“These results suggest that higher vitamin D levels in midlife may offer protection against developing these tau deposits in the brain,” said lead author Martin David Mulligan, “and that low vitamin D levels could potentially be a risk factor that could be modified and treated to reduce the risk of dementia.”
The good news is that something as simple as a routine blood test — the kind your doctor can order at your next physical — could tell you whether you’re in the 34% with low levels.