Caffeine and Nicotine : A Review of Their Combined Use, Interactive Effects and the Impact of Caffeine Abstinence on Tobacco Cessation and Withdrawal
There is good epidemiologic support to suggest a strong significant relationship between coffee consumption and smoking. In six epidemiological studies reviewed and analyzed, 86.4% of smokers consumed coffee versus 77.2% of nonsmokers. Seventeen experimental studies suggest that the phannacologic effect of caffeine in coffee may be partially but not totally responsible for the relationship. The behavioral relationship appears to be supported by conditioning, a reciprocal interaction (caffeine intake increases anxiety/arousal - nicotine decreases it), and combined effects of third variables (e.g., stress, alcohol). In abstinent smokers, caffeine plasma levels increase, remain elevated for as long as six months and may be sufficient to produce a caffeine toxicity syndrome. A review of 86 studies of nicotine withdrawal, caffeine withdrawal and caffeine toxicity suggests that the symptoms are similar enough to be confused. Symptoms reported as nicotine withdrawal may include symptoms of caffeine toxicity. In this study we tested whether caffeine abstinence influenced smoking cessation and whether smoking abstinence would induce high caffeine plasma levels and subsequent caffeine toxicity symptoms. One-hundred sixty-two caffeine using smokers were enlisted from 41 American Lung Association cessation clinics. Volunteers were randomly assigned by clinic to caffeine use or caffeine abstinence conditions and measured for 3 weeks post-smoking cessation, at six months and at one year. Caffeine abstainers were asked to use only decaffeinated products for at least one week. Results showed a significant linear increase in caffeine sputum levels across four time points for those who quit smoking and continued using caffeine. At 21 days post-cessation, sputum caffeine levels increased above 200% of baseline levels even though reported intake remained stable. Caffeine abstinence significantly increased headache, fatigue, muscle aches/twitches, tobacco craving, and decreased stimulation immediately following tobacco cessation. There were no differences between the groups on other withdrawal symptoms and no evidence of caffeine toxicity. These initial effects in the caffeine abstinence group might be counter productive in facilitating the process of smoking cessation, however, no significant difference in success existed in either group at 16 days, 6 months or 12 months. Short-term caffeine abstinence (reduction) appears to be neither helpful or harmful in smoking cessation.
Public Health Education and Promotion, Caffeine -- adverse effects; Nicotine -- adverse effects
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