Background: Premature adrenarche (PA) is often associated with bone age (BA) advanced by ≥2 years, which increases the concern for underlying pathology, but the frequency and clinical significance of this is unknown. Our objective was to identify the proportion of PA patients with very advanced BA and normal BA and compare the clinical characteristics of the two groups.
Methods: Charts of 427 patients aged 5-9 years, referred for early puberty over a 2-year period, were reviewed for clinical diagnosis, growth, parental heights, hormone levels and BA. We divided the PA patients into three separate groups based on degree of BA advancement. Predicted adult heights (PAH) were calculated and compared to mid-parental target height (TH).
Results: Of 427 patients, 266 (62%) had PA (82% female). Of the 121 with BA, 30.6% had very advanced BA (≥2 years) and this group was taller (Ht SD+1.72 vs. +0.72, p<0.00001) and had higher BMI (SD+1.70 vs. +0.99, p<0.001) than patients with BA advanced by <1 year, but hormone levels were quite similar. Mean PAH was slightly less than TH for patients with very advanced BA, but there were no girls with PAH <60 inches 152.4 cm or boys with PAH <65 inches 165.1 cm in height.
Conclusions: Very advanced BA is common in PA, and patients were significantly taller and more overweight than their peers. The impact of advanced BA on PAH appears to be minor. We question the need for ordering a BA in patients with PA, and suggest that extensive testing is unnecessary simply because of advanced BA.