ingestion could be put in place. In addition, FDA, working with the National Institutes of Health’s (NIH’s) Office of Dietary Supplements, could request that laboratory indicators of insulin resistance and diabetes, as well as blood glucosamine levels, be monitored in subsequent clinical studies of glucosamine.

If FDA chose to proceed with an integrative evaluation for glucosamine, it could follow either a broad-based or a more focused strategy. Glucosamine appears widely used by older individuals, whose baseline incidence rates for several health problems are relatively high. Thus a relatively small increase in risk of any of these conditions associated with glucosamine use might have substantial public health impact, and it might therefore be appropriate to conduct a broad-based evaluation and proactively evaluate all potential risks of harm.

Alternatively, because the signal identified a risk specifically for insulin resistance, FDA could focus its integrative evaluation on insulin resistance and diabetes. In this case, while the topics of a literature search would be fewer than with a more proactive evaluation of all possible risks, it would not be sufficient to look for mention of glucosamine and insulin resistance or glucosamine and diabetes in abstracts of publications. Instead, the literature search would need to identify a wider variety of studies to be read in detail to determine if relevant data on glucosamine and insulin resistance exist. Relevant data might be noted only as a minor point in clinical studies, or it might be revealed only by detailed reading of publications on nonhuman data. In summary, the literature search strategy would need to be sufficiently broad to identify all potentially relevant studies that would then be examined to decide which studies are of importance for the integrative evaluation.

Melatonin was flagged because of serious adverse event reports to SN/ AEMS. These events were cardiovascular and psychiatric/central nervous system related in nature. Another signal could have been melatonin’s regulation as a drug in other countries, a fact signaling that the ingredient’s potential risk should be examined.