Gastrointestinal Parasitic Infection, Anthropometrics, Nutritional Status, and Physical Work Capacity in Colombian Boys W.M. WILSON, 1 * D.L. DUFOUR, 1,6 L.K. STATEN, 2 M. BARAC-NIETO, 3 J.C. REINA, 4 AND G.B. SPURR 5,6 1 Department of Anthropology, University of Colorado, Boulder, Colorado 2 Arizona Prevention Center, University of Arizona College of Medicine, Tucson, Arizona 3 Department of Physiology University of Kuwait, Kuwait 4 Department of Pediatrics, Universidad del Valle, Cali, Colombia 5 Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 6 Department of Physiological Sciences, Universidad del Valle, Cali, Colombia ABSTRACT This article tests the hypothesis that the presence of gastro- intestinal parasites in Colombian boys is negatively associated with anthro- pometric characteristics, physical work capacity, blood hemoglobin (Hb) lev- els, and nutritional status. Anthropometric, Hb, V . O 2 max, and parasite load data were collected on 1,016 boys in Cali, Colombia. The boys were classified as lower socioeconomic class (SEC) from either urban or rural environments, and upper SEC from an urban environment. Sixty-three percent of the boys were infected with gastrointestinal parasites and, of the infected boys, 80– 95% had light parasite loads. Parasites found included Necator americanus, Ascaris lumbricoides, Entamoeba histolytica, Trichuris trichiura, Giardia spp., and Enterobius vermicularis. Infected boys had significantly lower weight, stature, weight-for-height (among 6–9-year-old boys), Hb levels, and V . O 2 max (ANCOVA, controlling for age and SEC). In terms of nutritional status, infected boys were 1.47 times more likely to be classified as iron deficient than noninfected boys (chi-square, P < 0.001), and 1.61 times more likely to be classified as stunted (P < 0.001). Infection was not associated with wasting in any SEC group. In conclusion, light to moderate gastrointestinal parasite loads were associated with significantly lower weight, stature, weight-for-height (in 6–9-year-old boys), Hb levels, and V . O 2 max, and a sig- nificantly higher frequency of IDA and stunting. These data suggest that comprehensive analyses of the nutritional status of populations in regions endemic for parasitic infection should include testing for the presence of infection. Am. J. Hum. Biol. 11:763–771, 1999. © 1999 Wiley-Liss, Inc. Infection with protozoal and helminthic parasites represents the most prevalent en- demic medical condition in the world (Bundy, 1994). Among infected populations, undernutrition is also quite common, sug- gesting a relationship between parasitic in- fection and undernutrition (Rosenberg and Bowman, 1984; Solomons and Keusch, 1981). Although it has been argued that This article won the Edward E. Hunt, Jr., Award for best student paper at the 20th Annual Meetings of the HBA in Oak- land, CA, March, 1995. Contract grant sponsor: NIH; Contract grant number: HD 10814; Contract grant sponsors: the Medical Research Service, World Veterans Administration Medical Center, and the Funda- cio ´n para la Educacio ´n Superior, Colombia. *Correspondence to: Dr. Warren M. Wilson, Anthropology De- partment, University of Colorado, Campus Box 233, Boulder, CO 80309. E-mail: warren.wilson@colorado.edu Received 22 April 1998; Revision received 16 October 1998; Accepted 29 October 1998 AMERICAN JOURNAL OF HUMAN BIOLOGY 11:763–771 (1999) © 1999 Wiley-Liss, Inc.