Calcium and vitamin D linked to an approximately 17% higher relative stroke risk

New research findings have drawn attention to a possible safety concern for a widely used supplement combination: calcium taken together with vitamin D. An analysis led by scientists at West Virginia University found that, in certain groups, the combined use of these supplements was associated with an approximately 17 percent higher relative risk of stroke.

The investigators examined how various vitamins, minerals and dietary supplements affect cardiovascular health, focusing particularly on people who already face increased risk from atherosclerosis — the buildup of fatty, cholesterol- and calcium-rich deposits in artery walls that can narrow vessels and ultimately trigger clots.

What the numbers mean

The reported link — about a 17 percent rise in relative stroke risk for some participants — does not mean the supplements directly cause strokes in every user. Experts note the difference between relative and absolute risk: a jump in relative risk can correspond to a small absolute change depending on age, baseline illnesses, lifestyle and other individual factors.

Vitamin D plays a key role in calcium absorption and bone health, while calcium itself is essential for muscles, nerves and the heart. The researchers and clinicians emphasise that these nutrients are not inherently harmful but problems can arise when supplements are taken in inappropriate amounts or without assessing individual need.

Those most likely to require caution include people with kidney disease, abnormal blood calcium levels or a history of cardiovascular problems. The broader review also found that for most vitamins and antioxidants there is no convincing evidence that routine use prevents heart disease; some analyses have suggested possible benefits from folic acid and omega‑3 fatty acids, but effects vary with dose, health status and product type.

Clinicians advise against stopping prescribed calcium and vitamin D therapy on one’s own. Anyone considering long‑term use of these supplements should have their needs and risks evaluated by a health professional.

Photo: press material from the event