Puberty and adipose tissue-derived adipokines, including leptin and adiponectin, play a critical role in bone mass accumulation. However, longitudinal relationships between leptin and adiponectin in puberty and bone mineral characteristics later in adolescence have not been studied previously. A recent manuscript, published online by Tamme et al. Bone Reports in December, explored the associations between leptin to adiponectin ratio (LAR) in puberty and bone mineral characteristics at the age of 18 years in healthy males.
The study was conducted in 2017–2018 and was a follow-up of a longitudinal project carried out between 2009 and 2013. Eighty-eight healthy boys with no chronic illnesses, that previously participated in the 12-month and 24-month follow-up study by the same research group, were recruited from local schools. The mean age of the participants at the three study time points, T1, T2 and T3, was 12.1, 14.0 and 18.0 years, respectively. Serum leptin and adiponectin were measured and LAR was calculated at all three time points. Bone age, using an X-ray of the left hand and wrist, and sexual maturation, using a self-report questionnaire of pubertal stages, were studied at T1 and T2. Bone mineral characteristics, body composition and physical activity were studied at T1 and T3.
Findings showed that LAR decreased significantly from T1 to T2 and increased thereafter to T3. Mean pubertal LAR appeared to be negatively correlated with lumbar spine (LS) bone mineral density (BMD) at T3 (r = − 0.23; P < 0.05) and LS bone mineral apparent density (BMAD), which is an estimate of volumetric bone density, at T3 (r = − 0.33; P < 0.05). These results remained significant in partial correlation analysis after adjusting for total body fat percentage, total testosterone, homeostasis model assessment of insulin resistance (HOMA-IR) and physical activity at T1. Authors noted however, that no significant correlations were found between LAR at T3 and the bone mineral characteristics at T3.
Authors concluded that there is a significant negative correlation between LAR in puberty and LS BMD and LS BMAD at 18 years of age in healthy Caucasian boys. In their own words, ‘These findings suggest a possible role of adipokines in puberty in further bone mineral accumulation’.