OBJECTIVE: Progress through puberty involves a complex hormonal cascade, but the individual contributions of hormones, particularly @entity442 , are unknown. We reanalysed Chard growth study data to explore the tempo of puberty based on changes in both height and hormone levels, using a novel method of growth curve analysis. DESIGN AND SUBJECTS: Schoolboys (n = 54) and @entity1 (n = 70) from Chard, Somerset, England, recruited in 1981 at age 8/9 and followed to age 16. MEASUREMENTS: Every 6 months, height and Tanner stages (genitalia, breast, pubic hair) were recorded, and in a subsample (24 @entity1 , 27 @entity1 ), blood samples were taken. Serum @entity442 , @entity251 ( @entity1 ) and @entity53 ( @entity1 ) were measured by radioimmunoassay. Individual growth curves for each outcome were analysed using variants of the super-imposition by translation and rotation (SITAR) method, which estimates a mean curve and subject-specific random effects corresponding to size, and age and magnitude of peak velocity. RESULTS: The SITAR models fitted the data well, explaining 99%, 65%, 86% and 47% of variance for height, @entity442 , @entity251 and @entity53 , respectively, and 69-88% for the Tanner stages. During puberty, the variables all increased steeply in value in individuals, the ages at peak velocity for the different variables being highly correlated, particularly for @entity442 vs height (r = 0  74 for @entity1 , 0  92 for @entity1 ). CONCLUSIONS: @entity442 , like height, the sex @entity230 and Tanner stages, rises steeply in individuals during puberty, with the timings of the rises tightly synchronized within individuals. This suggests that @entity442 may play an important role in determining the timing of puberty.

The relationship between XXXX , sex @entity230 and timing of the pubertal growth spurt.

@entity1 :: ('9606', 'Species') :: ['girls', 'boys'] @entity251 :: ('MESH:D013739', 'Chemical') :: ['testosterone'] @entity442 :: ('3479', 'Gene') :: ['IGF-1'] @entity53 :: ('MESH:D004958', 'Chemical') :: ['oestradiol'] @entity230 :: ('MESH:D013256', 'Chemical') :: ['steroids']
@entity442 :: (3479,Gene) :: ['Insulin-like Growth Factor 1']
