Re: Dietary Supplements and Cancer Prevention: Balancing Potential Benefits Against Proven Harms
Notice bibliographique
Résumé
Martínez et al. (1) recommended against vitamin D supplements for reducing the risk of cancer. However, the evidence that vitamin D reduces the risk of cancer is very strong despite reports to the contrary. There are several types of evidence: ecological, case–control, cohort, and randomized controlled trials. Each ap- proach has its strengths and limitations. The strengths of the ecological approach include the large number of cases and the large number of data sets available for such studies. The limitations include assessing the role of confounding factors, but many cancer risk–modifying factors are included in most recent ecological studies. A recent review of ecological studies found strong support for solar ultraviolet-B in reducing the risk of 15 types of cancer, with weaker support for another nine types of cancer (2). No factor other than vitamin D production has been proposed to explain the link. Case–control studies have the strength of determining serum 25-hydroxyvitamin D [25(OH)D] concentrations near the time of cancer diagnosis. Although there is a concern that the disease state may affect serum 25(OH)D concentration, there does not seem to be evidence to support this concern. Case–control studies have found the strongest inverse associations between serum 25(OH)D concentration and breast and colorectal cancer incidence (3). Cohort studies are perceived to be the strongest observational approach. The advantage is that the risk-modifying factors are determined before disease outcome. However, a little-recognized disadvantage is that a single blood collection at the time of enrollment in the cohort study is used to determine serum 25(OH)D concentrations, and this value loses predictive ability with increasing follow-up time (3). A recent analysis of the regression coefficient for two serum 25(OH)D concentration measurements for a cohort as a function of interval found a decrease of −0.020/year for intervals ranging from 1 to 14 years (4). In cohort studies of breast and colorectal cancer, the relative risks increased toward unity at a rate of 0.03/year to 0.05/year (3), whereas the hazard ratios for all-cause mortality rate increased at a rate of 0.017/year (4). In addition, only cohort studies that find direct relationships between serum 25(OH)D concentration and cancer incidence rates, such as for pancreatic and prostate cancer, are mentioned in References 66 and 68 (1). Many randomized-controlled trials such as the Women’s Health Initiative used only 400 IU/day vitamin D3. However, a reanalysis of the Women’s Health Initiative restricted to women who had not taken vitamin D or calcium (CaD) supplements before enrollment found that “CaD statistically significantly decreased the risk of total cancer, total breast cancer, and invasive breast cancers by 14–20% and nonsignificantly reduced the risk of colorectal cancer by 17%.” (5). Marshall et al. recently reported that for those with low-risk prostate cancer, supplementing with 4000 IU/day vitamin D3 led to biopsy-assessed tumor regression in 55% of case patients (6). When all the evidence regarding solar ultraviolet-B and vitamin D is evaluated using the criteria for causality in a biological system proposed by AB Hill, the evidence is found to be strong for several types of cancer (2,7). The author receives funding from the UV Foundation (McLean, VA), Bio-Tech Pharmacal (Fayetteville, AR), the Vitamin D Council (San Luis Obispo, CA), and the Vitamin D Society (Canada).
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,006 | 0,040 |
| Méta-épidémiologie (sens strict) | 0,002 | 0,001 |
| Méta-épidémiologie (sens large) | 0,003 | 0,001 |
| Bibliométrie | 0,002 | 0,001 |
| Études des sciences et des technologies | 0,006 | 0,005 |
| Communication savante | 0,006 | 0,008 |
| Science ouverte | 0,004 | 0,003 |
| Intégrité de la recherche | 0,089 | 0,090 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,012 | 0,012 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».