Calculating gambling odds and lung ages for smokers.

Interpreting spirometry as normal or abnormal using 95% confidence limits can obscure milder airflow decreases. Other analyses might better persuade cigarette smokers to quit. High-quality spirometric data of ambulatory never- and current-smokers of African-, European- and Latin-American ethnicity from the Third National Health and Nutrition Evaluation Survey (n>9000) were analysed. We desired to calculate, for each decade of life, the odds that specific ratios of forced expiratory volume in 1 s to 6 s (%FEV(1)/FEV(6)) and to forced vital capacity (%FEV(1)/FVC) values came from a current- or never-smoker. We also desired to develop new, simpler and better formulas to estimate changes in physiological lung age (Deltalung age) for males and females. For each decade of life, odds increase strikingly that smoking decreases %FEV(1)/FEV(6) and %FEV(1)/FVC. At least for these three ethnicities, Deltalung age can be easily calculated as the product of (predicted - actual) %FEV(1)/FEV(6) x 4 or (predicted - actual) %FEV(1)/FVC x 3. Through the sixth decade of life, smokers' Deltalung age increase rapidly but little thereafter, presumably due to the inabilities of older smokers to participate in the survey or their deaths. Using odds and Deltalung ages rather than traditional 95% confidence limits might better persuade smokers to quit.