In the GrassrootsHealth questionnaire that accompanies D*action, participants are asked whether they had a cold or flu in the previous 6 months. What can we learn from this data?

  • 33% of D*action participants experienced a cold and 10% experienced the flu during the 6 months before their most recent test.
  • Participants with vitamin D levels greater than 40 ng/ml (100 nmol/L) reported 41% fewer cases of the flu and 15% fewer colds than participants with levels <20 ng/ml.

graph cold flu for web