Letters to the Editor Health: Implications for Reducing Chronic Disease. Washington, DC: National Academy Press; 1989. 4. US Department of Health and Human Services. Healthy People 2000. Promoting Health and Preventing Disease: Year 2000 Health Objectives forthe Nation. Washington, DC: US Government Printing Office; 1990. 5. Centers for Disease Control. Year 2000 national health objectives. JAMA. 1989; 262:1919-1920.
Patterson and Block Respond We thank Dr. Blackburn for his response, which reinforces and expands on the message conveyed in our recent paper. In describing the potential economic impact of the deficiencies in the American diet, in particular in relation to fruit and vegetable consumption, Dr. Blackburn has provided additional justification for taking action to improve the diet. Given the present levels of consumption, it may be difficult to achieve the recommended levels of fruit and vegetable intake in the near future. We acknowledge Dr. Blackburn's suggestion that fortification of foods may be an appropriate vehicle for supplying those nutrients currently identified as being beneficial. In fact, it was through fortification that such diseases as rickets, pellagra and beri-beri have been eliminated in this country. In the context of inadequate fruit and vegetable consumption, fortification of commonly eaten foods with the antioxidant micronutrients might achieve important health benefits. If fortification is undertaken, however, it should be in conjunction with a campaign to increase consumption of the foods themselves because the mechanisms and the constituents that impact on health have not been completely identified. In addition, controlled trials are needed to investigate whether changes in diet will in fact lead to benefits predicted from epidemiologic data. We are hopeful that the US marketplace can not only respond to increased demands for these foods, but also participate in creating this demand. We recognize the role of cost, and this might be an appropriate issue for a national task force to address. In addition to cost, however, individual choice plays a role-an apple versus a small bag of chips. Choice can be influenced by promotion and education. Learning why people eat (or don't eat) garden vegetables, for example, which ones they prefer, and how food choices are made would improve the likelihood of success of a campaign.
466 American Journal of Public Health
It is clear that nutrition recommendations alone are not achieving desired goals, at least with respect to fruit and vegetable consumption. The USDA recommended 4 or more servings of these foods in 19571 and tied these recommendations to a health message in 1979.2 Yet, for the decade forwhich data are available (1976-1986), consumption of these foods has remained virtuaLly unchanged.3 We agree with Dr. Blackbum that the public health community must give this subject high priority. O Blossom H. Patterson, MA Gladys Block, PhD Blossom H. Patterson and Gladys Block are with the National Cancer Institute. Requests for reprints should be sent to Blossom H. Patterson, MA, Division of Cancer Prevention and Control, National Institutes ofHealth, National Cancer Institute, Executive Plaza North, Suite 344, Bethesda, MD 20892
References 1. United States Department of Agriculture, Agricultural Research Service. Essentials of an Adequate Diet-Facts In Nutrition Programs. Washington, DC: US Government Printing Office; 1957. Home Economics Research Report No. 3. 2. United States Department of Agriculture, Science and Education Administration. Food, Hone and Garden Bulletin No. 228. Washington, DC: US Government Printing Office; 1979. 3. Patterson BH, Block G. Fruit and vegetable consumption: National survey data. In Bendich A, Butterworth CE, eds. Prevention Nutrition. New York, NY: Marcel Dekker; In press.
Defining Carpal Tunnel Syndrome I congratulate Dr. Katz and colleagues on their paper, which critically examines the sensitivity, specificity, and predictive value of NIOSH's surveillance case definition for work-related carpal tunnel syndrome (C7S).1 I would like to point out the potential for misclassification of the physical examination maneuvers and comment on the implication this may have on the validity testing. The authors have defined a positive carpal Tinel's sign and a positive Phalen's sign as "pain or paresthesia in at least one of the first three digits." Having performed physical examinations of the upper extremities to detect cumulative trauma disorders for workers employed in high-risk industries,23 my experience has led me to define a positive Tinel's and Phalen's test as having symptoms in at least two of the first three digits. This stricter maneuver criterion would probably decrease the sensitivity and
increase the specificity, but towhat extent is unknown. It is interesting to note that Katz et al. designed a self-administered hand diagram to classify patients as classic, probable, possible, and unlikely for CIS.4 A classic or probable diagram required symptoms in at least trw of the first three digits. The hand diagram ratings were better predictors of crs than Phalen's or Tinel's tests in a bivariate analysis and had the strongest association with CTS in the logistic regression model.5 Whether the "two rather than one digit" criterion is responsible for this difference needs to be evaluated. Finally, I would like to emphasize Katz's comment, "carpal tunnel syndrome is just one of a variety of occupation-associated upper extremity disorders. Symptomatic workers who do not have carpal tunnel syndrome may have other occupation-related cumulative trauma disorders and might benefit from job modification and treatment."'(P 192) E] as R. Hales, MD
References 1. Katz JN, Larson MG, Fossel AH, Liang MH. Validation of a surveillance case definition of carpal tunnel syndrome.AmJPub Health. 1991;81:189-193. 2. Hales TR, Fine UJ. Health Hazand Evaluation Report HETA 89-251-1997. Cincinnati, Ohio: National Institute for Occupational Safety and Health, Division of Surveillance, Hazard Evaluations, and Field Studies; 1989. 3. Hales TR, HabesDH, Fine UJ, HornungRH,
HETA 88-180-1958. Cincinnati, Ohio: National Institute for Occupational Safety and Health, Division of Surveillance, Hazard Evaluations, and Field Studies; 1989. 4. Katz JN, Stirrat CS. A self-administered hand diagram for the diagnosis of carpal tunnel syndrome. J Hand Stg [Arn]. 1990;
15A:360-363. 5. Katz JN, Larson MC, Sabra A, et al. The carpal tunnel syndrome: diagnostic utility of the history and physical examination findings. Ann Intern MedL 1990;112:321-327. Requests for reprints should be sent to Thomas R. Hales, MD, National Institute for Occupational Safety and Health, Denver, CO 80294.
Katz Responds Dr. Hales argues thoughtfully that the sensitivity and specificity of diagnostic tests may depend upon how the tests are interpreted. Most authors reporting on the Tinel sign in carpal tunnel syndrome consider tingling "in the median nerve distribution" a positive response and do not indicate if tingling in one finger satisfies this criterion. Three studies employing such a vague criterion for the Tinel sign reported sensitivities of 0.26, 0.44, and
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