Table 3 Parameter estimates and 95% CIs of best-fitting models for SBP, DBP and BMI

From: Genetic and environmental influences on blood pressure and body mass index in Han Chinese: a twin study

Measures

 

h2 (95%CI)

c2 (95%CI)

e2 (95%CI)

Sex effects

SBP, mm Hg

Model 1

0.46 (0.30–0.62)

0.22 (0.06–0.36)

0.32 (0.29–0.37)

 
 

Model 2

0.41 (0.26–0.58)

0.25 (0.09–0.39)

0.34 (0.30–0.38)

 

DBP, mm Hg

Model 1

0.30 (0.14–0.48)

0.31 (0.15–0.46)

0.38 (0.34–0.43)

 
 

Model 2

0.27 (0.10–0.45)

0.32 (0.16–0.47)

0.41 (0.37–0.46)

 

BMI, kg m−2

 

0.74 (0.71–0.77)

 

0.26 (0.23–0.29)

k2=0.81

  1. Abbreviations: BMI, body mass index; c2, common environmental effects; CI, confidence interval; DBP, diastolic blood pressure; e2, unique environmental effects; h2, heritability; k2, scalar sex effect; SBP, systolic blood pressure.
  2. All (non-standardized) variance components for males are constrained to be equal to a scalar multiple, k2, of the female variance components, such that hm2=k2hf2, cm2=k2cf2 and em2=k2ef2. As a result, the standardized variance components, such as heritabilities, are equal across sexes.
  3. BMI was log-transformed and adjusted for age, sex and study site.
  4. Model 1: SBP and DBP were log-transformed and adjusted for age, sex and study site.
  5. Model 2: Model 1+ adjustment for BMI.
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