Stroke is the second leading cause of death among people aged 60 years and above, and is causing a substantial global disease burden. Based on the global burden disease (GBD) 2013 study, about 6.5 million people died from stroke and 10.3 million people suffered a stroke in 2013. That is a lot. China had about 2.4 million incidences of stroke each year and bore the heaviest burden of stroke across the world. Other factors include hypertension, diabetes, obesity, and tobacco use.

Vitamin D, which is classically known as a protective factor in bone metabolism, in recent years has been reported to play a vital role in cardiovascular health.

Some evidence also supported the hypothesis that low vitamin D intake may function as a predictor of long-term incidence of stroke