Coffee AND Cigarettes

By Robert Roose, MD MPH | 2.05.07

I admit: I like my coffee. Nearly every morning I look forward to a cup of that bitter tonic, with its heady rush getting me through the morning. And after a good supper, I’ll take a double espresso over dessert every time. According to the National Coffee Association, I am not alone. More than half of the United States population drinks coffee daily, with the average coffee drinker having over three cups a day. In the United States alone, over 300 million cups of coffee are consumed each day; coffee drinks account for 71% of the total consumption of caffeine; and overall coffee production and consumption is a multi-billion dollar industry.

But in the department of legal stimulants, coffee sales are still a distant second to cigarettes. In 2005, an estimated 378 billion cigarettes were inhaled in the United States and total expenditures were around $82 billion. Coffee and cigarettes are big business with two capital Bs. And as they both carry potent addictive potentials (via caffeine and nicotine, respectively) and health effects, they are big public health and social issues too.

Of course, we all know that coffee might be good and cigarettes are definitely bad. A potent review of several studies showed that coffee drinking might lower the risk of diabetes, while a library full of evidence proves cigarette smoking to increase the risk of heart attack, stroke, blood clots, and esophageal and lung cancers, among other things. But while this is true, we must remember that people often start smoking for the same reasons they start drinking coffee – “the buzz” – and it’s all the other stuff that makes cigarettes so toxic and harmful. It’s like if we find out in twenty years that the flavoring powder in a Frappuccino causes gallstones and liver cancer. On a molecular level, caffeine and nicotine are quite similar. Both are mild central nervous system stimulants that immediately increase alertness and may improve memory. People almost universally use coffee or cigarettes (or both, as caffeine is thought to potentiate the effect of nicotine) to wake themselves up, calm themselves down, or digest a meal. Although there are fewer and fewer places in the United States where you can both smoke and get a cuppa, it is clear that coffee and cigarettes share a common place in many people’s daily lives. So in order to see if that overlap is reflected in the scientific literature, we turn to our good friend PubMed.

You see, when you enter “and” in a PubMed search field, you retrieve the intersection of separate searches, like looking only at the middle of a Venn diagram. In this case, searches of “coffee” and “cigarettes” separately generate 5,880 and 10,771 articles respectively, but a combined search of “coffee and cigarettes” narrows the field to 243 articles.

Disappointingly, despite the linked search, most of the articles dealt with coffee and cigarettes independently. The majority of studies used coffee drinking and cigarette smoking as independent variables, testing whether or not they were associated with various illnesses like Parkinson’s disease or pancreatic cancer. One study in the American Journal of Public Health showed a positive, dose-related association between cigarette smoking and the risk of suicide among white men, after controlling for age, marital status, physical activity, alcohol intake, history of cancer, and coffee consumption. Others looked at prenatal exposure to coffee or cigarettes and the subsequent risks of miscarriage and infant febrile seizures. But I could only find one abstract for a study that looked at the consumption of our stimulants of interest as an outcome.

The study, entitled “Increased caffeine and nicotine consumption in community-dwelling patients with schizophrenia” was basically set up to document just how much people with schizophrenia smoke or drink caffeinated beverages. Patients were asked to recall all of the food and drinks they had in the previous 24 hours, as well as how much they smoked. From this data, the total amounts of caffeine and nicotine consumed in a day were calculated. Now, considering the potentially varying functional status of the study population, I’m not sure how valid these diaries really were -- a lot of non-schizophrenic people I know can barely remember what they ate yesterday – but the results were pretty uniformly staggering.

In this sample of 146 patients with schizophrenia from Pennsylvania, the rates of smoking were more than twice as high than the general United States population (59.6% vs. 23.4%). The study participants also reported smoking more cigarettes (24 vs. 13.5) and ingesting more caffeine (471.6mg vs. 254.2mg) at a rate of about ten more cigarettes and two more cups of coffee each day. Don’t tell Philip Morris or Starbucks!

Among schizophrenic patients, it has been hypothesized that patients smoke cigarettes to counteract an overall flattened mood or improve cognition. To me, this sounds awfully similar to why non-schizophrenics smoke cigarettes. Thus perhaps the higher rates of smoking in this population are simply a result of more pronounced anhedonia (a blunting of the normal experience of pleasure) and disorganized thinking and consequently a greater perceived benefit. Alternatively, it is possible that in part the nicotine or caffeine is being used to counteract common medication side effects. In certain areas of the brain, caffeine and nicotine enhance the transmission of dopamine, the main neurotransmitter involved in schizophrenia and the site of anti-psychotic medications. When dopamine rages, it can lead to psychosis. When it is completely blocked, it can cause muscle tremors and rigidity, among other things. And just maybe, by intermittently activating this system at a low-level, coffee and cigarettes might actually help schizophrenic patients manage their medications. Take one of these theories with a cup of coffee and call me in the morning.

References

Checkoway H, Power K, Smith-Weller T, Franklin GM, Longstreth WT Jr, Swanson PD. 2002. Parkinson’s disease risks associated with cigarette smoking, alcohol consumption, and caffeine intake. Am J Epidemiol. 155(8): 732-8.

Greenberg JA, Boozer CN, Geliebter A. 2006. Coffee, diabetes, and weight control. Am J Clin Nutr. 84(4): 682-93.

Miller M, Hemenway D, Rimm E. 2000. Cigarettes and suicide: a prospective study of 50,000 men. Am J Public Health 90(5): 768-73.

Qiu D, et al. 2005. Overview of the epidemiology of pancreatic cancer focusing on the JACC study. J Epidemiol. 15 Suppl 2: S157-67.

Rasch V. 2003. Cigarette, alcohol, and caffeine consumption: risk factors for spontaneous abortion. Acta Obstet Gynecol Scand. 82(2): 182-8.

Strassnig M, Brar JS, Ganguli R. 2006. Increased caffeine and nicotine consumption in community-dwelling patients with schizophrenia. Schizophr Res. 86(1-3): 269-75.

Vestergaard M, Wisborg K, Henriksen TB, Secher NJ, Ostergaard JR, Olsen J. 2005. Prenatal exposure to cigarettes, alcohol, and coffee and the risk for febrile seizures. Pediatrics 116(5): 1089-94.