Mixed longitudinal data on skeletal age from a group of Dutch children living in Utrecht and surroundings.

The height and weight of 1132 children, aged 8.0--17.0 years studied in 1970--72 in a semi-longitudinal survey in the Dental Institute of Utrecht, are compared with similar data from the national Dutch survey of 1965. Children measured in 1970--72 are somewhat taller than, but have the same weight as, those of the same ages in 1965. The increase in height since 1965 appears to be primarily due to the sub-group enrolled in vocational (as opposed to general) education. The maximal yearly increments in height and weight of the girls occurred between 11.0 and 12.0 years, and between 12.0 and 13.0 years, respectively. For boys the maximal increments in height and weight occurred between 14.0 and 15.0 years. Using the Tanner-Whitehouse 2 method, the skeletal age of this group of children was determined and compared with similar data from British standards. The results of the twenty-bone skeletal age indicated that Dutch boys, and to a lesser extent, girls, mature slightly later than English children at the approximate age range of 10.0--13.0 years and 8.0--10.0 years, respectively. After this age they follow roughly the growth curve of the British standards. The annual increment in skeletal age, plotted with chronological age as a time base, shows a peak for boys as well as girls that coincides with peak height velocity. The Carpal skeletal ages of boys and girls are almost identical in all age-groups with those of the British children, while the RUS skeletal age shows a much greater variability in the different age-groups. The variation in mean velocity (maturity points) between the two populations appears to be more marked in the RUS bones than in the round bones. The TW 1 skeletal age of each subject was plotted against the total TW 2, RUS or Carpal skeletal ages of the same individual. Equations are given for converting TW 1 skeletal ages into total TW 2 or RUS skeletal ages.