The Study
Elevation of erythrocyte creatine post-puberty unrelated to erythrocyte lifespan: Implications from the lack of correlation between HbA1c and erythrocyte creatine.
This study takes a snapshot of blood levels in kids at one point in time. It can show that two things are linked — like how older girls tend to have higher creatine in their red blood cells — but it can’t prove one causes the other.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
This study looked at kids' blood to see how a chemical called creatine in red blood cells changes with age and puberty, and whether it's linked to blood sugar.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 536 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The rise in creatine in girls after puberty isn't about blood sugar, so it might affect how we interpret certain blood tests in girls.
- 2Girls' red blood cell creatine goes up with age (R = 0.557) and after starting periods (1.64 vs 1.23), but boys' doesn't.
- 3Blood sugar levels (HbA1c) didn't change with creatine in either sex.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Clinica chimica acta; international journal of clinical chemistry
Year
2025
Authors
Takahide Kokumai, Shigeru Suzuki, Satoru Takahashi, T. Okumiya, Masafumi Koga
Related Content
Claims (4)
Your HbA1c number isn't just about your average blood sugar — it also depends on how long your red blood cells live. The longer they stick around, the more sugar builds up on them, which can raise your HbA1c even if your blood sugar is stable.
Girls who have started their periods tend to have higher levels of creatine in their red blood cells compared to those who haven’t, and this doesn’t seem to be because of differences in blood sugar control.
In teenage girls who don’t have diabetes or anemia, red blood cell creatine goes up as they get older, especially after puberty—but this doesn’t happen in boys. This rise isn’t linked to blood sugar levels.
In kids who don’t have diabetes or anemia, red blood cell creatine doesn’t seem to track with average blood sugar levels, so it might not be a good way to measure sugar exposure over time.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.