BODY & BRAIN
Abiding by new blood pressure
guidelines would save lives
The first estimate of how many deaths
and heart problems could be avoided
under new blood pressure guidelines
suggests it’s well worth it for Americans
to get blood pressure under control.
The guidelines, announced in 2017,
redefined hypertension as a blood pressure reading of 130/80 or higher (SN:
12/9/17, p. 13). The previous threshold
was 140/90. As a result, 105 million U.S.
adults are now considered to have hypertension, 31 million more than before.
An estimated 334,000 deaths could be
prevented annually if people aged 40 and
older keep their blood pressure below
the new threshold, researchers report
online May 23 in JAMA Cardiology. And
610,000 heart attacks, strokes and other
consequences of cardiovascular disease
could be avoided each year. The shift to
the lower blood pressure target would
prevent an additional 156,000 deaths and
340,000 cardiovascular-related illnesses
compared with the previous target.
But adhering to the guidelines means
doctors may recommend that 83 million
adults, 11 million more than before, take
blood pressure medications, epidemiologist Jiang He of Tulane University in New
Orleans and his colleagues estimate.
Those drugs carry a risk of side effects,
including kidney damage. More research
is needed on whether kidney damage
related to blood pressure drugs is long-term or temporary, He says. But taking
the medication is far less expensive than
dealing with a possible heart attack or
stroke, he adds. — Aimee Cunningham
BODY & BRAIN
Colorectal cancer screening should
start at an earlier age, experts say
Colorectal cancer screening should
begin at age 45 rather than 50, accord-
ing to new guidelines released May 30
by the American Cancer Society. The
recommendation is a response to the
steady rise in younger Americans’ rate of
colorectal cancer (SN: 4/1/17, p. 5).
For people at average risk for colorec-
tal cancer — those without a personal
or family history of the disease and
who haven’t had inflammatory bowel
disease — the American Cancer Society
suggests that regular screening begin at
age 45 with either stool-based tests or
visual exams, such as a colonoscopy.
Colorectal cancer is the second-most
common cause of cancer death in the
United States. Screening can catch pre-
cancerous polyps and early-stage cancers,
when they may be more easily treated, ac-
cording to the American Cancer Society.
“Overall rates of colorectal cancer
have declined by more than 45 percent
since the 1980s, owing in part to screen-
ing,” says gastroenterologist Andrew
Chan of Massachusetts General Hospital
in Boston, who was not involved in the
guidelines. “In sharp contrast, the rates
of colorectal cancer have been increas-
ing among all age groups between 20
and 49.” Those groups have experienced
NEWS IN BRIEF
ATOM & COSMOS
Methane ice dunes spotted on Pluto
Wind, sublimation could explain the formations, scientists say
BY LISA GROSSMAN
Pluto’s heart-shaped plains are striped
with sand dunes, where the sand is made
of methane ice, a new study finds.
Images from the New Horizons spacecraft’s 2015 flyby of Pluto show 357 linear
ridges that planetary scientist Matt Telfer
of the University of Plymouth in England
and colleagues interpret as dunes that
have been shaped by a novel process.
The ripples lie parallel to a mountain
range at the western edge of Sputnik
Planitia, the wide plains of nitrogen
and methane ice that form part of
Pluto’s famous heart-shaped region. Relatively strong winds, traveling about 1 to
10 meters per second, should blow from
the mountains across the plains, Telfer’s
group reports in the June 1 Science.
Computer simulations suggest that
despite Pluto’s thin atmosphere, these
winds are strong enough to keep sand-
sized methane ice particles moving once
they become airborne. But the winds are
probably too weak to lift the grains off
the ground in the first place.
Instead, little puffs of air coming from
Sputnik Planitia’s nitrogen ice as the sun
heats it could boost methane ice particles
skyward and into the wind, the team suggests. That process, by which solids turn
directly into vapor, is called sublimation.
“That’s a novel, interesting idea,” says
planetary scientist Alexander Hayes of
Cornell University, who was not involved
in the work. But sublimation alone could
explain some of the features, without the
need for wind, he says.
Dunes are found across the solar
system, including on Mars (SN Online:
2/10/10) and Saturn’s moon Titan (SN
Online: 8/28/13). These worlds have the
On Pluto, dunes (ripples in the center bottom
and right of this New Horizons image) form
along a mountain range. The dunes are made
of grains of methane ice, researchers report.
ingredients for dunes: a supply of loose,
grainy material and an atmosphere or
fluid to carry grains around.
“When you look at dunes across the
solar system, something that always
strikes me is that they form the same
patterns, regardless of the environment,” Hayes says. Finding dunes on
Pluto, too, suggests that the features may
be ubiquitous. “If you have the material
and a way to move it, you form dunes,”
he says. “That’s what this is telling us.” s