Researchers also urging close monitoring of elderly with hypertension during weather extremes; second study says thinking ability varies with blood pressure
The recent discovery that the blood pressure readings for senior citizens vary in reverse to the outside temperature – colder temperature equals higher blood pressure reading – may have something to do with the link between vitamin D and hypertension, according to a spokesman for European cardiologists. The French researchers also urge careful monitoring during extreme temperatures.
The French study reported in the January 12 issue of Archives of Internal Medicine (see sidebar link to story) has found a strong correlation between blood pressure and outdoor temperature in a large sample of the elderly.
As a result, the investigators advise that, during periods of extreme temperatures, careful monitoring of blood pressure and antihypertensive treatment “could contribute to reducing the consequences of blood pressure variations in the elderly”.
Vitamin D Connection
Speaking on behalf of the European Society of Cardiology (ESC), Professor Frank Ruschitzka from the University Hospital, Zurich, says that the study reaffirms the place of the elderly as a target group for blood pressure monitoring.
“The elderly, especially the increasing number of octogenarians, should not be neglected. They need extra care, and will benefit from monitoring and appropriate treatment. This study emphasizes the need for year-round vigilance,” Ruschitzka said.
One possible explanation for the study findings, adds Professor Ruschitzka, lies in the emerging link between vitamin D and blood pressure.
The elderly, especially those in care homes, are subject to vitamin D deficiency, largely as a result of their limited exposure to sunlight, and vitamin D deficiency can predispose to hypertension via activation of the renin-angiotensin-aldosterone system.
“The benefit of sunlight on vitamin D levels in the elderly is under appreciated,” says Professor Ruschitzka. “Fifteen minutes exposure to sunlight can produce the equivalent of 2000 international units vitamin D.”
A report from the Framingham Heart Study published in 2008 found that moderate vitamin D deficiency nearly doubles the risk of myocardial infarction, stroke and heart failure over a mean of 5.4 years in patients with high blood pressure.
The Nurses Health Study, also reporting in 2008, found that lower blood levels of vitamin D are independently associated with an increased risk of hypertension; women with the lowest levels had a 66 percent higher incidence of hypertension than those with the highest levels.
