“The time is always right to do what is right.”  Martin Luther King

When it comes to almost any situation, including smoking cessation, this quote is probably appropriate.  The hazards of smoking are detailed in recent several articles/editorial (NEJM 2013; 368: 341-350, 351-64, 389-90).

In the first article, the authors reviewed smoking-cessation histories from 113,752 women and 88,496 men.  All participants were older than 25 years and interviewed between 1997-2004.  These participants were from a cohort in U.S. National Health Interview Survey (NHIS).  The NHIS is a nationally representative cross-sectional health survey.

The second study involved large populations from the Cancer Prevention Study I (CPS I) which started in 1959 and CPS II which started in 1982.  These were prospective studies followed the mortality associated with smoking.  In all, the populations of these two studies exceeded 1.2 million.

What were the key findings?

1. The benefits of smoking cessation were noted in all age groups.  Those who quit between 25-34 years of age lived 10 years longer.  Those who quit between 35-44 years of age lived 9 years longer. Those who quit between 45-54 years of age lived 6 years longer. Those who quit between 55-64 years of age lived 4 years longer.

2. Smokers mortality worsened compared to the general population over a 50-year period. During the three time periods (1959-65, 1982-88, 2000-10), the mortality dropped by 50% in the overall study population.  However, female smokers mortality remained unchanged and male smokers experienced only a 24% reduction.

Specific hazard ratios (HR) for a large number of conditions are detailed in these studies.  For example, among men, the HR for death due to lung cancer was 24.97 in the contemporary cohort.  Due to the nature of these large cohorts, there are many limitations and it is difficult to draw conclusions about a specific threshold in terms of amount of smoking.  However, the conclusions may actually underestimate the effects of smoking due to undersampling of certain high risk populations, like incarcerated persons and those with mental illness.

The editorial notes that more women die from lung cancer than breast cancer.  Yet, due to smoking’s stigma, there are no ‘race for the cure’ promotions.  In addition, increasingly smoking is a behavior concentrated in persons of lower social status.  As such, it “risks becoming invisible to those who set health policies and research priorities.”

Even Nick Naylor might consider a career change if he read these studies (Thank You for Smoking (film) – Wikipedia, the free encyclopedia).