Gemellological Study on Genetic and Environmental Factors Affecting Serum Concentrations of Lipids and Electrolytes in Adult Twins

Abstract

A gemellological study was conducted on serum concentrations of lipids and electrolytes, blood pressure and obesity to estimate the relative strength of genetic and environmental influences. The subjects were 107 pairs of adult twins (81 monozygotic pairs, 26 dizygotic pairs), who were residing in the community and aged over 50. The items examined in this study were total cholesterol, LDL cholesterol, LDL cholesterol, triglyceride, β-lipoprotein, phospholipids, free fatty acid, apolipoproteins (A-I, A-II, B, C-II, C-III, E), thrombocytes, uric acid, Na, K, Ca, blood pressure, skinfold thickness, body weight and body height. The heritability was estimated from the data of male twins through variance analysis. The difference of environmental variance between monozygotic and dizygotic twins was statistically adjusted through multi-regression analysis.
1) Regarding the serum lipids, strong heritability was shown in HDL cholesterol (0.667), apo B (0.667) and LDL cholesterol (0.608). On the other hand, triglyceride, apo A-II and apo C-III showed a low level of heritability (0.2 and less).
2) Serum electrolytes (Na, K, Ca) and uric acid showed a low level of heritability (under 0.3).
3) Blood pressure showed a relatively high level of heritability (systolic: 0.549, diastolic: 0.598)
4) Strong influences of environmental factors were shown in skinfold thickness.