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From the book, do problems 4 and 14 in Chapter 7 (page 285).
The following reports come from various newspaper articles. For each one answer the following ques-tions: a. Was the study a controlled experiment or an observational study? If it was an observational study, was it unblinded, blind, or double blind? b. What were the treatment and response variables? c. If the study was not a controlled experiment, would a controlled experiment be feasible? If it was not (double) blind, would a (double) blind study be feasible? d. What is the population that the researchers intend for the study to provide information about? How were the samples (treatment and control groups) chosen? Comment on theappropriateness of the samples.
1. (McCaddon and Kelly Age and Aging, Vol. 23 7/94) Suspicion has been growing that a lack of vitamin B12 is somehow implicated in the development of Alzheimer’s disease. Now researchers inthe United Kingdom have confirmed this suspicion. They evaluated members of a family with geneticpredisposition towards Alzheimer’s disease. They found that four out of six of family members withconfirmed Alzheimer’s disease had abnormally low vitamin B12 levels in their blood. This comparesto only one out of 12 among the family members who were at equal risk for developing Alzheimer’sdisease but did not. The researchers speculate that a vitamin B12 deficiency could result in impairedmethylation reactions in the central nervous system — a characteristic feature in Alzheimer’s disease.
They also consider the possibility that the genetic predisposition to Alzheimer’s disease may actuallybe related to a genetic impairment in the ability to absorb vitamin B12. Vitamin B12 deficiency initself often causes disorientation and confusion and thus mimics some of the prominent symptoms ofAlzheimer’s disease.
2. In a study inspired and partly financed by the MacArthur Foundation, Dr. Katrine Spiegel, Dr. Eve Van Cauter, and Rachel Lepoult found that even in young, healthy people, as little as a week-longsleep debt of three or four hours a night has adverse effects on the body’s ability to process carbohy-drates, manage stress, maintain a proper level of hormones, and fight off infections. They conducteda study of 11 healthy men aged 18-27 who spent 16 consecutive nights in a clinical laboratory wherethe researchers tightly controlled the amount of time they spent in bed. After three 8-hour nights,they were restricted to six consecutive 4-hour nights, followed by seven 12-hour nights. None wereallowed to sleep during the day.
3. (Reuter’s Health July 13, 2002) New research shows that the most common form of skin cancer is found more frequently among smooth-skinned older adults than in their more wrinkled peers.
Griffiths and his colleagues at the University of Manchester in England studied 118 white patientswith basal cell carcinoma, comparing their skin characteristics with those of 112 adults without thedisease. All participants were older than 50. The investigators found that as a whole, the skincancer patients had less-wrinkled skin despite being slightly older — their average age was about 72,compared with the 69 in the comparison group. The findings were reported in a recent issue of theArchives of Dermatology.
Age would be a possible confounding factor here (why?), does it seem to be? 4. In 2001, 30,000 people in China died from AIDS while 26,000 died in Botswana (the figures come from UN councils). Does this mean AIDS is worse in China? 5. A study finds that more people who drink beer die at an early age than people who drink wine.
6. April 14, 2003, ACS News According to a new report, the anti-depressant medicine bupropion (Zyban) tripled quit rates for women and formerly depressed smokers when compared to control groups whosemembers took a placebo (sugar pill). Findings from a clinical trial were recently published in Nicotineand Tobacco Research (Vol. 5, No. 1: 99-109), and are the first to show high success rates for womenand people with a history of depression. After one year, approximately 26% of the women smokers whoused bupropion SR (sustained release) during the eight-week study were still tobacco free, comparedwith 8.5% of the placebo group. Among formerly depressed smokers, about 29% of the bupropiongroup members were still non-smokers one year later, compared with 8% of the placebo group. Themarketers of Zyban, GlaxoSmithKline, funded the original clinical trial, which was designed anddirected by CTRI researchers. It included 893 people, randomized into four groups. Two groupswere treated for eight weeks with bupropion SR tablets (one group also used nicotine patches; theother placebo patches). Two groups received placebo tablets (again one with nicotine patches, onewith placebo patches). The patch did not significantly improve quit rates for either group. Studyparticipants had brief counseling sessions weekly and brought in their pill bottles so researchers couldcount any unused medication. The close supervision ensured that they used the full course of pillsand patches — something that doesn’t happen enough in the real world, according to Glynn. ”Thenumber one problem with cessation now is compliance. The base problem behind relapse is whenpeople don’t continue with their treatment plan, or don’t follow it completely,” he said.

Source: http://dean.serenevy.net/teaching/classes/Fall2006/M111-2/Homework1.pdf