Objective To identify predictors of postnatal catch-up growth from birth to two years and its relation to size and obesity at five years. Design Regional prospective cohort study. Setting Avon longitudinal study of pregnancy and childhood, United Kingdom. Subjects 848 full term singletons from a 10% random sample of the Avon longitudinal study of pregnancy and childhood. Main outcome measures Maternal birth weight, prepregnancy weight, pregnancy weight gain, height, smoking, and parity, and paternal height. Weight and length of infants at birth, two years, and five years expressed as standard deviation (SD) scores from the UK reference scores for 1990. Percentage fat mass and total fat mass (estimated from skinfolds) and waist circumference at five years. Results Size at birth was representative of the national reference. Overall, 30.7% (260 of 848) of infants showed a gain in SD score for weight greater than 0.67 SD scores between zero and two years, indicating clinically significant catch-up growth. These children had lower weight, length, and ponderal index at birth than other children, and were more often from primiparous pregnancies. They also had taller fathers than other children, and their mothers had lower birth weights and were more likely to smoke during pregnancy. Children who showed catch-up growth between zero and two years were heavier, taller, and fatter (body mass index, percentage body fat, and waist circumference) at five years than other children. Conclusions In this contemporary well nourished cohort, catch-up growth was predicted by factors relating to intrauterine restraint of fetal growth. Children who showed catch-up growth between zero and two years were fatter and had more central fat distribution at five years than other children. Mechanisms that signal and regulate early catch-up growth in the postnatal period may influence associations between small size at birth and risks for disease in adulthood.Papers

To update the British growth reference, anthropometric data for weight, height, body mass index (weight/height2) and head circumference from 17 distinct surveys representative of England, Scotland and Wales (37,700 children, age range 23 weeks gestation to 23 years) were analysed by maximum penalized likelihood using the LMS method. This estimates the measurement centiles in terms of three age-sex-specific cubic spline curves: the L curve (Box-Cox power to remove skewness), M curve (median) and S curve (coefficient of variation). A two-stage fitting procedure was developed to model the age trends in median weight and height, and simulation was used to estimate confidence intervals for the fitted centiles. The reference converts measurements to standard deviation scores (SDS) that are very close to Normally distributed - the means, medians and skewness for the four measurements are effectively zero overall, with standard deviations very close to one and only slight evidence of positive kurtosis beyond+/-2 SDS. The ability to express anthropometry as SDS greatly simplifies growth assessment.

The causes and geographic distribution of 267 cases of iatrogenic Creutzfeldt-Jakob disease (CJD) are here updated at the millennium. Small numbers of still-occurring cases result from disease onsets after longer and longer incubation periods following infection by cadaveric human growth hormone or dura mater grafts manufactured and distributed before the mid-1980s. The proportion of recipients acquiring CJD from growth hormone varies from 0.3 to 4.4% in different countries, and acquisition from dura mater varies between 0.02 and 0.05% in Japan (where most cases occurred). Incubation periods can extend up to 30 years, and cerebellar onsets predominate in both hormone and graft recipients (in whom the site of graft placement had no effect on the clinical presentation). Homozygosity at codon 129 of the PRNP gene is over-represented in both forms of disease; it has no effect on the incubation period of graft recipients, but may promote shorter incubation periods in hormone cases. Knowledge about potential high-risk sources of contamination gained during the last quarter century, and the implementation of methods to circumvent them, should minimize the potential for iatrogenic contributions to the current spectrum of CJD.

A new family of mathematical functions to fit longitudinal growth data is described. All members derive from the differential equation dh/dt = s(t). (h1-h) where h1 is adult size and s(t) is a function of time. The form of s(t) is given by one of many functions, all solutions of differential equations, thus generating a family of different models. Three versions were compared. All were superior to previously described models. Model 1, in which s(t) was defined by ds/dt = (s1 - s)(s - s0) was especially accurate and robust, containing only five parameters to describe growth in stature from age two to maturity. Derived "biological" parameters such as Peak Height Velocity were very consistent between these three members of the family but, in some cases, differed signficantly from previous estimates.