THE SOURCE: “Taxes, Cigarette Consumption, and Smoking Intensity” by Jérôme Adda and Francesca Cornaglia, in The American Economic Review, Sept. ­2006.

Boosting taxes on cigarettes may be hurting the health of those it doesn’t drive to quit, researchers at University College London have found. That’s because smokers, especially the poor, react to the higher cost of cigarettes by smoking each cigarette more intensively. They take more puffs, inhale more deeply, smoke closer to the end, and block the ventilation holes on the ­filter.

Several studies since 2000 have found that as taxes rise, cigarette consumption goes down. But economists Jérôme Adda and Francesca Cornaglia write that many adult smokers are compensating by extracting far more nicotine from each cigarette. They studied levels of cotinine, a byproduct of nicotine, in 20,000 Americans who partici­pated in the National Health and Nutrition Examination Survey from 1988 to 1994 and 1999 to 2000. Their surprising finding: A one percent rise in taxes increased smoking intensity by 0.47 percent. And more intensive smoking is especially unhealthy. “Smoking a cigarette more intensively, up to the filter, leads the smoker to inhale more dangerous chemicals and has been shown to cause cancer deeper into the lung,” the researchers ­say.

Adda and Cornaglia write that most smokers would prefer to smoke more often but less inten­sively because the last part of a cigarette tastes worse. Tobacco near the filter or butt has been heated up by smoke. Less frequent but more intensive smoking also produces uncomfortable nicotine highs and lows during the ­day.

Today, combined federal, state, and local taxes range from a high of $4.05 a pack in Chicago to a low of 46 cents in South Carolina, and smokers are highly sensitive to price. A 10 percent increase in taxes results in an overall four per­cent decline in cigarette ­consump­tion—­with most of the “lost” sales involving teenagers and pregnant women, specialists say. Smokers are disproportionately likely to have low or medium levels of education, and to work in unskilled and manual occupations. Men and the young are more likely to smoke than women and older individuals, the authors ­write.

Smoking intensity also varies by race. Whites smoke about 40 percent more cigarettes per person than Hispanics and five percent more than African Americans, but blacks have the highest level of cotinine. Blacks extract 56 percent more nicotine per cigarette than Hispanics or whites, Adda and Cornaglia say. This figure helps explain the medical literature showing that even though African-American men are not the heaviest smokers, they have the highest incidence of lung ­cancer.