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Twin study of genetic and environmental effects on lipid levels.
Genet Epidemiol 1988; 5(5):323-41GE

Abstract

A study of 106 pairs of monozygotic (MZ) and 94 pairs of dizygotic (DZ) twins tested the hypothesis that part of the previously described genetic influence on blood lipid levels can be ascribed to closer similarities among MZ than among DZ twin pairs in environmental factors that affect lipid levels. Participants were adult twin volunteers (age 17-66; 64 male and 136 female pairs) who were selected from the NH & MRC Twin Registry or were respondents to advertisements. They completed a 4-day weighed food diary from which mean nutrient intake was derived. Information on lifestyle and demographic variables was obtained by questionnaire and a nonfasting blood sample was taken for measures of total, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol and the HDL2 and HDL3 subfractions. Height and weight were measured, and body mass index (BMI) was calculated (kg/m2). Estimates of the heritability of sex-adjusted lipid levels were 0.72 for total cholesterol, 0.79 for HDL cholesterol, 0.69 for HDL2, 0.20 for HDL3, 1.06 for LDL cholesterol, and 0.44 for sex-adjusted BMI. In all cases except for HDL3, genetic variance was statistically significant. After adjusting for the effects of environmental variables in three different ways, the estimates of heritability were somewhat lower for total cholesterol, HDL2, and BMI, and those for HDL cholesterol (borderline) and LDL cholesterol (definitely) remained statistically significant but were decreased. A genetic influence on HDL3 was not found. Adjusted heritability estimates obtained from one method of analysis were 0.35 for total cholesterol, 0.49 for HDL, 0.04 for HDL2, -0.34 for HDL3, 0.66 for LDL, and 0.32 for BMI. These results suggest that the assumptions made in the classical twin study approach are not appropriate when examining genetic effects on lipid levels or BMI, or indeed on any biological variable that may be affected by environmental factors that tend to be more similar in MZ twins than in DZ twins. In these circumstances, more complex models may be needed to differentiate between genetic and environmental influences.

Authors+Show Affiliations

Faculty of Medicine, University of Newcastle, N.S.W., Australia.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

3215507

Citation

O'Connell, D L., et al. "Twin Study of Genetic and Environmental Effects On Lipid Levels." Genetic Epidemiology, vol. 5, no. 5, 1988, pp. 323-41.
O'Connell DL, Heller RF, Roberts DC, et al. Twin study of genetic and environmental effects on lipid levels. Genet Epidemiol. 1988;5(5):323-41.
O'Connell, D. L., Heller, R. F., Roberts, D. C., Allen, J. R., Knapp, J. C., Steele, P. L., & Silove, D. (1988). Twin study of genetic and environmental effects on lipid levels. Genetic Epidemiology, 5(5), pp. 323-41.
O'Connell DL, et al. Twin Study of Genetic and Environmental Effects On Lipid Levels. Genet Epidemiol. 1988;5(5):323-41. PubMed PMID: 3215507.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Twin study of genetic and environmental effects on lipid levels. AU - O'Connell,D L, AU - Heller,R F, AU - Roberts,D C, AU - Allen,J R, AU - Knapp,J C, AU - Steele,P L, AU - Silove,D, PY - 1988/1/1/pubmed PY - 1988/1/1/medline PY - 1988/1/1/entrez SP - 323 EP - 41 JF - Genetic epidemiology JO - Genet. Epidemiol. VL - 5 IS - 5 N2 - A study of 106 pairs of monozygotic (MZ) and 94 pairs of dizygotic (DZ) twins tested the hypothesis that part of the previously described genetic influence on blood lipid levels can be ascribed to closer similarities among MZ than among DZ twin pairs in environmental factors that affect lipid levels. Participants were adult twin volunteers (age 17-66; 64 male and 136 female pairs) who were selected from the NH & MRC Twin Registry or were respondents to advertisements. They completed a 4-day weighed food diary from which mean nutrient intake was derived. Information on lifestyle and demographic variables was obtained by questionnaire and a nonfasting blood sample was taken for measures of total, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol and the HDL2 and HDL3 subfractions. Height and weight were measured, and body mass index (BMI) was calculated (kg/m2). Estimates of the heritability of sex-adjusted lipid levels were 0.72 for total cholesterol, 0.79 for HDL cholesterol, 0.69 for HDL2, 0.20 for HDL3, 1.06 for LDL cholesterol, and 0.44 for sex-adjusted BMI. In all cases except for HDL3, genetic variance was statistically significant. After adjusting for the effects of environmental variables in three different ways, the estimates of heritability were somewhat lower for total cholesterol, HDL2, and BMI, and those for HDL cholesterol (borderline) and LDL cholesterol (definitely) remained statistically significant but were decreased. A genetic influence on HDL3 was not found. Adjusted heritability estimates obtained from one method of analysis were 0.35 for total cholesterol, 0.49 for HDL, 0.04 for HDL2, -0.34 for HDL3, 0.66 for LDL, and 0.32 for BMI. These results suggest that the assumptions made in the classical twin study approach are not appropriate when examining genetic effects on lipid levels or BMI, or indeed on any biological variable that may be affected by environmental factors that tend to be more similar in MZ twins than in DZ twins. In these circumstances, more complex models may be needed to differentiate between genetic and environmental influences. SN - 0741-0395 UR - https://www.unboundmedicine.com/medline/citation/3215507/Twin_study_of_genetic_and_environmental_effects_on_lipid_levels_ L2 - https://doi.org/10.1002/gepi.1370050504 DB - PRIME DP - Unbound Medicine ER -