This classification required a large sample size and could therefore not be done in men because of insufficient numbers in individual BMI categories. Within each graph, the ellipse sequence on the left represents women and that on the right represents men.
Within each sex, vector down-sloping is observed with decreasing age, ie, the youngest group is represented by the shortest vector and the oldest group by the longest vector, respectively. ANOVA with Bonferroni post hoc test was used to compare the 6 age groups (1 = 18–29 y, 2 = 30–39 y, 3 = 40–49 y, 4 = 50–59 y, 5 = 60–69 y, and 6 = 70–80 y) within one BMI group.
Pearson’s correlation coefficients were calculated for relations between c and is explained in detail by Piccoli et al (1, 9).
Confidence ellipses describe the area in which the mean sex-, BMI-, and age-specific two-dimensional vectors fall within a 95% probability (1).
Sex differences in vector distribution were already apparent in children, although they were less pronounced than in adults.
Longer vectors were found in boys than in girls of the same age and BMI group, without a difference in mean vector direction between the sexes. Within each graph, the ellipse sequence on the left represents women and that on the right represents men.
, 35795 women were divided into 6 groups of a certain BMI and 6 age ranges.
The shape of both the tolerance and the confidence ellipses was determined by the coefficient of correlation between .
Within a BMI and age category, vectors for women were significantly shorter than those for men.
This implies that graphically nonoverlapping 95% confidence ellipses are significantly different from each other ().
The size of the confidence ellipses was influenced by the variability of the vector components and the sample size (smaller ellipses from a greater number of subjects with a similar SD).
In case of children, parents provided written informed consent.