An investigation by this reporter reveals hidden data not apparent in a recent vitamin D/influenza study. [Clinical Nutrition 2016]
A study was conducted in Japan 3327 employees (mean age 37 years) at companies in Japan, 5.5% (182 subjects) whom were doctor-diagnosed with the flu over a 5- month (winter) period. The flu vaccination rate was 26.3% among workers who were diagnosed with flu versus 27.5% among those who didn’t. There were 217 unvaccinated subjects out of the 3327 total subjects (6.5%).
Vitamin D blood levels were typically low, ~22 nanograms per milliliter of blood in the workers as a whole. Researchers compared a blood vitamin D level of under 20 ng/ml , 20-30 ng/ml and over 30 ng/ml. Data on subjects where flu diagnosis was confirmed by a diagnostic kit were also segregated.
The chart below is what The Vitamin D Council considers adequate vitamin D blood levels.
|Vitamin D Council|
Critics would quickly say all of the subjects in the first two groups (below 20 ng/ml and 20-30 ng/ml could be considered vitamin D deficient or at least inadequate. This is confirmed in the chart below where the group with mid-range vitamin D levels actually experienced a higher rate of infection (1.77% lowest vitamin D level; 4.18% mid-range vitamin D level).
The study confirmed the effectiveness of flu vaccination among generally healthy working-age adults. The rate of influenza was 3.37% in vaccinated subjects and 34.1% among unvaccinated subjects. However, there is another striking finding in this report.
Among the vaccinated, vitamin D levels over 30ng/ml reduced the risk for diagnosed influenza by almost 3-fold (0.86% to 0.38%), which means maintenance of vitamin D levels is beneficial even among the vaccinated.
What more, both vaccination and vitamin D alone (no vaccination) drove diagnosed influenza infection risk below 1%!
Oh, what researchers keep hidden from the public.
|Vitamin D Levels & Diagnosed Influenza|
|Vitamin D blood levels
|Under 20 ng/ml||20-30
|Over 30 ng/ml||Total|
|VACCINATED & UN-VACCINATED n= 3327|
|# diagnosed flu||59/3327||106/3327||14/3327||179/3327|
|% diagnosed flu||1.77%||3.18%||0.42%||5.5%|
|# diagnosed flu||27/3110||66/3110||12/3110||105/3110|
|% diagnosed flu||0.86%||2.12%||0.38%||3.37%|
|# diagnosed flu||32/217||40/217||2/217||74/217|
|% diagnosed flu||14.74%||18.43%||0.92%||34.1%|