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Low vitamin D levels do not lead to strokes but can result from them, according to the that looks at the relationship between the two.

Vitamin D is mostly known for helping the body absorb calcium and contributing to bone health. But research in recent decades also has looked at whether vitamin D levels affect cardiovascular disease, although with inconsistent results.

The new study looked at vitamin D levels among 9,680 people from the Dutch city of Rotterdam. It found people with low levels of the vitamin were more likely to have reported having a stroke in the past.

After excluding people who had already had a stroke, researchers tracked the remaining group over the next 10 years. They found no association between vitamin D levels and higher stroke risk. They did, however, notice the people who had strokes during the follow-up years were more likely to have a severe vitamin D deficiency.

The reason behind this was not explored by researchers, said Dr. Kamran Ikram, senior author of the study published Thursday in the Ãå±±ÊÓƵ's journal Stroke.

"When we started this study, our basic question was to see whether the vitamin D level proceeds the stroke. We just looked at one small, tiny piece of the puzzle," said Ikram, a professor of neurology and epidemiology at Erasmus University Medical Center in Rotterdam, the Netherlands. "The question now is, once somebody has a stroke, do we then have to do something with the vitamin D? That question we haven't tackled in the study."

The study did suggest people who have strokes "may have limited vitamin D production because of reduced exposure to sunlight and diet quality, among other factors." But Ikram said there's no clear evidence to support taking vitamin D supplements to reduce stroke risk.

A of past studies found an increased risk for stroke in people who had very low vitamin D levels. Yet, a released in July found taking vitamin D supplements, along with calcium, could increase stroke risk.

Vitamin D can build up in the body to toxic levels when taken in excess, said Dr. Tanya Turan, a neurologist who wasn't involved in the study.

"Most of the general public doesn't know that. They think vitamins – the more I take, the better, the healthier I'm going to be," said Turan, a vascular neurology professor at Medical University of South Carolina in Charleston. "But for the majority of people who eat a normal, well-balanced diet, they don't need vitamin supplementation. Most of what you need will come through diet and a mild amount of sun exposure."

While some research suggests treating low vitamin D levels after a stroke may result in better stroke recovery, more studies are needed, Turan said. "When it comes to vitamin D deficiency, it's probably better to try and identify what's the underlying cause of that – is there an intestinal absorption issue? Is there poor nutrition?"

"In cases where severe vitamin D deficiency is detected, it makes sense to supplement for other reasons, like bone health and all the things we know that vitamin D can benefit," Turan said. "To do it solely for stroke prevention doesn't seem warranted at this time."

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