Summary

Bone density studies of puberty blockers (drugs that pause puberty) usually report averages. Sociologist Michael Biggs argued that averages hide the patients who matter most: those whose bone density falls into the abnormal range. He used individual data released with England's 2011–15 early puberty blocker study, covering 24 patients scanned after 2 years. On average, bone density fell well behind other teens of the same age and sex. About a third of patients had hip bone density low enough to count as low bone mass, found in only about 2 in 100 teens. More than a quarter had low spine density, and four were in the lowest 1 in 750. The study originally excluded children who already had low bone density, but this was relaxed in 2012. This is a short re-analysis of a small group with no data on broken bones, but it shows reassuring averages can hide worrying individual results.

Key findings

• Pismo je ponovno analiziralo individualne kostne posnetke 24 najstnikov v angleški študiji zaviralcev pubertete (2011–15), del skupine 31, opisane v prejšnjem članku iz leta 2019.
• V 2 letih na zaviralcih pubertete je povprečna gostota kosti jasno zaostala za drugimi najstniki iste starosti in spola, za približno en „korak“ na standardni lestvici v kolku in hrbtenici.
• Po 2 letih je imel približno vsak tretji bolnik gostoto kosti kolka dovolj nizko, da velja za nenormalno, raven, ki jo najdemo le pri 2,3 % najstnikov iste starosti in spola.
• Več kot četrtina je imela nenormalno nizko gostoto kosti hrbtenice, štirje pa so bili med najnižjimi 0,13 % populacije (približno 1 od 750).
• Upoštevanje višine bolnikov ni odstranilo skupine z zelo nizkimi ocenami.
• Angleška študija je prvotno izključila otroke, katerih gostota kosti je bila že nenormalno nizka. Leta 2012 je bilo to sproščeno, da se omogoči zdravljenje „v izjemnih okoliščinah“, kljub tveganju za krhke kosti pozneje v življenju.
• Biggs trdi, da bi bilo treba zlome beležiti kot stranske učinke, in kritizira predloge, da bi kosti pregledovali redkeje ali spremenili običajne razpone za to skupino.

Conclusion

Biggs concludes that after 2 years of GnRHa, up to a third of patients had abnormally low bone density (Z-score below −2, the lowest 2.3% for sex and age), with a few in the lowest 0.13%. This undermines Joseph et al.'s reassuring conclusions. He calls their recommendations to reduce DXA monitoring and to redefine reference ranges for this cohort 'surprisingly complacent'. He argues that, rather than altering a measure that gives inconvenient findings, practitioners of puberty suppression must record fractures as adverse events. Whether cases of repeated fractures are exceptional is unknown because clinicians have not collected the relevant data.