Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, Beijing, China.
Hypertens Res. 2011 Feb;34(2):173-9. doi: 10.1038/hr.2010.194. Epub 2010 Nov 4.
The familial aggregation of blood pressure (BP) may be partly due to the familial aggregation of obesity, caused by genetic and/or environmental factors that influence both. Gene-obesity interactions are expected to result in different heritability estimates for BP at different obesity levels. However, the latter hypothesis has never been tested. The present study included 1243 monozygotic and 833 dizygotic Han Chinese twins (mean±s.d. age: 37.81 ± 9.82; range: 19.1-81.4) from the Chinese National Twin Registry. Body mass index (BMI) was used as the index of general obesity. The outcome measures were systolic BP (SBP) and diastolic BP (DBP). Quantitative genetic modeling was performed using Mx software. The SBP and DBP heritabilities were 46 and 30%, respectively. The positive correlations of BMI with SBP (r=0.26) and with DBP (r=0.27) were largely due to genetic factors (approximately 85%). Genetic factors, which also influence BMI, account for 6 and 7% of the total variance for SBP and DBP, respectively. The gene-obesity interaction analysis showed that both common and unique environmental influences on SBP increased with increasing levels of BMI, resulting in a lower heritability at higher BMI levels, whereas for DBP the heritability remained unchanged at higher BMI levels. Our results suggest that higher BMIs may reduce SBP heritability through a larger impact of environmental effects. These conclusions may be valuable for gene-finding studies.
血压（BP）的家族聚集部分可能是由于肥胖的家族聚集所致，这是由遗传和/或环境因素共同作用的结果。基因-肥胖相互作用预计会导致不同肥胖水平下 BP 的遗传度估计值不同。然而，后者的假设从未得到过验证。本研究包括来自中国双胞胎登记处的 1243 对同卵双胞胎和 833 对异卵双胞胎汉族人（平均±标准差年龄：37.81±9.82；范围：19.1-81.4）。体重指数（BMI）被用作一般肥胖的指标。结果测量指标为收缩压（SBP）和舒张压（DBP）。使用 Mx 软件进行定量遗传建模。SBP 和 DBP 的遗传率分别为 46%和 30%。BMI 与 SBP（r=0.26）和 DBP（r=0.27）的正相关主要归因于遗传因素（约 85%）。影响 BMI 的遗传因素也分别解释了 SBP 和 DBP 总方差的 6%和 7%。基因-肥胖相互作用分析表明，SBP 的共同和独特环境影响随着 BMI 水平的升高而增加，导致 BMI 水平较高时遗传度降低，而 DBP 的遗传度在 BMI 水平较高时保持不变。我们的研究结果表明，较高的 BMI 可能通过环境影响的更大作用降低 SBP 的遗传度。这些结论对于基因定位研究可能具有重要价值。
