Which of the following medications is safe to continue before an oral glucose tolerance test (OGTT)?

Continuing calcium before an oral glucose tolerance test (OGTT) is considered safe because calcium does not have a significant impact on glucose metabolism or insulin sensitivity. Unlike some medications and supplements that can interfere with the results of the test by lowering or influencing blood sugar levels, calcium primarily supports bone health and has minimal effects on blood sugar regulation.

In contrast, Vitamin C may affect glucose metabolism, and high doses could potentially influence the OGTT results. Aspirin, while an anti-inflammatory, may also interfere in certain cases. Oral contraceptives can affect hormonal balance and potentially alter glucose tolerance. Therefore, calcium is the most suitable choice for maintaining baseline conditions during the OGTT, allowing for accurate assessment of glucose metabolism without introducing variables that could skew results.