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Breaking Down the Study on NFL Life Expectancy

Mike Freeman of CBS Sports obtained a copy of an e-mail that was sent to retired players who played before 1993, and it contained reference to a recent study by the National Institute of Occupational Health and Safety that found NFL players are living longer than the general population.

The timing of this release is not coincidental, in the wake of the Junior Seau suicide last week and discussion about whether the game is safe, or even the discussion last night between Buzz Bissinger, Malcolm Gladwell, Jason Whitlock and Tim Green about whether college football should be banned. [UPDATE: According to the NFL, the summary release was sent by mail last week to the retired players directly from the NIOSH, and the NFL had no input in the timing of the release.]

Well, I like to go to the source, so I searched and found the actual study that was the basis for the NFL’s e-mail. It’s titled “Body Mass Index, Playing Position, Race, and the Cardiovascular Mortality of Retired Professional Football Players” in the American Journal of Cardiology. It was released online in January, and was in the March print edition.

Here are some basic parameters of the study. They used all players (subject to a few exclusions when they couldn’t confirm things like race) who played 5+ seasons between 1959 and 1988. Thus, the youngest players would have started in 1984, and the oldest began playing in 1950. The median player in the study was born in 1950. The data collection for the study closed on December 31, 2007, so events that happened after that date are not included. They began tracking a player for mortality rate purposes after he completed his fifth season, and continued until either death or the end of the study period. They compared mortality rates for various categories at each age.

The study found that NFL players during this period lived longer than the average male. 3,439 players were included in the study, and 334 were deceased by the end of 2007. Based on racial distribution, age, and calendar year, the expected number of deaths for a male population of that size was 625.

Now, there are reasons for this, and if you look at the specifics in Table 2 of the study, you can see this. The study also directly says that it is likely because NFL players smoked cigarettes far less frequently than the public at large during this time period and were in better shape. The former NFL players died of cancer at a much lower rate, particularly with lung cancer (16 actual vs. 52 expected). The former players were also far less likely to die of other diseases, such as tuberculosis and immunodeficiency diseases (4 actual vs. 29 expected), diabetes (7 vs. 17), mental and personality disorders (4 vs. 12), other respiratory diseases (6 vs. 32), and digestive diseases (9 vs. 34).

The NFL players as a group were also less likely to die of coronary diseases, with one exception: cardiomyopathy. I suspect that the reason that the NFL did not release this when it came out was because it appeared in the American Journal of Cardiology and discussed the increase in risk of cardiac issues depending on Body Mass Index, whereas the timing now, if it is couched in terms of overall mortality, is better for the league.

In conclusion, National Football League players from the 1959 through 1988 seasons had decreased overall mortality but those with a playing-time BMI ≥30 kg/m2 had 2 times the risk of CVD mortality compared to other players and African-American players and defensive linemen had higher CVD mortality compared to other players even after adjusting for playing-time BMI.

Now, remember, this study included mostly players from an earlier era, and we were just starting to see size increases. Only 1% of the players in this study had a BMI of 35.0 or greater, and 33% were between 30 and 35. Last year, just taking the Super Bowl champs as an example had 5 starters (23%) with a BMI greater than 35. In the modern NFL, most linemen, except for speed rushers, are going to have a BMI greater than 35, and a decent number of running backs, fullbacks, tight ends, linebackers, and all remaining defensive ends will be above 30.

As another example, the 1973 Bears (the median year in the study) had a defensive line with an average BMI of 30.2. The 2003 Bears defensive line was at 37.4, while the linebackers were also bigger, 31.2, as was the starting running back, Thomas Jones (31.6).

Now, what we don’t know, and can argue, is whether BMI is correctly measuring the risk today. Most players with a BMI in the 30-35 range in the modern NFL are in great shape and would not be considered obese, as a lot is muscle weight. While the average NFL player who debuted by 1984 was living longer than their peers, the subset that saw the increase in cardiac issues (30+ BMI) has grown dramatically in size over the last few generations.

As for the suicide issue, this study has very little to do with today. It is encouraging that the number of suicides for this group was lower than the expected (9 vs. 22). However, Andre Waters and Terry Long would have been included, as they both debuted in 1984, the final year of the study, and died before the study ended. Duerson, who debuted in 1983, would not, nor would others that have happened since 2007 or involving players that debuted after 1984. Basically, based on the data, there have been as many suicides of players who debuted since 1982 as those that occurred before, despite the vast difference in risk-years because players debuting after 1982 would be younger than 52.

I say it’s encouraging though, because it might show that however football was being played previously, before the dramatic size increases, increases in passing (and thus opportunities for collisions on passing plays), there were not suicide issues, and that those who played football generally lived longer than their peers. Ultimately, this study shows that former players are healthier than the general public and did not engage in risk activities that increased death rates, particularly cigarette smoking, but the fact that the heavier players were dying at a higher rate could be a concern going forward, since a BMI of 30 or more is far more typical these days.

[photo via US Presswire]

 

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