Wednesday, May 26, 2010
A favorite tactic of the Campaign for Tobacco-Free Kids and other anti-tobacco extremists is the gateway allegation – “tobacco use causes _____” (fill in the blank with an undesirable behavior). For example, one of the Campaign’s pamphlets blames smoking for teenage drug and alcohol use (read it here). Extremists rarely provide rigorous proof for such claims. Given this, it is not surprising that they claim that smokeless tobacco use is a gateway to smoking.
UAB epidemiologist Philip Cole and I looked at this issue in a new study, published in Nicotine and Tobacco Research (available here). We used the National Survey on Drug Use and Health (NSDUH), which is sponsored by the federal Substance Abuse and Mental Health Services Administration.
The NSDUH asks survey participants at what age they used cigarettes or smokeless for the first time. Using this information, we classified participants as cigarette initiators (meaning they smoked before they used smokeless), smokeless tobacco initiators, or both; we then determined the prevalence of current smoking among these groups using established criteria (available here). Our analyses were restricted to white men age 18+ years (who are most likely to have used smokeless tobacco). In addition, we looked at white boys aged 16-17 years, since the gateway claim often focuses on teenagers.
Our study showed that the prevalence of current smoking among white men who were cigarette initiators was 35%. In comparison, the prevalence of smoking among smokeless tobacco initiators was only 28%, a significantly lower statistic. If the gateway effect was real, smokeless initiators would have had smoking rates similar to – or higher than – cigarette initiators.
The results for boys were even more impressive. Current smoking among cigarette initiators was 43%, but only 18% of smokeless tobacco initiators smoked. This means that boys who had started with smokeless tobacco were less than half as likely to be smoking at the time of the survey.
A few published studies have looked at the gateway issue in the U.S. In 2003, Tomar claimed that teenage boys who used smokeless were 3.5 times more likely to become smokers than nonusers of tobacco (abstract here). However, a subsequent re-analysis (available here) of Tomar’s data found that he hadn’t considered other well-known predictors of teenage smoking, such as low grades, smoking by a family member or other risky behaviors. After including these factors, smokeless tobacco use was a non-significant risk factor. Another study, by Timberlake and colleagues (available here), found “no evidence for an increased risk of smoking among the [smokeless tobacco] users.”
Anti-tobacco extremists will continue to claim that smokeless tobacco leads to smoking. However, as we conclude in our paper, our results do “not support the hypothesis that [smokeless tobacco] use is a gateway to smoking among American white males of any age, including teenagers. In fact, there is evidence that, compared with cigarette initiators, [smokeless tobacco] initiators are significantly less likely to smoke, which suggests that [smokeless tobacco] may play a protective role.”
Tuesday, May 18, 2010
One of the most common – and challenging – questions regarding tobacco harm reduction is whether it is applicable to pregnant women who smoke.
According to the 2004 Surgeon General’s report, smoking during pregnancy is associated with increased risks for premature delivery, low-birth-weight infants, and stillbirth. Smoking is also associated with increased risk for problems with the placenta (the organ that nourishes the fetus). These problems include growth of the placenta in the wrong location (placenta previa) and separation of the placenta from the mother’s uterus (placental abruption), both of which can place the mother and developing fetus at risk. Paradoxically, pregnant women who smoke have a significantly lower risk of preeclampsia (a form of high blood pressure). But the overall effect of smoking on the developing fetus is decidedly negative.
Can a pregnant smoker who switches to smokeless tobacco benefit her health and that of her developing baby? Only one scientific study has addressed this issue. It reported information on pregnancy outcomes among Swedish women who used snus or smoked, compared with nonusers of tobacco, and it was published in 2003 by a group of investigators from the Karolinska Institute in Sweden and the National Institute of Child Health and Human Development in the U.S. The abstract is available here.
In this study, tobacco users had smaller babies than nonusers, although the reductions were modest. The average baby weight for nonusers was 7 pounds 14 ounces; babies of snus users weighed 7 pounds 13 ounces, while light smokers (1-9 cigarettes per day) and heavier smokers (10+ cigarettes) had babies that weighed less (7 pounds 8 ounces and 7 pounds 6 ounces, respectively).
Women who used snus were more likely than nonusers to have a premature delivery (adjusted odds ratio, aOR = 1.79, 95% confidence interval = 1.27 – 2.52), which was similar to that of light (aOR = 1.56, CI = 1.33 – 1.83) and heavier smokers (aOR = 1.84, CI = 1.53 – 2.21).
This study confirmed that smoking is protective for preeclampsia. The aOR for light smokers was 0.71 (CI = 0.59 – 0.88), and heavier smokers’ risk was even less (aOR = 0.48, CI = 0.36 – 0.64). However, snus users had a somewhat elevated risk for preeclampsia (aOR = 1.58, CI = 1.09 – 2.27).
In summary, pregnant women who use snus are at risk for slightly smaller babies, and they also have modestly elevated risks for premature delivery and preeclampsia. Women who are pregnant should refrain from using all tobacco products.
Note: The original link to the research study abstract was wrong. It was corrected on September 7, 2010.
Wednesday, May 12, 2010
The World Health Organization is the United Nations’ health authority. Although WHO has very little presence or direct influence on American health issues, its positions and policies are of considerable significance in other countries. Wielding its influence, WHO has attempted to impose an unnecessary tobacco policy on Norway.
WHO’s Tobacco Free Initiative (TFI) is blatantly prohibitionist. Each year, TFI sponsors “World No Tobacco Day” on May 31, and its 2006 celebration was especially memorable. That year, the theme was “Deadly in Any Form or Disguise,” (read about it here) and the message was simple: “Cigarettes, pipes, bidies, kreteks, clove cigarettes, snus, snuff, smokeless, cigars… they are all deadly.” Tobacco prohibitionists throughout the world sing from the same songbook.
As I wrote in a post last year, snus is available in Norway, and there is evidence that it has had a substantial positive effect on smoking among men. Apparently TFI is not happy; on May 5, its coordinator told the Norwegian government that TFI wants graphic warnings on snus boxes (translated article here).
The response from the Norwegian health ministry was entirely sensible. Secretary Roger Ingebrigtsen, rejecting TFI’s demand, stated “that scientists long have agreed [upon] and documented the harmful effects of cigarettes and rolling tobacco… but the consensus and the documentation is not as unambiguous” for the use of snus (translated link here).
The government of Norway should be commended for putting the health of its smokers ahead of a misdirected and counterproductive WHO campaign against safer cigarette substitutes.
Wednesday, May 5, 2010
In 1994, Jacob Sullum told the following story at a Cato Institute seminar on tobacco use:
“A few years ago when I was working on a story about the antismoking movement for Reason magazine, I interviewed Scott Ballin, chairman of the Coalition on Smoking or Health. I raised the question of why people smoke. ‘There is no positive aspect to it,’ he assured me. ‘The product has no potential benefits.’ Not everyone concurs with that assessment; in a recent column in Vanity Fair, for example, Christopher Hitchens wrote that ‘cigarettes improve my short-term concentration, aid my digestion, make me a finer writer and a better dinner companion, and in several other ways prolong my life.’”
Disparaging tobacco’s value is a familiar theme with tobacco prohibitionists. They claim that the substance is worthless, and that the beneficial effects reported by smokers are only symptoms of relief from nicotine withdrawal. But smokers believe that they derive specific benefits. Who is telling the truth?
A meta-analysis just published in the journal Psychopharmacology reviewed the effects of nicotine and smoking on aspects of human performance (abstract here). The lead author is Stephen Heishman, a scientist at the National Institute on Drug Abuse; he is joined by Bethea Kleykamp of Johns Hopkins University and Edward Singleton of Stevenson University. The study will not please anti-tobacco extremists.
Heishman et al. reviewed 15 years of published studies on the effects of nicotine and smoking on various measures of human performance. They had strict criteria for the studies they accepted; one of the most important was including only nonsmokers or smokers who had not been deprived, in order to eliminate the confounding effects of withdrawal on performance.
Heishman et al. found that nicotine and/or smoking produces positive effects involving fine motor skills, attention and memory. The investigators conclude: “The significant effects of nicotine on motor abilities, attention, and memory likely represent true performance enhancement because they are not confounded by withdrawal relief. The beneficial cognitive effects of nicotine have implications for initiation of smoking and maintenance of tobacco dependence.”
It’s time to be honest with the 50 million Americans, and hundreds of millions around the world, who use tobacco. The benefits they get from tobacco are very real, not imaginary or just the periodic elimination of withdrawal. It’s time to abandon the myth that tobacco is devoid of benefits, and to focus on how we can help smokers continue to derive those benefits with a safer delivery system.