Objectives: Parents share genes and environmental exposures with their offspring. Spouses are often unrelated and their excess of genetic sharing is low, but the similar lifestyles of spouses regarding, for example, tobacco consumption may also result in a familial clustering of disease. This study investigates the influence of gene-environment interactions on the relative risks of disease for the offspring and the spouses of affected individuals. Methods: Theoretical models were developed to explore the dependence of familial relative risks on environmental parameters (exposure frequency, relative risk of disease for exposed versus unexposed individuals, extent of environmental sharing), on genetic parameters (allele frequency, genotype relative risk and mode of inheritance), on the number of descendants in exposed versus unexposed individuals, and on the model of gene-environment interaction. Lung cancer was used as an example of a complex disease with smoking as a known risk factor. Results: The parent-offspring and the spouse-spouse relative risks of disease varied widely in the strength of the environmental and genetic components and their degree of interaction. The familial relative risk of lung cancer decreased with increasing smoking prevalence. The relationship between exposure frequency and relative risk was markedly different when genes and environment had similar effects on disease susceptibility. Conclusions: Estimates of the relative risk of disease for varying exposure frequencies may help to assess the relevance of genetic effects in disease etiology. In particular, a positive association between offspring relative risk and exposure frequency may be indicative of genes interacting with environmental factors of similar effect sizes, with the corresponding implications for gene identification studies.

This content is only available via PDF.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.