FRIDAY, Sept. 23, 2005 (HealthDay News) -- Doctors have long known that a sensitivity to salt in the diet can help lead to high blood pressure in some people.
Now, a new study finds that hormonal changes following menopause can trigger this salt sensitivity in women previously unaffected by salt.
In fact, in a group of younger women undergoing hysterectomy with ovary removal, levels of salt sensitivity doubled within four months of the surgery, researchers report.
"Among women who undergo surgical menopause, there is an increase in their sensitivity to salt, potentially raising their blood pressure," said lead researcher Dr. Ivonne Hernandez Schulman, from the Veterans Affairs Medical Center, Miami, and the University of Miami Miller School of Medicine.
The study was presented Friday at the American Heart Association's annual high blood pressure conference, in Washington, D.C.
In their study, Schulman, and her team studied 40 women, averaging 47 years of age, with no history of diabetes and normal blood pressure. All of the women underwent hysterectomy and ovary removal, which induced menopause.
The researchers found that the cases of salt sensitivity were significantly higher after menopause. Four months after surgery, 21 women (52 percent) were salt-sensitive compared with just nine women (22.5 percent) before surgery.
While the women in the study who developed salt sensitivity did not show an increase in blood pressure, other studies indicate that most women won't develop high blood pressure until five to10 years after menopause, Schulman said.
According to Schulman, some women will naturally develop salt sensitivity after menopause and run the risk of developing high blood pressure, which in turn increases risks for cardiovascular disease and stroke.
"About 50 percent of people with high blood pressure are considered to be salt-sensitive," Schulman said. "Even people with a normal blood pressure who are salt-sensitive have a higher risk of developing high blood pressure and possibly cardiovascular disease," she added.
One expert is skeptical of the findings.
"These findings need to be taken with a grain of salt," said Dr. Howard Weintraub, co-director of the NYU Lipid Treatment Program and associate professor of medicine at NYU School of Medicine.
Weintraub is concerned that the study didn't take into account the ethnic makeup of the people in the study, since different groups have different propensities to salt sensitivity. In addition, Weintraub noted that whether the women were obese or not was not mentioned. All of these factors could influence the findings, he said.
"Everything we know now about postmenopausal hypertensive women is that the problem is not salt sensitivity," Weintraub said. "The problem that we are looking at is the impact of women who develop obesity. Salt sensitivity is an added problem that goes on top of preexisting morbidity."
Weintraub is also concerned that this study sends the wrong message.
"I don't want people thinking that, in a 55-year-old woman, her blood pressure can be adequately handled by just diuretics, which reduce salt," Weintraub said.
But another expert believes that the study asks important questions.
"The observation that a high percentage of women who were salt-resistant before the removal of ovaries became salt-sensitive suggests that salt sensitivity may be partially responsible for the increase in the progression of hypertension after menopause," said Ana Paula Dantas, an assistant professor in the Department of Medicine Division of Nephrology and Hypertension and Center for the Study of Sex Differences in Health, Aging and Disease at Georgetown University.
This study could not directly associate the increase in salt sensitivity to blood pressure in those women, probably due to the short-term period of observation, Dantas noted.
"Even without this correlation, this study raises important questions: Should postmenopausal women be more concerned about dietary salt intake than men? Would diuretics be more effective in menopausal women than in men?" she said.
"This newly revealed effect of ovarian hormones can lead to the development of novel pharmacological and dietary approaches for preventing and treating cardiovascular disease in postmenopausal women," Dantas said.
The American Heart Association can tell you more about high blood pressure.