May 8, 1981 - Giardia cysts; Lee Cassin and Robert Nelson assisted in the ..... Richardson BD, Wadvalla M: The bearing of height, weight and skinfold.
PUBLIC HEALTH BRIEFS
evidence for acquired immunity to Giardia.'3'14 An investigation of an outbreak of giardiasis in Vail, Colorado in 1978 showed findings similar to those of this study, with clinical attack rates for giardia-like illness inversely related to length of residence in that community.t Among campers involved in an outbreak in Utah in 1974, persons who had had previous exposure to mountain stream water had a significantly lower attack rate for giardiasis than persons who had not drunk stream water.6 Some of the deficiencies in the Aspen Highlands water treatment facility were probably present in the months or years preceding the outbreak, allowing ample exposure for Giardia infection among residents using this water supply in the past. Chemical addition to induce flocculation is necessary to remove particles the size of Giardia.tt Proper filter maintenance might have decreased the magnitude of this outbreak, but probably would not have prevented it, since, without chemical addition and flocculation, the dual-media filter would not have been adequate to trap Giardia cysts.
REFERENCES
1. Moore GT, Cross M, McGuire D, et al: Epidemic giardiasis at a ski resort. N Engl J Med 1969; 281:402-407. 2. Lopez CE, Dykes AC, Juranek DD, et al: Waterbome giardiasis: a communitywide outbreak of disease and a high rate of asymptomatic infection. Am J Epidemiol 1980; 112:495-507. 3. Craun GF: Waterbome giardiasis in the United States: a review. Am J Public Health 1979; 69:817-819. 4. Weniger BG, Blaser MJ, Gedrose J, Lippy EC, Juranek DD: An outbreak of waterborne giardiasis associated with heavy water runoff due to warm weather and volcanic ashfall 1983; 73:868-872. 5. Wolfe MS: Giardiasis. N Engl J Med 1978; 298:319-321.
tCenters for Disease Control: unpublished data. ttLogsdon GS, Fox KR: Paper presented at Pacific Northwest Section Annual Meeting, American Waterworks Association, Spokane, Washington, May 8, 1981.
6. Barbour AG, Nichols CR, Fukushima T: An outbreak of giardiasis in a group of campers. Am J Trop Med Hyg 1976; 25:384-389. 7. Melvin DM, Brooke MM: Laboratory procedures for the diagnosis of intestinal parasites, 2nd Ed. DHEW Pub. No. (CDC)76-8282. 8. Jakubowski W, Erickson TH: Methods for detection of Giardia cysts in water supplies. In: Jakubowski W, Hoff JC (eds): Waterborne Transmission of Giardiasis. Proceedings of a Symposium, September 18-20, 1978. Cincinnati, OH: US Environmental Protection Agency, Office of Research and Development, Environmental Research Center, EPA-600/979-001, June 1979. 9. Rothman KJ, Boice JD: Epidemiologic Analysis with a Programmable Calculator. NIH Pub. No. 79-1649; 1979: pp 36-37. 10. Davies RB, Hibler CP: Animal reservoirs and cross-species transmission of Giardia. In: Jakubowski W, Hoff JC (eds): Waterborne Transmission of Giardiasis. Proceedings of a Symposium, September 18-20, 1978. Cincinnati, OH: US Environmental Protection Agency, Office of Research and Development, Environmental Research Center, EPA-600/9-79-001, June, 1979. 11. Dykes AC, Juranek DD, Lorenz RA, Sinclair S, Jakubowski W, Davies R: Municipal water borne giardiasis: an epidemiologic investigation. Beavers implicated as a possible reservoir. Ann Int Med 1980; 92:165170. 12. Marshall JR, Priore R, Graham S, Brasure J: Oil the distortion of risk estimates in multiple exposure level case-control studies. Am J Epidemiol 1981; 113:464-473. 13. Roberts-Thomson IC, Stevens DP, Mahmoud AH, Warren KS: Acquired resistance to infection in an animal model of giardiasis. J Immunol 1976; 117:2036. 14. Stevens DP, Frank DM, Mahmoud AH: Thymus dependency of host resistance to Giardia muris infection: studies in nude mice. J Immunol 1978; 120:680-682.
ACKNOWLEDGEMENTS
We thank the following people who provided valuable assistance in this investigation: Dr. Charles Hibler and his staff examined water filters for Giardia cysts; Lee Cassin and Robert Nelson assisted in the epidemiologic investigation; Rick Karlin, Tom Braidech, John Blair, and Jerry Beberstein analyzed the water-treatment facility; Edward Lippy provided technical advice; and Phyllis Wasson typed the manuscript. Funding for this investigation was provided in part by the Environmental Protection Agency, contract no. 68-03-2927, and by EPA cooperative agreement no. CR-8088010. This investigation was presented in part at the Epidemic Intelligence Service 31st Annual Conference, April 20, 1982, Atlanta, GA.
The Relationship between Weight-Height Indices And the Triceps Skinfold Measure among Children Age 5 to 12 ROBERT MICHIELUTTE, PHD, ROBERT A. DISEKER, DRPH, WAYNE T. CORBETT, VMD, DRPH, HARRY M. SCHEY, PHD, AND JOHN R. UREDA, DRPH Relative weight and skinfold measurements have been used frequently among adults and children to estimate Abstract: This study examines several weight for height indiadiposity. Both classes of measures have limitations,"S but ces-Quetelet's index W/H2, W/H, and Rohrer's index W/H3-for the research to date has suggested that skinfold measuretheir appropriateness in estimating adiposity among young children. ments are the best of the non-laboratory methods currently Data were obtained for a sample of 1,668 children age 5-12 residing in use. 6'4 Measures of relative weight cannot distinguish in Forsyth County, North Carolina. Although W/H2 was found to be adiposity, muscularity, or oedema.5 Skinfold meabetween index, no that suggest the results indices, these of useful most the surements are frequently used as one criterion for testing the including the tricep skinfold measure, can be considered completely usefulness of various measures of relative weight in estimatsatisfactory in estimating adiposity among children. (Am J Public ing adiposity among children and adults.1620 Health 1984; 74:604-606.) Despite the overall superiority of skinfolds when applied to adults, the best of the relative weight tneasures Quetelet's Index (W/H2) generally correlates highly with Address reprint requests to Robert Michielutte, PhD, Section on Commuskinfold thicknesses and laboratory measurements of body nity Medicine, Bowman Gray School of Medicine, Winston-Salem, NC 27103. fat. 15,17-23 Indices of relative weight are simpler to obtain and Drs. Diseker and Schey are also with that Section at the School of Medicine; Dr. Corbett is with North Carolina State University, School of Veterinary appear to be useful in providing a general assessment of Medicine; Dr. Ureda is with the University of South Carolina, Department of obesity among groups in field studies, and in estimating Health Education. This paper, submitted to the Journal August 18, 1983, was obesity for individuals in the clinical setting. revised and accepted for publication December 1, 1983. The potential usefulness of weight for height indices among children is not clear, however, since they have not © 1984 American Journal of Public Health 0090-0036/84 $1.50 AJPH June 1984, Vol. 74, No. 6
PUBLIC HEALTH BRIEFS
been studied as thoroughly in children. Some studies have noted several problems.6"16'20 Limited evidence is currently available concerning how well these indices correlate with more direct measures of body fat such as skinfold thicknesses, and whether the same measure of weight for height found to be generally superior for adults is the most appropriate for children. Little is also known as to whether a single weight for height measure is applicable for all children or whether variations exist by age, sex, race, and measures of social class. This study examines several weight for height indicesW/H, Quetelet's index W/H2, and Rohrer's index W/H3with respect to their appropriateness in estimating adiposity among a sample of children age 5-12.
TABLE 1-Correlations between Height, Weight, Triceps Skinfold and the WeighVHeight Indices
Method
Correlation between triceps skinfold and W/H W/H2
Sample
The sample of children was obtained from schools in the Forsyth County, North Carolina public school system, and from one of two private schools in the county. Data were obtained for a total of 1,668 students (832 boys, 836 girls) age 5-12, representing a response rate of 80 per cent. Measurements of height, weight, and triceps skinfold were obtained for each child. A detailed discussion of the data collection procedure is presented elsewhere.24
Boys* N= Correlation between weight and W/H W/H2 W/H3
Girls*
832
836 .980 .819 .229
.983 .846 .306
.762 .442 -.270
.777 .496 -.177
.715 .799 .614
.732 .808 .641
Correlation between
height and W/H W/H2
W/H13
W/H3
*All correlations are significant at p
