New study could change society

Chuchote

A huge study of a quarter of a million people over five years has revealed that cycling has an unprecedented effect on chances of getting and surviving cancer and heart disease.

The study of UK commuters, published in the British Medical Journal, is as important as the two studies - by the US surgeon-general and British doctors Doll and Hill - that finally proved beyond question that smoking was a major factor in these two modern killers, cancer and cardiovascular disease.

If European governments are sensible, they will immediately begin building infrastructure to allow the mass of the population to cycle rather than driving for all short journeys.

The BBC report on the study is here: http://www.bbc.com/news/health-39641122

during the course of the study, regular cycling cut the risk of death from any cause by 41%, the incidence of cancer by 45% and heart disease by 46%.
The cyclists clocked an average of 30 miles per week, but the further they cycled the greater the health boon.

"What we really need to do is change our infrastructure to make it easier to cycle - we need bike lanes, to make it easier to put bikes on trains, showers at work."

Surprisingly, cycling was far more effective than walking; in fact, its figures show that while people walking to work have a lower chance of contracting cancer, those who walk are more likely to die of cancer if they do contract it - while cycling as little as 30 miles a week (say 10km a day on work days, or 20 minutes to work and 20 back) has a startling protective effect.

Mrs OBumble

How did they prove causation rather than just correlation? Surely this is needed before the result can be extrapolated onto the whole population?

echo beach

Mrs OBumble wrote: »

How did they prove causation rather than just correlation? Surely this is needed before the result can be extrapolated onto the whole population?

They didn't prove causation and I don't think there is is any practical way to do so.
NHS choices has a section called Behind the Headlines which is excellent for getting more background on news stories related to health and assessing their merits. http://www.nhs.uk/news/2017/04April/Pages/Cycling-commuters-have-lower-rates-of-heart-disease-and-cancer.aspx

In this case they point out that it is a weakness of this type of research that it cannot prove causation

This type of study is useful for looking at data collected over a long period of time, but an inherent weakness of this study design is that it can only highlight possible associations, and not prove cause and effects

But it also has a lot of strengths

This observational evidence adds to other studies to confirm the benefits of physical activity and active commuting in reducing the risk of these conditions.
The main strength of the study is that it made use of real world data on lifestyle and health outcomes. It also adjusted for a wide range of other factors that might affect the risk of cardiovascular disease or certain types of cancer.
As it is often difficult to fit exercise into our daily routine, commuting by foot or bike could be a useful way of achieving recommended levels of physical activity.

If the evidence will be enough to persuade governments to pay more than lip-service to promoting more active lifestyles is another matter.

Chuchote

You could prove causation easily enough: look at the countries where cycling has been the practice for the vast majority of the population for 50 years and consider their health.

Cycling tends to make you eat more healthily too, but that's an extra added benefit rather than a slur on the causation.

echo beach

Chuchote wrote: »

You could prove causation easily enough: look at the countries where cycling has been the practice for the vast majority of the population for 50 years and consider their health.

That, like the observational study quoted, could give you a good clue but doesn't prove causation. There could be genetic or climate differences that explain differences.
Proving causation would require two groups. Randomly assign one to cycle daily and the other never allowed to get on a bike, but otherwise they live identical lives. Then follow up for decades. Not so easy.

Chuchote

echo beach wrote: »

That, like the observational study quoted, could give you a good clue but doesn't prove causation. There could be genetic or climate differences that explain differences.
Proving causation would require two groups. Randomly assign one to cycle daily and the other never allowed to get on a bike, but otherwise they live identical lives. Then follow up for decades. Not so easy.

Well, in effect, this is what the Scottish study did! They studied all commuters, and found that the cyclists performed way better in the most deadly health concerns!

The causation/correlation thing is generally pulled out only when people don't want something to be true, I suspect; for instance you might say "Mediterranean diet? Phooey! It's just because it's warm there! It's their genes! It's the Mediterranean Mammy factor!" but people deldom do.

tracey turnblad

I'd love to cycle to and from work. I wouldn't even have to own a bike. There's a Dublin bike station across the road from where I live and across the road from my job. But... I would not cycle down the quays... its mental and I'm a scardy cat

Chuchote

tracey turnblad wrote: »

I'd love to cycle to and from work. I wouldn't even have to own a bike. There's a Dublin bike station across the road from where I live and across the road from my job. But... I would not cycle down the quays... its mental and I'm a scardy cat

That's why the plan for a cycleway along the busiest 900 metres of the north quays needs to be supported - it will make it safe for many people t cycle who otherwise wouldn't.

There's opposition to this plan, mainly led by owners of profitable car parks. It will radically change the Liffeyside if it happens, in a good way.

Where's your route, roughly, tracey turnblad? (PM me if you want.) It's often possible to plan a route that cuts out the quays, for now.

Mrs OBumble

Chuchote wrote: »

Well, in effect, this is what the Scottish study did! They studied all commuters, and found that the cyclists performed way better in the most deadly health concerns!

The causation/correlation thing is generally pulled out only when people don't want something to be true, I suspect; for instance you might say "Mediterranean diet? Phooey! It's just because it's warm there! It's their genes! It's the Mediterranean Mammy factor!" but people deldom do.

No.

People who are able for cycling are likely to healthier / less disabled to start with - even if they don't cycle.

If you randomly assigned people to cycle or not it would likely make cycling look worse due to the injuries to people like me with poor balance and co-ordination.

Chuchote

Mrs OBumble wrote: »

No.

People who are able for cycling are likely to healthier / less disabled to start with - even if they don't cycle.

If you randomly assigned people to cycle or not it would likely make cycling look worse due to the injuries to people like me with poor balance and co-ordination.

If you're in normal health - within the normal range, not superfit - you can cycle. That's why your gran in Ballydehob and your auntie in Finglas cycled back and forth to the shops every day in the 1950s.

I'm asthmatic. I cycle. Not a big effort! Cycling is easier than walking.

echo beach

Chuchote wrote: »

Well, in effect, this is what the Scottish study did! They studied all commuters, and found that the cyclists performed way better in the most deadly health concerns!

The causation/correlation thing is generally pulled out only when people don't want something to be true, I suspect; for instance you might say "Mediterranean diet? Phooey! It's just because it's warm there! It's their genes! It's the Mediterranean Mammy factor!" but people deldom do.

The study didn't do that and didn't claim to do that. It was a study of commuters so doesn't include all those who don't work or who work from home or who for some other reason don't have a regular commute. It did correct for other possible factors but couldn't consider everything that might explain the difference.

I have do idea if the causation/correlation thing is generally pulled out when people don't want something to be true. Perhaps you have some evidence I'm not aware of. All I do know is that I personally didn't bring it up for that reason. I fully support active commuting. I walk to work. It isn't really far enough to be worth cycling but if it was a longer commute I would. I advise others to walk or cycle to work or school and have already used this study to encourage them to do so. I think it is a valuable piece of work but recognise that it isn't definitive proof, something that is seldom found when dealing with health and complex human behaviour.

Arbie

Chuchote wrote: »

The causation/correlation thing is generally pulled out only when people don't want something to be true...

I don't know what you are basing that assertion on. You could just as easily claim that if someone wants something to be true then they can state that correlation = causation, which is definitively not the case

This was a prospective cohort study, which is considered at best moderate quality methodology. It's useful, but only in the context of other studies. The media coverage is overblown.

I say all that as a cyclist and an XKCD fan: https://xkcd.com/552/

Icemancometh

Here's several examples of interesting correlations. I didn't think the age of Miss America would affect the numbers of people murdered with steam, but they're correlated, so I guess it does.

So people who cycle to work are healthier (much healthier!) than people who don't. Does this study tell us anything new?

Alun

Icemancometh wrote: »

So people who cycle to work are healthier (much healthier!) than people who don't.

Or alternatively, people who are otherwise healthy and live a healthy lifestyle are more likely to cycle to work than those who don't.