Read the article “Shining light on those pimples: No aging effect. New treatment

Question

Read the article “Shining light on those pimples: No aging effect. New treatment zaps acne, not healthy skin” by Jane E. Allen, Los Angeles Times, November 16, 2002. (It’s linked on the homework web page.) Specifically in this study (do not give general definitions), what are the

a) experimental units (abbreviated EU, also called individuals or subjects)?

b) treatments

c) How does this study use a matched pairs design?

HEADLINE: Shining light on those pimples: No aging effect. New treatment zaps acne, not healthy skin

SOURCE: Los Angeles Times November 16, 2002 Saturday Final Edition

BYLINE: JANE E. ALLEN

BODY: A new light treatment that eliminates acne-causing skin bacteria without burning, redness or irritation might be a good alternative to lotions and oral antibiotics for patients with moderate breakouts.

The U.S. Food and Drug Administration has approved the ClearLight system for moderate cases of inflammatory acne vulgaris, which is harder to treat than the superficial pimples some people suffer and which can leave permanent scars.

As many as 80 per cent of all people develop acne at some point, most frequently in adolescence when hormonal changes increase the amount of oil produced by the skin and create blockages of the pores.

With the ClearLight system, patients usually undergo twice-weekly treatments for four weeks at the dermatologist's office. During those visits, the affected skin of the face or back is exposed for 15 minutes to a narrow band of blue light, which destroys the Propionibacterium acnes bacteria without harming surrounding skin.

Unlike other types of light treatments that have been used on acne, such as UVB light, ClearLight doesn't age the skin and doesn't appear to cause skin cancer.

The product offers an alternative for patients worried about the side effects of oral isotretinoin (Accutane), which requires that they be monitored through regular blood tests. It's also designed to offer a choice for those whose skin is irritated by common treatments, such as Retin A, which causes drying and redness; or benzoyl peroxide, which can overly dry the skin; or those for whom antibiotics don't work well, said Alan Shalita, a dermatologist at the State University of New York Downstate Medical Centre.

In some patients, acne-causing bacteria become less sensitive to commonly used antibiotics, such as tetracycline, doxycycline and minocycline, he said. Dermatologists sometimes combine them with medications such as benzoyl peroxide.ClearLight, made by an Israeli company, Lumenis Ltd., makes a nonissue out of antibiotic insensitivity. However, Shalita said it might turn out to be more effective when used with other acne-fighting products, such as antibiotics, Retin A or benzoyl peroxide.

In the clinical trials led by Shalita, researchers used the light treatment on 28 volunteer patients, treating half of the face. After one month, they compared the untreated halves of the faces to the treated halves. About 70 per cent of the patients improved by at least 50 per cent on the treated side; about 30 per cent improved on the untreated side, which might indicate that the treatment had a systemic anti-inflammatory effect, Shalita said. Most patients continued to improve for at least one month after they finished the treatment; they maintained the improvement for up to three months.

A drawback of ClearLight is that it requires frequent visits to the doctor. But Shalita said doctors may be able to modify the treatment regimen to make it more convenient.

Explanation / Answer

Answers

a) Experimental units: Patients suffering from skin-related problems like inflamatory acne vulgaris etc.

b) Treatment: Clearlight System

c) By treating only half the patients' affected parts and leaving the other half untreated, the experimentors have achieved in effect the advantage of matched-pair design. It is just like treating the same individuals with two different medications (allowing enough time for nullifying the effect of the first treatment before administering the second) and using the difference in the response variable as the parameter for deriving inferences.

DONE

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