Fig. 4From: Vitamin D deficiency as a risk factor for dementia and Alzheimer’s disease: an updated meta-analysisPublication bias for studies examining the associations between vitamin D deficiency (serum 25(OH)D < 20 ng/ml) and dementia and AD. The size of each circle is proportional to the study’s weight. The Begg’s tests for the incidence of dementia (A) and AD (B) were roughly symmetrical (P(dementia) = 0.061, P(AD) = 0.076, greater than 0.05)Back to article page