A large government study on tobacco use, scheduled to be released Thursday, is unlikely to provide many details about e-cigarette use, experts say. The lack of data will make it more difficult to set policies about e-cigarettes, they note.

The Population Assessment of Tobacco and Health (PATH) Study, conducted over five years, included 46,000 people, according to Reuters. It is expected to provide information about smoking behavior that could influence regulations on warning labels, new product approvals and advertising restrictions.

“While all this data that is being accumulated through the PATH study is great, it is unclear to me how much is going to be useful for setting the policy and regulations of the future.” said Scott Ballin, a health policy consultant based in Washington, D.C.

Experts say the study may not provide enough detail to determine whether flavors in e-cigarettes make them appealing to children. There is also unlikely to be much data about the average dose of nicotine consumed with e-cigarettes, since many of the devices can be customized to release different levels of nicotine, the article notes.

The Food and Drug Administration (FDA), which funded the study, has issued a draft proposal to regulate e-cigarettes. The FDA is reviewing public comments on the proposal, which would ban the sale of e-cigarettes, cigars and pipe tobacco to anyone under age 18.

Manufacturers of e-cigarettes and cigars would have to register with the FDA, give the agency a detailed account of the products’ ingredients, describe their manufacturing process and scientific data, and submit to FDA inspections. Companies would no longer be allowed to offer free samples. E-cigarettes would be required to come with warning labels stating they contain nicotine, which is addictive. Vending machines in public places where minors are allowed could not carry e-cigarettes. The rules also ban online sales of e-cigarettes and cigars to minors.