While I'm a big fan of Vitamin D in general, one thing to watch out for is that while this paper cites meta-analysis of associations of serum levels of 25(OH)D and ACM as an argument for supplementation:
Garland, Cedric F., June Jiwon Kim, Sharif Burgette Mohr, Edward Doerr Gorham, William B. Grant, Edward L. Giovannucci, Leo Baggerly, et al. “Meta-Analysis of All-Cause Mortality According to Serum 25-Hydroxyvitamin D.” American Journal of Public Health 104, no. 8 (August 2014): e43–50. https://doi.org/10.2105/AJPH.2014.302034.
Recent meta-analysis seems to suggest that supplementation is not associated with lower ACM. In that case, Vitamin D would be primarily a marker for poor outcomes, not the actual primary cause.
n=75,454 "Vitamin D supplementation alone was not associated with all cause mortality in adults compared with placebo or no treatment. Vitamin D supplementation reduced the risk of cancer death by 16%. Additional large clinical studies are needed to determine whether vitamin D3 supplementation is associated with lower all cause mortality."
Zhang, Yu, Fang Fang, Jingjing Tang, Lu Jia, Yuning Feng, Ping Xu, and Andrew Faramand. “Association between Vitamin D Supplementation and Mortality: Systematic Review and Meta-Analysis.” BMJ 366 (August 12, 2019): l4673. https://doi.org/10.1136/bmj.l4673.
2011 Discussion on Vitamin D as a marker:
Jacobs, Elizabeth T., María Elena Martínez, and Peter W. Jurutka. “Vitamin D: Marker or Mechanism of Action?” Cancer Epidemiology, Biomarkers & Prevention : A Publication of the American Association for Cancer Research, Cosponsored by the American Society of Preventive Oncology 20, no. 4 (April 2011): 585–90. https://doi.org/10.1158/1055-9965.EPI-10-1257.
Garland, Cedric F., June Jiwon Kim, Sharif Burgette Mohr, Edward Doerr Gorham, William B. Grant, Edward L. Giovannucci, Leo Baggerly, et al. “Meta-Analysis of All-Cause Mortality According to Serum 25-Hydroxyvitamin D.” American Journal of Public Health 104, no. 8 (August 2014): e43–50. https://doi.org/10.2105/AJPH.2014.302034.
Recent meta-analysis seems to suggest that supplementation is not associated with lower ACM. In that case, Vitamin D would be primarily a marker for poor outcomes, not the actual primary cause.
n=75,454 "Vitamin D supplementation alone was not associated with all cause mortality in adults compared with placebo or no treatment. Vitamin D supplementation reduced the risk of cancer death by 16%. Additional large clinical studies are needed to determine whether vitamin D3 supplementation is associated with lower all cause mortality."
Zhang, Yu, Fang Fang, Jingjing Tang, Lu Jia, Yuning Feng, Ping Xu, and Andrew Faramand. “Association between Vitamin D Supplementation and Mortality: Systematic Review and Meta-Analysis.” BMJ 366 (August 12, 2019): l4673. https://doi.org/10.1136/bmj.l4673.
2011 Discussion on Vitamin D as a marker:
Jacobs, Elizabeth T., María Elena Martínez, and Peter W. Jurutka. “Vitamin D: Marker or Mechanism of Action?” Cancer Epidemiology, Biomarkers & Prevention : A Publication of the American Association for Cancer Research, Cosponsored by the American Society of Preventive Oncology 20, no. 4 (April 2011): 585–90. https://doi.org/10.1158/1055-9965.EPI-10-1257.