JAMA

doi: 10.1001/jama.1986.03380210011001pmid: N/A

doi: 10.1001/jama.1986.03380210014002pmid: N/A

Cole, Helene M.

doi: 10.1001/jama.1986.03380210015003pmid: N/A

FOUR YEARS AGO this week, one of the most widely publicized and debated medical experiments of the decade began at the University of Utah Medical Center, Salt Lake City. Seattle dentist Barney Clark, near death from idiopathic cardiomyopathy, consented to the removal of his failing heart. Clark became the first human recipient of the plastic and metal pneumatically powered Jarvik-7 (named for Robert K. Jarvik, MD) artificial heart. Clark, described as the "gallant pioneer" of this experiment (Time, April 4, 1983, p 62), lived 112 days with his mechanical heart. His life extension was complicated by seizures, depression, aspiration pneumonia, renal failure, epistaxis, ruptured pulmonary blebs, circulatory compromise from a fractured artificial valve strut, and, finally, overwhelming gram negative sepsis (pseudomonas, klebsiella, citrobacter) culminating in complete organ failure (N Engl J Med 1984;310:273278). Although many observers cheered Clark's heroism and marveled that the mechanical heart sustained him for an extended

Wyngaarden, James B.; ,

doi: 10.1001/jama.1986.03380210027004pmid: N/A

doi: 10.1001/jama.1986.03380210032005pmid: N/A

doi: 10.1001/jama.1986.03380210041006pmid: N/A

doi: 10.1001/jama.1986.03380210046007pmid: N/A

Knight, Kevin

doi: 10.1001/jama.1986.03380210054008pmid: N/A

To the Editor.— Stunkard and colleagues1 have convincingly demonstrated different concordance rates and correlation coefficients for monozygotic and dizygotic twins for various measures of overweight. However, the conclusion that human obesity is under substantial genetic control is valid only in the context of the range of environmental factors experienced by the study subjects. The data presented do not support general conclusions regarding the relative roles of heredity and environment in producing human obesity. One can easily imagine a situation in which similar heritability factors might be calculated in the face of a substantially different overall obesity prevalence caused by environmental factors. For example, the twins participating in this study probably experienced Western patterns of diet and exercise. It is conceivable that under a different set of diet and exercise patterns the overall prevalence of overweight might have been much lower, even though the heritability factor would have remained the

Peterson, Louis J.; Heinz, Grete

doi: 10.1001/jama.1986.03380210054009pmid: N/A

To the Editor.— A series of studies, of which "A Twin Study of Human Obesity"1 is the most recent example, have relied on the body mass index (BMI) to draw far-reaching conclusions about weight and health status. We question the validity of these interpretations. The BMI denotes how much a person's weight deviates from the average weight of young adults of the same height. This deviation in weight may result from excessive leanness or fatness. It may also represent normal weight for a bone structure that is not average for height or muscularity that differs from the average. By stating that work on the covariance of the BMI in twins has "confirmed the importance of genetic influences on human fatness," the authors assume that variations in fat account for these weight deviations. On the basis of our research on bone structure and body composition, we challenge the assumption that,

Uphoff, Eugene J.; Reagan, Peter

doi: 10.1001/jama.1986.03380210055012pmid: 3773207

To the Editor.— In the Aug 22/29,1986, issue of JAMA, Balfe et al1 attempt to address issues identified as being "critical to the future of health care in this country." It seems particularly tragic that the consideration of the risks of nuclear war was omitted from this list. Although others have stated that political and nuclear war issues should be considered outside the scope of the proper concern of health professionals, we believe that concern for the prevention of nuclear war is of critical importance as we plan for the future health and well-being of people worldwide. It is only by continuing to raise this issue at each consideration of health care priorities that we can ultimately bring about the necessary political policy changes that will ensure future peace— a prerequisite for all other health care considerations.