Public health

Schemes that promote cycling seem to have limited benefit

October 21, 2010 1 Comment

City wide programmes that promote cycling – such as London’s new bike hire scheme – seem a great way to get the public active and tackle the obesity epidemic. But new research published in the BMJ suggests that interventions to promote cycling don’t have much discernible effect after all.

Public health programmes that specifically aimed to increase cycling in a population found increases the the proportion of trips made by bike or the number of bike trips per person of 3.4 percentage points at the most, whereas there was little evidence that cycling increased physical activity or reduces obesity population wide.

Adults in the UK are supposed to at least 150 minutes of moderate intensity physical activity or 75 minutes of vigorous physical activity a week, but few manage. Cycling can fit relatively easily people’s daily routines as a means of travel from place to place, so people might be more inclined to adopt and maintain this type of physical activity than something like running or swimming. Also, if people cycle rather than take the bus or get in their cars, they’re helping to reduce harmful traffic pollution – so cycling could help the environment as well as provide a double whammy of health benefits.

The authors of this paper looked at 25 controlled or “before and after” studies on the effect of various different cycle schemes, such as free bike programmes, building new cycle routes, and promoting cycling to families. The studies were from seven countries, including the UK and the US.

Six studies assessed programmes that specifically aimed to promote cycling, of which four – an intensive one-to-one scheme for obese women, improvements to a cycle route network, and two multifaceted cycle promotion initiatives at town or city level – were found to be associated with increases in cycling. For example, one study found that improving the connectivity of the cycle route network in the Dutch city of Delft increased the proportion of household trips made by bicycle from 40% to 43% over a three year period compared with a change from 38% to 39% over the same period in an area where no improvements had been made.

A further 16 studies evaluated individualised marketing of “environmentally friendly” modes of transport (walking, cycling, and public transport) via marketing and incentives such as free bus tickets. On average this approach increased the number of cycling trips each individual made by eight a year.

Three other studies examined the effects of efforts to change travel behaviour in general, such as car sharing schemes. Two of these trials found small increases in the proportion of trips made by bicycle or the frequency of cycle trips per person (+1.1 and +0.17 a week, respectively), whereas the third actually found a decrease in the proportion of bike trips of almost 12%.

Only two of the 25 studies assessed looked at the health benefits of schemes to promote cycling, one of which reported a small but positive shift in the amount of overall physical activity in the population studied.

Discussing their less that glowing findings, the authors write that “There is nevertheless a strong case for promoting cycling on health grounds,” pointing to evidence that at an individual level cycling to work or school has been shown to improve cardiorespiratory fitness and reduce mortality. “Promoting cycling is, therefore, a viable approach to improving health,” they conclude.
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Yang L et al. (2010) Interventions to promote cycling: systematic review. BMJ 341:c5293. DOI: 10.1136/bmj.c5293

Public health

Hosting big sports events might not benefit the local population

May 24, 2010 5 Comments

Hosting an international sporting event like the Olympic Games or the Commonwealth Games is an expensive business. The London 2012 Olympic and Paralympic Games, for example, will cost a total of £9.35bn, equivalent to £150 for every man, woman, and child in the United Kingdom.

Such costs are generally justified in terms of collateral benefits for the population of the host city, both during the event and for years after – the so called “legacy” of the event.

However, Researchers in Glasgow – host of the 2014 Commonwealth Games – have searched through the sparse published and unpublished research on the topic and found little overall evidence that major multi-sport events provide health or socioeconomic benefits for the population of the host city.

They looked for studies on the long term effects of major sports events held between between 1978 and 2008 and came across very few papers – only 54 poor quality studies.

Five studies looked at the benefits on the host population in terms of health; more specifically, rates of suicide, paediatric health service demand, presentations for asthma in children (two studies), and problems related to illicit drug use. Overall, the data did not show a clear cut negative or positive health impact of major multi-sport events.

Of the studies that looked at whether sports participation in the population was affected, one found a decrease in the Manchester after the 2002 Commonwealth Games, whereas another reported upward trend in sports participation from the early 1980s to 1994 in association with the 1992 Olympic Games in Barcelona, Spain.

More studies – 18 in total – looked at whether big sports events improved economic factors, which in turn might have a positive effect on the health of the population; for example, by giving people the cash flow to pay their dentist’s fees or make healthy eating choices. But again the overall effect was unclear. Most studies did associate big sports events with an increase in economic growth and employment, but the studies often used lots of estimated data and didn’t collect the data very long after the event, so are hardly water tight. The more robust studies weren’t any more conclusive when looked at collectively – inflation increased in Barcelona and Atlanta in the run up to hosting the Olympic Games, but not in Sydney.

“The available evidence does not refute expectations of a legacy, positive or negative, but it does establish that very little is known about the impacts of previous large multi-sport events and, therefore, the possible impacts of future events,” conclude the authors. “This contrasts with official documentation used recently to promote such events,” they add curtly.

However, we Brits may not be throwing money down the drain by financing the next Olympic Games. As the authors of this study acknowledge, the research on the legacy benefits of major multi-sports events is patchy to say the least, hence why they were unable to draw any clear positive or negative conclusion. The London 2012 Olympics will be the first for which long term health and socioeconomic impacts will be explicitly measured, so should hopefully clear up whether or not hosting these big events really does benefit the local population.

Editorialist Mike Weed isn’t so sure that this effort will give us the evidence we need though, as he feels the measures being used for the 2012 event are not detailed enough. “The risk for the UK population is not that we will not get the benefits we want for our £150 a head investment in London 2012, but that there will be no robust evidence of what we have paid for,” he says.

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McCartney G et al. (2010). The health and socioeconomic impacts of major multi-sport events: systematic review (1978-2008). BMJ 340. DOI: 10.1136/bmj.c2369

Public health

Hookah smokers more likely to use marijuana or other illicit drugs

May 17, 2010 No Comments

Young people who smoke tobacco through a water pipe – also known as a hookah, shisha, or goza – are more likely to use illicit drugs than their non-smoking contemporaries, according to a study of young Canadians. Most notably, hookah smokers were much more likely to smoke marijuana: 74% of water-pipe users reported marijuana use, compared with 35% of non-users.

A hookah or shisha comprises an upright device with a small platform where tobacco, often flavoured, is burned, a metal body, a base half-filled with water, and a tube with a mouthpiece for inhaling.

Smoking tobacco using water pipes is an old Arabic tradition that is becoming more popular in the Western world, with an estimated 40% of US college students and 38% of British university students having ever used a hookah.

The rise in popularity is thought to be linked to the perception that smoking tobacco through a water pipe is harmless. However, water pipe smoke may contain greater amounts of tar and heavy metals, such as lead, than cigarette smoke and has been linked to lung cancer, heart disease, and infectious diseases.

In this study, the authors posted questionnaires to 1,208 18-24 year olds who lived in the Montreal area of Canada, 878 (73%) of whom responded and 871 (72%) of whom were included in the analyses.

A total of 204 participants (23%) reported having smoked tobacco using a water pipe in the past year. Among these water-pipe users, 78% smoked water-pipes less than once per month, 19% smoked 1-3 times per month, and 3% smoked 1-6 times per week. None used a water pipe every day.

Individuals who had used a hookah were younger, more likely to be male and not living with their parents, and had a higher household income than those who hadn’t, leading the authors to suggest that “Water-pipe users may represent an advantaged group of young people with the leisure time, resources, and opportunity to use water-pipes.” So hookah smokers are nice middle class kids with too much time on their hands then?

Compared with people who hadn’t used a water pipe in the previous year, those who had were more likely to have also used cigarettes and other tobacco products like chewing tobacco or snus and to have used alcohol, including having up to five or more drinks on one occasion (i.e. to a binge drinking level). Interestingly, a third of water-pipe users had not smoked cigarettes in the past year, perhaps using a hookah as a perceived “healthier” alternative.

Water-pipe users were more likely to have used marijuana (74% vs 35%) or other illicit drugs like speed or cocaine (33% vs 11%) in the past year, suggesting perhaps that smoking tobacco through a water pipe may act as a “gateway” to using more harmful substances. Nevertheless, the authors point out that the design of their study means no cause and effect inferences can be drawn between using a hookah and illicit drug use.
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Dugas E et al. (2010) Water-Pipe Smoking Among North American Youths. Pediatrics DOI: 10.1542/peds.2009-2335

Public health, Sexual health

A healthy life leads to a healthy sex life

March 16, 2010 No Comments

Being in good or excellent health increases the quality and quantity of sex for middle aged and older people, according to a big study that delved into the sex lives of 6,000 American adults aged 25-85. Plus being fit can keep you sexually active into a ripe old age, unlike your unhealthy peers.

The study also had a whole raft of other expected findings, some rather expected (e.g. men are more interested in sex) and others maybe less so (such as more than a third of men aged 75-85 are sexually active, as are 17% of women the same age).

The cross sectional study, published in the BMJ, looked at two large American health surveys: the national survey of midlife development in the United States (MIDUS), which assessed in 1995-6 adults aged 25-74, and the national social life, health and aging project (NSHAP), which in 2005-06 looked at people aged 57-85.

Overall, men were more likely than women to be sexually active and be interested in sex. Between 69% and 87% of men of all ages reported being sexually active in the past six months, compared with 43% to 76% of women, and men were significantly more likely to report being interested in sex than were women (66% versus 53% among those aged aged 25-74 and 62% versus 21% in those aged 57-85). These gender differences increased with age and were greatest in people aged 75-85 years: 38.9% of men compared with 16.8% of women were sexually active.

On the other hand, overall, sexual satisfaction was similar in the two genders: among sexually active respondents, about two thirds of men and women reported a good quality sex life. These proportions also changed as women aged though, so that only half women aged 57-85 who were sexually active reported a good quality sex life compared with nearly three quarters of men.

A novel aspect of this study was the use of a new measure devised by the authors called “sexually active life expectancy” – that is, the average number of remaining years a person could expect to remain sexually active.

At the age of 30, men had a sexually active life expectancy of 34.7 years (i.e., to within 10 years of the average life expectancy of 74.8 years) and women had 30.7 years (to 20 years less than their life expectancy of 80.6 years). This means that men spend 78% of their lives sexually active, compared with 61% for women. At 55, these figures changed to 14.9 remaining years for men and 10.6 years for women.

For me the most interesting finding was the link between good health and good sex. Men aged 25-74 who were in very good or excellent health were more than twice as likely to be sexually active than their less healthy counterparts, whereas women of the same age were 60% more likely to be sexually active.

Of those people who were sexually active, men and women who were in very good or excellent health were 70% more likely to report having a good quality sex life than those who were in less good shape, and were 40-80% more likely to be interested in sex.

Good health also increased how long people would remain sexually active compared with people reporting fair or poor health: men in very good health at age 55 were projected to gain on average 5-7 years of life as sexually active, whereas women were projected to gain 3-6 years.

It seems like good health keeps people keeping on in more way than one…
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Lindau S & Gavrilova N (2010) Sex, health, and years of sexually active life gained due to good health: evidence from two US population based cross sectional surveys of ageing. BMJ 340 (mar09 2). DOI: 10.1136/bmj.c810

Cardiovascular medicine, Diet and nutrition, Public health

Reducing dietary salt by half a teaspoon could save 92,000 lives a year

February 5, 2010 1 Comment

A Californian population based study has found that if everyone in the US reduced their daily salt intake by 3 grams – half a teaspoon – the annual number of deaths could be slashed by up to 92,000. In addition, the number of new people who get cardiovascular disease each year could drop by up to 120,000 – that’s equivalent to the population of Cambridge!

In fact, cutting dietary salt intake by as little as 1 gram a day could reduce the number of deaths from any cause by 15,000 to 32,000 and the number of new cases of cardiovascular disease by 20,000 to 40,000.

US regulations recommend that people consume less than 5.8 g of salt a day, yet the average American man gets through almost double that – 10.4 g of salt daily. This is bad news – high salt intake is associated with an increased risk of stroke and cardiovascular disease.

In this study, published in the New England Journal of Medicine, the authors used computer modelling to simulate heart disease and stroke in US adults aged 35-84 years.

They found that a population wide reduction in dietary salt of 3 g per day could potentially reduce the annual number of cases of cardiovascular disease by 60,000 to 120,000, stroke by 32,000 to 66,000, and heart attack by 54,000 to 99,000. The annual number of deaths from any cause could be cut by by 44,000 to 92,000.

Even a modest reduction of 1 g of salt per day could cut the yearly rates of cardiovascular disease, stroke, and heart attack by at least 20,000, 18,000, and 11,000, respectively. “It was a surprise to see the magnitude of the impact on the population, given the small reductions in salt that we were modeling,” Kirsten Bibbins-Domingo, lead author of the study, told Science Daily.

The effects seemed greater in black people – a population with high rates of hypertension and cardiovascular disease – and women would benefit in particular from a reduction in stroke incidence. The number of events related to cardiovascular disease – such as heart attack – would drop in older adults, whereas young people would benefit from lower overall mortality rates.

The public health benefits of a drop in salt intake of 3 g a day would be equivalent to half of all smokers quitting or a 5% reduction in body fat among obese adults, and would save $10 billion to $24 billion a year in healthcare costs.

“Reducing dietary salt is one of those rare interventions that has a huge health benefit and actually saves large amounts of money,” said senior author Lee Goldman. “At a time when so much public debate has focused on the costs of health care for the sick, here is a simple remedy, already proven to be feasible in other countries.”

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Bibbins-Domingo K et al. (2010) Projected Effect of Dietary Salt Reductions on Future Cardiovascular Disease. New England Journal of Medicine DOI: 10.1056/NEJMoa0907355

Public health, Technology

A new way of visualising health data

May 20, 2009 No Comments

Are smokers more likely to be obese? Is stroke more common in people with hypertension? Are old people more likely to have diabetes than young people?

The prospect of trawling through the scientific literature to get the answers to these questions isn’t terribly appealing – reams of tables and risk ratios aren’t helpful if you just want the information at a glance. Technology and health care company GE have developed a new way to present complex epidemiology data in graphic form.

Taking a New Look at Health allows you to compare various demographics, risk factors and diseases in a random sample of 100,000 patient records from GE’s proprietary database. Once you’ve picked the two variables you want to look at, legions of tiny men shoot across the graphic and align to show what proportion of people with variable also have variable y.

In this example, I have looked at smoking and BMI to see whether smokers are more likely to be obese than are non-smokers:

smoking-vs-obesity

Given that the figures are presented as an image rather than a table of numbers, it’s much easier to get a handle on the proportions and what they really mean. I can now see at a glance that actually more non-smokers and ex-smokers than smokers are obese (28%, 29% and 27%, respectively); that is, smokers are less likely to be obese.

Here are a couple more examples:

Is stroke more common in people with hypertension?

hypertension-vs-stroke

As well as showing that people with hypertension are considerably more likely to experience a stroke than those without hypertension (5% vs 1%), this particular graphic also allows us to see roughly what the incidence of hypertension is in the GE sample – not huge judging by the slim column on the right hand side.

Are old people more likely to have diabetes than young people?

age-vs-diabetes

Yup, look how many little orange people there are in the 65-74 column and the 75+ column!

Why not have a play with the visualisation yourself? Is the link between heart disease and hypertension what you expect? And what was the male:female ratio in this sample anyway? If you like epidemiology you’ll probably have a lot of fun!

Cardiovascular medicine, Public health

Here it is, your heart

January 12, 2009 No Comments

The British Heart Foundation has launched a new advertising campaign that features an amazing real-time simulation of a beating heart.

The campaign confronts viewers with the perhaps gory but nevertheless fascinating reality of the most vital of vital organs, and challenges them to think about heart and circulatory disease – Britain’s biggest killer.

British Heart Foundation Director of Policy and Communications, Betty McBride, said, “We wanted to confront people with the reality of what a working heart looks like. This is a rare chance for people to see in incredible detail how it works. We expect people to react in lots of different ways – whether it’s amazed, squeamish or disturbed. It’s vital that we get people to take time to think about their heart health.”

The Virtual Heart Simulator was developed in a collaboration between specialists at The Heart Hospital in London and design agency Glassworks. The British Heart Foundation boasts that this fantastic video represents “the biggest technical advancement since Leonardo da Vinci sketched the heart 500 years ago.”

The campaign advertises the guidance and advice that the British Heart Foundation provides, not least through its Heart Helpline, where cardiac nurses and information officers are on hand 9am-10pm, seven days a week, to provide free confidential information on heart health issues.

The campaign website also features a helpful A-Z of the heart, which explains in plain english cardiology terms such as ‘supraventricular tachycardia’ and ‘cardiomyopathy’.

You can call the Heart Helpline on 0300 333 1 333, or alternatively peruse the British Heart Foundation website www.bhf.org.uk for stacks of information on heart health

Children, Diet and nutrition, Events, Public health

Government to tackle obesity with Change4Life campaign

January 2, 2009 2 Comments

I recently blogged about the alarming rates of obesity among children in England, with one in four 4-5 year old children and one in three 10-11 year olds in this country obese or overweight. The Foresight report, published in 2007, ominously predicts that by 2050 90% of British children will be overweight or obese.

The British Government has now responded to this issue by launching a huge campaign to persuade the population to switch to a healthier lifestyle. The Change4Life strategy will promote the message “eat well, move more, live longer” on TV, in the press, on billboards and online initially for 3 months, and will continue over 3 years. The initiative will be supported by £200m of advertising and marketing donated by food companies such as Tesco, Mars, Nestlé and Flora.

Dawn Primarolo, minister for public health, said today: “We are trying to create a lifestyle revolution on a grand scale. There are very serious health consequences with allowing dangerous quantities of fat to build up in our bodies. This is not just an ad campaign – we are calling it a lifestyle revolution – it is a long-running concerted effort to change behavior.”

The television campaign launches on Saturday 3rd January with adverts designed by Aardman Animations, the people behind the much loved plasticine duo Wallace and Gromit. The engaging clip is designed to warn viewers of the health risks associated with being overweight and is targeted at helping young families change their lifestyle for good.

Change4Life is the biggest Government campaign ever launched and is expected to follow in the success of similar cross-media anti-smoking initiatives. Unlike anti-smoking public awareness strategies though, this campaign steers away from shock tactics and instead offers practical advice.

Critics have been quick to point out that the involvement of food companies in the campaign is a way for such corporations to cast their brand in a healthy light without actually changing the salt or fat content of their food. Tam Fry of the National Obesity Forum warned that junk food companies were donating millions to the campaign as a way of heading off the “regulation they fear”.

The Telegraph notes that “neither the leaflets nor the screen advertisements use the word obesity”, preferring instead to state that children could grow up to have “dangerous levels of fat in their body”. The campaign is designed to avoid pointing the finger at any one group, however, specifically avoiding talking about ‘fat bodies’ and blaming modern life rather than parents.

Let’s hope that the more kindly, blame-free approach of Change4Life gets the people of the UK off the sofa and helps to avert our obesity timebomb.

If you’re skeptical, the Big Question in The Independent casts a critical eye over the Change4Life campaign, asking whether the Government can really make us eat less.
On the other hand, it you want to get serious about improving your lifestyle there is stacks of information on how to eat better, move more and live longer on the Change4Life website.

Public health, Sexual health

You’ve got mail… or chlamydia

November 28, 2008 1 Comment

The young people’s sexual health charity Brook has teamed up with the NHS and the laboratory testing company Preventx to offer free chlamydia testing kits through the post.

By using the Freetest.me website, young people between the ages of 16 and 24 can order a postal home testing kit, return their urine sample or vaginal swab by post, and receive the results by text message, email or on the website’s tracking service.

According to Brook, chlamydia is the most common sexually transmitted infection, with 1 in 10 people affected. Up to 75% of women and 50% of men with chlamydia have no symptoms, but left untreated the disease can cause serious health problems such as pelvic inflammatory disease and scarring of the reproductive system, and can lead to infertility.

Chlamydia can be treated easily with antibiotics, but these drugs can stop the contraceptive pill or patch from working.

Cardiovascular medicine, Public health

British Heart Foundation petition against cigarette machines

November 23, 2008 No Comments

The British Heart Foundation has launched a petition to ban the sale of cigarettes from vending machines in the UK. The charity hopes that banishing cigarette vending machines will reduce the number of under 18s who take up smoking.

In the UK you need to be at least 18 years old to buy cigarettes from a shop and, technically, this old to get cigarettes from a vending machine. Vending machines aren’t manned, however, making it easier for under 18s to circumvent this rule and get their hands on cigarettes. 66% of adult smokers started when they were under age, so stopping people from taking up smoking as teenagers is crucial to prevent a livelong addition to cigarettes.

According to the BHF, 6% of children aged 11-15 are regular smokers and as many as one in six of these teenagers buy their cigarettes from cigarette vending machines. A 2007 study reporting on test purchases by young people found that teenagers were able to buy cigarettes from vending machines on more than four in ten occasions, with a number of councils reporting a 100% successful purchase rate. Using vending machines was the most successful way for young people to get hold of cigarettes – almost twice as successful as other ways tested such as purchasing cigarettes from a newsagent, off licence or petrol station kiosk.

Smoking is a leading risk factor for heart disease – of the 114,000 smokers who die as a result of smoking each year in the UK, one in four die from cardiovascular disease. Measures to help people quit smoking, or stop them from smoking in the first place, are thus a key part of the BHF’s strategy.

You can help put cigarette vending machines out of order for good by signing the BHF petition here.

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