Forty percent of tobacco consumers use more than one product, according to a new study. Half of all combinations include e-cigarettes, Reuters reports.

The most common tobacco product combination among both youth and adults was e-cigarettes and cigarettes.

The findings come from the ongoing Population Assessment of Tobacco and Health (PATH) study, which includes 46,000 people. It is designed to provide information about smoking behavior that could influence regulations on warning labels, new product approvals and advertising restrictions.

The study did not answer the question of whether people are relying on e-cigarettes to help them quit smoking, or are using them as an alternative in places where regular cigarettes are banned, the article notes.

“Is it a step towards people quitting, or are the hooks of nicotine just getting deeper?” asked lead researcher Dr. Andrew Hyland of the Roswell Park Cancer Institute in Buffalo, New York.

Mitch Zeller, who heads the Food and Drug Administration’s (FDA) tobacco division, said the tobacco industry is changing very quickly. “The evolution that has taken place in the marketplace makes your head spin,” he said.

The 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.