Racial and ethnic issues in diet and cancer epidemiology

Leading the Way in Exercise and Diet (Project LEAD): intervening to improve function among older breast and prostate cancer survivors

The U.S. population is aging, bringing with it an increased prevalence of chronic disease and concomitant declines in physical function. The risk of developing cancer increases significantly with age, and functional decline is much more likely once a cancer diagnosis is rendered. Thus, functional status in later life is a key concern, one that is heightened among elders who have been diagnosed with cancer. To date, however, there have been few trials that have exclusively addressed issues related to cancer survivorship among older cancer patients, and to our knowledge, none has focused on preserving or enhancing physical functioning. This paper describes the study design and methodological considerations of a randomized controlled trial to determine if a personally tailored workbook and telephone counseling program can positively affect physical activity and dietary behaviors and ultimately the physical functioning of up to 420 older men and women newly diagnosed with breast or prostate cancer. This trial is unique because the cancer diagnosis is used not only as a marker of risk for functional decline, but also as a "teachable moment" - an opportune time when elders may be more receptive to making beneficial lifestyle changes. Undoubtedly, as cure rates for cancer increase and intersect with ever-growing numbers of elderly, there will be numerous opportunities to provide and test interventions within this vulnerable population and to target functional status as a primary outcome. In reporting our methods, we hope to give others "a leg up," so that they can hurdle with greater ease the barriers we experienced, and thus advance the field more rapidly.

Dopamine transporter genotype as a risk factor for obesity in African-American smokers

OBJECTIVE

To assess the association between a polymorphism related to dopamine function, dopamine transport (SLC6A3), and obesity in smokers.

RESEARCH METHODS AND PROCEDURES

Logistic regression was used to assess the relationship between this genetic polymorphism and obesity (body mass index > or = 30 kg/m(2)) from a sample of 510 smokers who smoked at least 10 cigarettes per day and who were participating in a study designed to examine genetic and nongenetic predictors of response to a pharmacological treatment.

RESULTS

The likelihood of obesity in African Americans (N = 90) with the 10/10 SLC6A3 genotype was 5.16 times that of African Americans with 9/9 or 9/10 SLC6A3 genotypes (odds ratio = 5.16, confidence interval = 1.60 to 16.65). There was no association of the SLC6A3 genotype with obesity for non-Hispanic whites (N = 420).

DISCUSSION

These results suggest that variants of the dopamine transporter gene may be related to obesity in African-American smokers. Possible mechanisms responsible for the association between dopamine transport and obesity in African-American smokers are discussed.

Chemopreventive effects of S-(N,N-diethyldithiocarbamoyl)-N-acetyl-L-cysteine against benzo[a]pyrene

The putative antimutagenic/anticarcinogenic organosulfur compound, S-(N,N-diethyldithiocarbamoyl)-N-acetyl-L-cysteine (AC-DDTC), has been demonstrated to inhibit the metabolic activation and the genotoxicity of N-nitrosodiethylamine. We have investigated the chemopreventive activity of AC-DDTC against benzo[a]pyrene (B[a]P) in the Salmonella typhimurium bacterial mutation assay, in the chromosome aberration assay using Chinese hamster lung fibroblast (CHL), and in the mouse micronucleus assay in bone marrow cells. In the bacterial mutation assay, AC-DDTC produced a concentration dependent decrease in the number of mutant colonies induced by B[a]P. The chromosome damaging responses of B[a]P in CHL cells were abolished by the treatment of AC-DDTC, approximately to the level of the control. In the in vivo mouse bone marrow micronucleus test, pretreatment of AC-DDTC 1 h prior to B[a]P reduced the frequency of micronucleated polychromatic erythrocytes. The inhibitory effects were statistically significant and dose-dependent. Our results demonstrate that AC-DDTC, one of the mixed disulfide model compounds of disulfiram, prevents the mutagenic effects of B[a]P.

An epidemiologic review of dietary intake studies among American Indians and Alaska Natives: implications for heart disease and cancer risk

PURPOSE

Dietary factors play an important role in the occurrence of heart disease and cancer. While American Indians and Alaska Natives (AIANs) have unique heart disease and cancer mortality profiles, little is known about the effect of diet on heart disease and cancer risk in these populations. This paper reviews existing nutritional intake data from adult AIANs, and considers the potential impact of diet on heart disease and cancer in these communities.

METHODS

A review of the literature was conducted using the Medline database system and other reference materials. Studies documenting nutrient intakes only were included in this review. Studies were limited to those among healthy, non-pregnant adults.

RESULTS

A total of twelve reports from 1959 to 1996 were found. Sample sizes for the studies ranged from 20 to 575 subjects. Most studies were done among women, and a variety of nutritional assessment techniques (24 hour recall, food frequency questionnaire, multiple-day food record) were used. Most studies also had limited nutrient intake data, especially for dietary fiber and vitamin E. The majority of studies reported moderately high intakes of fat and saturated fat, and low intakes of polyunsaturated fat and fiber.

CONCLUSIONS

Based on the limited data, diet may play an important role in the heterogeneity of heart disease and cancer mortality in AIAN communities. More research is needed to assess the impact of diet on heart disease and cancer risk, including more longitudinal data, and data to assess the validity and reliability of traditional methods of dietary assessment.

Weight-related attitudes and behaviors of women who diet to lose weight: a comparison of black dieters and white dieters

Obesity is a significant health problem among black women in the United States. Black women are two to three times more likely than white women to be obese. The present study sought to examine race difference in attitudes and beliefs about dieting, motivations underlying dieting efforts, and actual dieting strategies and behaviors. To achieve this aim, a subset of female survey respondents (n = 324) was drawn from a pool of more than 20,000 subscribers to Consumer Reports. All survey respondents had made at least one dieting effort within 3 years of the time of the study. For this study, we used all black female respondents (n = 162) and a matched sample (i.e., matched on age, educational attainment, and personal income) of white women (n = 162). Black women did weigh significantly more than Caucasian women, therefore, BMI was used as a covariate in all subsequent analyses. Black and white women were significantly different in a number of domains. Compared to white women, black women experienced less social pressure about their weight, initiated dieting later in life, and were significantly less likely to diet at each developmental milestone. However, the two groups of women did not differ in reasons for undertaking their most recent dieting efforts, or in the types of weight loss strategies they had employed. Nor were there differences between the black and white women in methods for coping responses with dietary relapse or in rates of disordered eating. These findings are discussed in terms of their implications for both treatment and prevention of obesity in black women.