Longitudinal Growth of Cranial Structures in Three Ethnic Groups

Most growth data have been derived from children of European extraction; few data are available for racially diverse peoples. Objectives: We report here on anthropometric data on growth of the ears, nose, and mouth in mixed longitudinal series of children 3 to 18 years of age from American whites (New Holland, MI), American blacks (Tuskegee, AL), and Mayans (Yucatan, Mexico). Methods: These unpublished data were collected over a 10-year period by M. H. Steggerda of the Carnegie Institute, New York. Samples averaged 100 subjects per group. Race and sex differences were tested with generalized linear models using appropriate error terms for the repeated measures. Results: Nose breadth differed significantly at all ages, with whites narrowest, Maya intermediate, and blacks broadest. Nose heights were convergent with age, with no significant group difference after 10 years. Mouth width and height were significantly greater in blacks. Ear dimensions showed considerable sexual dimorphism, with blacks having broad ears but only minor differences occurred among groups for ear height. Velocity curves showed no parapubertal growth spurt, perhaps because these structures lack bony constituents. Peak velocities all occurred in early childhood, with linear decreases in magnitude thereafter. Indeed, no plateau (ie, 'final' size) was discernible in these data that were truncated at 18 years of age. Conclusions: In sum, the patterns for distance and velocity differed significantly by race and by sex, so reliance on published norms based on whites for treatment targets or to assess normal limits can be misleading. Supported in part by NIH training grant DE07258.