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Harley AE, Sapp AL, Li Y, Marino M, Quintiliani LM, Sorensen G. Sociodemographic and social contextual predictors of multiple health behavior change: data from the Healthy Directions-Small Business study. Transl Behav Med 2013; 3:131-9. [PMID: 24073163 DOI: 10.1007/s13142-013-0196-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Multiple modifiable health behaviors contribute to the chronic diseases that are the leading causes of death in the USA. Disparities for meeting recommended health behavior guidelines exist across occupational classes and socioeconomic levels. The purpose of this paper was to investigate sociodemographic and social contextual predictors of multiple health behavior change in a worksite intervention. We analyzed data on four diet and exercise variables from an intervention trial with worksite-level randomization. Eight hundred forty-one employees had complete data from baseline (response rate = 84 %) and follow-up surveys (response rate = 77 %). Multilevel logistic regression estimated associations between least absolute shrinkage and selection operator-selected sociodemographic and social contextual predictor variables and the multiple health behavior change outcome (changing 2+ versus 0 behaviors). Gender, being married/partnered, and perceived discrimination were significantly associated with multiple health behavior change. Sociodemographic and social contextual factors predict multiple health behavior change and could inform the design and delivery of worksite interventions targeting multiple health behaviors.
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Affiliation(s)
- Amy E Harley
- Joseph J. Zilber School of Public Health, Center for Urban Population Health, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201 USA
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Drake BF, Quintiliani LM, Sapp AL, Li Y, Harley AE, Emmons KM, Sorensen G. Comparing strategies to assess multiple behavior change in behavioral intervention studies. Transl Behav Med 2013; 3:114-121. [PMID: 23504621 DOI: 10.1007/s13142-013-0195-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND Alternatives to individual behavior change methods have been proposed, however, little has been done to investigate how these methods compare. PURPOSE To explore four methods that quantify change in multiple risk behaviors targeting four common behaviors. METHODS We utilized data from two cluster-randomized, multiple behavior change trials conducted in two settings: small businesses and health centers. Methods used were: (1) summative; (2) z-score; (3) optimal linear combination; and (4) impact score. RESULTS In the Small Business study, methods 2 and 3 revealed similar outcomes. However, physical activity did not contribute to method 3. In the Health Centers study, similar results were found with each of the methods. Multivitamin intake contributed significantly more to each of the summary measures than other behaviors. CONCLUSIONS Selection of methods to assess multiple behavior change in intervention trials must consider study design, and the targeted population when determining the appropriate method/s to use.
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Affiliation(s)
- Bettina F Drake
- Department of Surgery, Washington University School of Medicine (Drake), St. Louis, MO; Department of General Internal Medicine, Boston University Medical Center (Quintiliani), Boston, MA; Department of Biostatistics, Harvard School of Public Health (Li), Boston, MA; University of Wisconsin, School of Public Health (Harley), Milwaukee, WI; Center for Community-Based Research, Department of Society, Human Development and Health, Harvard School of Public Health (Sapp, Emmons, Sorensen), Boston, MA
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Fermented wheat aleurone induces enzymes involved in detoxification of carcinogens and in antioxidative defence in human colon cells. Br J Nutr 2010; 104:1101-11. [DOI: 10.1017/s0007114510001881] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Dietary fibre is fermented by the human gut flora resulting mainly in the formation of SCFA, for example, acetate, propionate and butyrate. SCFA, in particular butyrate, may be important for secondary cancer prevention by inducing apoptosis and inhibiting cell growth of cancer cells, thereby inhibiting the promotion and/or progression of cancer. Furthermore, SCFA could also act on primary cancer prevention by activation of detoxifying and antioxidative enzymes. We investigated the effects of fermented wheat aleurone on the expression of genes involved in stress response and toxicity, activity of drug-metabolising enzymes and anti-genotoxic potential. Aleurone was digested and fermented in vitro to obtain samples that reflect the content of the colon. HT29 cells and colon epithelial stripes were incubated with the resulting fermentation supernatant fractions (fs) and effects on mRNA expression of CAT, GSTP1 and SULT2B1 and enzyme activity of glutathione S-transferase (GST) and catalase (CAT) were measured. Fermented aleurone was also used to study the protection against H2O2-induced DNA damage in HT29 cells. The fs of aleurone significantly induced the mRNA expression of CAT, GSTP1 and SULT2B1 (HT29) and GSTP1 (epithelial stripes), respectively. The enzyme activities of GST (HT29) and CAT (HT29, epithelial stripes) were also unambiguously increased (1·4- to 3·7-fold) by the fs of aleurone. DNA damage induced by H2O2 was significantly reduced by the fs of aleurone after 48 h, whereupon no difference was observed compared with the faeces control. In conclusion, fermented aleurone is able to act on primary prevention by inducing mRNA expression and the activity of enzymes involved in detoxification of carcinogens and antioxidative defence.
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Hunt MK, Stoddard AM, Kaphingst KA, Sorensen G. Characteristics of participants in a cancer prevention intervention designed for multiethnic workers in small manufacturing worksites. Am J Health Promot 2007; 22:33-7. [PMID: 17894261 DOI: 10.4278/0890-1171-22.1.33] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To examine worker characteristics explicated in our social-contextual intervention model that might be associated with participation in a cancer prevention intervention. These characteristics included sociodemographic variables, mediating mechanisms, and modifying conditions. METHODS Randomized, controlled study in 24 small multiethnic manufacturing worksites. Analyses were conducted on an embedded cohort of 456 employees in the intervention condition, incorporating the clustering of respondents in worksites using generalized linear mixed modeling methods. The intervention was based on an inclusive, comprehensive social-contextual model targeting fruit, vegetable, and red meat consumption, multivitamin use, and physical activity. RESULTS Gender (p = .02) and self-efficacy (p < .01) were associated with participation. There were no differences in participation by race/ethnicity or occupational status. We observed no associations between participation of individual workers in intervention activities and health behavior change. CONCLUSIONS The intervention attracted workers across racial/ethnic and occupational groups. The combination of a comprehensive intervention with wide diffusion of program messages may have been more powerful in influencing participation and behavior change than characteristics of individual employees.
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Affiliation(s)
- Mary K Hunt
- Dana-Farber Cancer Institute, Center for Community-Based Research, Boston, Massachusetts, USA.
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Sorensen G, Barbeau E, Stoddard AM, Hunt MK, Kaphingst K, Wallace L. Promoting behavior change among working-class, multiethnic workers: results of the healthy directions--small business study. Am J Public Health 2005; 95:1389-95. [PMID: 16006422 PMCID: PMC1449371 DOI: 10.2105/ajph.2004.038745] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES We examined the efficacy of a cancer prevention intervention designed to improve health behaviors among working-class, multiethnic populations employed in small manufacturing businesses. METHODS Worksites were randomly assigned to an intervention or minimal-intervention control condition. The intervention targeted fruit and vegetable consumption, red meat consumption, multivitamin use, and physical activity. RESULTS Employees in the intervention group showed greater improvements for every outcome compared with employees in the control group. Differences in improvement were statistically significant for multivitamin use and physical activity. Intervention effects were larger among workers than among managers for fruit and vegetable consumption and for physical activity. CONCLUSIONS The social-context model holds promise for reducing disparities in health behaviors. Further research is needed to improve the effectiveness of the intervention.
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Affiliation(s)
- Glorian Sorensen
- Dana-Farber Cancer Institute, Center for Community-Based Research, 44 Binney St, Boston MA 02115, USA.
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Clipp EC, Carver EH, Pollak KI, Puleo E, Emmons KM, Onken J, Farraye FA, McBride CM. Age-related vulnerabilities of older adults with colon adenomas: evidence from Project Prevent. Cancer 2004; 100:1085-94. [PMID: 14983506 DOI: 10.1002/cncr.20082] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND This report addresses the interface between cancer and aging in the context of colorectal carcinoma (CRC), the second leading cause of cancer death in the U.S. overall and the first leading cause among individuals age > or = 75 years. Because polyp risk increases with age, interventions to prevent recurrent polyps among older adults likely would reduce CRC morbidity and mortality. METHODS Data for this study derive from Project Prevent, a multisite, randomized controlled trial designed to reduce behavioral risk factors for CRC among 1247 adults who underwent the removal of > or = 1 adenomatous colon polyps. Middle-aged and older patients were compared on key cognitive-behavioral mechanisms associated with CRC risk and established age-related factors associated with adverse health outcomes. Relations between cognitive-behavioral mechanisms and age-related vulnerability factors identified subgroups of older polyp patients that may have an enhanced risk for CRC. RESULTS Compared with middle-aged patients, older patients were less concerned about developing CRC, less motivated to reduce their risk, and less confident that their behavior change efforts would succeed. As expected, they also reported more age-related physical, social, and economic vulnerabilities, as expected. Evidence for enhanced CRC risk was found for older patients with multiple comorbid conditions, low social support for change, and perceptions of income inadequacy. CONCLUSIONS The presence of age-related vulnerability factors may enhance the risk of CRC among older cancer patients by creating barriers to behavioral change. Efforts to reduce the cancer burden in older populations will require attention beyond early detection and surveillance to interventions that account for the unique physical and psychosocial characteristics of older adults.
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Affiliation(s)
- Elizabeth C Clipp
- School of Nursing, Duke University Medical Center, Durham, North Carolina 27710, USA.
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Beyer-Sehlmeyer G, Glei M, Hartmann E, Hughes R, Persin C, Böhm V, Rowland I, Schubert R, Jahreis G, Pool-Zobel BL. Butyrate is only one of several growth inhibitors produced during gut flora-mediated fermentation of dietary fibre sources. Br J Nutr 2004; 90:1057-70. [PMID: 14641965 DOI: 10.1079/bjn20031003] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Dietary fibre sources are fermented by the gut flora to yield short-chain fatty acids (SCFA) together with degraded phytochemicals and plant nutrients. Butyrate, a major SCFA, is potentially chemoprotective by suppressing the growth of tumour cells and enhancing their differentiation. Conversely, it could lead to a positive selection pressure for transformed cells by inducing glutathione S-transferases (GST) and enhancing chemoresistance. Virtually nothing is known about how butyrate's activities are affected by other fermentation products. To investigate such interactions, a variety of dietary fibre sources was fermented with human faecal slurries in vitro, analysed for SCFA, and corresponding SCFA mixtures were prepared. HT29 colon tumour cells were treated for 72 h with individual SCFA or complex samples. The growth of cells, GST activity, and chemoresistance towards 4-hydroxynonenal were determined. Fermentation products inhibited cell growth more than the corresponding SCFA mixtures, and the SCFA mixtures were more active than butyrate, probably due to phytoprotectants and to propionate, respectively, which also inhibit cell growth. Only butyrate induced GST, whereas chemoresistance was caused by selected SCFA mixtures, but not by all corresponding fermentation samples. In summary, fermentation supernatant fractions contain compounds that: (1) enhance the anti-proliferative properties of butyrate (propionate, phytochemical fraction); (2) do not alter its capacity to induce GST; (3) prevent chemoresistance in tumour cells. It can be concluded that fermented dietary fibre sources are more potent inhibitors of tumour cell growth than butyrate alone, and also contain ingredients which counteract the undesired positive selection pressures that higher concentrations of butyrate induce in tumour cells.
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Affiliation(s)
- Gabriele Beyer-Sehlmeyer
- Department of Nutritional Toxicology, Institute for Nutrition, Friedrich Schiller University, Dornburger Str. 25, D-07743 Jena, Germany
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Levi F, Pasche C, Lucchini F, La Vecchia C. Selected micronutrients and colorectal cancer. a case-control study from the canton of Vaud, Switzerland. Eur J Cancer 2000; 36:2115-9. [PMID: 11044650 DOI: 10.1016/s0959-8049(00)00195-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The association between dietary intake of various micronutrients and colorectal cancer risk was analysed using data from a case-control study conducted between 1992 and 1997 in the Swiss Canton of Vaud. Cases were 223 subjects (142 (64%) males, 81 (36%) females; median age 63 years) with incident, histologically confirmed colon (n=119; 53%) or rectal (n=104; 47%) cancer, and controls were 491 subjects (211 (43%) males, 280 (57%) females; median age 58 years; range 27-74) admitted to the same university hospital for a wide spectrum of acute non-neoplastic conditions, unrelated to long-term modifications of diet. Dietary habits were investigated using a validated food frequency questionnaire (FFQ). Odds ratios (OR) were obtained after allowance for age, sex, education, smoking, alcohol, body mass index, physical activity, and total energy and fibre intake. No significant association was observed for calcium, retinol, folate, vitamin D or E. The risk of colorectal cancer was directly associated with measures of iron intake (OR=2.43 for the highest tertile, 95% confidence interval (CI): 1.2-5.1) and inversely associated with vitamin C (OR=0.45; 95% CI: 0.3-0.8), and non-significantly with total carotenoids (OR=0.66, 95% CI: 0.4-1.1). Among various individual carotenoids considered, inverse associations were observed for alpha-carotene, beta-carotene and lutein/zeaxanthin. These findings were consistent across the strata of gender and age, and support the hypothesis that selected micronutrients have a favourable effect on colorectal carcinogenesis.
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Affiliation(s)
- F Levi
- Unité d'Epidémiologie du Cancer, Institut Universitaire de Médecine Sociale et Préventive, Bugnon 17, 1005, Lausanne, Switzerland.
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Abrahamse SL, Pool-Zobel BL, Rechkemmer G. Potential of short chain fatty acids to modulate the induction of DNA damage and changes in the intracellular calcium concentration by oxidative stress in isolated rat distal colon cells. Carcinogenesis 1999; 20:629-34. [PMID: 10223191 DOI: 10.1093/carcin/20.4.629] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Short chain fatty acids (SCFA) are considered to be beneficial fermentation products in the gut by exerting trophic effects in non-transformed colon cells and by slowing proliferation and enhancing differentiation in colonic tumour cells. We have studied the further effects of SCFA on cellular events of early carcinogenesis, genotoxicity and cytotoxicity in rat distal colon cells. Cytotoxicity was assessed by measuring trypan blue exclusion and by determining the H2O2-induced changes in intracellular calcium concentration ([Ca2+]i) using a fluorospectrophotometer and the calcium-sensitive fluorescent dye Fura-2. The microgel electrophoresis technique (COMET assay) was used to assess oxidative DNA damage. Individual SCFA and physiological SCFA mixtures were investigated for their potential to prevent DNA and cell damage induced by H2O2. For this, freshly isolated colon cells were treated with H2O2 (100-500 microM) and 6.25 mM SCFA. We have found 100-500 microM H2O2 to cause a fast initial increase in [Ca2+]i, whereafter the levels gradually further increased. Addition of SCFA did not affect [Ca2+]i nor did it reduce the H2O2-induced increase in [Ca2+]i. Butyrate and acetate were able to reduce the induction of DNA damage by 100, 200 and 500 microM H2O2, respectively. In contrast, i-butyrate and propionate were ineffective. The degree of reduction of DNA damage for the two protective SCFA was similar. Physiological mixtures containing acetate, propionate and butyrate in ratios of 41:21:38 or 75:15:10 that are expected to arise in the colon after fermentation of resistant starches and pectin, respectively, did not show significant antigenotoxic effects. The major difference between butyrate and acetate, on one hand, and i-butyrate and propionate, on the other hand, is that the former compounds are utilized best as energy sources by the colon cells. Therefore, our results on antigenotoxicity coupled with the findings on [Ca2+]i homeostasis indicate that molecular effects on the energy system render these non-transformed, freshly isolated colon cells to be less susceptible to H2O2.
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Affiliation(s)
- S L Abrahamse
- Institute of Nutritional Physiology, Federal Research Centre for Nutrition, Karlsruhe, Germany
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Rijnkels JM, Hollanders VM, Woutersen RA, Koeman JH, Alink GM. Absence of an inhibitory effect of a vegetables-fruit mixture on the initiation and promotion phases of azoxymethane-induced colorectal carcinogenesis in rats fed low- or high-fat diets. Nutr Cancer 1998; 30:124-9. [PMID: 9589430 DOI: 10.1080/01635589809514651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The potential inhibitory effects of a vegetables-fruit mixture on the initiation and promotion phases of azoxymethane-induced colorectal carcinogenesis were examined in rats fed low- or high-fat diets. Rats were fed low-fat diets (20 energy percent, Diets A and B) or high-fat diets (40 energy percent, Diets C and D), supplemented with a vegetables-fruit mixture (19.5% wt/wt, Diets B and D) or unsupplemented (Diets A and C) for 36 weeks. After the animals were maintained on the respective diets for four weeks, they were given three weekly injections of azoxymethane at 15 mg/kg body wt sc. Eight weeks after the start of the study, animals maintained on Diet A were switched to Diet B or C or maintained on the same diet. Animals maintained on Diet B or D were switched to Diet A or C, respectively. Furthermore, animals maintained on Diet C were switched to Diet A or D or maintained on the same diet. Multiplicity of colorectal tumors did not differ between groups fed a vegetables-fruit mixture during the initiation or the promotion phase (Group B-->A vs. Group A-->B; Group D-->C vs. Group C-->D). However, multiplicity was significantly lower in animals fed low-fat diets than in animals fed high-fat diets in combination with a vegetables-fruit mixture (Group A-->B/B--A vs. Group C-->D/D-->C). Furthermore, multiplicity was significantly increased in groups fed a high-fat diet during the promotion phase only in comparison with animals fed a low-fat diet during the whole experiment (Group A-->C vs. Group A-->A). No other differences in multiplicity or tumor incidences were observed among the eight experimental groups.
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Affiliation(s)
- J M Rijnkels
- Department of Toxicology, Wageningen Agricultural University, The Netherlands.
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Rijnkels JM, Hollanders VM, Woutersen RA, Koeman JH, Alink GM. Modulation of dietary fat-enhanced colorectal carcinogenesis in N-methyl-N'-nitro-N-nitrosoguanidine-treated rats by a vegetables-fruit mixture. Nutr Cancer 1998; 29:90-5. [PMID: 9383790 DOI: 10.1080/01635589709514607] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The modulation of a vegetables-fruit mixture on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced colorectal carcinogenesis was studied in rats maintained on a low- or a high-fat diet. For this purpose, 120 rats received a semisynthetic diet without (Groups A and C) or with a vegetables-fruit mixture (19.5% wt/wt, Groups B and D) for 35 weeks. Diets of Group A and B contained 20 (low) energy percent (20e%) fat, whereas diets of Groups C and D contained 40e% (high) fat. Between Weeks 4 and 9 the animals were given weekly intrarectal instillations of 6 mg MNNG/kg body wt. The colorectal adenocarcinoma incidences showed a significant decrease in animals fed high-fat diets with a vegetables-fruit mixture compared with animals fed a high-fat diet alone. Furthermore, without a vegetables-fruit mixture, diets high in fat caused a significant increase in adenocarcinoma incidence compared with diets low in fat. Although not significant, the adenoma incidences tended to be lower in animals fed a vegetables-fruit mixture than in animals maintained on a diet without this mixture. The results demonstrate that a vegetables-fruit mixture has a significant inhibitory potency on the development of colorectal tumors induced by MNNG in rats fed diets high in fat.
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Affiliation(s)
- J M Rijnkels
- Department of Toxicology, Wageningen Agricultural University, The Netherlands.
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La Vecchia C, Braga C, Negri E, Franceschi S, Russo A, Conti E, Falcini F, Giacosa A, Montella M, Decarli A. Intake of selected micronutrients and risk of colorectal cancer. Int J Cancer 1997; 73:525-30. [PMID: 9389567 DOI: 10.1002/(sici)1097-0215(19971114)73:4<525::aid-ijc12>3.0.co;2-8] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The relationship between various micronutrients and colorectal cancer risk was investigated using data from a case-control study conducted between January 1992 and June 1996 in Italy. Cases were 1,953 incident, histologically confirmed colorectal cancers (1,225 of the colon and 728 of the rectum), admitted to the major teaching and general hospitals in the study areas, and 4,154 controls with no history of cancer, admitted to hospitals in the same catchment areas for acute, non-neoplastic diseases unrelated to the digestive tract and requiring no long-term modifications of the diet. Dietary habits were investigated using a validated food-frequency questionnaire. Odds ratio (ORs) were computed after allowance for age, sex and other potential confounding factors, including physical activity, total energy and fibre intake. For most micronutrients, ORs were below unity with increasing quintile of intake. The most consistent protective effects were for carotene, riboflavin and vitamin C (Multivariate ORs from the continuous model, with unit set as the difference between the upper cut-point of the 4th quintile and that of the 1st one, were 0.65, 0.73 and 0.80, respectively). Inverse relationships were observed also for calcium and vitamin D (ORs of 0.85 and 0.93, respectively). When the combined effect of calcium and vitamin D and selected anti-oxidants was considered, the OR reached 0.46 in subjects reporting high calcium/vitamin D and high anti-oxidant intake compared to those reporting low intake of both groups of micronutrients. Most results were apparently stronger for colon cancer and among females. Our results provide further support for a protective effect of several micronutrients on colorectal cancer risk and some indications for a specific and stronger effect of selected anti-oxidants.
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Affiliation(s)
- C La Vecchia
- Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
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Rijnkels JM, Hollanders VM, Woutersen RA, Koeman JH, Alink GM. Interaction of dietary fat with a vegetables-fruit mixture on 1,2-dimethylhydrazine-induced colorectal cancer in rats. Nutr Cancer 1997; 27:261-6. [PMID: 9101556 DOI: 10.1080/01635589709514536] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aim of the present investigation was to study the interaction of dietary fat in combination with a vegetables-fruit mixture on 1,2-dimethylhydrazine (DMH)-induced colorectal carcinogenesis in rats. For this purpose, 120 weanling male. Wistar rats received a semisynthetic diet without (Groups A and C) or with a vegetables-fruit mixture (Groups B and D; vegetables and fruit content 19.5% wt/wt) for 35 weeks. Diets of Groups A and B contained 20 energy percent (20e%) fat, whereas diets of Groups C and D contained 40e% fat. The vegetables and fruit used the amount of fat, and its fatty acid composition were chosen according to the mean consumption values of The Netherlands. After the animals were maintained for four weeks on the respective diets, they were given 10 weekly injections of DMH at 50 mg/kg body wt sc. After sacrifice, their colons were removed and examined macroscopically and microscopically for the presence of tumors. Rats fed high-fat diets developed significantly more tumors than rats fed low-fat diets. Furthermore, although not statistically significant, a lower number of colorectal tumors was observed in rats fed a low- or a high-fat diet containing the vegetables-fruit mixture than in rats fed diets without the vegetables-fruit mixture. No differences were observed in intestinal tumor incidences among all groups. The results suggest that the vegetables-fruit mixture used in this experiment, present in an amount comparable with the mean consumption in The Netherlands, has no significant inhibitory effect on the development of colorectal tumors induced by DMH in rats maintained on diets low or high in fat.
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Affiliation(s)
- J M Rijnkels
- Department of Toxicology, Wageningen Agricultural University, The Netherlands.
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