Brid Ryan

PhD MPH

NCI

Investigator

PLCO (Learn more about this study)

PLCO-357

Mar 23, 2018

Racial differences in the smoking duration and smoking dose attributable risk of lung cancer

Lung cancer incidence is higher in African Americans compared with European Americans. Heterogeneity in tobacco exposure across populations is a plausible root of disparities, but the relationship between smoking and disparities is complicated 1, 2. In addition to status (i.e., current, former and never), dose (cigarettes per day [CPD]), duration, age at initiation, time to first cigarette and daily versus non-daily use are key aspects of smoking relevant to its relationship with cancer—dose and duration are among the most significant. However, the relative importance of smoking intensity versus smoking duration is not equivalent 1, 3-6. For instance, the effect of smoking duration on lung cancer risk is stronger than smoking dose 1, 3-6 and lung cancer risk does not linearly increase with CPD—excess relative risk diminishes beyond 20 CPD 2, 6, an observation that is sometimes called the “wasted dose” effect. Haiman and colleagues demonstrated that lung cancer incidence is higher among African Americans with equal cigarettes per day, even after adjustment for smoking duration 7. However, a specific analysis of how smoking dose and duration contribute to lung cancer risk separately in African Americans and Europeans has not been conducted to our knowledge. This proposal seeks to extend previous studies and examine the relationship between lung cancer risk by both CPD and duration and to compare the relationship in European Americans and African Americans.

These data will be pooled with other data from studies within the International Lung Cancer Consortium. A DTA already exists between NCI/PLCO and ILCCO. I will not share the data with anyone outside of the delivery to me.

Hypothesis

We hypostheize that the effect size of smoking duration and lung cancer risk is higher in African Americans than European Americans

Specific Aims
1) 1) Estimate the odds of lung cancer diagnosis for increasing cigarettes per day among African Americans and European Americans
2) 2) Estimate the odds of lung cancer diagnosis for increasing smoking duration among African Americans and European Americans
3) 3) Compare the effect size of each analysis between European Americans and African Americans