Passive smoking causes heart disease and lung cancer

Tobacco industry efforts to undermine policy-relevant research

The tobacco industry, working through third parties to prevent policy-relevant research that adversely affected it between 1988 and 1998, used coordinated, well-funded strategies in repeated attempts to silence tobacco researcher Stanton A. Glantz. Tactics included advertising, litigation, and attempts to have the US Congress cut off the researcher's National Cancer Institute funding. Efforts like these can influence the policymaking process by silencing opposing voices and discouraging other scientists from doing work that may expose them to tobacco industry attacks. The support of highly credible public health organizations and of researchers' employers is crucial to the continued advancement of public health.

Tobacco industry efforts undermining evidence linking secondhand smoke with cardiovascular disease

BACKGROUND

The scientific consensus that secondhand smoke (SHS) increases cardiovascular disease (CVD) risk by 30% is based on epidemiological and biological evidence. The tobacco industry has contested this evidence that SHS causes CVD, but how and why they have done it has not been described.

METHODS AND RESULTS

About 50 million pages of tobacco industry documents were searched using general keywords and names of industry consultants and scientists. Tobacco industry-funded epidemiological analyses of large data sets were used to argue against an epidemiological association between SHS and CVD and smoke-free regulations, but these analyses all suffered from exposure misclassification problems that biased the results toward the null. More recent industry-funded publications report an increased risk of CVD associated with SHS but claim a low magnitude of risk. When early tobacco industry-funded work demonstrated that SHS increased atherosclerosis, the industry criticized the findings and withdrew funding. RJ Reynolds focused on attacking the biological plausibility of the association between SHS and CVD by conducting indirect platelet aggregation studies, exposure chamber experiments, and literature reviews. Although these studies also suffered from exposure misclassification problems, several produced results that were consistent with a direct effect of SHS on blood and vascular function. Instead, RJ Reynolds attributed these results to an unproven epinephrine-related stress response from odor or large smoke exposure, which supported their regulatory and "reduced-harm" product development efforts. Philip Morris' recent "reduced-harm" efforts seem supportive of a similar corporate agenda.

CONCLUSIONS

The tobacco industry attempted to undermine the evidence that SHS causes CVD to fight smoke-free regulations while developing approaches to support new products that claim to reduce harm. The industry interest in preserving corporate viability has affected the design and interpretation of their cardiovascular studies, indicating the need for great caution in current debates about future tobacco industry regulation and development of reduced-harm tobacco products.

Second hand smoke stimulates tumor angiogenesis and growth

Exposure to second hand smoke (SHS) is believed to cause lung cancer. Pathological angiogenesis is a requisite for tumor growth. Lewis lung cancer cells were injected subcutaneously into mice, which were then exposed to sidestream smoke (SHS) or clean room air and administered vehicle, cerivastatin, or mecamylamine. SHS significantly increased tumor size, weight, capillary density, VEGF and MCP-1 levels, and circulating endothelial progenitor cells (EPC). Cerivastatin (an inhibitor of HMG-coA reductase) or mecamylamine (an inhibitor of nicotinic acetylcholine receptors) suppressed the effect of SHS to increase tumor size and capillary density. Cerivastatin reduced MCP-1 levels, whereas mecamylamine reduced VEGF levels and EPC. These studies reveal that SHS promotes tumor angiogenesis and growth. These effects of SHS are associated with increases in plasma VEGF and MCP-1 levels, and EPC, mediated in part by isoprenylation and nicotinic acetylcholine receptors.

The controversial controversy of a passionate controversialist

Alvan Feinstein was among the pioneers who perceived the need to apply epidemiologic principles and methods to clinical medicine. In his attempt to convert his peers to his own views, he was very liberal in criticizing the work of others. Epidemiologists still recall his 1988 article in Science entitled "Scientific Standards in Epidemiologic Studies of the Menace of Daily Life," in which he criticized observational epidemiology for its lack of scientific rigor. In this context, Feinstein's work has also been the center of controversies. One in particular, related to the fact that he carried out research and consulted for industries, in particular the tobacco industry, has tainted the last years of Feinstein's career. My purpose in this article is to discuss Feinstein's relationship with the tobacco industry. It is not to judge the validity of his work. Against this background, a question of historic relevance, one that can be discussed on the basis of some evidence, is whether Feinstein, world-reknowned epidemiologist and editor of this journal from 1982 until his recent death, helped the tobacco industry to publish articles minimizing the deleterious effects of smoking in the Journal of Chronic Diseases and (since 1988) the Journal of Clinical Epidemiology. To address this question I have searched the articles related to the effects of tobacco that were published in the Journal since 1978. The tobacco industry has had the opportunity, via its consultants, to defend its own ideas in the "Variance and Dissent" section. Perhaps in hindsight Feinstein could be criticized for not having clearly indicated the sponsorship of the tobacco industry behind these publications, of which he was fully aware. However, this does not suffice to infer that he was the tobacco industry's "man." Feinstein's attitude in matters of publication appears balanced.

Passive smoking by self report and serum cotinine and the prevalence of respiratory and coronary heart disease in the Scottish heart health study

STUDY OBJECTIVE

To explore the relationship between self reported environmental tobacco smoke exposure (or passive smoking), the serum cotinine concentration, and evidence of respiratory or coronary disease in men and women who have never smoked.

DESIGN

Cross sectional random population survey identifying disease markers and relating them to measures of passive smoking. Disease markers were previous medical diagnoses, response to standard symptom questionnaires, and electrocardiographic signs.

SETTING

Samples of men and women aged 40-59 years drawn from general practitioner lists in 22 local government districts of Scotland, between 1984 and 1986.

PARTICIPANTS

A total of 786 men and 1492 women who reported never having smoked tobacco, and who had serum cotinine concentrations below 17.5 ng/ml, the cut off point for smoking "deceivers", took part.

RESULTS

Fewer than one third of never smokers reported no recent exposure to environmental tobacco smoke and the same proportion had no detectable cotinine. Women had lower cotinine values than men but reported more exposure to smoke. The correlation between the measures of exposure was poor. Self-reported exposure showed strong, statistically significant, dose response relationships with respiratory symptoms and with the coronary disease markers. These relationships were weak or absent for serum cotinine, except for diagnosed coronary heart disease. Here the dose response gradient was as strong as that for self report, with an odds ratio of 2.7 (95% CI 1.3, 5.6) for the highest v the lowest exposure group, adjusted for age, housing tenure, total cholesterol, and blood pressure, and not explained by fibrinogen.

CONCLUSIONS

The validity of different measures of tobacco smoke exposure needs further investigation. The gradient of diagnosed coronary heart disease with both self reported exposure and serum cotinine was, however, surprisingly strong, statistically significant, and unexplained by other factors. These findings reinforce current policies to limit passive tobacco smoke exposure.

Metoprolol does not attenuate atherosclerosis in lipid-fed rabbits exposed to environmental tobacco smoke

BACKGROUND

We previously demonstrated that exposure to environmental tobacco smoke (ETS) increases the development of atherosclerosis in lipid-fed rabbits. Clinical studies have suggested a protective effect of beta-blockers in smokers. Accordingly, we evaluated the effects of metoprolol in this animal model to see whether this beta-blocker would block the atherogenic effects of ETS.

METHODS AND RESULTS

Thirty-two New Zealand White male rabbits on a 0.3% cholesterol diet were randomly divided into four groups: ETS-metoprolol (ETS-M), ETS-control (ETS-C), and non-ETS with metoprolol (NETS-M) and without metoprolol (NETS-C). The two metoprolol-treated groups received metoprolol at a dose of 0.4 mg.kg-1.h-1 administered subcutaneously by an osmotic pump. Rabbits in the ETS groups were exposed to sidestream smoke from four Marlboro cigarettes per 15 minutes, 6 hours a day, for 10 weeks. Average air carbon monoxide (CO), nicotine, and total particulates (TP) in the exposure chambers were 67.2 +/- 3.1 (SEM) ppm, 1133.7 +/- 78.4 micrograms/m3, and 37.7 +/- 3.0 mg/m3, respectively. Plasma nicotine was significantly higher in ETS-exposed rabbits than in nonexposed rabbits (7.1 +/- 1.9 versus 0.5 +/- 0.1 ng/mL, P < .01). Blood carbon monoxide hemoglobin (COHb) in the ETS-M group was significantly higher than that in the NETS-M group (4.0 +/- 0.2% versus 1.3 +/- 0.1%, P < .0001). The lipid lesions in the aorta and pulmonary artery were 57.2 +/- 7.6% and 33.1 +/- 6.4% (ETS-M), 62.8 +/- 8.4% and 58.4 +/- 6.1% (ETS-C), 38.7 +/- 9.4% and 24.8 +/- 7.7% (NETS-M), and 49.8 +/- 8.7% and 32.7 +/- 7.1% (NETS-C). There were significant differences in lipid deposits of the arteries between the controls and the ETS-exposed rabbits (37 +/- 1% versus 53 +/- 1%, P = .004) and between the controls and metoprolol-treated rabbits (51 +/- 1% versus 38 +/- 1%, P = .027). The benefit of metoprolol was independent of ETS exposure (ETS x metoprolol interaction, P = .595).

CONCLUSIONS

Exposure to ETS significantly accelerated and metoprolol decreased the development of atherosclerosis in lipid-fed rabbits, but there was no interaction between the effects of ETS exposure and metoprolol. Metoprolol did not protect against the effects of ETS on atherosclerosis, suggesting that the beta-adrenergic system is not the mechanism of ETS-induced atherosclerosis.