Study analysis · The Journal of clinical endocrinology and metabolism · 1999
Vitamins didn't stop bone loss—just made it slightly slower.
Even with vitamins, women on this hormone drug still lost bone in just six months—though two vitamins together helped a little.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study tried two supplements on women taking a medicine that weakens bones, and found that the supplements helped a little—but didn’t stop the bone loss completely. It’s like seeing that wearing a helmet might make you fall a little less hard, but doesn’t stop you from falling.
What’s the bottom line?
Women on a hormone drug that lowers estrogen lost bone, but those who also took vitamin K2 and another vitamin lost a little less.
How strong is this study?
The study randomly gave different treatments to different people, which is good—it’s like flipping a coin to decide who gets what. But we don’t know if the doctors or patients knew who got what, which could mess up the results. So it’s a decent start, but not perfect.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
67 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=110)+8.5/20
- Follow-up+10/10
100 / 100
23 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 549 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Randomization is explicitly stated in the abstract, allowing causal inference, but lack of blinding information introduces potential bias that limits confidence.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding information were disclosed in the provided text, and there is no evidence of industry influence or author affiliations that suggest bias.
The study appears methodologically sound with randomization and clear outcome measures, but the absence of any COI or funding disclosure limits transparency. No industry ties or author affiliations are indicated.
Key takeaways
- 01
Bone loss: 5.25% without vitamins, 3.59% with both vitamins.
- 02
Even with vitamins, bones still lost over 3% in six months — a meaningful loss for older women at risk of fractures.
Surprising findings
- Vitamin K2 increased bone formation markers the most—but also had the highest (though not statistically significant) bone resorption markers.People think vitamin K2 only helps build bone, but here it may have also triggered more bone breakdown, making its net benefit unclear.
Practical takeaways
If you're on leuprolide or similar hormone therapy, talk to your doctor about bone density monitoring and whether supplements might modestly slow loss.
This study only looked at six months; long-term effects are unknown. Supplements did not stop bone loss.
low confidenceWhy this study matters
Vitamins slowed bone loss—but didn't stop it
Women taking leuprolide lost 5.25% of spine bone density in six months. Those taking vitamin K2 alone lost 3.72%, and those taking both vitamin K2 and 1,25-dihydroxyvitamin D3 lost the least—3.59%. But all groups still lost bone.
People assume supplements can prevent bone loss, but this shows even the best combo only reduces loss by about 30%—not enough to prevent risk, especially for older women.
Bone formation went up—but so did bone breakdown
Bone formation markers increased the most in the vitamin K2 group, yet bone resorption markers rose significantly in ALL groups. Net result: bone loss everywhere.
It’s not enough to boost bone building—when breakdown increases even more, supplements can’t win. This flips the script on 'build stronger bones' advice.
The combo worked best—but still failed
The group taking both vitamin K2 and 1,25-dihydroxyvitamin D3 had the smallest loss (-3.59%) and it was statistically significant (P < 0.01) compared to leuprolide alone. But 3.59% loss in six months is still clinically meaningful.
This is the closest thing to a 'win' in the study—and it’s still a loss. It shows how powerful GnRH agonists are at breaking down bone.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Women on a hormone drug that lowers estrogen lost bone, but those who also took vitamin K2 and another vitamin lost a little less.
Research results
Bone loss: 5.25% without vitamins, 3.59% with both vitamins.
What this means - more context
Even with vitamins, bones still lost over 3% in six months — a meaningful loss for older women at risk of fractures.
To evaluate whether vitamin K2 and 1,25-dihydroxyvitamin D3 can prevent bone loss in women undergoing GnRH agonist (leuprolide) therapy for estrogen-dependent diseases.
In 110 women randomly assigned to four groups receiving leuprolide alone or with vitamin K2, 1,25-dihydroxyvitamin D3, or both, all groups experienced lumbar spine bone mineral density loss over six months. The greatest reduction occurred in the leuprolide-only group; the combination group had the smallest loss. Bone formation markers increased in all groups, most in the vitamin K2 group, but bone resorption markers also increased significantly in all groups, resulting in net bone loss.
Methods Used
Randomized controlled trial with 110 women allocated into four groups; lumbar spine bone mineral density measured by dual-energy x-ray absorptiometry before and after 6 months; bone formation and resorption markers measured pre- and post-treatment.
Main Finding
Bone mineral density decreased in all groups: -5.25% (leuprolide only), -3.72% (vitamin K2), -4.13% (1,25-dihydroxyvitamin D3), and -3.59% (combination). The combination group showed the smallest loss (P < 0.01 vs. leuprolide only), but bone loss still occurred despite supplementation.
Confidence Level
Limited - based on abstract only, full methodology not available
Study Flags
Red Flags
- •Full text not available - methodology details cannot be verified
- •Effect sizes reported without confidence intervals
- •No information on blinding or adverse events
Surprising Findings
Vitamin K2 increased bone formation markers the most—but also had the highest (though not statistically significant) bone resorption markers.
People think vitamin K2 only helps build bone, but here it may have also triggered more bone breakdown, making its net benefit unclear.
Practical Takeaways
If you're on leuprolide or similar hormone therapy, talk to your doctor about bone density monitoring and whether supplements might modestly slow loss.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 549 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study tried two supplements on women taking a medicine that weakens bones, and found that the supplements helped a little—but didn’t stop the bone loss completely. It’s like seeing that wearing a helmet might make you fall a little less hard, but doesn’t stop you from falling.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Explicit randomization reported
- Clear control groups and intervention arms
- Objective outcome measures (bone mineral density, biomarkers)
Weaknesses
- Blinding status unknown - risk of performance and detection bias
- Full methodology not available - based on abstract only
- No reporting of allocation concealment or intention-to-treat analysis
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Women on a hormone drug that lowers estrogen lost bone, but those who also took vitamin K2 and another vitamin lost a little less.
Research results
Bone loss: 5.25% without vitamins, 3.59% with both vitamins.
What this means - more context
Even with vitamins, bones still lost over 3% in six months — a meaningful loss for older women at risk of fractures.
To evaluate whether vitamin K2 and 1,25-dihydroxyvitamin D3 can prevent bone loss in women undergoing GnRH agonist (leuprolide) therapy for estrogen-dependent diseases.
In 110 women randomly assigned to four groups receiving leuprolide alone or with vitamin K2, 1,25-dihydroxyvitamin D3, or both, all groups experienced lumbar spine bone mineral density loss over six months. The greatest reduction occurred in the leuprolide-only group; the combination group had the smallest loss. Bone formation markers increased in all groups, most in the vitamin K2 group, but bone resorption markers also increased significantly in all groups, resulting in net bone loss.
Methods Used
Randomized controlled trial with 110 women allocated into four groups; lumbar spine bone mineral density measured by dual-energy x-ray absorptiometry before and after 6 months; bone formation and resorption markers measured pre- and post-treatment.
Main Finding
Bone mineral density decreased in all groups: -5.25% (leuprolide only), -3.72% (vitamin K2), -4.13% (1,25-dihydroxyvitamin D3), and -3.59% (combination). The combination group showed the smallest loss (P < 0.01 vs. leuprolide only), but bone loss still occurred despite supplementation.
Confidence Level
Limited - based on abstract only, full methodology not available
Study Flags
Red Flags
- •Full text not available - methodology details cannot be verified
- •Effect sizes reported without confidence intervals
- •No information on blinding or adverse events
Surprising Findings
Vitamin K2 increased bone formation markers the most—but also had the highest (though not statistically significant) bone resorption markers.
People think vitamin K2 only helps build bone, but here it may have also triggered more bone breakdown, making its net benefit unclear.
Practical Takeaways
If you're on leuprolide or similar hormone therapy, talk to your doctor about bone density monitoring and whether supplements might modestly slow loss.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 549 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study tried two supplements on women taking a medicine that weakens bones, and found that the supplements helped a little—but didn’t stop the bone loss completely. It’s like seeing that wearing a helmet might make you fall a little less hard, but doesn’t stop you from falling.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Explicit randomization reported
- Clear control groups and intervention arms
- Objective outcome measures (bone mineral density, biomarkers)
Weaknesses
- Blinding status unknown - risk of performance and detection bias
- Full methodology not available - based on abstract only
- No reporting of allocation concealment or intention-to-treat analysis
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The study randomly gave different treatments to different people, which is good—it’s like flipping a coin to decide who gets what. But we don’t know if the doctors or patients knew who got what, which could mess up the results. So it’s a decent start, but not perfect.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
67 / 100
- Randomization+20/20
- Blindingblinding unclear
- Control group+15/15
- Sample size (n=110)+8.5/20
- Follow-up+10/10
100 / 100
23 / 100
- P-values+15/15
- Effect sizeno effect size reported
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 549 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. Randomization is explicitly stated in the abstract, allowing causal inference, but lack of blinding information introduces potential bias that limits confidence.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding information were disclosed in the provided text, and there is no evidence of industry influence or author affiliations that suggest bias.
The study appears methodologically sound with randomization and clear outcome measures, but the absence of any COI or funding disclosure limits transparency. No industry ties or author affiliations are indicated.
Standing
Who’s using this study?
The videos and claims on this site that lean on this study, and the researchers who wrote it.
1 video from Dr Brad Stanfield cite this study, drawing 1 claim from it.
- Very strong evidence
Randomized or controlled trials support this claim, alongside consistent supporting evidence.
Evidence
Authored by
4 researchersIf this is your work, this is how we attribute it on Fit Body Science. Yoshiaki Somekawa is listed as the lead author.