NEW YORK (Reuters Health) - The combination of the G460W polymorphism of alpha-adducin and a high sodium intake is associated with higher systolic blood pressure in men, according to a report in the May issue of the American Journal of Hypertension.
Alpha-adducin regulates transmembrane ion transport, the authors explain, and an alpha-adducin polymorphism was previously associated with salt-sensitive hypertension in a hypertensive strain of rats. The association was also noted in Caucasians patients in Italy and France.
The lack of a population-based study to show a gene-environment interaction among alpha-adducin polymorphism, salt intake, and blood pressure prompted Dr. Hiroyasu Iso from University of Tsukuba, Japan and colleagues to examine the relationship between the alpha-adducin gene polymorphism and blood pressure levels, stratified by sodium intake, in 2823 men and women in a rural farming community in central Japan.
For men, the mean systolic blood pressure tended to be higher among those with the WW genotype, the authors report, but this association reached statistical significance only for men at least 55 years old. Blood pressure did not differ by genotype among women.
Mean systolic blood pressure was higher among WW men (compared with GG men) with higher urinary sodium excretion or higher previous sodium intake scores, the report indicates, but not among WW men with lower urinary sodium excretion or lower previous sodium intake scores.
Present sodium intake scores did not influence the systolic blood pressure difference between the WW and GG groups, the researchers note, but other associations became stronger when patients receiving antihypertensive medications were excluded from the analysis.
“As we hypothesized,” the investigators write, “we found a positive association between the alpha-adducin G460W genotype and systolic blood pressure levels among men with higher urinary sodium excretion. This finding suggests that the alpha-adducin genotype may be a genetic risk factor for salt-sensitive hypertension.”
“Our study also suggests that hypertensives with salt sensitivity may benefit from diuretics,” Dr. Iso told Reuters Health. “Clinical trials will be necessary to clarify this.”
“Our previous study showed that the AGT T174M allele was also a potential salt-sensitive marker,” Dr. Iso added. Dr. Iso’s group is also “seeking other polymorphisms concerning salt-sensitivity. We believe that the accumulation of such evidence will lead to sound recommendations in the future.”
Source: Am J Hypertens 2004;17:385-390. [ Google search on this article ]
MeSH Headings:Sodium, Dietary: Sodium Chloride, DietaryCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
