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Mendelian Randomization In Environmental Epidemiology Vladimír Bencko & Ladislav Novotný Charles University in Prague 1 st Faculty of Medicine & General.

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Presentation on theme: "Mendelian Randomization In Environmental Epidemiology Vladimír Bencko & Ladislav Novotný Charles University in Prague 1 st Faculty of Medicine & General."— Presentation transcript:

1 Mendelian Randomization In Environmental Epidemiology Vladimír Bencko & Ladislav Novotný Charles University in Prague 1 st Faculty of Medicine & General University Hospital Institute of Hygiene and Epidemiology

2 cruciferous vegetables rich in isothiocyanates (ITC) chemopreventive properties against malignancies at different cancer sites including lungs - animals humans ? because of potential confounding dietary and life-style factors ASSOCIATION vs. CONFOUNDING

3 ITC tissue  concentration  BIOTRANSFORMATION cruciferous glucosinolate storage to ITC animals & humans vegetable consumption ITC eliminated by glutathione-S-transferases + /.. GST genes - / - … DNA responsive elements - antioxidant - electrophile metabolism phase II proteins  production chemoprotection GSTM1 GSTT1.5 GSTT1.6 independent roles of genes to other dietary, lifestyle factors, reducing the possibility of confounding glucosinolate myrosinase

4 Our institute participated in a case-control study of 2141 cases and 2168 controls in six countries of central and eastern Europe, a region that has traditionally high rates of cruciferous vegetable consumption lung cancer cases and age-sex matched hospital or population controls recruited from 15 centres in Poland, Slovakia, Czech Republic, Romania, Russia, and Hungary by use of an identical protocol and questionnaire STUDY DESIGN - Lung Ca vs. dietary cruciferous vegetables

5 all participants completed a detailed standardised lifestyle and food frequency questionnaire that had been piloted in all centres before use the dietary component of the questionnaire listed 23 foods, of which three were cruciferous vegetables : cabbage and a combination of brussels sprouts with broccoli the questionnaire was repeated for two different periods: 1. the year before interview 2. before political and market changes in 1989 (1991 in Russia) a weighted age-specific average of the two was calculated STUDY DESIGN – vegetable consumption asessment

6 for all individuals PCR-based genotyping for GSTM1 and GSTT1 neither GSTM1 nor GSTT1 were related to potential confounding factors in the controls: country, age, smoking status, education, and dietary variables incl. cruciferous vegetables = Mendelian randomization in action written informed consent was provided by all participants before their involvement in the study ethical approval for recruitment of participants and genotyping was obtained from institutional review boards in all the study centres, and from the IARC ethics committee STUDY DESIGN – GST genotyping, ethics

7 weekly consumption of cruciferous vegetables protected against lung cancer (OR, 95% CI) in homozygotes - GSTM1 null 0·67, 0·49–0·91 - GSTT1 null 0·63, 0·37–1·07 - M1 / T1 null/null0·28, 0·11–0·67 similar protective results were noted for consumption of - cabbage and - combination of broccoli and brussels sprouts no protective effect was seen in people who were - both GSTM1 and GSTT1 positive (0·88, 0·65–1·21) RESULTS these data provide strong evidence for a substantial protective effect of cruciferous vegetable consumption on lung cancer incidence

8 CONCLUSIONS an overall protective effect was seen for consumption of cruciferous vegetables at least once a week compared with less than monthly adjusted OR = 0·78, 95% CI 0·64–0·96, which was much the same for both cabbage consumption and for broccoli and brussels sprout consumption the results also accord with those of several smaller studies of lung cancer, breast cancer, and colorectal adenomas, which showed a protective effect in GSTM1 and GSTT1 null carriers

9 Acknowledgement PROJECT - supported by EC INCO-COPERNICUS grant IC15-CT , - NCI grant CA A2 Effect of cruciferous vegetables on lung cancer in patients stratified by genetic status: a mendelian randomisation approach. Lancet 2005; 366: Paul Brennan, Charles C Hsu, Norman Moullana, Neonilia Szeszenia-Dabrowska, Jolanta Lissowska, David Zaridze, Peter Rudnai, Eleonora Fabianova, Dana Mates, Vladimir Bencko, Lenka Foretova, Vladimir Janout, Federica Gemignani, Amelie Chabriera, Janet Hall, Rayjean J Hung, Paolo Boffetta and Federico Canzian

10 Acknowledgement INSTITUTIONS France-Lyon-International Agency for Research on Cancer Poland-Warsaw- Dept Cancer Epidemiol & Prev, Cancer Ctr & M Sklodowska-Curie Inst of Oncology -Lodz-Dept Epidemiol, Inst Occupational Medicine Russia-Moscow-Inst Carcinogenesis, Cancer Research Ctr Hungary-Budapest-Foder Jozsef National Ctr for Public Health Romania-Bucharest-Inst of Public Health Slovakia- Banska Bystrica -Regional Authority of Public Health Czech Republic -Prague- Inst of Hygiene & Epidemiology, 1st Faculty of Medicine, Charles University -Brno- Dept. of Cancer Epidemiol & Genetics, Masaryk Memorial Cancer Inst -Olomouc- Dept of Preventive Medicine, Palacký University of Medicine

11 Address for correspondence: Prof Vladimir Bencko, MD, PhD Charles University in Prague 1 st Faculty of Medicine & General University Hospital Institute of Hygiene and Epidemiology T h a n k s f o r y o u r a t t e n t I o n


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