How can I tell if smoking has damaged my health?

Your level of risk to develop a tobacco-related illness is based on the number of years and the number of cigarettes you have smoked in your lifetime. A common equation for estimating your risk is by the number of "pack years" that you have smoked. A "pack year" is the equivalent of smoking a pack of cigarettes a day for a year. To calculate this equation, first estimate the number of years that you have smoked. Then estimate the number of packs of cigarettes that you smoked per year at different times during your smoking habit; then use that number to estimate how many "pack years."

For example, John began smoking in 1980, and smoked about a half a pack a day until 1983. Then, he met and married a woman who also smoking, and his smoking increased to a pack a day. This continued until John began a very stressful job and jumped to two packs a day in 1990. Here is John's pack year estimate:

Smoking for less than ten "pack years" (the number of years that you have averaged a cigarette pack-a-day) places a person at low risk for developing illnesses commonly related to tobacco use. If a person has smoked more than ten pack years, some tissue damage is to be expected. However, the earlier a person reduces or quits her smoking, the lower the level of tissue damage. Reducing or quitting smoking will greatly enhance your health at all times, no matter how many pack years you have smoked.

Your health risks are increased if you have risk factors that make people more susceptible to smoking-related illnesses. These high risk categories include:
- Pregnant women.
- Women over thirty who take birth control pills.
- Members of families who are high risk for heart   disease.
- Smokers who already have a tobacco-related illness.
- Smokers who are exposed to toxic agents in the   workplace.
- Smokers with high risk lifestyles (i.e., overweight,   extremely thin, heavy drinker, inactive).
- Smokers with high risk personalities (i.e., Type A   personality, accident-prone, adrenaline addicts).
- Smokers about to undergo surgery.
- Smokers with abnormal lab tests.
- Smokers who are heavily addicted to nicotine or their   smoking habit.
- Smokers who smoke their cigarettes close to the   filter.
- Smokers who inhale deeply.