Published Online: March 14, 2014
Mary K. Caffrey
Fifty years ago, when the original Smoking and Health report to the US Surgeon General1 declared that cigarette smoking caused lung cancer in men and probably caused it in women, the news was alarming but easily understood. After all, the action of smoking involves inhaling. With each successive Surgeon General’s Report, evidence mounts about smoking’s insidious path of destruction through the human body, not just for smokers but for all around them: their families, their unborn children, and, depending on where they travel, the hospitality workers who serve them. Statistics show that most of these bystanders will never pick up a cigarette themselves.2
Now, type 2 diabetes mellitus (T2DM) can be added to the roster of health ailments that, while not caused solely by cigarettes, can be caused by them. Diabetes is most certainly aggravated by smoking. A mountain of long-term evidence shows that smoking wreaks havoc with the body’s ability to maintain insulin levels, but it’s the research of the past decade that’s even more troubling: nicotine’s effects hit at the cellular level in the developing fetus, setting up the next generation to battle America’s fastest-growing epidemic.
For payers, especially state Medicaid officials, the implications of these findings are daunting, as the evidence escalates of interwoven relationships among cigarette smoking, diabetes, and poverty (Figure).
Diabetes was part of the evidence entered into history January 17, 2014, when Acting Surgeon General Rear Admiral Boris D. Lushniak, MD, MPH, Department of Human Services Secretary Kathleen Sebelius, and a host of others, including relatives of the pioneering Surgeon General Luther Terry, gathered to release The Health Consequences of Smoking: 50 Years of Progress.3 While the 980-page report includes information on both T2DM and type 1 diabetes mellitus, most of discussion on the disease focuses on T2DM.
Two top officials with the Center for Disease Control and Prevention’s Office of Smoking and Health—Director Timothy McAfee, MD, and Associate Director for Science Terry F. Pechacek, PhD—discussed the findings and implications of the report with Evidence-Based Diabetes Management.
The report made 3 chief conclusions about diabetes and smoking: • The evidence is sufficient to infer that cigarette smoking is a cause of diabetes. • The risk of developing diabetes is 30-40% higher for active smokers than nonsmokers. • There is a positive dose-response relationship between the number of cigarettes smoked and the risk of developing diabetes.3 Biologic Connections
Some of the findings in the report are not brand new, Pechacek explained, but the report consolidates and draws a greater level of attention to studies released over the past decade that show how smoking and nicotine affect a diabetic’s ability to control insulin levels, and how oxidative stress accelerates diabetes symptoms.4-6
Pechacek cited smoking’s relationship to kidney damage, and to the studies referenced in the report over an extended period that show smoking’s association with known markers associated poor insulin control.7-10 He also mentioned studies that cite impairment of the body’s endothelial function.11,12 The report’s long-term evidence is important for payers, especially as the Medicaid rolls expand nationwide under the Affordable Care Act: treating a smoker with diabetes costs more than treating a nonsmoker, because of research that shows the smoker will require more insulin to maintain glycemic control.13 More recent findings, the report says, “indicate that people with diabetes may be particularly susceptible to the detrimental effects of smoking on insulin resistance.” 14,15 “All these things are not really new,” Pechacek said. “We have not placed enough emphasis on the evidence that was already out there. We’re focusing more attention on the fact that smoking is one of the more dangerous aspects of the increasing diabetes incident prevalence.”
The last portion of the biologic evidence summarizes evidence since 2005 on the effects of nicotine on beta cells in the pancreas, which takes on more meaning in light of McAfee’s emphasis on the fact that smoking now affects as many women as men. This was not the case 50 years ago. A study by Yoshikawa et al in 200516 showed the presence of nicotinic receptor in pancreatic islets and beta cells, and additional studies cited in the report have found connections between nicotine use by pregnant women and beta cell death in the fetus.17-19 This can set in motion the process by which diabetes develops after the child is born. Metanalysis on Smoking and Diabetes
Of great value is the epidemiologic evidence, which features a meta-analysis of 51 comparisons over 46 studies that overwhelmingly find a positive association between cigarette smoking and incident T2DM:
• 40 comparisons showed a significantly increased risk of diabetes among smokers • 10 comparisons showed a nonsignificant association between smoking and risk of diabetes (in 8 studies, the risk ratio exceeded 1.0) • One comparison showed a slightly increased association between not smoking and risk of diabetes3 The heterogeneity in the studies concerned the report’s preparers; after further examination, they noted that those studies using measurements of blood glucose at baseline and endpoint were more likely to have strong associations between smoking and T2DM than those relying on patient reports and physician registries.3
A Public Health Response What can be done? McAfee said the most important response he has seen since the report’s release has been the announcement by CVS Caremark that the retail pharmacy chain will remove tobacco products from its 7600 stores nationwide by October 1, 2014.20
“It’s a very powerful statement that enough is enough,” McAfee said, predicting that CVS’ step will be “the beginning of a trend.”
Pechacek said the evidence that smoking makes T2DM more difficult to treat makes it essential that insurers make smoking cessation services available. “Every diabetic smoker should be given access to the best available treatment services as quickly as possible,” he said, putting such care on par with exercise, nutrition counseling and glycemic control. When asked what to tell a smoker who is afraid to quit because he or she will gain weight, Pechachek was adamant: Whatever risk is present from gaining weight is relatively small, he said, and it cannot compare with the risk presented by smoking. Pechacek wasn’t as blunt as the title of a 2013 study published too late to make the report: “It is better to be a fat ex-smoker than a thin smoker.”21 Unfortunately, as the American Lung Association (ALA) reported in its 2014 “State of Tobacco Control,” most states fall short in ensuring that those Americans who most need access to smoking cessation services get them, especially through Medicaid. ALA reports that only 2 states, Alaska and North Dakota, fund tobacco prevention programs at levels recommended by the Centers for Disease Control and Prevention (CDC). Only 2 states provide coverage to Medicaid enrollees for all 7 medications approved by the US Food and Drug Administration for smoking cessation, and all 3 forms of counseling, 22 despite evidence that multipronged approaches work best.23 The ALA report singled out Alabama and Georgia—among the states with the highest diabetes and obesity rates—for offering “virtually no help” with smoking cessation for Medicaid recipients.24
Yet Medicaid, by design, is tied to poverty. And data show an undeniable nexus of poverty, diabetes, and cigarette smoking. Poverty is emerging as a powerful indicator for likelihood of diabetes; a review published just this month found social determinants have a strong impact on glycemic control, blood pressure, and LDL cholesterol.25,26
Similarly, CDC data show that the best predictors of smoking status are a person’s education level and poverty status: while the overall smoking levels have fallen to 18.1%, they remain at 27.9% for those below the poverty line; only 9.1% of individuals with a bachelor’s degree smoke, but 41% of those with only a GED do.27
Acting Surgeon General Lushniak took note of these disparities in presenting the report at the White House. “The burden of tobacco use is not shared equally by all of us. Our education, income, race; where we live, especially the Midwest and Southeast; our sexual orientation, and whether we have a mental illness—these factors affect whether we are harder hit by tobacco.”
“The last century has taught us that public health leadership is essential to effectively deal with the aggressive tactics of the tobacco industry,” he said. “Enough is enough.” EBDM