One study by scientists at Penn State College of Medicine surveyed 7,610 smokers, more than half of which who had cancer. The findings showed that smokers who smoked a cigarette within the first 30 minutes of waking up were 80 percent more likely to develop lung cancer compared to those who wait between 30 and 60 minutes of waking up, who have a 30 percent increased risk.
Another study, both published in the American Cancer Society's journal entitled Cancer, revealed that early morning smokers have a heightened risk for developing head and neck cancer as well. Smoking in the first half hour of awaking led to a 60 percent heightened risk while smokers who waited up to an hour increased their chances for head and neck tumors by 40 percent.
Lead author of the study, Joshua Muscat of Penn State College of Medicine, attributed the cause to nicotine dependence, pointing out that smokers who light up upon awaking tend to inhale heavily, regardless of their smoking habits throughout the day.
"These smokers have higher levels of nicotine and possibly other tobacco toxins in their body, and they may be more addicted than smokers who refrain from smoking for a half hour or more," Muscat said in a statement to CNN.
While the findings of the increased risk for "time to first cigarette" were statistically adjusted for factors like total cigarettes smoked per day, the results were more dependent on the intensity of inhaling smoke rather than the frequency.
Muscat told ABC the reason is "not because they are smoking more frequently or for a greater number of years, but rather it represents a smoking behavior that seems to reflect the intensity of smoking."
The exact reasons for the heightened risk when less time is elapsed for morning cigarettes are unknown. However, Muscat cites that the intensity of early morning smoking increases exposure to cancer-causing chemicals.
Muscat and his team plan to measure the amount of smoking ingested during the first hour of waking up relative to cancer development.
The study also points out that delaying morning cigarettes do not lessen the risk for cancer, although the statistics allude to this theory, but rather these highly dependent smokers would be ideal targets for programs for quitting smoking.