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Can comparison of MZ- and DZ-twin concordance rates be used invariably to estimate heritability?
Twin Res Hum Genet. 2007 Oct; 10(5):712-7.TR

Abstract

Proponents of the validity of the classical MZ-DZ twin comparison model for calculating heritability claim that the environments influencing MZ and DZ twin individuals are essentially identical. This 'equal environments assumption' may or may not be universally true when applied to the analysis of subjective traits. We examined the validity of this assumption as applied to the propensity for smoking cigarettes, reasoning that equality of environments should lead to equal smoking prevalences in MZ and DZ twin individuals. We identified 8 twin populations with data on smoking. We compiled odds ratios (ORs) for ever smoking in MZ and DZ twin individuals in these 8 studies and overall, using a fixed-effects meta-analytic method based on the Mantel-Haenszel procedure. The prevalence of smoking was less in MZ twin individuals than in DZ twin individuals in 7 of 8 studies. The overall OR was 0.86 (95% confidence interval 0.84, 0.89). ORs were virtually unchanged when the analyses were stratified for gender and age, and no differences were found in relation to the location of the study, the date of the study or the birth years of the cohorts. For cigarette smoking, the environments of MZ and DZ twins may not be co-equal. For subjective traits, heritability estimates may be influenced by these unequal environmental factors that differentially affect their development and characteristics in MZ and DZ twins.

Authors+Show Affiliations

Genetics Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. peter.tishler@channing.harvard.eduNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Meta-Analysis
Twin Study

Language

eng

PubMed ID

17903111

Citation

Tishler, Peter V., and Vincent J. Carey. "Can Comparison of MZ- and DZ-twin Concordance Rates Be Used Invariably to Estimate Heritability?" Twin Research and Human Genetics : the Official Journal of the International Society for Twin Studies, vol. 10, no. 5, 2007, pp. 712-7.
Tishler PV, Carey VJ. Can comparison of MZ- and DZ-twin concordance rates be used invariably to estimate heritability? Twin Res Hum Genet. 2007;10(5):712-7.
Tishler, P. V., & Carey, V. J. (2007). Can comparison of MZ- and DZ-twin concordance rates be used invariably to estimate heritability? Twin Research and Human Genetics : the Official Journal of the International Society for Twin Studies, 10(5), 712-7.
Tishler PV, Carey VJ. Can Comparison of MZ- and DZ-twin Concordance Rates Be Used Invariably to Estimate Heritability. Twin Res Hum Genet. 2007;10(5):712-7. PubMed PMID: 17903111.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Can comparison of MZ- and DZ-twin concordance rates be used invariably to estimate heritability? AU - Tishler,Peter V, AU - Carey,Vincent J, PY - 2007/10/2/pubmed PY - 2008/3/15/medline PY - 2007/10/2/entrez SP - 712 EP - 7 JF - Twin research and human genetics : the official journal of the International Society for Twin Studies JO - Twin Res Hum Genet VL - 10 IS - 5 N2 - Proponents of the validity of the classical MZ-DZ twin comparison model for calculating heritability claim that the environments influencing MZ and DZ twin individuals are essentially identical. This 'equal environments assumption' may or may not be universally true when applied to the analysis of subjective traits. We examined the validity of this assumption as applied to the propensity for smoking cigarettes, reasoning that equality of environments should lead to equal smoking prevalences in MZ and DZ twin individuals. We identified 8 twin populations with data on smoking. We compiled odds ratios (ORs) for ever smoking in MZ and DZ twin individuals in these 8 studies and overall, using a fixed-effects meta-analytic method based on the Mantel-Haenszel procedure. The prevalence of smoking was less in MZ twin individuals than in DZ twin individuals in 7 of 8 studies. The overall OR was 0.86 (95% confidence interval 0.84, 0.89). ORs were virtually unchanged when the analyses were stratified for gender and age, and no differences were found in relation to the location of the study, the date of the study or the birth years of the cohorts. For cigarette smoking, the environments of MZ and DZ twins may not be co-equal. For subjective traits, heritability estimates may be influenced by these unequal environmental factors that differentially affect their development and characteristics in MZ and DZ twins. SN - 1832-4274 UR - https://www.unboundmedicine.com/medline/citation/17903111/Can_comparison_of_MZ__and_DZ_twin_concordance_rates_be_used_invariably_to_estimate_heritability L2 - https://www.cambridge.org/core/product/identifier/S183242740000832X/type/journal_article DB - PRIME DP - Unbound Medicine ER -