“Free bus passes are spreading good health among older people,” the Daily Mail reported today.
The story is based on research that found that older people who had a free bus pass were more likely to take part in what the researchers describe as “active travel”. The definition of active travel includes riding on a bus and activities such as walking and riding a bike. While not studied by the researchers, they did speculate that frequent active travel may have a positive effect on mood and mental health.
This study comes at a time when the government is reportedly considering scrapping free travel for pensioners or making it means tested. It is useful to consider the contribution free bus passes may make to levels of physical activity among older people.
Even a small amount of physical activity is known to reduce the risk of disability in older people. And, while the national free bus pass scheme is estimated to cost taxpayers around £1 billion a year, the annual health costs associated with disability and physical inactivity far outweigh that at an estimated £10.7 billion.
Where did the story come from?
The study was carried out by researchers from the Imperial College Faculty of Medicine, UK. It was funded by a number of public bodies, including the National Institute for Health Research.
The study was published in the peer-reviewed American Journal of Public Health.
The study was reported fairly. However, the Daily Mail’s claim that the benefits of bus passes include a lower risk of heart disease, falls and broken bones, is an extrapolation and not proven by this study.
What kind of research was this?
The study’s authors point out that with physical activity decreasing globally, there is increasing interest in promoting “incidental” physical activity. They define “incidental” physical activity as a byproduct of activity that has some other purpose, such as going to the shops or visiting a friend. Walking, cycling and use of public transport can all fall into this category.
Using public transport rather than private vehicles may raise physical activity levels and offer significant health benefits, they suggest.
The purpose of this cross-sectional study was to examine whether free bus travel was associated with increased use of “active” transport (such as buses, walking and cycling) and regular walking. It also aimed to look at whether different socio-economic groups benefitted equally from the bus pass scheme. The researchers speculated that people who were financially better off would prefer using private means of transport such as their own car or a taxi.
Because cross-sectional studies look at all data at the same time they cannot be used to see if one thing follows another, but are useful for showing up patterns or links in the data.
What did the research involve?
The researchers used an annual cross-sectional national travel survey of more than 15,000 private households in the UK, in which people are interviewed about their modes and frequency of travel and also asked to complete a one-week travel diary. The researchers extracted data from the survey for England for the years 2005 (the year before free bus passes were introduced in the UK) to 2008 (the most recently available data). They excluded from their study participants younger than 60 (who would not be eligible for a free bus pass) and residents of Scotland and Wales (because the timing of the introduction of free bus travel varied across countries).
People who were very frequent users of buses (more than 75 times a week) were also excluded as the researchers stated that such a pattern of behaviour would not be representative of most people with a bus pass and could distort the results (these types of statistical oddities are known as outliers).
Their total sample size was 16,911 people over the four-year study period. Participants were classified into those with a free bus pass (11,218) and those without (5,693).
Using the detailed one-week travel diaries that participants had kept during each year of the survey, researchers looked at:
- whether they used “active” or “non active” transport (“active” transport consisted of walking, cycling and using public transport; “non active” transport consisted of cars, motorcycles, taxis and private hire buses)
- how much bus travel they did
- whether they walked three or more times a week or fewer than three times a week (significant health benefits, they say, have been observed in older adults who do “normal” walking – on between three or five days a week)
- whether people owned or rented their homes (the researchers used this information as an indicator of socio-economic status)
They used statistical techniques to analyse the association between having a free bus pass and:
- use of active transport
- use of buses
- access to a car
- walking three or more times a week
They also analysed whether owning or renting a home made any difference to these outcomes.
What were the basic results?
The researchers found that having a free bus pass was significantly associated with:
- greater active travel among both disadvantaged (adjusted odds ratio [AOR] 4.06, 95% confidence interval [CI] 3.35 to 4.86) and advantaged groups (AOR 4.72, 95% CI 3.99 to 5.59)
- greater bus use in both disadvantaged and advantaged groups (AOR 7.03, 95% CI 5.53 to 8.94 and AOR 7.11, 95% CI 5.65 to 8.94, respectively)
- greater likelihood of walking more frequently (AOR 1.15, 95% CI 1.07 to 1.12)
How did the researchers interpret the results?
The researchers point out that public subsidies enabling free bus travel for older people “may confer significant health benefits through increased incidental physical activity”. While the cost of providing free bus travel is “considerable”, they argue that it may offer value for money since promoting physical activity among older people may help to reduce inactivity-related illness.
This was a large study based on comprehensive, detailed data gathered about the travel patterns of adults of 60 and over in England. However, it has some limitations that may affect the reliability of its results. In particular, the analysis was based on cross-sectional surveys, which can only provide a “snapshot” of people’s lives at one point in time and cannot show cause and effect. It is possible, for example, that people who use public transport or walk more frequently are more likely to obtain a bus pass. This is called reverse causality.
The authors also point out that:
- The survey’s response rate was 60%. Previous studies have found that certain groups of people, such as men, people with long-term health conditions and people with low levels of education are less likely to respond to surveys. This may have influenced the results.
- The study relied on people self-reporting their modes of travel, which is a limitation, although the use of travel diaries may have helped to minimise inaccuracy.
- Type of housing may not accurately reflect socio-economic status – for example many people have relatively high levels of assets but choose to rent for personal reasons.
At a time when the government is considering means testing eligibility for free bus travel or scrapping it completely, information about its potential association with more physical activity is useful.
Analysis by Bazian
Edited by NHS Website
Links to the headlines
BBC News, 21 September 2012
Daily Telegraph, 20 September 2012
Daily Mail, 21 September 2012
Links to the science
American Journal of Public Health. Published online September 20 2012