Joel L. Weissfeld
Joel L. Weissfeld
Department of Epidemology and Division of Gastroenterology and Hepatology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213-5582
Robert E. Schoen
Robert E. Schoen
Department of Epidemology and Division of Gastroenterology and Hepatology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213-5582

Global tests of general association do not show statistically significant associations between sex-specific VAT quartile and IGF measures, dichotomized as sex-specific median cut-points. Scatter plots do not provide strong evidence for an inverse U-shaped association between IGF-I and VAT, in men (Fig. 1) or women (Fig. 2). The elevated odds of high median IGF-I in women with second quartile VAT relative to women with first quartile VAT probably represents a chance occurrence related to the specific cut-points chosen to convert variables (e.g., IGF-I and VAT) measured on an interval scale into analytic variables measured on an ordinal scale.

The abbreviations used are: VAT, visceral adipose tissue; IGF, insulin-like growth factor.

Fig. 1.
Fig. 1. Association between IGF-I and VAT, in men (n = 267), with least square quadratic regression curve (F value = 0.28, 2 degrees of freedom; P = 0.76).
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Association between IGF-I and VAT, in men (n = 267), with least square quadratic regression curve (F value = 0.28, 2 degrees of freedom; P = 0.76).

Fig. 1.
Fig. 1. Association between IGF-I and VAT, in men (n = 267), with least square quadratic regression curve (F value = 0.28, 2 degrees of freedom; P = 0.76).
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Association between IGF-I and VAT, in men (n = 267), with least square quadratic regression curve (F value = 0.28, 2 degrees of freedom; P = 0.76).

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Fig. 2.
Fig. 2. Association between IGF-I and VAT, in women (n = 165), with least square quadratic regression curve (F value = 0.59, 2 degrees of freedom; P = 0.56).
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Association between IGF-I and VAT, in women (n = 165), with least square quadratic regression curve (F value = 0.59, 2 degrees of freedom; P = 0.56).

Fig. 2.
Fig. 2. Association between IGF-I and VAT, in women (n = 165), with least square quadratic regression curve (F value = 0.59, 2 degrees of freedom; P = 0.56).
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Association between IGF-I and VAT, in women (n = 165), with least square quadratic regression curve (F value = 0.59, 2 degrees of freedom; P = 0.56).

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2003