Thursday, December 8, 2016

Smoking Cessation

Intuitively the numbers didn't make sense. Interesting statistics were shown in a workshop today regarding smoking/tobacco use. In 1999, the US average was 23.3%. In 2014, it's down to 17.3%. Positive trend! Younger people have a higher rate of smoking than older people. (I think that's been true for decades now.) Teenage brains are believed to be more susceptible to addictive behaviors. When you add the information that 44% of smokers try to quit but only 6% of them succeed, you wouldn't think the attrition rate would be very high. Thus, you would expect the smoking prevalence to increase over the last 15 years. Or remain the same.

Smoking prevalence for 18-24 year-olds is 21.8%, about the national average in 1999. The 'inbound' population group would maintain the 20+% of the population. It drops for the 25-44 year olds slightly and in line with the cessation success rate. It seemed to me that either young adults are over-reporting their smoking habits or the success rate is higher than 6% in order for smoking to decrease 25% over 15 years.

To check my gut feel on this, I ran a simple spreadsheet simulation starting with the 23.3% in 1999. I plugged in 44% of those try to quit each year (not accounting for multiple attempts--it takes 8-9 attempts on average for a smoker to finally quit) and the 6% of those succeeding. In the first year, 0.6% of the overall population drops out of the Smokers category. Run that scenario for 15 years and the rate is 15.2% by the year 2014. Close but far enough from the reported 17.3% to question either the 44% attempting to quit and/or the 6% success rate. Or the 8-9 average attempts.

If it takes 8-9 attempts before succeeding at cessation, then the success rate would be closer to 5% than 6%. At 5% success, the projected smoking prevalence in 2014 would be 16.3%, closer to the reported number.

Either way, the 15 year overall trend is a lot lower than the 15 year demographic trend would indicate. Moving from the middle young adult category of 18-24 (21 years-old) to the middle of the next demographic category of 25-44 (35 years-old) is about 15 years. If the percentage attempting to quit (44%) and the success rate (5-6%) is correct, we'd expect the older demographic group to be in the 15-17% smoking prevalence range. They're not. They report at smoking rates near 20%! Very little drop from their younger selves.

It's another check on what the data seems to indicate. It's not all stacking up that smokers are attempting to quit at the reported rate nor succeeding at the reported rate. If smoking cessation is less successful than it used to be, we would over the next decade or so expect to see higher national prevalence for smokers.

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