Publication of the 2014 US Surgeon General’s Report entitled, “The Health Consequences of Smoking – 50 Years of Progress”, has concluded the existence of a causal realtionship between cigarette smoking and neovascular and atrophic forms of age-related macular degeneration. The finding elevates the evidence for a causal link between smoking and AMD from “suggestive” to “sufficient” and recommends that, “because smoking causes both nuclear cataracts and AMD, it is important for ophthalmologists, optometrists, and other health care providers to assess and address the smoking status of their patients.” The report highlights the progress and challenges of tackling smoking-related disorders on the 50th anniversary of the original Surgeon General’s Report on Smoking and Health in 1964, the first US government report linking smoking and ill health, including links to lung cancer and heart disease.
The Surgeon General’s 1964 report, today considered a seminal public health document, laid the foundation for tobacco control efforts in the United States. The new report however highlighted that smoking continues to be the leading preventable cause of death in the US, estimating that 20 million Americans have died as a result of tobacco use since 1964, including over 6.5M deaths from cancer, 7.7M deaths from cardiovascular and metabolic disease and 3.8M from pulmonary disease. In addition, the report estimated that annual costs attributed to smoking in the US are estimated at $289 to $333 billion, including $130 billion in direct medical care and over $150 billion in lost productivity due to premature death.
In assessing the impact of tobacco use on eye related disorders the report highlighted a range of studies showing an increased risk for both the incidence and progression of AMD. Results from mouse models supported human population findings, showing that mice reared in smoke-contaminated environments had histologic retinal changes similar to those observed in AMD patients. In particular, the report highlighted four studies which found evidence for an interaction of smoking with a genetic factor in regard to risk for AMD, including (1) Schmidt et al (2006) showing associations between high-risk AMD genotypes and smoking; (2) Chu et al (2008) showing, in a Han Chinese population, that an interaction among heterozygotes for a variant in the CFH gene and smoking had increased risk of neovascular AMD but not for homozygotes; (3) Tuo et al (2008) showing a significant interaction between smoking and a variant in the HTRA1 gene. Together, Tuo showed that the risk variant and smoking increased the odds of AMD to 17.71 (95% CI, 7.49– 41.88) compared to those who had never smoked, and; (4) Spencer et al (2007) found a protective effect for intermediate and advanced AMD considered together in smokers with a haplotype spanning the CFH gene. The association between smoking and increased risk of AMD appeared significant in the interaction model. The Surgeon General concluded that, “taken together, these studies provide strong evidence for a causal relationship between smoking and AMD. Further work is needed on the possible interactions of smoking with high-risk genetic polymorphisms.” The full report is available at http://www.surgeongeneral.gov/.