Misguided doctors or marketing agents?


In the 1980′s, Bell, a helmet manufacturer, was keen to expand the market for bicycle helmets, its most profitable product. It approached the Snell foundation and offered funding for research on bicycle helmets. The Snell foundation chose avid helmet lobbyists to conduct this “research”.

The helmet lobbyists initial “research” claimed that helmets reduce 85% of head injuries. This claim is impossible due to inherent limitations of helmets. The authors had to re-work their data, and withdrew their claim.

The Snell foundation has kept funding these researchers. Boosted by the “research”, the market for bicycle helmets expanded. At $100 for a piece of polystyrene, the profits are huge. Helmets manufacturers have reinvested their profits into lobbying for helmet legislation. They sent executives all the way to Australia to lobby for a helmet law.

In 2013, the US government dropped its claim that helmets reduce 85% of head injuries. It first made the claim based on the research mentioned above, but then admitted that there was no credible basis for the claim.


The misleading “research”

A 1989 study on bicycle helmets claimed:

“we found that riders with helmets had an 85 percent reduction in their risk of head injury”

How can helmets reduce 85% of head injuries considering they don’t cover the face where 70% of head injuries are?

Injuries to the skull (the part of the body a helmet covers) constitute 10% of cycling injuries,
or 30% of what is usually classified as head injuries (including face injuries).

How did they arrive at such impossible claims?
They compared a helmeted group who rode supervised in parks with an un-helmeted group who rode unsupervised on busy roads. The difference between the two groups was attributed to helmets. They failed to consider confounding factors, a common error in statistics.

The study compared helmeted cyclists in bicycle paths with un-helmeted cyclists on roads. It attributed the difference to helmets.

This flawed study was widely criticized. It failed to select a representative control group. It misused the odds-ratio. It lacked serious injuries. It failed to adjust the results by age group.

As summarised in this review:

“The study compares groups of cyclists who chose to wear helmets with those who did not. Many variables, such as the reasons for wearing a helmet and attitudes to risk, were not controlled for by the researchers and may have influenced the results.”

The 85% figure is meaningless. It does not correspond to physical protection provided by helmets. It is the authors own generous estimate misrepresented as the result of their “study”. Many researchers have tried to replicate its results, but have been unable to do so. The authors had to re-work their data, and withdrew the claim.

The data from the study indicates that helmet wearers were 7 times more likely to have accidents. The study ignored this.

Instead of claiming
“Helmets protect x% of head injuries”
A more objective assessment would be:
“Helmets appear to protect against some head injuries. However, they are also associated with more accidents.  It is not clear whether there is a net safety benefit.”

This study was influential. Few questioned it, as they were eager to believe its claims. Despite the authors withdrawing the claim, it is still quoted as if it was true.

This research became a model for further “research” replicating its flaws and bias. Such research tends to jump to a predetermined conclusion. Such studies exaggerate the protection provided by helmets while ignoring the increase in accidents. The sheer volume of this “research” has misled the medical community.

The vested interests behind this “research”

In 1956, a racing driver called Peter Snell died from head injuries despite wearing a Bell helmet. His death to the creation of the Snell foundation. Since, Bell has developed a close relationship with the Snell foundation.

In the 1970′s, Bell introduced polystyrene bicycle helmets. They were not adopted by mainstream cyclists. In the 1980′s, Bell started to market bicycle helmets more aggressively. They became the most profitable range of helmets. In the mid 1980′s, Bell suggested that the Snell foundation should commission research into bicycle helmets, and provided funding to do so.

Snell chose 3 researchers to do the study, including Dr. Frederick Rivara. Dr. Rivara was a bicycle helmet advocate and an active helmet lobbyist. This was an odd choice. Helmet research conducted by helmet lobbyists was likely to be biased.

Snell requested that the study was

“done to demonstrate the effectiveness of bicycle helmets in reducing head injury”.

Note the assumption of effectiveness upfront instead of asking an open-ended question. The bias also came from the Snell foundation.

Using sponsored “research” to promote helmets and lobby for legislation

Bell used the commissioned study in its advertising:

Bell advertising, using the “study” it sponsored to claim that helmets prevent 85% of head injuries

Scaremongering is a key tactic. Parents are an easy target, scared into buy a product to protect their child from an exaggerated danger.

Bell then used this commissioned research to lobby governments to promote helmets. Lobbyists funded by Bell started to lobby for mandatory legislation. The commercial benefits of such legislation was clear to the helmet industry.

Bell funded organisations like SafeKids. This was shrewd, as it made it look like there was popular demand for helmet legislation. This lobbying resulted in mandatory helmet laws for children in various US jurisdictions.

A vice-president from Bell flew to Australia to attend EVERY mandatory helmet law hearing.

The market for helmets almost doubled between 1993 and 1995. This lead to record profits for Bell bicycle helmet division. In 1995, the bicycle helmet market was worth about $200 million dollars. Large profits could be re-invested into further lobbying and funding of “studies”.

Funding more research

The Snell Foundation has kept funding these researchers. In 1996, they published a study claiming:

“Bicycle helmets, regardless of type, provide substantial protection against head injuries for cyclists of all ages involved in crashes, including crashes involving motor vehicles.”

There was a failure to disclose conflicts of interests:

“This research was supported by a grant from the Snell Memorial Foundation, to which the principal bicycle helmet manufacturers are contributors.”

The study attracted much criticism. The authors again failed to consider confounding factors. They made more implausible claims.

Close analysis of their data indicates that:

“The data show that, apparently, the protective effect of a helmet increases with increasing severity of injury. It is extremely difficult to accept such a result, and indeed, it is the opposite of what is seen in population level studies, which return the more sensible outcome of declining protection with increasing severity of injury. It must be the case that confounding factors systematically caused non-helmeted cyclists to be in more severe crashes”

These implausible claims did not cause the “researchers” to question their assumptions. Such lack of scientific discipline is disturbing.

The implausible Cochrane review

In 1999, the same researchers published a “review” of helmet studies in the Cochrane review, that claims

“helmet dramatically reduces the risk of head and facial injuries for bicyclists involved in a crash, even if it involves a motor vehicle”

This claim ignores the limitations of helmets.  Polystyrene helmets are designed for minor impacts. They do not cover the face.

Brian Walker,  a helmet testing expert from helmet-testing lab Head Protection Evaluations, reports:

“Cycle helmets are designed for falls without any other vehicle involved …

The tests that cycle helmets currently go through mean that they should offer similar protection to a pedestrian who trips and falls to the ground …

In today’s road traffic accidents, it’s not unlikely for a cycle helmet to be subjected to severity loads greater than it is designed to cope with.”

The study misleading claims were rebutted by an independent researcher:

“It is concluded that the review takes no account of scientific knowledge of types and mechanisms of brain injury

This biased review attracted much criticism, including the following:

“The review is not independent. Four of the seven papers selected for inclusion were the work of the reviewers themselves 

Only case-control studies were considered for inclusion, … studies of this type are acknowledged to be prone to bias …

The paradox presented by the failure of other types of studies to show any benefit from large increases in helmet use is left unstated and unaccounted for

The authors are dismissive of the possibility of risk compensation. However, it has subsequently been demonstrated that child cyclists often ride more riskily and suffer more crashes when wearing a cycle helmet (Mok et al, 2004).

No consideration is given to rotational injuries, which dominate the most serious injuries. Helmets … may increase the risk and/or severity of rotational injury.(BHRF, 1039).

Claims are accepted of efficacy for which no plausible mechanism exists (e.g. the prevention of mid-face injuries), … and which would not be possible even if helmets prevented all head injuries (e.g. an increase of 35% in cyclists wearing helmets leading to 66% fewer head injuries).

There is misleading interpretation of ‘odds ratio’ … This exaggerates the predicted benefit of helmets and masks the fact that studies of this type are not truly predictive, being essentially the authors’ estimate … The reviewed paper showing the least benefit from helmets is omitted from computation of odds ratio, thus again exaggerating benefit.”

One of the study included reported a higher accident rate and higher neck injuries for helmeted cyclists. This was ignored in the summary.

The review claimed that cyclists would need to increase their risk-taking four-fold to overcome the protection of helmets. This claim was refuted by an independent researcher.

From research to lobbying

The helmet lobbyists used their “research” to peddle their beliefs. For example, this article entitled “Bicycle helmets: it’s time to use them” claims:

“Further delays in promoting the use of helmets will be measured in the number of lives ruined by the devastating consequences of preventable brain injury.”

This ignores that helmets can increase brain injury.


This “research” contradicts the limitations of polystyrene helmets. It ignores whole-population studies, where a large rise in helmet wearing did not show any benefit. Yet it has been influential.

Manufacturing an artificial perception has delivered profits to the helmet industry. With a piece of polystyrene selling for $100, the profits are huge. No wonder Bell sponsors racing cyclists. Let the profits roll.

 Bell advertising in the Tour de France 2011

Update July 2013

In June 2013, the US government dropped its claim that helmets reduce 85% of head injuries. It first made the claim based on the research mentioned above, but then admitted that there was no credible basis for the claim.

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