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Monthly Archives: May 2015

Potential new regulatory options for e-cigarettes/ANDS in NZ

Monday, May 25th, 2015 | Kate Sloane | 24 Comments

By a group of nine academic tobacco/nicotine researchers*

Smoking e-cigE-cigarette usage is growing in NZ and around the world but the scientific evidence-base regarding the benefits and risks of these types of products remains uncertain. The health-based policy experience is also minimal. In this blog post we outline some of the possible regulatory options around e-cigarettes (alternative nicotine delivery systems – ANDS) that the NZ Government could explore and that further NZ based research could help clarify.

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Faster mortality decline – slower population ageing. How could this be?

Thursday, May 21st, 2015 | Kate Sloane | 3 Comments

Professor Alistair Woodward and Professor Tony Blakely

SNZ predictions of number of New Zealanders aged 65 plus

SNZ predictions of number of New Zealanders aged 65 plus

Have you sat in a meeting recently, or listened to the radio, where someone is invoking the aging population as a harbringer of doom and gloom due to the tsunami of older people with poor health? A tsunami that will overload health and social services, etc. Have you then asked yourself “Hang on a minute, if people are living longer are they not also healthier?”. Or even “Why on earth do government agencies and some academics keep talking about the number of people aged greater than 65 as a marker of some dependency on the state?”. Well, this Blog is for you. We use a paper just published in PLoS ONE that demonstrates how with falling mortality rates, population aging may actually slow due to a rapid increase in the age at which your remaining life expectancy is 15 years or less. And we draw on analyses from our own book, The Healthy Country? A History of Life and Death in New Zealand, to critique naïve assumptions about population aging. Which begs many questions, such as “Why is the age of entitlement for New Zealand superannuation still 65?” Read on.

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The Smokefree 2025 goal is in danger of receding – will the Ministry of Health’s ‘realignment’ get it back on track?

Monday, May 18th, 2015 | Kate Sloane | No Comments

Professors Richard Edwards, Chris Cunningham, and Janet Hoek; Associate Professors George Thomson and Nick Wilson

Smokefree2025The Ministry of Health proposes realigning tobacco control services to progress New Zealand’s Smokefree 2025 goal. However, will a ‘realignment’ of existing services ensure the goal is realised? In this blog, based on a recently published letter in the New Zealand Medical Journal (1) we suggest it may help. However, we argue more fundamental change is required and outline how the Government could do more and the priority actions that could catalyse achievement of this world-leading goal.

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The allure of a Virtual Supermarket for public health nutrition research

Monday, May 11th, 2015 | Nick Wilson | 1 Comment

Dr Wilma Waterlander, National Institute for Health Innovation – University of AucklandVS_image5

The Virtual Supermarket is a 3D computer model of a real supermarket that we started developing some years ago. When we first published on the Virtual Supermarket topic [1], there were highly variable reactions ranging from people willing to spend a significant sum of money to use the tool, to reviewers wondering whether it is anything more than a game. In this blog post we look at some recent research on this virtual reality approach and attempt to answer the question – what is the allure of a virtual supermarket for public health nutrition research?

Testing food pricing strategies

Maybe the best place to start answering this question is the original reason as why we built the Virtual Supermarket: to test food pricing strategies. Most people will have heard of this public health intervention in the form of fat tax, sugar tax, soft drink tax or similar policy. The idea behind these taxes is simple and goes back to one of the fundamentals of economic theory – if you increase the price of a good, demand will decrease and vice versa [2]. So, if we want people to eat less unhealthy foods, we increase the price, “problem solved”.

If only it was that simple.

Apart from any practical concerns, the effectiveness of food taxes is highly uncertain. The biggest issue being so-called cross price elasticity effects. Let me explain – if you increase the price of sugary drinks, we expect people will buy less sugary drinks. But, maybe, people like their sugary drinks so much that they keep buying them, leaving them with less money to spend on other foods (no money left for broccoli!). The same applies to subsidies. If you make fruit and vegetables cheaper, people might buy more of them. But, chances are, they spend the money they saved from the cheap produce on other (unhealthier) products (I can have chocolate after I eat my broccoli) [3,4].

Now, the question is how to study taxing effects properly. Any public health scholar will know that randomised controlled trials are the gold standard. Here we mean an experiment where one group of people is exposed to the intervention (say a soft drink tax) while the other group is not (the control group). There are a few of such studies present in the literature. Simone French pioneered much of this work in the US where she tested several pricing strategies in high-school cafeteria and vending machines [5]. However, a major limitation of these studies is that they did not look into cross price elasticity properly. Vending machines have only a limited number of options and don’t allow testing how changing soft drink prices impact on broccoli consumption.

What we really need are supermarket trials

Now, here it becomes tricky. Supermarkets are not queuing up to open their store for a fat tax experiment. Particularly, when only some stores will get a fat tax, while others don’t. Consequently, supermarket pricing trials are very scarce and limited to studies testing subsidies (i.e., clearly, supermarkets have less concerns about introducing discounts on healthy foods, especially when researchers pay for them) [6,7].

This is where the Virtual Supermarket comes in

The Virtual Supermarket is a 3-D computer simulation of a real supermarket. It has images of all products you would normally find in a supermarket located on 3-D shelves. People can navigate their trolley around the store and purchase products with a mouse click. The cool thing is, we can manipulate this environment. We have conducted numerous of such trials already, all providing important new insights into food pricing strategies [8,9]. Originally developed in the Netherlands – we now have a NZ Virtual Supermarket and a UK version in the making.

How realistic is the Virtual Supermarket?

Now the million dollar question is, how realistic is the Virtual Supermarket? Can people really use it? Do they not see it as a game instead of a serious task? To figure this out, we asked 123 NZ shoppers to complete 3 shops in the Virtual Supermarket and collect their real-life grocery receipts during 3 consecutive weeks. Then, we compared their virtual and real groceries across 18 major food groups. The paper just recently got published in the Journal of Medical Internet Research [10].

Result – the purchases were very similar. Expenditures within the biggest and smallest food groups were the same in the Virtual and real supermarkets. Also people felt a high level of presence in the Virtual Supermarket, which means they could well imagine themselves doing real shopping. This makes sense as evidence from other fields has shown that virtual environments are frequently used to improve surgical technical skills, as a therapeutic instrument in clinical psychology, and in the treatment of several phobias.

Is the Virtual Supermarket the perfect tool? No – it must be noted that we observed some differences between the virtual and the real shops. Of the 18 studied food groups, 3 groups showed important differences including ‘fruits and vegetables’, ‘dairy’ and ‘snacks’. We are now working to further improve the software to accommodate future trials. Also, the Virtual Supermarket does not have cool features such as avatars and people do not pay with real money or receive real groceries. All great ideas to work on!

Bringing important new evidence to public health

Can the Virtual Supermarket provide much needed evidence to inform public health policy? Definitely yes in our view. Without real-life case studies, virtual experiments are as close are we are going to get. While the external validity might not be 100%, the internal validity is a lot higher compared to real-life experiments. In the Virtual Supermarket, we can control every single factor (price, promotions, placement, etc.) – which is really tricky in the real world where thousands of things are going on in a supermarket. Results from Virtual Supermarket trials can be the step between having no evidence and setting up real-life trials. Also, very importantly, the tool allows academics to conduct trials without needing co-operation from food industry. This protects their integrity and objectiveness.

We are still working on improving the software – and of course working in public health, limited funding means the tool is not as fancy as we’d like it to be. But building on what we already have and by starting new collaborations we hope to create something that is useful for many academics when testing interventions in a complex environment. Ultimately this means that when a Government wants to explore nutritional policies to advance public health – there will be high quality experimental data to inform decision-making.

Acknowledgements

The author would like to thank and acknowledge Professor Cliona Ni Mhurchu who initiated the Virtual Supermarket validation study and obtained funding through the University of Auckland Faculty Research & Development Fund for this study. Thanks also to Professor Ingrid Steenhuis with whom I developed the original idea for a Virtual Supermarket for public health nutrition research. The Virtual Supermarket software is developed by SURFsara Amsterdam (funded by the VU University Amsterdam), with particular thanks to Tijs de Kler for making the tool in the great shape it is today.

References 

  1. Waterlander WE, Scarpa M, Lentz D, Steenhuis IH. The Virtual Supermarket: An Innovative Research Tool to Study Consumer Food Purchasing Behaviour. BMC Public Health 2011; 11(1): 589.
  2. Perloff JM. Microeconomics. 4 ed. Boston: Pearson Education; 2007.
  3. Andreyeva T, Long MW, Brownell KD. The impact of food prices on consumption: a systematic review of research on the price elasticity of demand for food. Am J Public Health 2010; 100(2): 216-22.
  4. Waterlander WE, Steenhuis IH, de Boer MR, Schuit AJ, Seidell JC. Introducing taxes, subsidies or both: The effects of various food pricing strategies in a web-based supermarket randomized trial. Prev Med 2012.
  5. French SA. Pricing effects on food choices. J Nutr 2003; 133(3): 841S-3S.
  6. Ni Mhurchu C, Blakely T, Jiang Y, Eyles HC, Rodgers A. Effects of price discounts and tailored nutrition education on supermarket purchases: a randomized controlled trial. Am J Clin Nutr 2010; 91(3): 736-47.
  7. Waterlander WE, de Boer MR, Schuit AJ, Seidell JC, Steenhuis IH. Price discounts significantly enhance fruit and vegetable purchases when combined with nutrition education: a randomized controlled supermarket trial. Am J Clin Nutr 2013; 97(4): 886-95.
  8. Waterlander WE, Ni Mhurchu C, Steenhuis IH. The use of virtual reality in studying complex interventions in our every-day food environment. In: Tang X, ed. Virtual Reality Human Computer Interaction. Rijeka, Croatia: InTech; 2012: 229-60.
  9. Waterlander WE, Ni Mhurchu C, Steenhuis IH. Effects of a price increase on purchases of sugar sweetened beverages. Results from a randomized controlled trial. Appetite 2014; 78C: 32-9.
  10. Waterlander WE, Jiang Y, Steenhuis IH, Ni Mhurchu C. Using a 3D Virtual Supermarket to Measure Food Purchase Behavior: A Validation Study. J Med Internet Res 2015; 17(4): e107.

 

Reducing salt in food good for health and NZ’s health budget – New research

Monday, May 4th, 2015 | Nick Wilson | No Comments

Associate Professor Nick Wilson, Dr Nhung Nghiem, Dr Cristina Cleghorn, Professor Tony Blakely

Sources of saltIn this blog post we report on a new study from the BODE3 Programme that suggests that strategies to reduce the dietary salt intake of New Zealanders could produce major health gains and major cost savings for the publicly-funded health sector. We also put these results into a wider context of how nutrition could be improved in NZ.

This study was done given the high importance of dietary sodium (salt) as a global disease risk factor – it is the eleventh most important risk factor globally [1], with the same ranking for Australasia. In particular, we aimed to model the health benefits and costs for NZ of reducing salt intakes – given this is a country that still has a high burden of heart attacks and stroke.

Salt is ubiquitous in processed food, and often at levels that vary widely within the same type of food product eg, different breads. The good news, though, is that salt can be readily reduced by food reformulation – and because people’s taste buds adapt, it is possible to lower salt in food by about 10% a year with virtually no one noticing. Indeed, there is even some research suggesting that when people are on lower sodium diets they may actually prefer them, based on research that measured the hedonic value of dietary sodium [2]. Potassium salts, which are beneficial for health [3], can also be used to replace the sodium in processed foods (which has already been happening to some NZ food such as soups).

In our study, published in the journal PLoS One [4], we modelled reducing sodium in the food supply, but also changes in consumer behaviour eg, via the impact of counselling, food labelling and a UK-style mass media campaign on salt.

We found that the largest benefit to health (from reducing heart attacks and strokes) came from the strategy of a “sinking lid” on the amount of food salt released to the national market to achieve an average adult intake of 2300 mg of sodium per day. Such an amount compares to around 3500 mg of sodium per day (around 9 grams of salt – or 1.5 teaspoons of salt) currently for the typical NZ adult – mainly from salt hidden in processed foods. This “sinking lid” strategy generated an extra 211,000 quality-adjusted life-years in the adult NZ population alive in 2011 over the remainder of their lifetimes. For many people this will only save days or weeks of life, but for those at risk of heart attacks and strokes in their 50s – the benefit could be measured in decades of extra life. This “sinking lid” strategy resulted in $1.1 billion in cost savings from fewer heart attacks and strokes – even when considering that people would live longer and cost the health system more in their extra life.

The next highest impact strategy was from a salt tax. It also had the advantage of raising revenue which was estimated at reaching about $450 million per year.

Other effective interventions studied were a mandatory 25% reduction in sodium levels in all processed foods and a package of salt reduction strategies performed in the United Kingdom (including a mass media campaign). We also “gave the tick” to NZ’s own “Tick Programme” which is run by the Heart Foundation and was assessed as being a good investment for reducing salt intakes (it is also good for nutrition in other ways: [5]).

Indeed, seven of the eight salt reduction interventions studied generated both health gain for New Zealanders and saved overall health costs. The exception was dietary counselling by dietitians which was found to be good value for the money invested, but just not to the point of actually saving money overall. See the graph below for the key results of all the 8 interventions studied.

Figure: Impact of different interventions to reduce dietary salt intake in the NZ population – showing large health gains and also large financial savings to the health system Results - PlosNotes: The mandatory 25% reduction is for the sodium level in all processed foods. For “selected” foods, this is just for bread, processed meats and sauces. QALY: quality-adjusted life-years gained from the intervention (by reducing heart attacks and strokes).

When considered alongside the international literature (which we reviewed in our paper [4]), there were no big surprises in our results. Indeed, there is now a quite large body of evidence that interventions to lower salt intakes are good for population health and are cost-effective. What was new in our study was being able to give results for the NZ population using our own disease and cost data. This work was also able to show that the health gain per person will likely be greater for Maori men and women compared to non-Maori – so salt reduction strategies could help reduce the health gaps.

In terms of the feasibility of introducing these interventions we note that two are already in place in NZ (dietary counselling and the Tick Programme). We also suspect that policymakers may be particularly interested in the other potential interventions as these might be achieved with food industry cooperation – as seen with the past success in reducing salt in bread in NZ.

But while salt reduction strategies would help improve health in adults – there is also an urgent need to tackle adult and child obesity eg, following other countries with a tax on sugar-sweetened beverages (see these two relevant systematic reviews [6], [7] and a meta-analysis [8], our previous publications [9] [10], and past blogs on this topic [eg, here]).

We acknowledged in our new paper that the evidence relating to dietary salt and health is still regarded by some people to be controversial (and we have blogged on this topic previously [eg, here]). But there are some recent publications that strengthen the linkage between salt and increased disease risk – not just heart attacks and stroke but also kidney disease and stomach cancer eg, see: this 2015 review [11]; this 2014 systematic review on the DASH diet [12]; this 2015 systematic review on salt and increased cardiovascular disease mortality [13]; this meta-analysis on stomach cancer risk [14]; and this study on renal cancer risk [15]. There is also growing evidence of damage from dietary salt to blood vessel walls which is separate from the impact on raising blood pressure [16].

We plan to soon publish the results of additional modelling work on salt reduction interventions (including substitution with potassium chloride). We have also been using mathematical modelling to design different types of heart healthy bread – which combines both lower sodium levels with the benefit of higher potassium levels, and other improvements such as higher fibre and levels of omega-3 fatty acids. Such “ideal” bread could be used by government-funded institutions (eg, hospitals) or be promoted via providing healthy bread vouchers for those with existing cardiovascular disease.

The health gains (measured in quality-adjusted life-years) and cost savings reported in this study were all discounted at 3% per annum. For example, $1 earned in 10 years time is worth 74 cents at the current value, in 20 years 54 cents, in 40 years 30 cents, and so on. Such discounting is standard practice in economic analyses. But in scenario analyses in the main paper we also considered no discounting and 6% discount rate.

In summary, there are many potential salt reduction interventions available to NZ policymakers if they wish to take the salt reduction path for achieving health gains and to save health sector costs.

 

References

  1. Lim SS, et al. A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012, 380(9859):2224-2260.
  2. Blais CA, et al. Effect of dietary sodium restriction on taste responses to sodium chloride: a longitudinal study. Am J Clin Nutr 1986, 44(2):232-243.
  3. Peng YG, et al. Effects of salt substitutes on blood pressure: a meta-analysis of randomized controlled trials. Am J Clin Nutr 2014, 100(6):1448-1454.
  4. Nghiem N, et al. Health and Economic Impacts of Eight Different Dietary Salt Reduction Interventions. PLoS One 2015, 10(4):e0123915.
  5. Wilson N, et al. Possible impact of the Tick Programme in New Zealand on selected nutrient intakes: Tentative estimates and methodological complexities. N Z Med J 2014, 127(1399):85-88.
  6. Thow AM, et al. A systematic review of the effectiveness of food taxes and subsidies to improve diets: understanding the recent evidence. Nutr Rev 2014, 72(9):551-565.
  7. Eyles H, et al. Food pricing strategies, population diets, and non-communicable disease: a systematic review of simulation studies. PLoS Med 2012, 9(12):e1001353.
  8. Cabrera Escobar MA, et al. Evidence that a tax on sugar sweetened beverages reduces the obesity rate: a meta-analysis. BMC Public Health 2013, 13:1072.
  9. Ni Mhurchu C, et al. Twenty percent tax on fizzy drinks could save lives and generate millions in revenue for health programmes in New Zealand. N Z Med J 2014, 127(1389):92-95.
  10. Blakely T, et al. Taxes on sugar-sweetened beverages to curb future obesity and diabetes epidemics. PLoS Med 2014, 11(1):e1001583.
  11. Farquhar WB, et al. Dietary Sodium and Health: More Than Just Blood Pressure. J Am Coll Cardiol 2015, 65(10):1042-1050.
  12. Siervo M, et al. Effects of the Dietary Approach to Stop Hypertension (DASH) diet on cardiovascular risk factors: a systematic review and meta-analysis. Br J Nutr 2014:1-15.
  13. Poggio R, et al. Daily sodium consumption and CVD mortality in the general population: systematic review and meta-analysis of prospective studies. Public Health Nutr 2015, 18(4):695-704.
  14. D’Elia L, et al. Habitual salt intake and risk of gastric cancer: a meta-analysis of prospective studies. Clin Nutr (Edinburgh, Scotland) 2012, 31(4):489-498.
  15. Deckers IA, et al. Long-term dietary sodium, potassium and fluid intake; exploring potential novel risk factors for renal cell cancer in the Netherlands Cohort Study on diet and cancer. Br J Cancer 2014, 110(3):797-801.
  16. Edwards DG, Farquhar WB: Vascular effects of dietary salt. Curr Opin Nephrol Hypertens 2015, 24(1):8-13.