A study published in the New England Journal of Medicine found that cigarettes cause a smoker’s life to literally go up in smoke. On average, smoking shortens life expectancy by more than a decade. According to data analyzed from the US National Health Interview Survey, women lose approximately 11 years and men lose 12. The researchers call smoking the leading preventable cause of death in the United States and believe education is the key to stop people from puffing their years away.

The Centers for Disease Control and Prevention (CDC) report that cigarette smoking causes more than 443,000 premature deaths in the United States every year, which represents 20 percent of all deaths. It is estimated that cigarette smoking accounts for a third of all cancers and 90 percent of lung cancer diagnoses. Smoking also causes lung diseases and increases the risk of heart disease and stroke.

The main culprit in cigarettes’ lure is nicotine, a naturally occurring chemical found in various types of plants including tobacco. Nicotine is an alkaloid, meaning it contains nitrogen. It is also considered a drug because of its physiological effects on the body. Nicotine can be readily absorbed through the skin when applied topically and through the mucous membranes in the nose and mouth and the lungs when inhaled. While cigars and pipe tobacco have just as much nicotine as cigarettes, those smokers do not inhale so life their expectancy is impacted less than cigarettes users.

But while nicotine can be poisonous if ingested in high enough doses—it used to be a popular insecticide—it does not directly cause cancer. It is the other chemicals in tobacco smoke such as formaldehyde, cyanide, and ammonia that pose the health risks. But nicotine is what keeps the smokers coming back, shortening their life expectancy with each cigarette.

Nicotine reaches the brain within just 10 seconds of taking a puff, increasing heart rate, blood pressure, heart muscle oxygen consumption rate, and heart stroke volume by stimulating the adrenal glands to release the hormone epinephrine, better known as adrenaline. Nicotine also increases levels of the hormone dopamine, a neurotransmitter that can cause increased alertness, a feeling of euphoria, and a sense of relaxation. Research suggests that other compounds found in tobacco smoke might increase nicotine’s effects on the brain.

The physical rush provided by nicotine makes it highly addictive; the American Heart Association (AHA) puts it on par with heroin. That additive quality is why people will go through several packs a day and continue to smoke despite knowing they are shortening their life expectancy and exposing themselves to a host of respiratory and circulatory illnesses and conditions. It is also why it is so difficult to stop. It is estimated that around 35 million people try to stop smoking every year. More than 93 percent of those will resume smoking within the year.

Kicking the habit is emotionally and physically challenging. Just like a heroin or methamphetamine addict, smokers suffer withdrawal symptoms that can include anxiety, depression, moodiness, irritability, weight gain, attention difficulties, and painful cravings for tobacco. But the New England Journal of Medicine study stressed the struggle is worth it in terms of longevity. A 40-year-old who quits reduces the excess risk of death by about 90 percent. Within a day of quitting, heart rate and blood pressure drop and the blood’s carbon monoxide level drops to normal. The sooner you stop, the fewer years you will puff away.