrochemical plant emissions and lung cancer, a population-based case-control study (LMRICS) was conducted in eleven Louisiana parishes bordering the Mississippi River. Cases and age, gender, and race-matched controls were interviewed regarding potential risk factors. Residential history was geocoded to provide indices of long-term proximity to industrial sites. Cases were more likely to have lived near a petrochemical site. Models adjusted for other risk factors, however, showed small or no association with lung cancer (odds ratio for residence within a half-mile of a site = 1.10, 95% confidence interval 0.58–2.08). While associations were strongest for exposures exceeding 15 years, none approached statistical significance and there was no clear dose-response across exposure duration, distance categories, or when sites were grouped according to carcinogenicity rating of chemical releases. Residential proximity to petrochemical plants along the lower Mississippi thus showed no significant association with lung cancer.

CD8 T-cell immune phenotype of successful aging

The nonagenarian population by definition represents individuals who have demonstrated success in aging. We determined the status of CD8(+) T-cell senescence in nonagenarians by analyzing the expression of CD28 and Fas (CD95), and analyzing activation and activation-induced cell death (AICD). Peripheral blood mononuclear cells (PBMCs) were isolated from three groups of subjects: adults (20-64-year-old), older adults (65-89-year-old), and nonagenarians (>or=90-year-old). PBMCs were stimulated with phytohemagglutinin (PHA) (10 microg/ml). The cells were labeled with conjugated antibodies specific for CD4, CD8, CD28, CD45RO, and Fas, and were analyzed by FACS((R)). There was a strong negative correlation of the percentage of CD28(+)Fas(-) CD8(+) T-cells with the age of each individual prior to stimulation in vitro (R(2)=0.76, p<0.0001). Compared to other biomarkers (CD28(-), CD28(-)CD45RO(+), and Fas(+)) that have been associated with CD8(+) T-cell aging, the loss of the CD28(+)Fas(-) CD8(+) T-cell population exhibited the strongest correlation with the individuals chronologic age. After stimulation with PHA, there was a decrease in the percentage of CD8(+) T-cells from individual >or=65-year-old that expresses both CD28(+) and Fas(+) at day 3. Surprisingly, the AICD response of CD8(+) T-cells at day 7 in the nonagenarians was higher than that in the other two groups. These results suggest that successful aging does not prevent development of the senescent phenotype of unstimulated CD8(+) T cells, but is associated with preservation of CD8 T cell functions including activation and AICD. Increased AICD may result in enhanced rejuvenation capacity of T cells and limit the impact of aging on T cell function in nonagenarians.

Intake of grains and dietary fiber and prostate cancer aggressiveness by race.

Purpose. To examine the associations among intake of refined grains, whole grains and dietary fiber and aggressiveness of prostate cancer in African Americans (AA, n = 930) and European Americans (EA, n = 993) in a population-based, case-only study (The North Carolina-Louisiana Prostate Cancer Project, PCaP). Methods. Prostate cancer aggressiveness was categorized as high, intermediate or low based on Gleason grade, PSA level and clinical stage. Dietary intake was assessed utilizing the NCI Diet History Questionnaire. Logistic regression (comparing high to intermediate/low aggressive cancers) and polytomous regression with adjustment for potential confounders were used to determine odds of high prostate cancer aggressiveness with intake of refined grains, whole grains and dietary fiber from all sources. Results. An inverse association with aggressive prostate cancer was observed in the 2nd and 3rd tertiles of total fiber intake (OR = 0.70; 95% CI, 0.50–0.97 and OR = 0.61; 95% CI, 0.40–0.93, resp.) as compared to the lowest tertile of intake. In the race-stratified analyses, inverse associations were observed in the 3rd tertile of total fiber intake for EA (OR = 0.44; 95% CI, 0.23–0.87) and the 2nd tertile of intake for AA (OR = 0.57; 95% CI, 0.35–0.95). Conclusions. Dietary fiber intake was inversely associated with aggressive prostate cancer among both AA and EA men.

Patient-health care provider communication among patients with newly diagnosed prostate cancer: findings from a population-based survey.

OBJECTIVE To examine the multidimensional concept of patient-health care provider (HCP) communication, its effects on patient satisfaction with oncology care services, and related racial differences. METHODS The current analysis draws from a population-based survey sample of 1011 African American and 1034 Caucasian American men with newly diagnosed prostate cancer. The variables of satisfaction with health care services, interpersonal treatment, contextual knowledge of the patient, and prostate cancer communication were analyzed using multiple-group structural equation modeling. RESULTS Regardless of race, patient-HCP communication was related positively to interpersonal treatment by the HCP, HCPs contextual knowledge of the patient, and prostate cancer communication. More positive patient-HCP communication was related to more satisfaction with health care services. Racial differences were significant in the relationships between patient-HCP communication and prostate cancer communication. CONCLUSION Content and interpersonal relationships are important aspects of patient-HCP communication and affect patient satisfaction with oncologic care for prostate cancer. PRACTICE IMPLICATIONS HCPs need to integrate the transfer of information with emotional support and interpersonal connection when they communicate with men with newly diagnosed prostate cancer.

Coffee Consumption and Prostate Cancer Aggressiveness Among African and Caucasian Americans in a Population-Based Study

This study evaluated the relationship between caffeinated and decaffeinated coffee and prostate cancer (CaP) aggressiveness using data from a population-based incident CaP study within the North Carolina-Louisiana Prostate Cancer Project (PCaP). Classification of CaP aggressiveness at diagnosis was based on clinical criteria for 1,049 African-American (AA) and 1,083 Caucasian-American (CA) research subjects. Coffee consumption was measured using a modified NCI Dietary History Questionnaire. No significant associations were found between CaP aggressiveness and consumption of either caffeinated or decaffeinated coffee. The OR for high aggressive CaP among consumers of more than 4 cups per day was 0.92 (95%CI = 0.61, 1.39), compared to non-coffee-drinkers. Results stratified by race found no significant associations and no noticeable trends in either AAs (P for trend = 0. 62) or CAs (P for trend = 0.42). In contrast to a recent report on a select population that has less complete information on CaP aggressiveness suggesting that coffee prevents aggressive CaP, this rapid case ascertainment population-based study, in a biracial population with differing risks of CaP did not demonstrate a protective relationship between high coffee consumption and risk of high aggressive CaP.