After a study showed smokers spent disproportionately more in its slots parlor, PhiladelphiaPark Casino this week got permission to open more space to gamblers who light up.

That raises the question: Do gamblers smoke more than other people?

As with so many questions, the answer is that experts disagree. But there is evidence that the people who gamble the most also smoke the most.

First the facts. Because of the state's Clean Indoor Air Act, the PhiladelphiaPark began allotting 75 percent of its slots machines to nonsmokers in September. Given that only about 20 percent of the nation's adults smoke, that would seem a reasonable ratio.

The state then looked at 90 days' worth of revenue at the Bensalem casino, where 25 percent of machines were in smoking areas. It found the average revenue from slot machines per day was 21/2 times more in smoking vs. nonsmoking areas.

As a result, the state is now letting PhiladelphiaPark reserve half its machines for smokers, which is expected to mean more tax revenue for state coffers, as well as the casino itself.

Darlene Monzo, vice president of marketing for the casino, said she thought gamblers were more likely to smoke, but had no statistics on the subject. Nor does she know whether smokers bet more than nonsmokers. The state Department of Revenue did not gather that information.

To be sure, casinos already think smoking is good for business. Atlantic City casino owners recently won a one-year reprieve from that city's smoking ban.

Researchers are less sure of a correlation. Chris Pritsos, a biochemist who teaches at the University of Nevada, Reno, studied smoking rates at casinos throughout Nevada two years ago and found that the percentage of smokers at casinos in Las Vegas and Reno was not significantly higher than the national average. The smoking rate at Lake Tahoe resorts was actually lower. The proportion of slots players who smoked was 21.3 percent.

"I think that the notion that gamblers are more likely to smoke is absolutely unfounded," said Pritsos, who also studies the effect of smoking on casino employees.

Pritsos said that other factors, such as the location of the nonsmoking area or the quality of its machines, might skew the results of a revenue comparison.

Monzo said most of PhiladelphiaPark's smoking area was on the casino's first floor.

Marc Potenza, director of the Problem Gambling Clinic at Yale, said his research had found higher rates of smoking among gamblers, especially among those with a gambling problem. "Both in men and women, the more severe the gambling that was reported, the higher rates of nicotine dependence," he said.

In a 2007 survey, he said, more than 43 percent of pathological gamblers said they were also addicted to nicotine, about four times the rate for non-gamblers. Sixteen to 18 percent of low-risk gamblers were smokers.

Smoking was also associated with losing more money. When Potenza studied people who sought treatment for a gambling problem, those who reported using tobacco every day said they had lost $21,000 gambling in the previous year, $7,000 more than nonsmokers in the group.

Alcohol abuse or dependency also is higher among problem gamblers, Potenza said.

Charles O'Brien, director of the University of Pennsylvania's Center for the Study of Addictions, said compulsive gambling was similar to other addictive disorders. Addictions to gambling, alcohol, nicotine and cocaine tend to run together.

They all activate the brain's reward system, which normally rewards behaviors that are good for the species. You feel good when you drink water, eat tasty food, or have sex. But in addicts, the normal system goes awry and produces uncontrollable habits. Brain-imaging studies show that addicts tend to have especially intense reactions, O'Brien said.

He could not think of any reason gamblers would wager more money while smoking. But, he said, if they are in nicotine withdrawal, they might spend less.