Height and ethnicity are associated with mortality, according to a study on risk factors in NBA players

African-American former NBA players and those who are tallest generally die before shorter and white ex-players, according to the conclusions of a study conducted by Spanish researchers and published in Applied Sciences on 1 February. Nevertheless, the study also found that the annual mortality rate among former NBA players is lower than among the general population of the United States.
 
The study, one of the largest to be undertaken in terms of the sample, examines a total of 3,985 players who played in the American professional basketball league between its inception in 1946 and April 2015. 481 of them are still playing professionally. 687 of the total (19.1%) had died before 15 April 2015. The research uses statistical models to analyse their survival, and considers various control variables related to the players' physiological, demographic and competition characteristics.
 
The study was led by José A. Martínez, of the Department of Business Economics of the Technical University of Cartagena; and Martí Casals, of the Physical Activity and Sports Studies Centre (CEEAF) of the University of Vic - Central University of Catalonia (UVic-UCC) and the Department of Sports Sciences of FC Barcelona - Barça Innovation Hub. Other participants were Klaus Langohr, of the Department of Statistics and Operations Research at the Polytechnic University of Catalonia - Barcelona Tech (UPC) and the UPC’s Research Group in Biostatistics and Bioinformatics (GRBIO); and the data journalist Julián Felipo, of the basketball section at the sports newspaper El Mundo Deportivo. The multidisciplinary team has experience "not only in the area of basketball but also in the field of epidemiology, statistics, data journalism and science in general," say the authors.
 
Premature deaths of retired players
In recent years, associations of players and former players, as well as the the media, have expressed their concern over the premature death of former NBA players. One of the most srtiking examples was the death of several former players, all aged under 60, between February and September 2015: Moses Malone (aged 60), Darryl Dawkins (58), Jerome Kersey (52), Jack Haley (51), Christian Welp (50) and Anthony Mason (48). " I tell my wife all the time, 'You don't see many 7-footers walking around at the age of 75," said Larry Bird, a champion with the Boston Celtics, in a report by Jackie MacMullan on the ESPN sports portal that includes the study. In the same article, another legendary center, Bill Walton, added that "we athletes are our own worst enemies, because we don't listen to our bodies, we don't listen to our doctors and we don't realise until later in life that health is everything ".
 
"This made a lot of people think about whether playing basketball professionally could be a risk factor for health," explained José A. Martínez and Martí Casals. In fact, the NBA and the players' association reacted in 2016 by creating a plan to carry out check-ups on retired players. Since 2013, a study has analysed the structure and cardiac functions of 526 players who were members of professional teams. Previously, the league already conducted a mortality study that covered a total of 2,810 players in the NBA's 50th anniversary year in 1996.
 
Tallest players and African-Americans die earlier
After analysing the 3,985 players who played in the NBA between its inception in 1946 and April 2015, the results of this study suggest that height and ethnicity are associated with mortality. The tallest players and African-Americans generally die earlier than shorter and white players. At the same time, "we have empirically shown that the annual mortality rate is generally lower among these former players than in the general population," say Martinez and Casals
 
Among the factors that could account for these differences, and particularly for African-American players, the study suggests the impact of the "healthy worker effect", or in other words, "the tendency among the active and employed population to present more favourable mortality rates than the general population," the researchers explained. It also points to the hypothesis of the salary gap as a factor that could account for the differences in mortality.
 
The conclusions of the study may be useful for designing strategies for health plans and in the criteria for allocating funds related to healthcare policies. In the case of height, "a clearly identified risk factor," the study "can help to implement specific prevention and monitoring measures." As for ethnicity, the results "can help to clarify whether in addition to socio-economic factors, there is some kind of cause related to the morphology of the heart, as some research has already previously suggested," according to Martínez and Casals. It also provides estimates of players' life expectancy, based on their height and ethnicity, taking into account the year of their debut in the NBA.
 
The data on height and ethnicity, which were crucial in the final result, were obtained from multiple sources with a validation process that involved a double manual and independent coding process by the research team. The study has been published respecting the codes of 'Open Science' to provide open public access, based on criteria of transparency and permitting the data to be reproduced, and is linked to a previous study on lung thromboembolism carried out by Martínez and Casals and to an article by Julián Felipo about whether playing as a center could be a high-risk profession in the NBA.