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“Lethal pancreatic cancer grows for decades,” according to the BBC. The cancer may “lurk in the body for many years before patients fall ill”, it said.

The news is based on a study that has estimated the way pancreatic cancer progresses by examining tumours taken from seven patients killed by the disease. By examining the genetics of these tumours, scientists calculated that the first cancer-related mutations in pancreatic cells take place on average 18 years before the cancer is able to spread to other organs. It takes about 20 years before patients die from the disease.

This laboratory study has used genetic sequencing and a mathematical model to estimate the patterns of progression for pancreatic cancer, a disease that often goes undetected until it reaches an incurable stage. While its conclusions would need to be confirmed in further studies, they suggest that there could be a large window of opportunity to detect and treat the cancer before it spreads and becomes lethal. As things stand, only 2-3% of people with advanced pancreatic cancer are alive five years after their first diagnosis, and research in this area is of great importance.

 

Where did the story come from?

The study was carried out by researchers from the Johns Hopkins Medical Institutions, the Kimmel Cancer Centre in Baltimore, Harvard University and the University of Edinburgh. It was funded by the US National Institutes of Health and several charitable foundations and research centres.
The study was published in the peer-reviewed journal Nature.

It was well reported by the BBC, which explained the methods used by the researchers and reported the opinions of independent experts.

 

What kind of research was this?

This was a laboratory study that used genetic analysis to look at cancer cells removed from seven patients who had died of end-stage pancreatic cancer. In particular, researchers studied the relationship between cancer mutations in the primary tumour (found in the pancreas) and cancer cells in secondary tumours found in other organs.

The authors point out that metastasis (the spread of cancer cells from the primary tumour to other organs) is the most common cause of death in cancer patients. This is particularly true of pancreatic cancer where, it is reported, most patients are diagnosed with metastatic disease and few are successfully treated. They say that it is unknown whether the “dismal” outlook for these patients compared to those with other cancers is due to late diagnosis or early spread of the disease.

 

What did the research involve?

The researchers performed rapid autopsies of seven individuals who had died of end-stage pancreatic cancer. All of these patients were confirmed as having secondary cancers in two or more organs other than the pancreas – most often in the liver, lung and peritoneum (lining of the abdominal cavity).

The researchers took tissue samples from both the primary tumours in the pancreas and secondary tumours in other parts of the body.

They sequenced the DNA in the genes of seven of these secondary tumours, to determine the “clonal relationship” between cells in the primary tumour and those in the secondary cancer deposits, i.e. whether there were any genetic differences between the cancers cells at different tumour sites.  They then used a mathematical model to estimate the timing of the development of various stages of the cancer progression (its “genetic evolution”).

 

What were the basic results?

The researchers found that on average, each of the secondary tumours studied had 61 cancer-related mutations. On average, 64% of these had been present in the original primary tumour in the pancreas.

They also estimated that on average:

• it took 11.7 years for the original cancer-related gene mutation in the pancreas to progress into a primary cancer
• there was a further gap of 6.8 years between the development of the primary cancer and the development of cells with the ability to spread and form secondary deposits (metastases)
• there was a gap of 2.7 years between the appearance of these metastatic cancer cells and  the patients dying

 

How did the researchers interpret the results?

The researchers say there is a “window of opportunity” of at least a decade for early detection and treatment during which the disease it is still curable. At present, most patients are not diagnosed until the last two years of the cancer process, when the condition is far harder to treat and the chances of survival are much lower. The challenge we now face is to detect these tumours at an earlier stage. Their findings, the researchers say, could have major implications for screening policies to prevent cancer deaths.

 

Conclusion

As external experts have pointed out, pancreatic cancer is the UK’s fifth biggest cause of cancer deaths. Survival rates have not improved in the past 40 years. This small study, involving tissue from seven patients with advanced pancreatic cancer, appears to suggest that the cancer slowly progresses from its early stages over a number of years and that there is a lengthy time lag between the first cell changes and the appearance of secondary tumours.

These findings will need to be replicated in larger studies. But, as the researchers say, they provide further understanding of the genetics of prostate cancer and may possibly indicate an opportunity for early detection and treatment of this disease, which proves fatal in the majority of cases.

Links To The Headlines

Lethal pancreatic cancer ‘grows for decades’. BBC News, October 29 2010

Links To Science

Yachida S, Jones S, Bozic I et al. Distant metastasis occurs late during the genetic evolution of pancreatic cancer. Nature 467, 1114-1117 October 28 2010

Moving clocks forward would cut road deaths in Scotland,” reported The Guardian. It said that a new study claims that moving the clocks forward by an hour all year round would cut road deaths, improve health, and benefit industry and tourism in Scotland.

The news story is based on an article in the British Medical Journal, and a report by the Policy Studies Institute (PSI). Both are opinion pieces by Dr Meyer Hillman, who is in favour of the UK time zone being permanently moved forward by an hour in winter, and by another hour in summer. He argues that such a move would align most people’s waking hours with daylight, providing numerous health and economical benefits.

The report focuses on the benefits for Scotland in particular, as those in opposition of such a move have often argued that the loss of daylight in the morning there would offset any benefit of the extra light gained in the afternoons and evenings.

The report makes a strong case. However, these are the author’s views and interpretations of the evidence, and there may be other unconsidered evidence. Also, as the author acknowledges, many of the figures presented are estimates only. This review alone will probably not solve the debate. Further research and consideration of public opinion would probably need to take place before any changes were made.

 

Where did the stories come from?

The news stories are based on an article in the British Medical Journal, and the publication of a report by the Policy Studies Institute (PSI). Both were written by Dr Meyer Hillman, who works for the PSI. The report states that the views and interpretations of the evidence are entirely those of Dr Hillman, and should be considered in this context. Similarly, the BMJ article is a personal opinion piece.

The PSI carries out research relevant to social, economic, industrial and environmental policy in the UK. It is reportedly one of the UK’s leading research institutes aimed at promoting economic wellbeing and improving quality of life.  Dr Hillman received funding from the Crescent Trust. No methods are provided in the PSI report or the BMJ piece.

 

What is the issue?

The report discusses the debate over how the UK should change its clocks to conserve daylight hours during the summer and winter months. Currently, the UK conforms to Greenwich Mean Time (GMT) during the winter, and British Summer Time (BST) in the summer when the clocks move forward by one hour. The report argues for the merits of changing this so that the clocks are permanently moved forward by an hour in winter, and then by another hour in summer. This proposed arrangement is called ‘Single Double Summertime’ (SDST). The author says the time shift is supported by road safety organisations, the tourism and leisure industry, trade bodies, sporting, cultural and recreational facilities, youth groups, and those supporting pensioners and people in rural communities.

There are two sides to the debate, however. Some are concerned that the most northerly parts of the UK would lose a considerable amount of daylight in the morning, offsetting any benefit from the extra light gained in the afternoons and evenings. The debate has been hampered by the lack of an evidence-based assessment of the costs and benefits for Scotland. The report therefore presents many of the expected benefits of advancing daylight hours for this region.

 

What would be the potential benefits of the suggested change?

The report says that a change to SDST would have the following benefits:

• Alignment of waking hours with daylight: the report says that a shift to SDST would be better matched to when the majority of people get up and go to bed. Adults working normal 9-to-5 hours would gain 300 additional hours of daylight every year, and would only be affected by the later sunrise on about 60 weekdays in winter. It says that children in Scotland would gain 200 extra daylight hours a year, with about half of these falling on school days.
• Road Safety: the report says that surveys show that road crashes are more likely to occur during the evening peak-time hours, due to less visibility and reduced driver attentiveness. If the evening peak-time was in daylight, the number of accidents would be expected to go down. A 1998 study by the Transport Research Laboratory on the impact of the clock change on road safety estimated that SDST would lead to an overall reduction of 0.7% deaths and serious injuries on Scotland’s roads, with a 0.2% reduction in casualties of all severities. Applying this to 2009 road casualty figures for Scotland, the author suggests that with SDST there would be 20 fewer deaths or serious injuries per year, with 30 fewer casualties of all severities. Figures from the Department for Transport suggest that reductions in road casualties by this amount would save about £8 million per year.
• Tourism: the report estimates that a change to SDST would boost tourism revenues by £3.5 billion a year and generate around 80,000 jobs in the UK. In Scotland, it is estimated that this would boost earnings by £300 million and provide 7,000 more jobs. Currently, tourism is responsible for about 11% of the Scottish economy.
• Sport and leisure: surveys find that the majority of people prefer to do sports and other outdoor leisure activities during daylight hours. Therefore, it is suspected that an extra hour of daylight in the evenings will result in more people taking advantage of sports and recreation facilities.
• Health: health and wellbeing is expected to increase as a result of more people taking part in sport and recreation. There may possibly be a reduction in levels of Seasonal Affective Disorder (SAD) and people getting more vitamin D through daylight exposure.
• Electricity consumption: advancing the clocks could lower electricity demand on every evening of the year due to a reduced need for artificial light. Demand in the morning would only rise in the winter months. The report estimates that Scottish domestic electricity bills would be reduced by 1.5%, saving Scottish bill-payers around £15 million annually.
• Carbon emissions: due to the fall in demand for artificial lighting in the evenings, less greenhouse gas emissions from power stations would be expected. Carbon dioxide emissions from power stations across the UK would potentially drop by about 450,000 tonnes.
• Better security: many crimes, e.g. muggings and vehicle thefts, occur after nightfall. Fear of crime is higher in the dark, so lighter evenings could result in a lower sense of vulnerability for parents in particular, who may otherwise put restrictions on their children.
• Trade and industry: SDST would better align the UK with working hours of other countries, thus potentially improving trade and economic relations.
• Farming: this is an area where a change to SDST might be expected to have a negative impact due to a loss of morning daylight. However, the report counters this by saying that all dairy cows are already milked in artificially lit automated parlours from October through to April. Also, new farming techniques are said to have reduced the need for work in the very early morning. The report says that the National Farmers Union in Scotland have a ‘neutral’ stance on the issue of advancing daylight hours.

The opinion piece in the BMJ focuses on the potential benefits of advancing daylight hours in terms of increased recreation, and relates this to the UK’s growing obesity epidemic. The author highlights the 300 extra daylight hours a year that adults would have for activity, and the 200 extra daylight hours for children.

 

What are the interpretations of the author?

The author concludes that the evidence gathered in the report indicates that advancing the clocks “would bring the Scottish people at least as great benefits as those predicted for the rest of the UK”. Scottish poll findings indicate an even divide in support for and against the change. This he says, ‘adds up to an exceptionally strong case for reform’.

 

Conclusion

This is a wide-ranging report in which the author has gathered together survey findings and national figures to give an estimate of the benefits from a change to what is termed ‘Single Double Summertime’ (SDST).

The report provides various pieces of evidence to support the move, and describes the many potential benefits. It is important to note that much of the predicted benefit are estimates, and it is difficult to know whether all possible factors have been taken into account. With regard to the reduction in road deaths in Scotland in particular, these figures are based on estimates from a 1998 study by the Transport Research Laboratory (TRL). As the author of the current report says, the TRL report acknowledged a fair degree of uncertainty in their estimates and “there are strong grounds for suggesting that they are conservative”. Therefore the reduction in deaths and casualties should be considered with due caution.

As with all narrative reviews, and as this report acknowledges, the views and interpretations of the evidence are entirely those of the author. The report should be considered in this context, and there may be other evidence that has not been considered, which could support the opposing view. If the change were to be made, it is difficult to know in advance what effect the darker mornings would have when people are heading to work and school. Currently the vast majority of British school children go to school and leave school during daylight hours all year round. Single Double Summertime would mean most children would be travelling to school in darkness during the winter months.

Links To The Headlines

Changing clocks could make you fitter. Daily Express, October 29 2010

Putting clocks back damages our health, says expert. BBC News, October 29 2010

Moving clocks forward would cut road deaths in Scotland, claims study. The Guardian, October 29 2010

A question of time: changing the clocks. BBC News, October 29 2010

More daylight ‘would make UK healthier’. The Independent, October 29 2010

Links To Science

Hillman M. More daylight, better health: why we shouldn’t be putting the clocks back this weekend. BMJ 2010; 341:c5964

Dr. Mayer Hillman. Making the most of daylight hours. The implications for Scotland. Policy Studies Institute, University of Westminster

 

 

Scientists are developing a “golden bullet against breast cancer”, the Daily Mail has reported. The newspaper says that the new research has tested the use of tiny shards of gold to heat up and destroy the deadly cells that help tumours grow.

The story is based on a laboratory study using lasers to heat tiny gold “nano-shells” injected into breast cancer tissue extracted from humans and mice. It specifically looked at using the technique to fight cancer stem cells, a type of resilient cancer cell thought to cause relapses and spreading of cancer. Combining this heating, known as ‘hyperthermia’, with radiotherapy reduced the stem cells’ growth compared to when radiotherapy was used alone.

Although this particular treatment shows promise, it is some way from being usable as a treatment for women with breast cancer. Before it could be tested in humans, this type of new treatment would have to undergo the usual, well-defined sequence of pre-clinical trials to demonstrate its safety and effectiveness. However, the authors report that similar types of heat are currently being trialled as treatments for other types of cancer, which may soon inform us of the technique’s potential.

 

Where did the story come from?

The study was carried out by researchers from Baylor College of Medicine and the M.D. Anderson Cancer Center in Houston, Texas. It was supported by grants from several research foundations, including the US National Cancer Institute and National Institutes for Health. The study was published in the peer-reviewed journal Science Translational Medicine.

It was accurately covered by the Daily Mail, which highlighted that this research is still at a developmental stage.

 

What kind of research was this?

This was an experimental, early-stage laboratory study, using both mice and human breast cancer cells to explore the behaviour of breast cancer stem cells, in particular when they were exposed to radiotherapy and an experimental form of heat treatment (called hyperthermia).

The researchers say that “residual” cancer stem cells are thought to be resistant to conventional cancer treatments and, as a type of stem cell, can renew themselves over long periods of time. They could therefore be responsible for breast cancer recurring or spreading to other sites in the body, even years after treatment.

The researchers say that clinical trials of heat treatment (called hyperthermia) have shown that it can damage breast cancer cells, either by killing them directly or by making them more sensitive to radiation treatment. Advances in technology also mean that heat can now be directed to specific locations, such as cancer cells, using safe and non-invasive delivery methods.

 

What did the research involve?

The researchers used two laboratory models to test the use of heat therapy. These models used specially cultured breast cancer tumours either grown in genetically engineered mice or grown as tissue taken from human breast cancers. For their experiments, they chose a cancer type that is more aggressive and less responsive to standard treatments.

From both types of tissue, the researchers grew populations of cancer stem cells to test the effects of radiation treatment, both alone and when combined with heat treatment. Heat treatment was performed using gold nano-shells – microscopic particles made of silica coated with an ultra-thin layer of gold. These are designed to settle near cancer cells, where they could then be heated to 42ºC using a laser, transferring heat to the cancer cells to damage them.

The cancer cells were first identified using special staining techniques. One group was injected with the gold nano-shells, treated with radiotherapy, then immediately given 20 minutes of heat treatment. Other groups of cells were exposed to radiotherapy alone, heat treatment alone and mock heat treatment (where the gold was injected but the heat was not applied).

To determine whether heat treatment had any effect on how tumours behaved, the treated cells were transplanted into mice, and the number of cells, the tumour size and cancer markers were measured up to 96 hours after treatment.

 

What were the basic results?

The researchers found that in both sets of breast cancer tissue, the cancer stem cells were more resistant to radiotherapy than other tumour cells, increasing in number 48-72 hours after treatment.

However, they found that where cancer cells had been treated with heat after radiotherapy, the tumour size was reduced and the percentage of stem cells had not increased.

Forty-eight hours after treatment, the cells from tumours treated with both radiation and heat were less able to reproduce than cells treated with radiation alone.

 

How did the researchers interpret the results?

The researchers say their study confirms that cancer stem cells are resistant to radiotherapy used alone, and that they continue to divide and grow after treatment. They conclude that localised heat treatment using gold nano-shells can reduce this resistance to radiotherapy.

 

Conclusion

This laboratory study using mice and human breast cancer cells appears to demonstrate that localised heat treatment can reduce breast cancer stem cells’ resistance to radiotherapy. This is of particular note as these are the type of cells that are thought to be responsible for relapses of the disease. As such, this novel technique holds some promise for the future.

However, this was an early, experimental test of the technology in isolated tissue. Far more research is needed before we can determine the efficacy and safety of this treatment or use it to treat women with breast cancer. The technology is reportedly being trialled for the treatment of neck and head cancers, which may soon give a clearer picture of its potential.

Links To The Headlines

Golden bullet for breast cancer uses precious metal thinner than a human hair. Daily Mail, October 28 2010

Links To Science

Atkinson RL, Zhang M, Diagaradjane P et al. Thermal Enhancement with Optically Activated Gold Nanoshells Sensitizes Breast Cancer Stem Cells to Radiation Therapy. Science Translational Medicine, 27 October 2010

“Walking tall can increase a man’s chances of developing testicular cancer,” reported The Independent. It said a study has found that for “every extra two inches in height, the risk of being diagnosed is raised by around 13%”.

This was a large well-designed review of past research of body size and the risk of testicular cancer. The researchers combined the results of 13 previous studies looking at the relationship between height and testicular cancer risk. Combining and re-analysing these data suggested that for every 5cm increase in height there was a 13% increase in risk.

The newspapers covered this study responsibly, all stating prominently that any potential link between height and testicular cancer risk is not fully understood and is not necessarily a causal one. Testicular cancer is rare and responds well to treatment. Even with an increased risk, tall men still have a low likelihood of developing the disease. Nonetheless, men of all heights should be aware of the symptoms and check with their doctor if they notice any changes to the size of their testicles. Visit the Health A-Z pages to find out more.

 

Where did the story come from?

The study was carried out by researchers from Yale University and the National Cancer Institute in the US. It was published in the peer-reviewed British Journal of Cancer. No sources of funding are given.

The study was well-reported by BBC News, The Independent and the Daily Mail. They all explain that any potential link between height and testicular cancer risk is not fully understood and that individuals actually have a low risk of developing the disease. The BBC helpfully quotes experts as saying that the absolute risk for men in the UK is low – only one in every 210 for men will develop the disease. The newspapers also quote the researchers, who say that family history is a more important risk factor. The Independent’s headline might be considered more alarming than is justified, considering the balance of the rest of the report.

 

What kind of research was this?

Previous research has suggested that height and weight can affect a man’s risk of developing testicular cancer. Here, the researchers carried out a systematic review of these studies, searching four databases of medical literature to try to find all the studies that had been published on body size and the risk of testicular cancer. They then performed a meta-analysis of the studies, combining their results to give more power to the question of whether body size affects testicular cancer risk.

Adult height is influenced by a number of factors, including genetics, childhood health and nutrition. These factors also influence the risk of a number of other diseases.

Testicular cancer is rare, with around 2,000 new cases diagnosed in the UK each year. Most of the studies included in this research were case-control studies, which had specifically compared the height and weight of men with the disease to those without it. A meta-analysis is a valid way of exploring a potential relationship between a risk factor and a disease. One weakness is that in meta-analyses of case-control and cohort studies, it is possible that the original studies were carried out in very different ways, affecting the accuracy of the combined result.

 

What did the research involve?

The researchers searched four large databases of medical literature for all studies that compared body size and the risk of testicular cancer. The search identified 14 studies that were suitable for inclusion in the analysis.

The results of these studies were combined for the meta analysis. The studies differed in several ways, for instance, weight was defined differently by different studies. Some recorded weight at a specific age (20 to 21), while others selected weight at cancer diagnosis or at some specified point prior to diagnosis. Height was defined as height at age 18 or older. The studies that were included in the final analysis all focused on testicular germ cell tumours, which are the most common type of testicular cancer.

The analysis was concerned with whether there was a relationship between testicular cancer risk and adult height, body mass index (BMI) or weight. The analysis of height involved 13 of the 14 studies, including 5,764 cases. The analysis of weight used 12 of the studies, including 5,505 cases. The analysis of BMI included 13 studies and 13,993 cases. Studies were excluded from a particular analysis if they did not report the relevant data for that risk factor.  None of the analyses adjusted for other potentially influential lifestyle factors or family history.

 

What were the basic results?

The analysis of height and testicular cancer risk showed that the risk of cancer increased by 13% with every 5cm increase in height (OR=1.13, 95% confidence interval [CI] 1.07 to 1.19). The analysis of BMI showed that men who were overweight were less likely to develop testicular cancer compared with those of normal weight (OR 0.92, 95% CI 0.86 to 0.98). However, men who were obese were as likely to develop the disease as people of normal weight (OR 0.92, 95% CI 0.75 to 1.15). There was no association between weight and testicular cancer risk.

 

How did the researchers interpret the results?

The authors state that their research “provides support for a positive association between height and [testicular germ cell tumours (TGCT)], but little support for an association between weight and TGCT. Further investigation of the inverse relationship between BMI and TGCT may be warranted, for which the present findings lend only limited support.”

 

Conclusion

This study suggests that taller men may have a greater risk of developing testicular cancer. But it is not clear why this should be the case, or if height and cancer risk are both associated with some other factor (such as diet), which has a role to play in the risk of disease.

A meta-analysis is a good way of gathering larger numbers of cases together than might be possible in a single study. There are, however, some potential limitations to this approach:

• The analysis only included studies that had been published. Problematically, some studies that do not find an association between a risk factor and a disease are not published. This creates a potential source of bias known as ‘publication bias’, which revolves around the idea that had these studies been included, a different result may have been achieved.
• Another limitation is that the individual case-control studies and cohort studies that are combined together in meta-analyses often have very different study methods, or the original analyses took into account different risk factors. These differences can affect the results.
• A well-conducted systematic review and meta-analysis can still give an inaccurate result if the studies on which it is based are poorly conducted.
• In this particular study, the researchers were not able to adjust their analysis to take into account other factors that might influence the association between body size and testicular cancer, such as lifestyle or socioeconomic factors or family history.

Overall, this is a well-designed study that suggests a useful avenue for further research. The results cannot be used to deduce whether this is a direct relationship or if some other factor is responsible for this link. Research on other factors associated with height, such as hormone levels or diet, may shed more light on this relationship.

Although testicular cancer is rare, all men should be aware of the signs and symptoms, regardless of their height. Visit the Health A-Z bundle to find out more.

Links To The Headlines

Testicular cancer risk ‘greater’ for tall men. BBC News, October 28 2010

Testicular cancer ‘more likely’ in taller men. Daily Mail, October 28 2010

Warning over cancer risk among taller men. The Independent, October 28 2010

Links To Science

Lerro CC, McGlynn KA and Cook MB. A systematic review and meta-analysis of the relationship between body size and testicular cancer. British Journal of Cancer 2010; 103, 1467-1474

Researchers have identified five lifestyle changes that could cut the risk of bowel cancer by 23%, the Daily Mail reported. It said that one in four cases of bowel cancer could be prevented if people drank less alcohol, cut down on red meat, took more exercise, watched their waist size and stopped smoking.

This Danish study enrolled 57,053 adults aged 50 to 64 without cancer. Measurements of lifestyle risk factors for colorectal cancer were taken at the beginning of the study. Their cancer incidence was then tracked over the next 10 years. People who followed public health recommendations (not smoking, a healthier diet, etc.) for each of these areas had a lower risk of developing colorectal cancer during this time.

The newspaper report is well balanced. This was a large, well-conducted study, and the findings are further evidence that changeable lifestyle factors affect the risk of cancer, including colorectal cancer. The research has some limitations, such as its inability to show the exact contribution of each lifestyle factor, and how following the recommendations at different stages of life affects cancer risk.

 

Where did the story come from?

The study was carried out by researchers from the Institute of Cancer Epidemiology and Aarhus University, both in Denmark, and was funded by the Danish Cancer Society. It was published in the peer reviewed British Medical Journal.

The study was generally well reported in a number of newspapers. Most of them reported both the overall reduction of risk and the fact that following the recommendations in just one area can make a great difference to risk.

 

What kind of research was this?

This study investigated how a number of lifestyle risk factors affect the likelihood of developing colorectal cancer. It used a cohort study design and, for a number of years, followed a large number of people who did not have cancer to see who developed the disease.

Colorectal cancer is one of the most common cancers in developed countries. More than 100 new cases are diagnosed in the UK each day. Several lifestyle factors can contribute to the risk of this cancer, including physical activity, smoking, alcohol intake, waist circumference and diet.
 
This study focused on whether following the public health advice for these factors affects the risk of developing the cancer, and whether there is a greater reduction in risk if more recommendations are followed. The study design is an appropriate choice for this type of research question, although it may be beneficial to follow the participants for longer, as colorectal cancer can take a long time to develop. It might also have been been useful to monitor whether people followed the recommendations over time, as this study only measured people’s adherence at the start of the study.

 

What did the research involve?

Between 1993 and 1997, 57,053 people aged between 50 and 64 were recruited to the Diet, Cancer and Health Cohort Study in Copenhagen. Participants were selected if they had no previous diagnosis of cancer according to the Danish Cancer Registry. Each participant was asked to fill in a questionnaire asking about their current smoking, alcohol consumption, physical activity (from work and exercise) and diet. The questionnaire also contained questions on a number of other lifestyle, health and social factors. Some body measurements, such as waist circumference, were also collected.

From the data collected at the start of the study, each participant was given a score on a lifestyle index scale, according to how many areas in which their lifestyle or measurements matched the recommendations from the World Health Organization, the World Cancer Research Fund and the Nordic Nutrition Recommendations. A score of zero indicated the least healthy lifestyle and a score of five indicated the healthiest. One point was allocated for each of the following:

• Not smoking.
• Being physically active for at least 30 minutes per day or having a job with light or heavy manual activity.
• Waist circumference of less than 88 cm for women and 102cm for men.
• Weekly alcohol consumption of fewer than seven alcoholic drinks for women and 14 for men.
• A ‘healthy diet’, defined as eating more than or equal to 600g of fruit and vegetables per day, less than or equal to 500g of red and processed meat per week, more than or equal to 3g of dietary fibre per megajoule (MJ) of dietary energy, and less than or equal to 30% of total dietary energy from fat.

Cases of colorectal cancer were detected in the follow-up period from the Danish Cancer Registry (median follow up time 9.9 years). Data were also collected from the Central Population Registry to monitor death from other causes, or emigration. The researchers then calculated whether there was an association between a person’s score on the lifestyle index scale and whether they developed colorectal cancer in the follow-up period. The researchers adjusted their results for variables known or thought to be associated with colorectal cancer, such as family history, use of aspirin-like drugs and hormone replacement therapy.

 

What were the basic results?

Of the 57,053 people initially recruited, 55,487 were included in the analysis. Some were excluded if they were diagnosed with cancer shortly after the start of the study, or if information from the questionnaire was missing. Of the participants analysed, 8% scored zero or one on the lifestyle index scale, 26% scored two, 40% scored three, 25% scored four and 1% scored the maximum of five. There were 678 cases of colorectal cancer detected during the follow-up period.

People who had higher scores on the lifestyle index scale had lower incidence of colorectal cancer. After taking into account potential confounders, such as family history, an increase of one point on the lifestyle index scale gave an incidence rate ratio of 0.89 (95% Confidence interval [CI] 0.82 to 0.96).

When limiting the analysis to just men or women, this association was still significant for men (incidence rate ratio 0.85, 95% CI 0.76 to 0.94) but not for women. Separating the cancers into subtypes of cancer (colon or rectal) the association between healthy lifestyle and colon cancer remained (incidence rate ratio 0.88, 95% CI 0.80 to 0.98), but was not observed for rectal cancer.

 

How did the researchers interpret the results?

The researchers say that “following the public health recommendations on smoking, alcohol intake, physical activity, waist circumference, and diet was associated with a substantially lower risk of colorectal cancer”.

They estimated that if all the participants had followed the health recommendations for all five risk factors, 23% of colorectal cancer cases could have been avoided (95% CI 9% to 37%). If every person had followed one additional recommendation, the number of cases would have been reduced by 13% (95% CI 4% to 22%).

 

Conclusion

These findings are further evidence that lifestyle factors affect the risk of cancer, including colorectal cancer. Although the greatest reduction in risk is seen when people follow the recommendations in all areas, just sticking to the guidelines in one additional area reduces a person’s risk.

This was a large, well-conducted study. There are, however, some limitations:

• The lifestyle factors were measured on a single occasion at the start of the study. It is possible, and even probable, that people change their behaviour over time, and this might affect their overall risk.
• Colorectal cancer takes a long time to develop. This study followed people for about 10 years, from the ages of 50 and 64. The results therefore may not reflect how following the recommendations throughout adulthood, or at a particular stage in life, affects cancer risk.
• Some of the lifestyle factors included in the study, such as diet and alcohol intake, can be difficult to measure, as people are prone to underestimating or overestimating their consumption of alcohol and some food types.
• It is possible that there are other factors, for example, lifestyle or socioeconomic factors, which may also contribute to cancer risk but were not measured or adjusted for in the analysis. The size of the effect may have been reduced had these been taken into account.

Further studies that follow people for longer and measure their adherence to health recommendations over a longer period may support the findings of this research. Few people were found to achieve all five areas of healthy living, and further research into how to change this may be beneficial.

Links To The Headlines

Five ways to cut risks of bowel cancer. The Daily Express, October 27 2010

Five ways you can avoid bowel cancer: Lifestyle changes could prevent 25% of cases. The Daily Mail, October 27 2010

Five tips to cut bowel cancer risk. Daily Mirror, October 27 2010

Links To Science

Kirkegaard, H, Johnsen, NF, Christensen, J, et al. Association of adherence to lifestyle recommendations and risk of colorectal cancer: a prospective Danish cohort study. British Medical Journal, [Published online ahead of print] October 26 2010

“The flu pandemic in England killed 70 children in 2009,” The Guardian has reported. The newspaper says that “most of those who died had pre-existing health problems but one in five were healthy before they caught the virus”.

The news story was based on a report that examined all of England’s swine flu deaths in children under 18 during the 2009 pandemic. The research found that there was a higher risk of dying from the influenza A H1N1 strain of flu among certain groups of children, such as those with pre-existing conditions and those of a Pakistani or Bangladeshi background. However, the reasons behind this ethnic bias were not determined.

This report has illustrated that there may be children who are more at risk of dying from certain flu strains, a phenomenon that will require further research. Also, this research was carried out in England where the overall proportion of children who died during the pandemic was low, at a rate of six per million people. The researchers have now called for an analysis of global data on childhood mortality to help us further understand and prevent childhood deaths from seasonal and pandemic flu.

 

Where did the story come from?

The study was carried out by researchers from the Department of Health and the National Patient Safety Agency, including Sir Liam Donaldson, who was Chief Medical Officer for England during the recent swine flu pandemic. The study was funded by the Department of Health and published in the peer-reviewed medical journal The Lancet.

This research was covered fairly by The Guardian and The Daily Telegraph. Both papers discuss the implications for vaccination programmes and for the early use of antiviral treatments.

 

What kind of research was this?

This was an observational, population-based study that aimed to analyse child deaths related to pandemic influenza A H1N1 (swine flu) in England in order to inform clinical and public health policies relating to seasonal and pandemic flu.

The researchers said that the overall death rate from seasonal flu is low, and that it predominantly affects people above 65 years old. However, the recent swine flu pandemic affected children disproportionately and, despite global reports of the complications associated with the pandemic influenza A H1N1 virus, they are not aware of a detailed analysis focusing on the effects that it had on children.

 

What did the research involve?

During the flu pandemic, reporting systems were established so that all suspected and confirmed deaths from pandemic influenza A H1N1 in England could be recorded. Further deaths were identified through cross-checking of records held by the Regional Directors of Public Health and by the Health Protection Agency’s influenza reference centres.

All cases of death where the influenza A H1N1 virus was suspected were assessed by a member of the Chief Medical Officer’s clinical team. A death was related to influenza A H1N1 if there was laboratory evidence of infection with this virus or if H1N1 infection was recorded on the death certificate.

The researchers identified all deaths in children aged less than 18 years from the records. A a paediatrician from the Chief Medical Officer’s team interviewed the child’s doctor about pre-existing disorders and medical history of the child, their symptoms and the clinical course of their flu. The researchers also collected demographic information about the child.

 

What were the basic results?

A total of 70 child deaths related to pandemic influenza A H1N1 occurred in England between June 2009 and March 2010. All of these cases were confirmed by laboratory testing. This corresponds to a rate of six per million of the population.

There were a similar number of boys (31) and girls (39) who had died. Deaths were reported in children aged between 3 months and 17 years, with an average (median) age at death of 7 years.

Six of the children who died were Bangladeshi or British Bangladeshi. This corresponds to a rate of 47 deaths per million of the Bangladeshi population in the UK. There were also 11 deaths in Pakistani or British Pakistani children, which corresponds to a rate of 36 per million in the population, plus 37 deaths in white British children (4 per million of the white population). There were no differences in pre-existing health conditions between the children from these three ethnic groups.

Analysis of the 70 deaths also show that:

• 25 deaths (64%) were in children with severe pre-existing disorders
• 15 deaths (21%) were in children who were previously healthy
• half of the children who died had either pre-existing chronic neurological, gastrointestinal or respiratory disease
• 19 of the children had spastic cerebral palsy affecting all of their limbs
• 11 children had stomach problems
• 41 of the children had conditions that required regular feeding through a tube
• 5 children had asthma
• 8 children had a pre-existing heart condition
• After taking into account the different prevalence of pre-existing disorders, having a chronic neurological disorder was associated with the greatest risk of death.

Among the 70 deaths, 19 occurred before the children could be admitted to hospital. Children in this group were more likely to have been healthy or had only mild pre-existing disorders than those who died after admission to a hospital.

Forty-five of the 70 children received the antiviral drug oseltamivir (Tamiflu). Seven of the children received Tamiflu within 48 hours of the onset of their symptoms. On average (median), the children received Tamiflu five days after the onset of their symptoms. The latest that Tamiflu was given was on the seventh day after symptom onset. Two of the 45 children who received Tamiflu had swine flu that was resistant to the drug.

 

How did the researchers interpret the results?

The researchers said that of the 70 deaths in children in England related to pandemic influenza A H1N1, “mortality disproportionately affected ethnic minorities and those with pre-existing disorders”. They also say that “many deaths occurred before hospital admission and in healthy children or those with only mild pre-existing disorders”. They highlight the fact that the 70 child deaths recorded is greater than the number of children killed by leukaemia each year.

The researchers said that the high population mortality rates observed in Bangladeshi and Pakistani Britons might be attributable to clustering of the virus in London and the West Midlands. But they also highlight that there was a lower proportion of these ethnic groups in other areas that had high numbers of flu cases, such as the East Midlands and Yorkshire. The researchers called for further investigation as to why the death rates were higher in these groups.

The researchers said that although antiviral use for the treatment of influenza in children is controversial, the drugs are most effective if given within 48 hours of treatment. They say that their study was not designed to assess antiviral use but suggest that “early treatment with antiviral therapy may maximise the effectiveness of the treatment”, and that “further investigation into the contribution of pre-hospital antivirals to the outcome of affected children is needed”.

The researchers also suggested that their findings support the vaccination of children against pandemic influenza A H1N1.

 

Conclusion

This is a useful report that has analysed child deaths related to pandemic influenza A H1N1 in England, which identified that there may be certain children who were more at risk from this strain of flu than others. However, the researchers acknowledge that overall there was a small number of child deaths in the UK related to the pandemic, therefore an international study that pooled data from a larger, world-wide number of children who had died would be greatly informative. Such as study might improve understanding of what factors increase the risk of death in children following exposure to similar flu strains.

The authors point to a few limitations of the research, noting that correctly recording deaths can be difficult, especially when classifying deaths as having occurred pre- or post hospital admission. They took steps to record this as accurately as possible and to take into account those children who may not have sought medical help.

This report has raised questions that require further follow-up, such as why particular ethnic groups had an increased mortality rate, and what is the most appropriate antiviral treatment plan for children. It also highlighted that some pre-existing conditions carried a higher risk of death from this flu strain. This will need to be addressed when planning a response to future pandemics.

Links To The Headlines

Flu pandemic in England killed 70 children in 2009, study shows. The Guardian, October 27 2010

Swine flu killed three times more children than ordinary influenza: research. The Daily Telegraph, October 27 2010

Links To Science

Sachedina N, Donaldson LJ. Paediatric mortality related to pandemic influenza A H1N1 infection in England: an observational population-based study. The Lancet, September 27 2010