Comparison of cotton and acrylic socks using a generic cushion sole design for runners

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Sockwear Recommendations for People With Diabetes
Carol B. Feldman, MSN, RN, CDE and Ellen D. Davis, MSN, RN, CDE

Case Presentation

A.B., a 55-year-old man who had been diagnosed with type 2 diabetes 6
months ago, was a new patient in the foot clinic of the Durham VA
Medical Center. At the time of his first visit, he was taking
metformin, 500 mg twice a day, and maintained adequate blood glucose
control. His most recent HbA1c was 6.5%.

The skin on his feet was intact, without redness, and its texture was
smooth and soft. His nails were intact without signs of onychomycosis.
The shape of his feet was normal, and monofilament testing confirmed
that foot sensation was intact. He had easily palpable pedal pulses
and no edema.

During routine discussion of foot-care precautions, he asked what kind
of socks he should wear to prevent problems.


Discussion
Top
Case Presentation
Discussion
References


Good foot care practices are important for people with diabetes. A
large percentage of diabetic patients undergo nontraumatic amputation
after diabetic neuropathy renders them unable to feel festering foot
injuries. What’s more, within 3 years of a first amputation, up to
half of these patients have a second either new same side or
contralateral amputation. Within 5 years, as many as 80% have died.
1,2

As care providers, we are responsible for the self-care practices our
patients use every day. Pronounce-ments such as, "People with diabetes
need to keep their feet dry" and "Moisture promotes fungal growth" are
common, and it is widely assumed that the sock fabric our patients
wear determines how moist or dry the skin on their feet will be.

There are three schools of thought regarding the best fabric for socks
worn by people with diabetes. Some professionals recommend cotton/wool
socks. Others recommend socks or stockings of acrylic or a synthetic
blend. And still others advise their patients to wear comfortable,
well-fitting socks without regard to the type of fabric.

Sockwear Recommendation Survey
Diabetes care providers often answer questions such as A.B.’s without
considering whether there are any research data to support their
answer. We conducted an informal survey of physicians, podiatrists,
staff nurses, and certified diabetes educators (CDEs) from Duke
University Medical Center, the Durham VA Medical Center, and
surrounding areas to explore providers’ sockwear recommendations and
the reasoning behind them.

Physicians and podiatrists
Our survey of 12 physicians and podiatrists revealed that sockwear is
not a subject about which physicians feel particularly concerned. Most
said they never make sock recommendations. One said he was more likely
to make a comment on socks if a patient had signs of tinea pedis.

Of those who do make recommendations, one said she usually asks
patients to wear cotton or wool socks because they are associated with
less moisture and because she prefers natural fibers. Another
recommends and wears acrylic socks because these were recommended to
him by staff at an athletic shoe store. A podiatrist said he prefers a
cotton/wool/acrylic blend.

Doctors who suggest that patients wear particular socks recommend
comfort above all else. Two physicians mentioned that socks should not
be too tight.

General staff nurses
When we performed the same survey with 11 general staff nurses, it
became clear that nurses had a different focus. Although they
expressed concern that socks should be comfortable, they were also
likely to recommend specific fabric types. Most of the nurses thought
people with diabetes should wear cotton or wool socks. But those
recommending acrylic fabrics said they were "better," more absorbent,
and more comfortable.

Diabetes educators
Our third survey involved 11 CDEs, who were the most vocal group on
the subject of sockwear. Like the general staff nurses, most of the
CDEs thought that cotton or wool socks were preferable. The main
reason for their recommendation was absorbency. Several CDEs referred
to perspiring feet or excess moisture and said that cotton was better
at addressing this problem.

However, some of the CDEs surveyed did recommend acrylic socks. One
educator said she had changed her advice regarding cotton versus
acrylic based on an article she had read in the American Diabetes
Association (ADA) magazine Diabetes Forecast, which stated that people
with diabetes should not wear cotton.3

One CDE warned against wearing dark socks "because of the dye." That
recommendation, outdated by at least 50 years, is based on the fear
that dyes will not be colorfast and will "bleed" into open wounds.

At least one person in each of our three surveyed groups mentioned
Thorlo socks. However, these professionals seemed unaware that Thorlo
socks are made of an acrylic/nylon/spandex blend; they recommended
that people wear this brand while also recommending cotton/wool
fabrics.

Educational Materials Review
A sampling of patient education materials from different sources also
suggests that patients are not getting uniform information about
sockwear.

Government and pharmaceutical company literature
Government sources recommend cotton and wool socks for diabetic
patients to help keep feet dry.4,5 They also reinforce the need to
wear socks at all times.

Health care providers often use general diabetes care and diabetes
foot care literature provided by pharmaceutical companies in making
recommendations to patients. Virtually all of these materials make
some reference to wearing socks.6–11

Many do not make specific fabric recommendations, but they do suggest
that people avoid tight socks. Some suggest that white cotton or wool
socks are preferable, saying this is because "cotton socks allow feet
to breathe and helps prevent sweating."

Rarely do these materials cite research data for what they present.
Roche Diagnostics/Boehringer Mannheim Corporation lists an Accu-Chek
Amputation Prevention Initiative Advisory Board on the back page of
its foot care pamphlet.9 The Takeda/Lilly10 diabetes care materials
contain a fairly lengthy bibliography. Unfortunately, their only
reference to socks is a warning that people should not go barefoot.

Books and magazines for patients
A wealth of health care information, including sockwear
recommendations, can be found in the numerous books and periodical
publications produced for people with diabetes. Recent articles in
Diabetes Forecast,3,12 for example, have offered several common-sense
tips on choosing socks.

One article3 reminded readers to wear socks that fit well, so that
lumps and seams in the material do not increase pressure on the foot.
It also noted that, although cushioned socks can help prevent callus
formation, they may be too tight in some shoes.

The article also cautioned against wearing cotton socks during
exercise. The rationale was that the cushioning fibers compress over
time, and cotton does not wick away moisture; therefore, feet remain
moist. (Wicking is the ability of the fiber to pull moisture from the
skin’s surface toward the outer surface of the fabric, where it can
evaporate.13

The most recent Diabetes Forecast article on this topic14 suggests
that any sock fabric is fine for everyday wear, whereas acrylic or
polypropylene fabrics are best for exercising.

Articles in other publications for people with diabetes also offer
differing recommendations. One article in Diabetes Self-Management,15
for example, advised wearing only cotton socks and recommended
avoiding knee-high and tight socks and changing socks frequently for
people who tend to perspire heavily. The article noted that tight
socks are more constricting, and cotton allows air to penetrate and
absorb perspiration. Another article from the same publication16
recommended wearing socks made of synthetic fibers that wick away
moisture when participating in active sports.

In her book 101 Foot Care Tips for People With Diabetes,17 advanced
practice diabetes nurse Jessie H. Ahroni offers perhaps the most
comprehensive set of foot care recommendations for people with
diabetes. Echoing the Diabetes Forecast articles mentioned above, she
advises people whose feet perspire excessively to wear acrylic blends
because of the wicking action of acrylic fibers. She recommends socks
with cotton or wool because these fibers are "breathable," but she
notes that the sock fabric should include some acrylic or other
synthetic for its wicking action. She also notes the importance of
keeping feet dry to prevent fungal growth.

Professional education materials
Many educators at programs officially recognized by the ADA or the
American Association of Diabetes Educators generally advise patients
to wear good-fitting socks with shoes and to select socks made from
materials that will wick moisture away from the skin, such as cotton
or wool and synthetic/acrylic blends.

Although diabetes educators base their practices on many sources, one
important source is the handbook titled A Core Curriculum for Diabetes
Educators.18 This resource advises diabetes educators to teach people
to wear cotton or wool socks. It does not mention fabrics with wicking
action.

In another text on diabetes foot care, McDermott2 offers an
interesting cautionary note: people with diabetes are often given
"misinformation" that is not scientifically based. He advises
educators to recommend cotton but notes that blends are also
acceptable.

Haas and Ahroni19 advise educators to teach patients who have a
tendency toward "sweaty" feet to wear cotton or wool socks to absorb
moisture.

Clearly, then, the people educating the diabetes educators also have
differing opinions on the most appropriate fabric for socks.

The Research
Luckily, some research-based evidence is available on this topic. A
few studies have looked at what happens to feet wearing socks of
differing fabrics and constructions. Also, the textile industry has
conducted research into fiber composition and characteristics.

In 1989, Veves et al.20 used Thorlo socks to show that cushioning
decreased vertical pressure to the diabetic foot. They concluded that
in conjunction with wearing proper orthoses, cushioning can help to
prevent ulcer formation.

In 1990, the same authors21 looked at the duration of cushioning
effects. In this study, they found that a cushioned sock, while losing
some of its effects, provided more pressure relief than being
barefoot, even after 6 months. They concluded that a high-density sock
is probably the best choice for the insensitive foot.

Murray et al.22 also used Thorlo socks to look at the acceptability of
cushioned socks for people with diabetes who have insensitive feet.
They found a high acceptance of these socks over time.

Herring and Richie conducted two studies23,24 comparing the degree of
moisture on feet and socks, foot temperature, and blister formation
resulting from wearing acrylic and cotton socks. In the first study,23
they used socks with thickly padded cushioning in the soles. In the
second study,23 the socks had no extra padding. Interest-ingly, in the
study using padded socks, they found a significant advantage to using
acrylic, whereas in the study of generic cushioned socks, they found
no demonstrable difference in moisture.

Herring and Richie’s results agreed with textile industry claims that
natural cotton and wool fibers absorb moisture from the skin.13
However, socks are like towels. If a cotton towel is used to dry the
skin after a bath, the cotton does well at absorbing the water from
the skin, but the towel is then damp because it retains the moisture.
A characteristic of acrylic is that it does not absorb moisture well.
However, it is able to wick moisture from the skin. Herring and Richie
concluded that people whose feet are exposed to increased moisture
because of exercise should wear socks that are not only made of
acrylic fabric, but also densely padded.

Summary
Clearly, diabetes educators and other health care professionals often
base advice on tradition rather than on scientific evidence. The
available evidence suggests that people with diabetes who have
"normal" feet should be able to wear whatever socks they find to be
comfortable. Socks should fit well, without constricting cuffs, lumps,
or uncomfortable seams. Therefore, fitted socks are preferable to tube
socks. Lighter-colored socks may alert wearers with compromised
sensation to a draining wound. Patients can judge for themselves which
type of fabric feels the most comfortable.

Patients who are at risk for ulcer development because of decreased
pressure sensation should be advised to wear densely padded socks. In
the studies cited here, the padded socks used were the Thorlo brand,
which are made of 100% acrylic fiber with nylon and spandex for
elasticity. Because cotton was not used, it is difficult to say
whether a 100% cotton padded sock would also produce less vertical
pressure.

Herring and Richie found that padded acrylic socks produce less
moisture at the skin surface and less blistering in runners than do
cotton socks. Therefore, educators should recommend that their
patients wear padded acrylic socks when engaging in vigorous
exercise.



Footnotes

Carol B. Feldman, MSN, RN, CDE, is a primary care nurse at the Durham
VA Medical Center in Durham, N.C. Ellen D. Davis, MS, RN, CDE, is a
diabetes clinical nurse specialist at the Duke University Health
System in Durham, N.C.

Source:
http://www.japmaonline.org/cgi/content/abstract/83/9/515