The number of people who smoke a pack of cigarettes or more a day has been decreasing since tobacco’s peak in the 1940s and 50s; the percentage of adults who smoke has dropped from 42.4 percent in 1965 to 19 percent in 2011, according to the Centers for Disease Control & Prevention (CDC). But it appears that casual, or “very light” smoking, might actually be increasing — and particularly among young women, according to a new study out of the University of Texas at Austin.

The researchers examined 9,789 women between the ages of 18 and 25, using data from the 2011 National Survey on Drug Use and Health. Women who had smoked part or all of a cigarette in the past 30 days were classified as smokers, while those who didn’t but had smoked before were classified as former smokers. The researchers found that 27 percent of women in the study, and 62 percent of those who identified as current smokers, felt like they were “light smokers.” Light smokers are typically defined as people who smoke less than five cigarettes a day, or people who occasionally pick up a cigarette every week or month.

Women aged 18-20, who had received some education, were the most likely to identify as light smokers. These light smokers don’t always perceive the health risks of smoking as being applicable to them, which is possibly one of the reasons why light smoking has increased among them, the authors believe.

“Some studies report that the smoking pattern of very light smokers is unstable,” the authors wrote. “However, other research suggests that an intermittent pattern of smoking may be maintained for an extended period of time. Although very light smokers express an interest in quitting, they may be less motivated to quit and may have relapse rates similar to those of heavy smokers.”

And perhaps here’s the key: “Nondaily smokers may be resistant to quitting because of their reluctance to identify themselves as smokers.” Indeed, young people often feel invincible and smoking an occasional cigarette may seem harmless, when in reality that’s not the case. In fact, as the number of cigarettes or packs a day smoked decrease, it’s likely that sporadic or light smoking may increase; and young people need to be aware of the hazards of that switch.

While not much research has been done to track light smokers and later effects on their health, it’s fairly common knowledge that every cigarette you smoke will have long-lasting implications. A recent study examined the effect of social smoking on teens, and found that even light amounts are harmful.

“All smoking counts,” Stephen Amrock, a student of pediatric medicine at NYU School of Medicine and the lead author of that study, said. “Social smoking has a price, and even the occasional cigarette truly is bad for you. Light and intermittent smokers face tremendous future health risks.”

Source: Li X, Holahan C, Holahan C. Sociodemographic and Psychological Characteristics of Very Light Smoking Among Women in Emerging Adulthood, National Survey of Drug Use and Health, 2011. Preventing Chronic Disease. 2015.