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Key Points
- Low vitamin D levels were linked to higher mortality risk
- Severe vitamin D deficiency showed the strongest risk
- Benefits strongest in individuals without diabetes or cardiovascular disease CVD
- Higher doses of vitamin D showed greater risk reduction
- Combining vitamin D with calcium increased benefits
Vitamin D Status and Risk of Death Assessed in National Survey Data
This study analyzed NHANES data collected between 2001 and 2018 and followed 19,500 adults with hypertension for an average of 8.8 years to assess all-cause and CVDmortality.
Vitamin D supplementation was evaluated across a range of intakes:
- Low dose: less than 400 IU/day vitamin D
- Higher doses: over 2,000 IU/day up to 4,000 IU/day vitamin D
Vitamin D status was measured using blood levels of 25-hydroxyvitamin D [25(OH)D], which best reflects vitamin D from diet, supplements, and sunlight exposure.
Vitamin D Reduced Mortality Risk
Compared with individuals who had sufficient vitamin D levels, those with deficiency had a 71% higher risk of all-cause mortality. Severe deficiencies nearly doubled the risk.
Vitamin D supplementation, however, showed a 24% lower risk.
"Participants with hypertension who used vitamin D supplements exhibited reduced all-cause mortality compared to non-users."
Larger daily doses of vitamin D were associated with greater reductions in risk, including both overall mortality and deaths related to cardiovascular disease.
"High-dose vitamin D supplementation, specifically 4000 IU (100 µg) daily, is associated with reduced all-cause and CVD mortality in adults with hypertension."
Benefits Were Strongest in Healthier Subgroups
Researchers found people with high blood pressure, but no diabetes or cardiovascular disease also saw a risk reduction in CVD mortality.
Vitamin D supplementation was associated with:
- Lower all-cause mortality in individuals without diabetes
- Lower all-cause mortality in individuals without cardiovascular disease
- Lower cardiovascular mortality specifically in individuals without diabetes or CVD
"Notably, the use of vitamin D supplements in those without a history of diabetes or CVD was associated not only with reduced all-cause mortality, but also with reduced CVD mortality."
Vitamin D Plus Calcium Showed Additional Benefit
When taken alongside calcium, the combination outperformed vitamin D or calcium alone in mortality risk reduction. Normal-dose vitamin D + normal-dose calcium showed:
- 32% lower all-cause mortality
- 49% lower cardiovascular mortality
"Normal dose vitamin D combined with normal dose calcium supplementation was significantly associated with reduced all-cause mortality… Combining normal-dose calcium and vitamin D supplementation, showing a superior effect on mortality."
Conclusion
In adults with hypertension, vitamin D supplementation produced a significantly lower risk of death, particularly in those without diabetes or cardiovascular disease.
This is especially relevant for people with hypertension, where vascular function and arterial health strongly influence long-term cardiovascular outcomes.
Higher doses and combination use with calcium showed stronger protective effects, highlighting the therapeutic potential of vitamin D in hypertension.
"Vitamin D supplementation had a strong and significantly positive correlation with reduced all-cause and CVD mortality among hypertensive individuals without diabetes or CVD."
"This positive correlation suggests that vitamin D supplementation could potentially be an effective strategy to reduce the risk of mortality in this specific group of people."
