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All older women need vitamin D supplementation to get to even 20 ng (results of modeling) – May 2018

Prediction of insufficient serum vitamin D status in older women: a validated model

Osteoporos Int (2018). https://doi.org/10.1007/s00198-018-4410-3
T. Merlijn tmerlijn at gmail.com, K. M. A. SwartP. LipsM. W. HeymansE. SohlN. M. Van SchoorC. J. NetelenbosP. J. M. Elders

  • Study made models which predicted which elderly women would needed Vitamin D supplementation in order to get to 30, 40, 50 and 60 nmol/L.
  • Concluded that ALL older women needed supplementation, other than the summer, in order to stay above 20 ng (50 nmol)
  • They also noticed that the seasonal variation is NOT sinusoidal
    • (which many other studies have assumed)

See also VitaminDWiki

13 reasons why many seniors need more vitamin D (both dose and level) - July 2023 has the following

  1. Senior skin produces 3X less Vitamin D for the same sun intensity
  2. Seniors have fewer vitamin D receptor genes as they age
    Receptors are needed to get Vitamin D in blood actually into the cells
  3. Many other Vitamin D genes decrease with age
  4. Since many gene activations are not detected by a blood test,
    more Vitamin D is often needed, especially by seniors
  5. Seniors are indoors more than when they were younger
    not as agile, weaker muscles; frail, no longer enjoy hot temperatures
  6. Seniors wear more clothing outdoors than when younger
    Seniors also are told to fear skin cancer & wrinkles
  7. Seniors often take various drugs which end up reducing vitamin D
    Some reductions are not detected by a vitamin D test of the blood
    statins, chemotherapy, anti-depressants, blood pressure, beta-blockers, etc
  8. Seniors often have one or more diseases that consume vitamin D
    osteoporosis, diabetes, Multiple Sclerosis, Cancer, ...
  9. Seniors generally put on weight at they age - and a heavier body requires more vitamin D
  10. Seniors often (40%) have fatty livers – which do not process vitamin D as well
  11. Reduced stomach acid means less Magnesium is available to get vitamin D into the cells
  12. Vitamin D is not as bioavailable in senior intestines
  13. Seniors with poorly functioning kidneys do not process vitamin D as well
       Seniors category has 406 items

 Download the PDF from VitaminDWiki

Seasonal variation in Vitamin D levels is NOT sinusoidal


  • "However, in our data, the mean levels over 3 years show a pattern in which the rise of serum 25(OH)D in spring is steeper than the decrease in autumn, a narrow peak in summer and a wide dip in winter. The result of this pattern is that the optimal model does not exactly follow the seasons. The peak is in the months of July and August; the dip is from December until the end of April. The other months are between these summer and winter levels"

We developed an externally validated simple prediction model to predict serum 25(OH)D levels < 30, < 40, < 50 and 60 nmol/L in older women with risk factors for fractures. The benefit of the model reduces when a higher 25(OH)D threshold is chosen.

Vitamin D deficiency is associated with increased fracture risk in older persons. General supplementation of all older women with vitamin D could cause medicalization and costs. We developed a clinical model to identify insufficient serum 25-hydroxyvitamin D (25(OH)D) status in older women at risk for fractures.

In a sample of 2689 women ≥ 65 years selected from general practices, with at least one risk factor for fractures, a questionnaire was administered and serum 25(OH)D was measured. Multivariable logistic regression models with backward selection were developed to select predictors for insufficient serum 25(OH)D status, using separate thresholds 30, 40, 50 and 60 nmol/L. Internal and external model validations were performed.

Predictors in the models were as follows:

  • age,
  • BMI,
  • vitamin D supplementation,
  • multivitamin supplementation,
  • calcium supplementation,
  • daily use of margarine,
  • fatty fish ≥ 2×/week,
  • ≥ 1 hours/day outdoors in summer,
  • season of blood sampling,
  • the use of a walking aid and
  • smoking.

The AUC was 0.77 for the model using a 30 nmol/L threshold and decreased in the models with higher thresholds to 0.72 for 60 nmol/L. We demonstrate that the model can help to distinguish patients with or without insufficient serum 25(OH)D levels at thresholds of 30 and 40 nmol/L, but not when a threshold of 50 nmol/L is demanded.

This externally validated model can predict the presence of vitamin D insufficiency in women at risk for fractures. The potential clinical benefit of this tool is highly dependent of the chosen 25(OH)D threshold and decreases when a higher threshold is used.

Created by admin. Last Modification: Tuesday May 29, 2018 00:25:08 GMT-0000 by admin. (Version 5)

Attached files

ID Name Comment Uploaded Size Downloads
9905 Seasonal is not a sinusoid.jpg admin 28 May, 2018 23:46 14.62 Kb 521
9904 Seasonal.jpg admin 28 May, 2018 23:45 27.74 Kb 507
9903 Prediction of insufficient serum vitamin D status in older women.pdf PDF 2018 admin 28 May, 2018 23:44 615.36 Kb 535