Puberty age pitches testicular cancer risk
MedWire News: Males who start puberty later than their peers may have a decreased risk for testicular cancer, show study findings.
While early onset of puberty does not seem to be linked to testicular cancer risk, evidence does point to a conferred advantage with later than average onset, report Milena Maule (University of Turin, Italy) and team.
In a meta-analysis of eight studies conducted in North America, the UK, and Denmark between 1983 and 2010, late age at puberty was inversely associated with testicular cancer risk whereas no effect of early puberty was found.
Early puberty has previously been suggested as a potential risk factor for testicular cancer but the topic has been poorly investigated, say Maule and team. "Results are often inconsistent and some of the studies have a small sample size; in addition, male age at puberty is poorly measured retrospectively, and different studies use different indicators," they explain.
In the current analysis, the team considered the three indicators of puberty onset most frequently assessed by the studies, namely, age when started shaving, age at voice change, and self-reported age at puberty onset and compared the testicular cancer risk according to age at puberty onset relative to the average among peers.
As reported in the International Journal of Andrology, men who started puberty at an older age than their peers were 20% less likely to develop testicular cancer than men who started puberty at the same age as or earlier than their peers.
Compared with individuals who started shaving at the same age as their peers, late shaving was associated with a significant 16% reduction in testicular cancer risk, while no such association was observed for early shaving.
Similarly, late age at voice change and self-reported age at puberty onset were associated with risk reductions of 13% and 33%, respectively, while no such association was observed with the presence of these indicators at early ages.
"These results were robust to all sensitivity analyses, did not change using a random effect model... and did not show evidence of publication bias," reports the team.
In a further meta-analysis of the effect of late age versus usual or early age at puberty onset, the odds ratio for testicular cancer risk was 0.81.
The team says a possible explanation for their findings is that testicular cancer and age at puberty share genetic factors or postnatal risk factors, such as childhood nutrition, childhood obesity, and exposure to specific chemicals, among other potential mechanisms.
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By Sally Robertson