There is, at present, no cure for the killer nerve disorder (motor neurone disease) that has claimed the lives of Joost van der Westhuizen, Tinus Linee and other sports people.
There is also no concrete proof that sporting activity is a contributing factor to a person contracting the disease.
According to Dr Franclo Henning, specialist neurologist at the University of Stellenbosch’s division of neurology, theories that motor neurone disease (MND) is more prevalent among sports people have not been conclusively proven, “although there are such suggestions from studies of soccer players and NFL players”.
“Although there are a lot of theoretical risk factors associated with sports, like recurrent head injuries, pesticides on the fields, etc, none of these have been shown to carry a significant risk in population-based studies,” said Henning.
MND, also known as ALS (amyotrophic lateral sclerosis) or Lou Gehrig’s disease (after the New York Yankees baseballer who died of it in 1941), is a group of disorders that affect the motor neurons (nerves that stimulate muscle function as opposed to sensory or “sensation” nerves).
The condition is degenerative, progressive and incurable. It affects limb muscles, swallowing, speech and breathing, in any order.
Average survival from onset is 2-4 years; only 10-20% of cases start before 45 years of age, and it is slightly more common in men.
Other ALS sufferers were American professional golfer Jeff Julian and Tom Watson’s caddie, Bruce Edwards, while New Orleans Saints footballer Steve Gleason, who was diagnosed with ALS at about the same time as Joost, is still holding on to life.
Henning added: “Large population-based studies have shown that exercise and sport are not associated with an increased risk of ALS, and neither is head injury.
“Although this is still only a theory, it is quite possible that people with above-average/elite athletic capabilities are at increased risk of developing ALS.
"In other words, athleticism and a nervous system vulnerable to early degeneration may 'cluster' together because of a specific genetic make-up.
“However, it has to be emphasised that this is nothing more than a theory, and that it will be very hard to prove because MND is a rare disease, and a very small group of individuals can be regarded as elite athletes,” said Henning.
Joost van der Westhuizen himself revealed the theory about contaminants on sports fields in a 2011 interview after an American specialist, Cleveland-based Dr Erik Pioro, had confirmed he was suffering from MND.
“Dr Pioro asked me whether I had been exposed to fertilisers? I remembered having spent some time on farms as a child, but then it struck me: from the age of five I played rugby, and what did I do? I passed the ball, and what did I do before feeding a scrum or passing? I licked my fingers.
“Dr Pioro told me there’s a soccer team in Italy in which six out of 11 players contracted ALS. On American football fields poison was discovered in the paint used to mark the fields. They’re focusing on fertiliser on sports fields being a contributor to coming down with ALS, as there is also an unusually high incidence of it among American farmers,” said Van der Westhuizen as he started his long but futile battle against MND.
Sports physician Dr Jon Patricios, founder of Sport Concussion SA and a member of World Rugby’s advisory panel on concussion, said that “vigorous physical exercise itself has been proposed as a risk factor”.
“Other proposed risks include recurrent head trauma, performance-enhancing drugs and environmental toxins such as fertilisers and pesticides.
"Scientific literature thus far is conflicting: there are papers that argue the case both for and against a link between collision sport and MND.
“Moreover, retrospective studies are often biased by poor recall. Larger prospective studies comparing the incidence in sportsmen and the general population are required.
“I suspect that there may be a link in those in whom a 'perfect storm’ of genetic predisposition is triggered by recurrent trauma, intensive exercise and environmental factors,” said Patricios.
Apart from Van der Westhuizen and Linee, there have been three other reported cases of rugby players contracting MND: Ryan Walker of the Sharks, John van Dyk of WP and the former Zimbabwean Danny Delport, who now lives in Perth. Interestingly, all are backline players.
Identifying the cause of MND is complex, says Henning. “We know that between 5 and 10% of cases are due to a mutation in one of a number of genes that been been identified.
"Most researchers believe that, in the rest, the condition is caused by a combination of a genetic predisposition and some (so far unidentified) environmental/lifestyle trigger.
“In other words,” said Henning, “for most people both these need to be present to develop the condition.”
Henning says the search for a cure is constant. “Although this is not necessarily visible to the public or even health care professionals, every minor discovery in genetics, epidemiology, etc, brings us closer to a cure.
“Keep in mind that to find an effective treatment, we need to understand how the disease starts and progresses, which people are at higher or lower risk, etc. Therefore, whenever research is being done, we are getting closer to an effective treatment.”
Patricios stressed the value of physical activity. “These stories (about the ravages of MND) understandably focus on the negative, but the physical and social beneficial effects of sport far outweigh the potential negatives.”