CHANCE News 2.04 
               (7 Feb to 29 Feb 1993)

Prepared by Laurie Snell

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>>>>>==========>> Note: These notes have lines breaks after about 50 characters. It would be better for me with no line breaks but I fear for some this would just be a long line. If you have a better suggestion please pass it on. =================================================== Get the facts first, and then you can distort them as much as you please. Mark Twain =================================================== <<<========<<

>>>>>==========>> Suggested by Bob Abelson When Black Soldiers Were Hanged: A war's Footnote. The New York Times 7 Feb 1993, Sec.1 Page 20 In doing research in England on prison punishment J. Robert Lilly observed that during World War II almost four times as many black soldiers as whites were executed in Europe after military courts-martial, even though blacks made up less than 10 percent of the troops. Lilly says that his data shows that blacks were punished much more severely than whites for crimes such as rape of English civilians while for less serious, less interracially explosive offenses, such as barracks dishonesty and drunkenness the punishments were represented proportionately between whites and blacks. Lilly feel feels his analysis of this historical data will substantiate a kind of racial discrimination that will shed light on current problems such as the Los Angeles riots. <<<========<<

>>>>>==========>> 'Threats' to left-handed invisible in new study. The New York Times, 16 Feb, 1993 C3 Researchers at the National Institutes of Health and Harvard University examined the rates of death among the elderly people in East Boston, Mass.,and found that over a six-year period the death rate was 32.2 percent among right-handers and 33.8 percent for left-handers. 9.1 percent of the men and 5.8 percent of the women in the study were left-handed. Previous studies by Coren and Halpern had indicated that left-handers lived significantly less long than right- handers. The authors of this study feel that these and other previous studies were flawed or interpreted incorrectly. This study will be published in the February issue of the American Journal of Public Health. <<<========<<

>>>>>==========>> The powers and pitfalls of parsimony. Nature 13 Feb 1993 Caro-Beth Stewart A parsimony trees using nucleotide sequences to trace evolution is the tree that requires the fewest total evolutionary changes (nucleotide substitutions). The problem of finding these trees has led to interesting statistical problems. The method itself was highly publicized recently by the African Eve hypothesis. This article written for the non-expert describes how you find the parsimony tree and indicate some of the problems involved in its proper use. A letter in the 25 Feb Nature outlines the use of parsimony analysis in the case of the Florida dentist to test the dental transmission hypothesis against the null hypothesis that the patients independently acquired similar variants of the HIV virus within the local community. He reports that available data are consistent with both the transmission and the null hypotheses. This would be an attractive topic to try to do in a Chance course but looks hard. <<<========<<

>>>>>==========>> Race link to drug use may be overstated. USA TODAY, 24 Feb 1993, Pg 1D Mike Snider A 1988 federal study found that Blacks and Hispanics were twice as likely to use crack cocaine as whites. The 24 Feb issue of the Journal of American Medical Association has an article by Shuster, Anthony and Lillie-Blanton which analyses the data by grouping the survey respondents into more homogeneous strata to control for factors that might confound the effect of race, for example, differences in availability of crack from neighborhood to neighborhood. When this is done there are no longer significant differences between races. An editorial related to this study remarks that while it is appropriate in some studies to use race as an explanatory variable "we must be precise about the research questions that we pose and the relationship race plays in the analyses we conduct." This article was not widely reported despite being a subject of an editorial in JAMA. <<<========<<

>>>>>==========>> New Caution, and Some Reassurance, on Vasectomy. The New York Times 21 Feb, 1993, Sec 4 page 2 Two studies reported in the Feb 14 issue of the Journal of the American Medical Association linked vasectomy and prostate cancer. Two similar studies had failed to find such a link. Little is said about the results in this study. Rather the focus is on who gets vasectomy's (white, well educated and affluent, in mid-to-late thirties, has at least one son, lives in the West and strongly dislikes other contraceptive methods), and the accompanying editorial that says that men seeking a vasectomy should be advised of the findings, but cautioned against an over-reaction. Those that have already them them should not rush out to have them reversed but rather have the recommended yearly check for prostate problems. <<<========<<

>>>>>==========>> A bald spot on top may predict heart risk. The New York Times, February 24, 1993, Section A; Page 1; Column 2 Lawrence K. Altman A study reported in the Feb 24 issue of the Journal of the American Medical Association of men under 55 showed that a bald spot on the top of the head was correlated with increase in the risk of heart attack. The more extensive the baldness the higher the risk. This risk was found to be independent of other well-known risk for heart attacks. Previous studies have found such a correlation though not consistently. No satisfactory explanation for this correlation has been found but the authors of the study speculated that the increased risk might be related to a male sex hormone known as dihydrotestosterone. This hormone has also been proposed as a factor responsible for the fact that younger men have more heart attacks then premenopausal women. <<<========<<

>>>>>==========>> Exercise slashes risk of heart disease. San Francisco Chronicle, 25 Feb, 1993, A20 David Perlman The Harvard study has involved more than 15,000 Harvard Alumni over a 30 year period. In the 25 Feb issue of the New England Journal of Medicine Paffenbarger and colleagues report on their findings on the effect of exercise in the prevention of heart disease. Those who participated in moderately vigorous sports such as jogging, swimming or tennis at least three hours a week had half the risk of death from all causes during the three decades of the study compared with those who did minimal exercise. It is concluded that moderately vigorous exercise and quitting smoking could add a average of 2 and 1/2 years to your lifetime. A second study in the same issue looked at the benefits of exercise in a group of 2,000 men in Norway 40 to 59 by testing their physical fitness, dividing them into 4 groups according to fitness, and then following their health for 16 years. The least fit men were twice as likely to die during the 16 years of study then the men who were most physically fit. Some reports of this article emphasized the small average increase in lifetime (ten months) for those who exercised significantly. A good example to compare increased risk (30 percent) with relatively small increase in average lifetime. <<<========<<

>>>>>==========>> Studies say mammograms fail to help many women. The New York Times, 26 Feb 1993 Gina Kolata New data, reported at a two-day meeting sponsored by the National Cancer Institute confirmed the earlier Canadian study reported last fall that women in their 40's who have mammograms had the same death rate from breast cancer as those who did not have the screening. All studies have shown a substantial benefit in mammograms for women over 50. Medical experts had hoped that the data would justify the guidelines issued by the cancer society and the cancer institute recommending the screening for younger women issued ten years ago. The National Women's Health Network is advising women not have to have mammograms until they are 50. The cancer society will review the data and will continue to recommend mammograms for women in the 40's until they finish this review but most experts at this meeting felt that screening should not be routinely recommended for younger women. <<<========<<

>>>>>==========>> Tint in red wine may help heart, study says. LA Times, 19 Feb 1993, A25 From Associated Press Report of an article in the current Lancet which attempts to show that the color chemicals called phenols counter the ill effects of cholesterol. It is said that "red wine phenols are antioxidants, such as Vitamins A and E. Antioxidants mop up free radicals--highly charged particles--that are linked to an increased risk of heart disease." This is one more attempt to explain why the people in southern France have such a low rate of heart disease. <<<========<<

>>>>>==========>> Aspirin benefit to heart patients detailed Doctor's OK. urged before drug is taken Dallas Morning News, 9 Feb 1993 Laura Bell A report from American Heart Association to be published in the journal Circulation will again verify that heart patients who take an aspirin every day may prevent a second attack and reduce the complications of bypass surgery. It is also suggested that aspirin may help prevent a first heart attack in middle-aged or older men. A study on the effect of aspirin on women hasn't been completed. The authors caution against taking aspirin on a regular basis unless under a doctor's care because of possible harmful side effects. <<<========<<

>>>>>==========>> Personal Health. The New York Times 24 Feb, 1993, C12 Jane E. Brody Jane Brody provides guidelines to help the reader cope with the numerous studies that are reported relating to your health. The difference between association and cause is discussed. Tips are given on how to interpret risks -- a 300 percent increase in something for which the risk is small in the first place may be less important than a 50 percent increase in something with initially has a larger risk. She suggests that articles in serious journals like the New England Journal of Medicine should be taken more seriously etc. <<<========<<

>>>>>==========>> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! CHANCE News 2.04 (7 Feb to 29 Feb 1993) !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Please send suggestions to: jlsnell@dartmouth.edu >>>==========>>|<<==========<<<