New research: Stroke risk and too much sleep; genes that make the body salt-sensitive

High blood pressure, or hypertension, affects one third of—or 70 million—US adults¹, and the healthcare costs associated with treating the disease are approximately $46 billion². From May 15 - 19, 2015, members of the medical community from around the world will gather at the 30th Annual Scientific Meeting of the American Society of Hypertension (ASH) in New York City to discuss new scientific findings, state-of-the-art diagnostic tools and new treatments for hypertension. During the conference, more than 200 new studies about the epidemic will provide the most up-to-date information about how to prevent, diagnose and control hypertension and wide-ranging conditions thought to be associated with the "silent killer."

Among the findings from the ASH meeting is research that suggests clocking too many hours of sleep—or getting too little—significantly ups one's risk for stroke. In addition, two new studies provide insights into falls among the elderly and whether or not hypertension or anti-hypertensive meds play a role. Another compelling study helps shed light into the genes responsible for making some individuals' blood pressure sensitive to salt in the diet. Below are research highlights from the 2015 conference:

Sleep and Stroke: What's the Connection?

Sleeping less than five hours—or more than eight hours—per night is associated with a nearly twofold greater risk of stroke compared to a "healthy" length of sleep among hypertensive patients, according to research led by Oluwaseun Akinseye, M.D., from the Icahn School of Medicine at Mount Sinai in New York and sponsored by NYU School of Medicine.

Using data from the National Health Interview Survey (2004-2013) about 203,794 hypertensive U.S. adults, researchers determined that risk for stroke was nearly 14 percent among long sleepers (>8 hours), 11 percent among insufficient sleepers (<5 hours), about 6 percent for short sleepers (5-6 hours), and about 5 percent for healthy sleepers (7-8 hours). This information demonstrates that "insufficient" and "long" sleepers had an 83 percent and 74 percent increased risk for stroke compared to "healthy" sleepers.

Hypertension Medications and Falls: What the Elderly Should Know

According to the Centers for Disease Control and Prevention, falls are the leading cause of both fatal and nonfatal injuries among adults aged 65 and older³. A new study presented by Dan Berlowitz, M.D., of Bedford VA Hospital in Bedford, Mass., aimed to determine whether low blood pressure or anti-hypertensive meds are associated with a greater fear of falling among elderly subjects with hypertension, since many elderly adults with hypertension stop taking or refuse to increase their anti-hypertensive medications due to concerns about falling.

Researchers reported that a mild fear of falling was present in 29 percent of study subjects and moderate to severe fear of falling was present in 18 percent of subjects. While no associations between low blood pressure and fear of falling were reported, researchers did find subjects with moderate to severe fear of falling were taking more anti-hypertensive medications in general and were in overall worse health.

A second study on a related topic, presented by Daichi Shimbo, M.D., of Columbia University Medical Center in New York, N.Y., addressed whether the fear of falling among the elderly is founded. Researchers determined the risk for serious fall injury among individuals aged 65 and older was increased by 36 percent within the first 15 days of initiating hypertension medication, but the risk was not long-term. The researchers recommend that precautions be undertaken to prevent falls when initiating anti-hypertensive medication in older persons.

Salt-sensitive? It May Not Be Sodium Intake; It May be in your Genes

There is much research and discussion about the role of sodium in hypertension, but sodium and other environmental factors are not the sole determinants of hypertension. Previous research suggests that the Renalase gene plays a role in essential hypertension, the type of hypertension that is not linked to environmental factors, such as body weight or dietary sodium. A new study, presented by Yang Wang, M.D., of Jiatong University, Xi'an, China, examined the association between genetic variants in the Renalese gene and blood pressure responses to strict dietary interventions of salt and potassium intake.

In this study, 334 subjects from 124 families were put on a low-salt diet for seven days, followed by a high-salt diet for seven days and then a high-salt, high-potassium diet for seven days. The results of this family-based study indicate that genetic variants in the Renalese gene are significantly associated with blood pressure responses to dietary salt intake, showing that genetics plays a role in determining how sensitive a person's blood pressure is to sodium intake.