Recent Submissions

  • Legionellapreventie: betere naleving Waterleidingwet nodig

    Versteegh, A.; Brandsema, P.; Aa, M. van der; Dik, H. (Dekker en Nordemann, Rotterdam, 2007-11-01)
    Ongeveer 20 procent van de zorginstellingen en zwembaden heeft in 2005 te maken gehad met een legionellabesmetting in de leidingwaterinstallatie. Dit gold ook voor 5 procent van de hotels en campings. Vooral in zorginstellingen kan Legionella in de waterleidingen gevaarlijk zijn, omdat de mensen hier vaak een zwakkere gezondheid hebben. Circa 90% van de instellingen leeft niet alle wettelijk voorgeschreven preventiemaatregelen volledig na. Bij hercontrole is echter een groot deel van de problemen opgelost. Dit toont de effectiviteit en het belang van de controles: eenmaal op de hoogte van de risico’s zijn de eigenaren meestal bereid de nodige aanpassingen te doen. Het aantal collectieve leidingwaterinstallaties met Legionella nam tussen 2000 en 2006 niet duidelijk af. Een betere naleving van de legionellapreventie regelgeving en installatievoorschriften leidt naar verwachting wél tot minder Legionella in leidingwaterinstallaties. Tussen 2000 en 2006 steeg het aantal gemelde patiënten met legionellose. Een betrouwbare schatting van het aantal patiënten dat gerelateerd is aan een collectieve leidingwaterinstallatie als besmettingsbron is echter niet mogelijk.
  • Functional foods: the case for closer evaluation.

    Jong, Nynke de; Klungel, Olaf H; Verhagen, Hans; Wolfs, Marion C J; Ocké, Marga C; Leufkens, Hubert G M (2007-05-19)
    Current regulations focus on the mandatory safety evaluation of functional foods before they come to market, but Nynke de Jong and colleagues argue that the effects of such foods should also be evaluated after they have been launched
  • Depression and cardiovascular mortality: a role for n-3 fatty acids?

    Kamphuis, Marjolein H; Geerlings, Mirjam I; Tijhuis, Marja A R; Kalmijn, Sandra; Grobbee, Diederick E; Kromhout, Daan (2006-12-01)
    BACKGROUND: Recent studies indicate that depression plays an important role in the occurrence of cardiovascular diseases (CVDs). The underlying mechanisms are not well understood. OBJECTIVE: We investigated whether dietary intake of the n-3 fatty acids (FAs) eicosapentaenic acid and docosahexaenoic acid could explain the relation between depressive symptoms and cardiovascular mortality. DESIGN: The Zutphen Elderly Study is a prospective cohort study conducted in the Netherlands. Depressive symptoms were measured in 1990 with the Zung Self-rating Depression Scale in 332 men aged 70-90 y and free from CVD and diabetes. Dietary factors were assessed with a cross-check dietary history method in 1990. Mortality data were collected between 1990 and 2000. Logistic and Cox regression analyses were performed, with adjustment for demographics and CVD risk factors. RESULTS: Compared with a low intake (x: 21 mg/d), a high intake (x: 407 mg/d) of n-3 FAs was associated with fewer depressive symptoms [odds ratio: 0.46; 95% CI: 0.22, 0.95; P for trend = 0.04] at baseline and no significant reduced risk of 10-y CVD mortality [hazard ratio (HR): 0.88; 95% CI: 0.51, 1.50]. The adjusted HR for an increase in depressive symptoms with 1 SD for CVD mortality was 1.28 (95% CI: 1.03, 1.57) and did not change after additional adjustment for the intake of n-3 FAs. CONCLUSION: An average intake of approximately 400 mg n-3 FA/d may reduce the risk of depression. Our results, however, do not support the hypothesis that the intake of n-3 FAs explains the relation between depression and CVD.
  • Spores from mesophilic Bacillus cereus strains germinate better and grow faster in simulated gastro-intestinal conditions than spores from psychrotrophic strains.

    Wijnands, L M; Dufrenne, J B; Zwietering, M H; Leusden, F M van (2006-11-01)
    The species Bacillus cereus, known for its ability to cause food borne disease, consists of a large variety of strains. An important property for discrimination of strains is their growth temperature range. Psychrotrophic strains can grow well at refrigerator temperatures but grow at 37 degrees C with difficulty. Mesophilic strains on the other hand are unable to grow below 10 degrees C, but grow well at 37 degrees C. Spores of six psychrotrophic and six mesophilic strains were investigated for their ability to survive and grow in simulated gastro-intestinal fluids, mimicking the conditions in the gastro-intestinal tract. The germination potential of psychrotrophic and mesophilic spores in simulated intestinal fluid does not differ much. Under conditions simulating the gastro-intestinal passage, 5 out of 6 mesophilic strains showed growth, and only 2 out of 6 psychrotrophic strains. Temperature (37 degrees C) and simulated gastro-intestinal conditions together influenced germination and growth.
  • the potential of AGE MODE, an age-dependent model, to estimate usual intakes and prevalences of inadequate intakes in a population.

    Waijers, Patricia M C M; Dekkers, Arnold L M; Boer, Jolanda M A; Boshuizen, Hendriek C; Rossum, Caroline T M van (2006-11-01)
    Dietary intake data often stem from short-term measurements. However, for dietary assessment, generally the habitual intake distribution is of interest. Currently, habitual intake distributions are often estimated separately for subgroups of gender and age and do not take into account the variation in intake caused by age within age groups. Therefore, we developed an age-dependent dietary assessment model, which was demonstrated and tested using folate intakes from the third Dutch National Food Consumption Survey, conducted in 1997/98. The proposed model produced estimates of the mean habitual intake and intake percentiles as a function of age. The methodology has clear advantages in estimating habitual intakes in children. Also, given the large variation in intakes of several dietary components, estimated habitual intakes produced by other methods may have low precision and be less reliable if numbers are small. In our age-dependent model, all available data can be used to estimate the parameters of the habitual intake distribution, improving the precision of the estimates, and providing consistent estimates for a larger population sample as no subgroups need to be created. Although the model may still be further developed, the feature of age dependency shows clear advantages above methods currently used to estimate habitual intakes.
  • Approaches to the risk assessment of genotoxic carcinogens in food: a critical appraisal.

    O'Brien, J; Renwick, A G; Constable, A; Dybing, Erik; Müller, D J G; Schlatter, J; Slob, Wout; Tueting, W; Benthem, Jan van; Williams, G M; Wolfreys, A (2006-10-01)
    The present paper examines the particular difficulties presented by low levels of food-borne DNA-reactive genotoxic carcinogens, some of which may be difficult to eliminate completely from the diet, and proposes a structured approach for the evaluation of such compounds. While the ALARA approach is widely applicable to all substances in food that are both carcinogenic and genotoxic, it does not take carcinogenic potency into account and, therefore, does not permit prioritisation based on potential risk or concern. In the absence of carcinogenicity dose-response data, an assessment based on comparison with an appropriate threshold of toxicological concern may be possible. When carcinogenicity data from animal bioassays are available, a useful analysis is achieved by the calculation of margins of exposure (MOEs), which can be used to compare animal potency data with human exposure scenarios. Two reference points on the dose-response relationship that can be used for MOE calculation were examined; the T25 value, which is derived from linear extrapolation, and the BMDL10, which is derived from mathematical modelling of the dose-response data. The above approaches were applied to selected food-borne genotoxic carcinogens. The proposed approach is applicable to all substances in food that are DNA-reactive genotoxic carcinogens and enables the formulation of appropriate semi-quantitative advice to risk managers.
  • Effects of Fusarium toxin-contaminated wheat and feed intake level on the biotransformation and carry-over of deoxynivalenol in dairy cows.

    Seeling, K; Dänicke, S; Valenta, H; Egmond, H P van; Schothorst, R C; Jekel, A A; Lebzien, P; Schollenberger, M; Razzazi-Fazeli, E; Flachowsky, G (2006-10-01)
    An experiment was carried out to examine the effects of feeding Fusarium toxin-contaminated wheat (8.21 mg deoxynivalenol (DON) and 0.09 mg zearalenone (ZON) per kg dry matter) at different feed intake levels on the biotransformation and carry-over of DON in dairy cows. For this purpose, 14 ruminal and duodenal fistulated dairy cows were fed a diet containing 60% concentrate with a wheat portion of 55% (Fusarium toxin-contaminated wheat (mycotoxin period) or control wheat (control period)) and the ration was completed with maize- and grass silage (50 : 50) on a dry matter basis. Daily DON intakes ranged from 16.6 to 75.6 mg in the mycotoxin period at dry matter intakes of 5.6-20.5 kg. DON was almost completely biotransformed to de-epoxy DON (94-99%) independent of the DON/feed intake, and the flow of DON and de-epoxy DON at the duodenum related to DON intake ranged from 12 to 77% when the Fusarium toxin-contaminated wheat was fed. In the serum samples, de-epoxy DON was detected in the range of 4-28 ng ml-1 in the mycotoxin period, while concentrations of DON were all below the detection limit. The daily excretion of DON and de-epoxy DON in the milk of cows fed the contaminated wheat varied between 1 and 10 microg and between 14 and 104 microg, respectively. The total carry-over rates as the ratio between the daily excretion of DON and de-epoxy DON into milk and DON intake were in the ranges of 0.0001-0.0002 and 0.0004-0.0024, respectively. Total carry-over rates of DON as DON and de-epoxy DON into the milk increased significantly with increasing milk yield. In the urine samples, de-epoxy DON was the predominant substance as compared with DON with a portion of the total DON plus de-epoxy DON concentration to 96% when the Fusarium toxin-contaminated wheat was fed, whereas the total residues of DON plus de-epoxy DON in faeces ranged between 2 and 18% of DON intake in the mycotoxin period. The degree of glucuronidation of de-epoxy DON was found to be approximately 100% in serum. From 33 to 80% of DON and from 73 to 92% of de-epoxy DON, and from 21 to 92% of DON and from 86 to 100% of de-epoxy DON were glucuronidated in the milk and urine, respectively. It is concluded that DON is very rapidly biotransformed to de-epoxy DON in the rumen and only negligible amounts of DON and de-epoxy DON were transmitted into the milk within the range of 5.6-20.5 kg day-1 dry matter intake and milk yields (fat corrected milk) between 10 and 42 kg day-1.
  • Risk assessment of substances that are both genotoxic and carcinogenic report of an International Conference organized by EFSA and WHO with support of ILSI Europe.

    Barlow, S; Renwick, A G; Kleiner, J; Bridges, J W; Busk, L; Dybing, Erik; Edler, L; Eisenbrand, G; Fink-Gremmels, J; Knaap, A G A C; Kroes, R; Liem, D; Müller, D J G; Page, S; Rolland, V; Schlatter, J; Tritscher, A; Tueting, W; Würtzen, G (2006-10-01)
    The European Food Safety Authority (EFSA) and the World Health Organization (WHO), with the support of the International Life Sciences Institute, European Branch (ILSI Europe), organized an international conference on 16-18 November 2005 to discuss how regulatory and advisory bodies evaluate the potential risks of the presence in food of substances that are both genotoxic and carcinogenic. The objectives of the conference were to discuss the possible approaches for risk assessment of such substances, how the approaches may be interpreted and whether they meet the needs of risk managers. ALARA (as low as reasonably achievable) provides advice based solely on hazard identification and does not take into account either potency or human exposure. The use of quantitative low-dose extrapolation of dose-response data from an animal bioassay raises numerous scientific uncertainties related to the selection of mathematical models and extrapolation down to levels of human exposure. There was consensus that the margin of exposure (MOE) was the preferred approach because it is based on the available animal dose-response data, without extrapolation, and on human exposures. The MOE can be used for prioritisation of risk management actions but the conference recognised that it is difficult to interpret it in terms of health risk.
  • The use of the DR CALUX bioassay and indicator polychlorinated biphenyls for screening of elevated levels of dioxins and dioxin-like polychlorinated biphenyls in eel.

    Hoogenboom, Ron; Bovee, Toine; Traag, Win A; Hoogerbrugge, Ronald; Baumann, Bert; Portier, Liza; Weg, Guido van de; Vries, Jaap de (2006-10-01)
    The DR CALUX bioassay is a very suitable screening method for dioxins and dioxin-like-PCBs in feed and food. This was, e. g. demonstrated in a survey in the Netherlands to control the dioxin levels in eel. The DR CALUX assay, but also indicator polychlorinated biphenyls (PCB) were evaluated as a screening method. Based on the limit for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F) [at that time 8 pg toxic equivalents (TEQ)/g eel], and the relation between PCDD/F and dioxin-like-PCB, a decision limit of 30 pg TEQ/g eel was used for screening of 153 field samples. Suspected samples (21) and part of the higher contaminated negative samples (35) were analyzed by GC/MS for dioxins, non-ortho, mono-ortho and indicator PCB, revealing 13 samples exceeding the action limit of 30 pg TEQ/g eel. Only one sample slightly exceeded the dioxin level of 8 pg TEQ/g eel. The relatively low sensitivity for mono-ortho PCB was overcome by the use of reference samples, as shown by the correlation of 0.93 between GC/MS and CALUX determined total TEQ levels. The present data show that the DR CALUX assay can be used for screening of total TEQ levels in eel. The use for dioxins only requires a safe, and therefore relatively low, decision limit. The indicator PCB also showed a good correlation with total TEQ levels, mainly due to the large contribution of the mono-ortho PCB at higher concentrations. The relation with dioxins was very poor and as such indicator PCB seem less suitable than the DR CALUX assay for screening for dioxins only. The present study clearly shows that part of the wild eel samples contains high total TEQ levels and will exceed the future European Union limit of 12 pg TEQ/g eel for dioxins and dioxin-like PCB. Especially at high TEQ levels, dioxin-like PCB contribute most to the total TEQ. In practice, wild eel presents only a minor part of the eel consumed.
  • Environmental determinants of fruit and vegetable consumption among adults: a systematic review.

    Kamphuis, Carlijn B M; Giskes, Katrina; Bruijn, Gert-Jan de; Wendel-Vos, Wanda; Brug, Johannes; Lenthe, Frank J van (2006-10-01)
    The current ecological approach in health behaviour research recognises that health behaviour needs to be understood in a broad environmental context. This has led to an exponential increase in the number of studies on this topic. It is the aim of this systematic review to summarise the existing empirical evidence pertaining to environmental influences on fruit and vegetable (FV) consumption. The environment was defined as 'all factors external to the individual'. Scientific databases and reference lists of selected papers were systematically searched for observational studies among adults (18-60 years old), published in English between 1 January 1980 and 31 December 2004, with environmental factor(s) as independent factor(s), and fruit intake, vegetable intake or FV intake combined as one outcome measure as dependent factor(s). Findings showed there was a great diversity in the environmental factors studied, but that the number of replicated studies for each determinant was limited. Most evidence was found for household income, as people with lower household incomes consistently had a lower FV consumption. Married people had higher intakes than those who were single, whereas having children showed mixed results. Good local availability (e.g. access to one's own vegetable garden, having low food insecurity) seemed to exert a positive influence on intake. Regarding the development of interventions, improved opportunities for sufficient FV consumption among low-income households are likely to lead to improved intakes. For all other environmental factors, more replicated studies are required to examine their influence on FV intake.
  • Effectiveness of customary use of phytosterol/-stanol enriched margarines on blood cholesterol lowering.

    Wolfs, Marion; Jong, Nynke de; Ocké, Marga C; Verhagen, Hans; Monique Verschuren, W M (2006-10-01)
    Postlaunch monitoring of functional foods can encompass monitoring of effectiveness under conditions of customary use. To this end, the effectiveness of phytosterol/-stanol enriched margarine consumption in free-living conditions was investigated with data from the Dutch "Doetinchem cohort study". In total, 4,505 subjects (aged 26-70 years) were examined in 1994-1998 and re-examined during 1999-2003. A general and a food frequency questionnaire and non-fasting blood samples for total and HDL cholesterol determination were obtained. Subjects were stratified into phytosterol/-stanol enriched margarine users (n = 84) and non-users (n = 4,421) based on the re-examination data, as these margarines were available on the Dutch market from 1999 onwards. Mean spontaneous daily use (g +/- SD) of phytosterol-containing margarine (n = 71) was 15 +/- 8 and of phytostanol-containing margarine (n = 13) 9+/-6. After five years, total blood cholesterol had increased with 0.26 mmol/l in non-users while it had not significantly changed in users. The difference in total blood cholesterol change in users versus non-users was -0.30 mmol/l (p < 0.001). The beneficial effect of the phytosterol/-stanol enriched margarine, used under customary conditions can be characterized as a stabilization of cholesterol levels. This is the first report finding a modest beneficial effect on blood cholesterol level under customary conditions thereby partly confirming findings from clinical trials.
  • Can Transgenic Maize Affect Soil Microbial Communities?

    Mulder, Christian; Wouterse, Marja; Raubuch, Markus; Roelofs, Willem; Rutgers, Michiel (2006-09-29)
    The aim of the experiment was to determine if temporal variations of belowground activity reflect the influence of the Cry1Ab protein from transgenic maize on soil bacteria and, hence, on a regulatory change of the microbial community (ability to metabolize sources belonging to different chemical guilds) and/or a change in numerical abundance of their cells. Litter placement is known for its strong influence on the soil decomposer communities. The effects of the addition of crop residues on respiration and catabolic activities of the bacterial community were examined in microcosm experiments. Four cultivars of Zea mays L. of two different isolines (each one including the conventional crop and its Bacillus thuringiensis cultivar) and one control of bulk soil were included in the experimental design. The growth models suggest a dichotomy between soils amended with either conventional or transgenic maize residues. The Cry1Ab protein appeared to influence the composition of the microbial community. The highly enhanced soil respiration observed during the first 72 h after the addition of Bt-maize residues can be interpreted as being related to the presence of the transgenic crop residues. This result was confirmed by agar plate counting, as the averages of the colony-forming units of soils in conventional treatments were about one-third of those treated with transgenic straw. Furthermore, the addition of Bt-maize appeared to induce increased microbial consumption of carbohydrates in BIOLOG EcoPlates. Three weeks after the addition of maize residues to the soils, no differences between the consumption rate of specific chemical guilds by bacteria in soils amended with transgenic maize and bacteria in soils amended with conventional maize were detectable. Reaped crop residues, comparable to post-harvest maize straw (a common practice in current agriculture), rapidly influence the soil bacterial cells at a functional level. Overall, these data support the existence of short Bt-induced ecological shifts in the microbial communities of croplands' soils.
  • Short- and long-term variations of norovirus concentrations in the Meuse river during a 2-year study period.

    Westrell, Therese; Teunis, Peter F M; Berg, Harold H J L van den; Lodder, Willemijn J; Ketelaars, Henk; Stenström, Thor Axel; Roda Husman, Ana Maria de (2006-08-01)
    Faecally impacted surface waters used for drinking water production may encompass risk for norovirus infections. To be able to assess a possible health risk, noroviruses should be quantified and fluctuations identified. In 2001, norovirus concentrations in the river Meuse displayed a seasonal distribution with high peaks during wintertime as determined by RT-PCR on serially diluted RNA. An intensified day-by-day sampling scheme in the winter of 2002/2003 revealed that the winter peak consisted of several peaks of varying duration and magnitude, possibly due to contamination events in the catchment. The highest estimated concentration was 1700 PCR-detectable units per litre (95% CI 250-8000), which if coinciding with failing treatment could lead to significant numbers in drinking water. Adaptive dynamic filtering was shown to adequately predict subsequent sample concentrations. If valid, such analyses could prove to be useful as early warning systems in risk management of water sources.
  • Real-time detection of noroviruses in surface water by use of a broadly reactive nucleic acid sequence-based amplification assay.

    Rutjes, Saskia A; Berg, Harold H J L van den; Lodder, Willemijn J; Roda Husman, Ana Maria de (2006-08-01)
    Noroviruses are the most common agents causing outbreaks of viral gastroenteritis. Outbreaks originating from contaminated drinking water and from recreational waters have been described. Due to a lack of cell culture systems, noroviruses are detected mostly by molecular methods. Molecular detection assays for viruses in water are often repressed by inhibitory factors present in the environment, like humic acids and heavy metals. To study the effect of environmental inhibitors on the performance of nucleic acid sequence-based amplification (NASBA), we developed a real-time norovirus NASBA targeting part of the RNA-dependent RNA polymerase (RdRp) gene. Specificity of the assay was studied with 33 divergent clones that contained part of the targeted RdRp gene of noroviruses from 15 different genogroups. Viral RNA originated from commercial oysters, surface waters, and sewage treatment plants in The Netherlands. Ninety-seven percent of the clones derived from human noroviruses were detected by real-time NASBA. Two clones containing animal noroviruses were not detected by NASBA. We compared the norovirus detection by real-time NASBA with that by conventional reverse transcriptase PCR (RT-PCR) with large-volume river water samples and found that inhibitory factors of RT-PCR had little or no effect on the performance of the norovirus NASBA. This consequently resulted in a higher sensitivity of the NASBA assay than of the RT-PCR. We show that by combining an efficient RNA extraction method with real-time NASBA the sensitivity of norovirus detection in water samples increased at least 100 times, which consequently has implications for the outcome of the infectious risk assessment.
  • Filet américain oorzaak van eerste landelijke uitbraak van Shigatoxine-producerende Escherichia coli O157-infecties

    Doorduyn, Y; Jager, C M de; Zwaluw, W K van der; Friesema, I H M; Heuvelink, A E; Boer, E de; Wannet, Wim J B; Duynhoven, Yvonne T H P van (RIVM, 2006-08-01)
    In September 2005, the first nationwide outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 infections was observed. A total of 21 confirmed and 11 probable patients were reported, who fell ill between September 11 and October 10. Preliminary investigation by the local public health services revealed two possible risk factors: consumption of steak tartare and contact with other persons with gastroenteritis. The results of the subsequent case-control study suggested steak tartare as the most likely cause of the outbreak. Samples of steak tartare taken at a supermarket chain where most of the patients bought the product, tested negative for STEC O157. However, sampling took place 3 days after the date of symptom onset of the last outbreak case. Because 88% of the cases became ill within a two-week period and samples taken shortly afterwards tested negative, point source contamination of steak tartare was considered most plausible.
  • A simple steady-state model for carry-over of aflatoxins from feed to cow's milk.

    Eijkeren, Jan C H van; Bakker, Martine I; Zeilmaker, Marco J (2006-08-01)
    A simple steady-state model is derived from two kinetic one-compartment models for the disposition of aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1) in the lactating cow. The model relates daily intake of AFB1 in feed of dairy cattle and the cow's lactation status to resulting concentrations of AFM1 in milk. Moreover, assuming a linear relationship between the cow's lactation status and feed intake, the model relates daily milk production and AFB1 concentration in total feed to AFM1 levels in milk. The model explains similar experimental outcomes from different investigations into carry-over of aflatoxins from feed to milk. Although it is difficult to set a permanent limit for AFB1 in feed, the European Union (EU) limit of 5 microg AFB1 kg(-1) concentrate has proved, thus far, to be an appropriate level in preventing the EU limit of 0.05 microg AFM1 kg(-1) milk being exceeded.
  • Detection of noroviruses in foods: a study on virus extraction procedures in foods implicated in outbreaks of human gastroenteritis.

    Rutjes, Saskia A; Lodder-Verschoor, Froukje; Poel, Wim H M van der; Duynhoven, Yvonne T H P van; Roda Husman, Ana Maria de (2006-08-01)
    Disease outbreaks in which foods are epidemiologically implicated as the common source are frequently reported. Noroviruses and enteric hepatitis A viruses are among the most prevalent causative agents of foodborne diseases. However, the detection of these viruses in foods other than shellfish is often time-consuming and unsuccessful. In this study, three virus concentration methods were compared: polyethylene glycol (PEG) plus NaCl, ultracentrifugation, and ultrafiltration. Two RNA extraction methods, TRIzol and RNeasy Mini Kit (Qiagen), were compared for detection of viruses in whipped cream and lettuce (as representatives of the dairy and vegetable-fruit food groups, respectively). A seeding experiment with canine calicivirus was conducted to determine the efficiency of each virus extraction procedure. The PEG-NaCl-TRIzol method was most efficient for the detection of viruses in whipped cream and the ultracentrifugation-RNeasy-Mini Kit procedure was best for detection on lettuce. Based on the seeding experiments, food items implicated in norovirus-associated gastroenteritis outbreaks were subjected to the optimal procedure for a specific composition and matrix. No noroviruses were detected in the implicated food items, possibly because the concentration of virus on the food item was too low or because of the presence of inhibitory factors. For each food group, a specific procedure is optimal. Inhibitory factors should be controlled in these procedures because they influence virus detection in food.
  • Polymorphisms in the genes involved in the arachidonic acid-pathway, fish consumption and the risk of colorectal cancer.

    Siezen, Christine L E; Bueno-de-Mesquita, H Bas; Peeters, Petra H M; Kram, Nicolien R; Doeselaar, Marina van; Kranen, Henk J van (2006-07-15)
    The objective of this study on colorectal cancer was to investigate the associations between SNPs in the genes involved in the arachidonic acid (AA)-pathway, their haplotypes and colorectal cancer. Moreover, interactions between SNPs and fish consumption were considered. In this study, a total of 508 cases and 772 controls were included, originating from 2 prospective cohorts, the Monitoring Project on Cardiovascular Disease Risk Factors (PPHV) and Diagnostisch Onderzoek Mammacarcinoom (DOM). Genotypes of 23 SNPs in 7 candidate genes were determined and the modifying effect of fish consumption was considered. A protective effect of the minor allele of SNP V102V in PTGS2 was observed (odds ratio (OR), 0.37; 95% confidence intervals (CI), 0.16-0.87). The haplotype representing this allele showed a weaker inverse association, indicating that 2 alleles are necessary to obtain this protective effect. Fish consumption data was available for 209 cases and 418 controls. Increased fish consumption was inversely associated with cancer, although not significant (OR, 0.83; 95% CI, 0.57-1.20). Despite the substantial reductions in cancer risk for some genotypes in combination with high fish intake, no significant interactions between any SNP studied and fish consumption were observed. We have previously described an association between colorectal adenomas and SNP V102V in PTGS2 and have now confirmed this association for colorectal adenocarcinomas. Fish consumption of once a week or more might protect against colorectal cancer, but no significant interactions with SNPs in the genes involved in the AA-pathway could be detected within the study.
  • Body size and risk of colon and rectal cancer in the European Prospective Investigation Into Cancer and Nutrition (EPIC).

    Pischon, Tobias; Lahmann, Petra H; Boeing, Heiner; Friedenreich, Christine; Norat, Teresa; Tjønneland, Anne; Halkjaer, Jytte; Overvad, Kim; Clavel-Chapelon, Françoise; Boutron-Ruault, Marie-Christine; Guernec, Gregory; Bergmann, Manuela M; Linseisen, Jakob; Becker, Nikolaus; Trichopoulou, Antonia; Trichopoulos, Dimitrios; Sieri, Sabina; Palli, Domenico; Tumino, Rosario; Vineis, Paolo; Panico, Salvatore; Peeters, Petra H M; Bueno-de-Mesquita, H Bas; Boshuizen, Hendriek C; Guelpen, Bethany van; Palmqvist, Richard; Berglund, Göran; González, Carlos Alberto; Dorronsoro Iraeta, Miren; Barricarte, Aurelio; Navarro, Carmen A; Martínez-García, Carmen; Quirós, José Ramón; Roddam, Andrew; Allen, Naomi E; Bingham, Sheila A; Khaw, Kay-Tee; Ferrari, Pietro; Kaaks, Rudolf; Slimani, Nadia; Riboli, Elio (2006-07-05)
    BACKGROUND: Body weight and body mass index (BMI) are positively related to risk of colon cancer in men, whereas weak or no associations exist in women. This discrepancy may be related to differences in fat distribution between sexes or to the use of hormone replacement therapy (HRT) in women. METHODS: We used multivariable adjusted Cox proportional hazards models to examine the association between anthropometric measures and risks of colon and rectal cancer among 368 277 men and women who were free of cancer at baseline from nine countries of the European Prospective Investigation Into Cancer and Nutrition. All statistical tests were two-sided. RESULTS: During 6.1 years of follow-up, we identified 984 and 586 patients with colon and rectal cancer, respectively. Body weight and BMI were statistically significantly associated with colon cancer risk in men (highest versus lowest quintile of BMI, relative risk [RR] = 1.55, 95% confidence interval [CI] = 1.12 to 2.15; P(trend) = .006) but not in women. In contrast, comparisons of the highest to the lowest quintile showed that several anthropometric measures, including waist circumference (men, RR = 1.39, 95% CI = 1.01 to 1.93; P(trend) = .001; women, RR = 1.48, 95% CI = 1.08 to 2.03; P(trend) = .008), waist-to-hip ratio (WHR; men, RR = 1.51, 95% CI = 1.06 to 2.15; P(trend) = .006; women, RR = 1.52, 95% CI = 1.12 to 2.05; P(trend) = .002), and height (men, RR = 1.40, 95% CI = 0.99 to 1.98; P(trend) = .04; women, RR = 1.79, 95% CI = 1.30 to 2.46; P(trend)<.001) were related to colon cancer risk in both sexes. The estimated absolute risk of developing colon cancer within 5 years was 203 and 131 cases per 100,000 men and 129 and 86 cases per 100,000 women in the highest and lowest quintiles of WHR, respectively. Upon further stratification, no association of waist circumference and WHR with risk of colon cancer was observed among postmenopausal women who used HRT. None of the anthropometric measures was statistically significantly related to rectal cancer. CONCLUSIONS: Waist circumference and WHR, indicators of abdominal obesity, were strongly associated with colon cancer risk in men and women in this population. The association of abdominal obesity with colon cancer risk may vary depending on HRT use in postmenopausal women; however, these findings require confirmation in future studies.
  • Probabilistic dietary exposure assessment taking into account variability in both amount and frequency of consumption.

    Slob, Wout (2006-07-01)
    Probabilistic dietary exposure assessments that are fully based on Monte Carlo sampling from the raw intake data may not be appropriate. This paper shows that the data should first be analysed by using a statistical model that is able to take the various dimensions of food consumption patterns into account. A (parametric) model is discussed that takes into account the interindividual variation in (daily) consumption frequencies, as well as in amounts consumed. Further, the model can be used to include covariates, such as age, sex, or other individual attributes. Some illustrative examples show how this model may be used to estimate the probability of exceeding an (acute or chronic) exposure limit. These results are compared with the results based on directly counting the fraction of observed intakes exceeding the limit value. This comparison shows that the latter method is not adequate, in particular for the acute exposure situation. A two-step approach for probabilistic (acute) exposure assessment is proposed: first analyse the consumption data by a (parametric) statistical model as discussed in this paper, and then use Monte Carlo techniques for combining the variation in concentrations with the variation in consumption (by sampling from the statistical model). This approach results in an estimate of the fraction of the population as a function of the fraction of days at which the exposure limit is exceeded by the individual.

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