According to a study in Nicotine & Tobacco Research, the relative coronary heart disease (CHD) risk is greater for smokers who consume cigarettes over a longer period of time vs. smokers who consume the same quantity over a shorter period. 

The risk of CHD has long been associated with the number of cigarettes smoked in a day, the smoking intensity, and total exposure over time. Researchers analyzed data from nearly 120,000 participants over 27 years and found that the risk was higher for smokers with longer exposure to cigarettes. 

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A person who smoked 20 cigarettes a day for 50 years had a higher relative risk (RR) of CHD (RR 2.2) compared to a person who smoked 50 cigarettes a day for 20 years (RR 1.7). Both participants may have smoked the same quantity of cigarettes but the length of exposure influences the risk of CHD; this relationship was described as the “delivery rate effect.” 

Findings from this study suggest that the long-term effects of smoking lead to a higher consequence when compared to the short-term effects. The authors added that the link between CHD risk from long-term smoking appears to be more widespread than once thought. 

Jay H. Lubin, PhD, with the U.S. National Cancer Institute at the NIH, and lead author, added that, “We now have observed inverse smoking intensity effects in multiple cohorts with differing smoking patterns and other characteristics, suggesting a common underlying phenomenon.”

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