Genetic and environmental influences on blood pressure in elderly twins.

Abstract

We used 289 pairs of Swedish twins reared apart or together to evaluate the importance of genetic and environmental influences on blood pressure. Unlike other twin and family studies, the adoption/twin design allows a distinction between estimates of the importance of shared rearing environments and genetic effects. Genetic factors were observed to play an important role for individual differences in blood pressure. Model-fitting analyses suggested upper limits of heritability for systolic and diastolic blood pressures in the entire sample of 0.44 and 0.34, respectively. More interestingly, substantial influences of shared family effects accounting for up to 27% of the variation were also revealed. Effects of correlated H ypertension is a common disease and also one of the main risk factors for coronary heart disease. It is commonly accepted that blood pressure (BP) level is a function of genetic and environmental factors originating either early in utero, possibly as a consequence of maternal nutritional conditions, or later during adult life. Family and twin studies have been used to decompose genetic and environmental contributions to systolic and diastolic BP variation. Heritability estimates for systolic BP range from 13% to 82% and for diastolic BP from less than 1% to 64%, with average levels for both of approximately 50%.' Typically, results from family studies have resulted in lower estimates than those from twin studies. Heritability estimates may be somewhat inflated in twin studies by the effects of genetic dominance. However, it is not clear whether or to what extent BP is affected by genetic dominance. Higher estimates of heritability in classic twin studies may also result when monozygotic twins have experienced more similar environments than fraternal twins. On the other hand, the family study design may underestimate heritability predominantly because of age differences between parents and offspring 2 or possible violation of the equal environment assumption in twin studies. In classic studies of families or twins

Both the Environment and Genes Are Important for Concentrations of Cadmium and Lead in Blood

“…In our study, covariance matrices for the two zygosity groups were subjected to structural-equation modeling with the LISREL 7 program (17) to estimate the genetic and environmental components of variance. The application of these techniques in the SATSA project has been described previously (18,19 gg/L). BPb was not influenced by smoking, and was slightly higher for men than for women (Table 1).…”

Blood pressure and its reactivity in the offspring of first cousin hypertensive and first cousin normotensive parents: a preliminary report

“…Since 50-79% of the blood pressure variation in humans is thought to be due to genetic factors 6,7 we expect this percentage to be much higher in this and other similar populations. However shared environment in such intricate societies will be more difficult to address.…”

“…4,5 Twins, family and adoptive studies have shown that at least 50-79% of the blood pressure variation in humans can be attributed to genetic factors. 6,7 Compared to the offspring of two normotensive parents, blood pressure is higher in the offspring of one normotensive and one hypertensive parent, and highest in the offspring of two hypertensive parents. 8 These distributions are evident in infancy and persists through late adulthood.…”

Ethnic variation in hypertension prevalence of women in Taiwan

“…4 Hypertension, a multifactorial disorder, results from the interaction of a complex set of environmental and genetic factors, which may vary with ethnicity, gender and geography. 5,6 It is essential to elucidate the prevalence and risk factors of hypertension, the most common atherosclerotic risk factor, for women to develop effective and efficient strategies for the prevention of CVD.…”