Violation
The findings from a meta-analysis of 24 clinical trials conducted over 20 years, involving vitamin D supplementation to prevent dental caries in children aged 5-14 years, reveal there is wide variation in the results between the studies. Which of the following differences is LEAST likely responsible for this variation?
Years when the studies were conducted.
Baseline caries levels of children.
Stage of dentition of children.
Age of the children.