By far the most commonly studied health outcome involving data from the MLB is mortality. The first analysis of MLB mortality was published in 1975 in the Statistical Bulletin of the Metropolitan Life Insurance Company.(1) This study, which was conducted in the days before personal computers, drew upon the vital status of over 10,000 baseball players from the 1974 Baseball Encyclopedia. Using these data, the authors calculated standardized mortality ratios (SMRs) using US general population mortality rates as a baseline. In comparison to the US general population, players whose careers began between 1876 and 1900 experienced only 97% of the expected mortality, those who debuted between 1901 and 1930 experienced only 64% of the expected, and those who debuted between 1931 and 1973 experienced only 55% of the expected deaths. As early as the 1930s, Major League baseball players were exhibiting the healthy worker effect and/or the health benefits of the rigorous fitness regimen of professional athlete.
A much more detailed analysis was conducted in 1988 by Waterbor et al. and published in the New England Journal of Medicine.(2) This study followed 958 players who debuted between January 1, 1925 and December 31, 1984. The authors obtained death certificates on the decedents and coded the deaths using the ICD-9 system. All-cause mortality was significantly reduced for the cohort as a whole (SMR=94%). On a cause-specific basis, deaths due to several chronic diseases were insignificantly underrepresented, while deaths due to arteriosclerotic heart disease and cancer were insignificantly overrepresented among MLB players. Stratifying the analysis by player position, infielders were found to have the lowest SMR, and catchers had the highest; mortality rates for other positions were not statistically different from those of the general population. Longevity was also correlated with in-game achievements (e.g., runs per game, number of at-bats, and runs batted in per game) and weight-to-height ratio.
A group of researchers from the University of Houston and the University of Texas Health Science Center at Houston published a paper on life expectancy in MLB in 2008.(3)The researchers found that MLB players had a life expectancy anywhere from 4 to 6 years greater than that of the general population of US males at ages up to 50, and 1 or 2 years greater life expectancy at ages over 50.
Other analyses of MLB mortality have focused on the effect of sinistrality (aka “lefthandness”),(4-7) the effect of education,(8) and the so-called "healthy worker effect".(9)
Baseball data are naturally useful for other purposes as well. MLB data have been used extensively in economics research, sports medicine, political science and of course, in analyses about the best way to play and win the game of baseball. Major League Baseball offers a growing dataset rich in information spanning a number of scientific disciplines.
- Longevity of Major League Baseball players. Stat Bull Metropol Life Insur Co. 1975 Apr;56:2-4.
- Waterbor J, Cole P, Delzell E, Andjelkovich D. The mortality experience of major-league baseball players. N Engl J Med. 1988 May 12;318(19):1278-80.
- Saint Onge JM, Rogers RG, Krueger PM. Major League Baseball players' life expectancies. Soc Sci Q. 2008 Jul 17;89(3):817-830.
- Abel EL, Kruger ML. Left-handed Major-League Baseball players and longevity re-examined. Percept Mot Skills. 2004 Dec;99(3 Pt 1):990-2.
- Coren S, Halpern DF. A replay of the baseball data. Percept Mot Skills. 1993 Apr;76(2):403-6.
- Fudin R, Renninger L, Lembessis E, Hirshon J. Sinistrality and reduced longevity: Reichler's 1979 data on baseball players do not indicate a relationship. Percept Mot Skills. 1993 Feb;76(1):171-82.
- Hicks RA, Johnson C, Cuevas T, Deharo D, Bautista J. Do right-handers live longer? An updated assessment of baseball player data. Percept Mot Skills. 1994 Jun;78(3 Pt 2):1243-7.
- Kalist DE, Peng Y. Does education matter? Major League Baseball players and longevity. Death Stud. 2007 Aug;31(7):653-70.
- Abel EL, Kruger ML. The healthy worker effect in Major League Baseball revisited. Res Sports Med. 2006 Jan-Mar;14(1):83-7.