Sex chromosome aneuploidy and anthropometry: a new proportionality assessment using the phantom stratagem.

Reported anthropometric data on 121 subjects with 47,XYY,47XXY,47,XXX, and 45,X aneuploidies were compared to those from 578 male and female control subjects by use of a single, unisex reference person ("phantom"). Subjects and controls were geometrically scaled to a standard stature of 170.18 cm, thus eliminating variance due to height. Deviations of anthropometric variables from specified phantom values were expressed as standard z-scores. By comparing z-scores of individual aneuploidy classes with those of their controls, further differences in proportionality came to light. The stratagem disclosed a systematic proportionality pattern between subjects and controls which appeared to be related to each specific sex chromosome aneuploidy. The phantom stratagem for proportional growth assessment appears to merit further use in genetic investigations where individual differences in size and shape confound the analysis of anthropometric data.

Sex chromatin scores in oral mucosa and hair root sheaths of human females.

The preparation and the utility of oral mucosa and hair root sheaths for quantitative sex chromatin studies is discussed. In buccal smears requirements for reliable scoring are frequently not fulfilled. Counting is time-consuming and disturbing measurement errors cannot be avoided. On the other hand, hair root sheath slides can be quickly prepared, the method yields preparations of good quality, and sex chromatin is displayed with considerable clarity. This procedure thus provides a high degree of accuracy and simplicity and counting can be quickly done with a relatively small measurement error. The incidence of sex chromatin in hair nuclei is observed to be about 20 per cent higher than in oral mucosa of the same female. In hair root sheaths non-peripheral sex chromatin can easily be recognized; including these into the scores significantly increases the actual incidence of sex chromatin positive nuclei.

Nuclear area and sex chromatin frequency in oral mucosa and hair root sheats of human females.

In 36 oral mucosa and in 25 hair root sheath slides nuclear area was measured in about 100 nuclei per slide. Within one slide no differences were found in nuclear area between nuclei with or without sex chromatin, or with a non-peripheral sex chromatin. No correlation was found between nuclear area and sex chromatin frequency, except for a weakly significant negative correlation between nuclear area and those nuclei without either peripheral or non-peripheral sex chromatin.

Centiles of body mass index for Dutch children aged 0-20 years in 1980--a baseline to assess recent trends in obesity.

OBJECTIVE: To document the distribution of body mass index (BMI) in Holland in 1980 when obesity was uncommon. DESIGN: Nationally representative growth survey. SUBJECTS: Forty-one-thousand boys and girls age 0-20 years. METHOD: BMI centiles based on the original height and weight data were derived using the LMS method. RESULTS: Median BMI showed the familiar pattern of a rise in the first year, followed by a fall, then a second rise after 6 years. The level of overweight was less than for children from the USA, France and Norway measured at the same time or earlier. CONCLUSIONS: Dutch children in 1980 were relatively free of obesity, so the BMI centiles are a suitable baseline to monitor international trends in obesity since then.

A Monte Carlo test of weight as a critical factor in menarche, compared with bone age and measures of height, width, and sexual development.

The correlation coefficients for each of nine traits measured at menarche (bone age, pubic hair and breast stages, and five physical measurements) have been calculated. These have been compared with the corresponding correlation coefficients obtained by using a Monte Carlo technique, where the ages of menarche are randomly redistributed over the sample. The difference between the random and actual results are most pronounced for bone age, sitting height and the development of pubic hair and breasts, showing that these characteristics may indeed be critically related to menarche, while the same differences for weight, height, sitting height/height, and biacromial and bi-iliocristal diameters show that these latter are only moderately related to menarche. These results do not support the exclusivity of body weight as a critical factor in menarche (critical body weight hypothesis).

Estimation of growth velocities from individual longitudinal data.

Since the construction of growth velocity curves using the simple increment method (i.e., plotting the increments deltaxt vs, time, t) involves a number of methodological problems, when mathematical curves are fit, they are generally fit to the "distance traveled", plot (of xt vs. t) and the corresponding velocity curve is then obtained by differentiation. However, most of the traditional methods for accomplishing this (e.g., fitting the Gompertz or logistic curves) require that the course of growth be studied over a sufficiently long time period to allow accurate determinations of the upper and lower asymptotes of these S-shaped functions. This is not always feasible in practice: a case in point being the mixed-longitudinal Nijmegen Growth Study where each of the cohorts comprising the sample is followed for but a five-year period. In such situations, alternative approaches to the problem of constructing growth velocity curves may be of considerable practical as well as theoretical interest. One such approach is developed in this paper and its use is illustrated on some data collected as part of the Nijmegen Growth Study. These results are then compared with those obtained using the increment method on the same data.

Reference curves for biceps, triceps, subscapular and suprailiac skinfolds in Dutch children from 7-14 years.

Box-Cox transformation of skinfold measurement data from the Nymegen Growth Study produced reference curves for biceps, triceps, subscapular and suprailiac skinfolds and their sums with an acceptable Gaussian distribution at all ages. The population sample, resulting in 1850 skinfold measurements for boys and 2250 for girls by a single observer, was obtained by random selection and can be considered as representative for The Netherlands. The Gaussian distribution after Box-Cox transformation allows the use of standard deviation scores. Seven percentile curves are presented for boys and girls of 7-14 years of age.

Continuing positive secular growth change in The Netherlands 1955-1997.

Since 1858, an increase of mean stature has been observed in the Netherlands, reflecting the improving nutritional, hygienic, and health status of the population. In this study, stature, weight, and pubertal development of Dutch youth, derived from four consecutive nationwide cross-sectional growth studies during the past 42 y, are compared to assess the size and rate of the secular growth change. Data on length, height, weight, head circumference, sexual maturation, and demographics of 14,500 boys and girls of Dutch origin in the age range 0-20 y were collected in 1996 and 1997. Growth references for height and weight were constructed with a method that summarizes the distribution by three smooth curves representing skewness (L curve), the median (M curve), and coefficient of variation (S curve). The relationship between height and demographic variables was assessed by multivariate analysis. Reference curves for menarche and secondary sex characteristics were estimated by a generalized additive model using a logit transformation. A positive secular growth change has been present in the past 42 y for children, adolescents, and young adults of Dutch origin, although at a slower rate in the last 17 y. Height differences according to region, educational level of child and parents, and family size have remained. In girls, median age at menarche has decreased by 6 mo during the past four decades to 13.15 y. Environmental conditions have been favorable for many decades in the Netherlands, and the positive secular change in height has not yet come to a halt, in contrast to Scandinavian countries. Main contributors to the increase in height may be improved nutrition, child health, and hygiene, and a reduction of family size.