Chris Sampson’s journal round-up for 24th April 2017

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

The association between socioeconomic status and adult fast-food consumption in the U.S. Economics & Human Biology Published 19th April 2017

It’s an old stereotype, that people of lower socioeconomic status eat a lot of fast food, and that this contributes to poorer nutritional intake and therefore poorer health. As somebody with a deep affection for Gregg’s pasties and Pot Noodles, I’ve never really bought into the idea. Mainly because a lot of fast food isn’t particularly cheap. And anyway, what about all those cheesy paninis that the middle classes are chowing down on in Starbuck’s? Plus, wouldn’t the more well-off folk have a higher opportunity cost of time that would make fast food more attractive? Happily for me, this paper provides some evidence to support these notions. The study uses 3 recent waves of data from the National Longitudinal Survey of Youth, with 8136 participants born between 1957 and 1964. The authors test for an income gradient in adult fast food consumption, as well as any relationship to wealth. I think that makes it extra interesting because wealth is likely to be more indicative of social class (which is probably what people really think about when it comes to the stereotype). The investigation of wealth also sets it apart from previous studies, which report mixed findings for the income gradient. The number of times people consumed fast food in the preceding 7 days is modelled as a function of price, time requirement, preferences and monetary resources (income and wealth). The models included estimators for these predictors and a number of health behaviour indicators and demographic variables. Logistic models distinguish fast food eaters and OLS and negative binomial models estimate how often fast food is eaten. 79% ate fast food at least once, and 23% were frequent fast food eaters. In short, there isn’t much variation by income and wealth. What there is suggests an inverted U-shape pattern, which is more pronounced when looking at income than wealth. The regression results show that there isn’t much of a relationship between wealth and the number of times a respondent ate fast food. Income is positively related to the number of fast food meals eaten. But other variables were far more important. Living in a central city and being employed were associated with greater fast food consumption, while a tendency to check ingredients was associated with a lower probability of eating fast food. The study has some important policy implications, particularly as our preconceptions may mean that interventions are targeting the wrong groups of people.

Views of the UK general public on important aspects of health not captured by EQ-5D. The Patient [PubMed] Published 13th April 2017

The notion that the EQ-5D might not reflect important aspects of health-related quality of life is a familiar one for those of us working on trial-based analyses. Some of the claims we hear might just be special pleading, but it’s hard to deny at least some truth. What really matters – if we’re trying to elicit societal values – is what the public thinks. This study tries to find out. Face-to-face interviews were conducted in which people completed time trade-off and discrete choice experiment tasks for EQ-5D-5L states. These were followed by a set of questions about the value of alternative upper anchors (e.g. ‘full health’, ‘11111’) and whether respondents believed that relevant health or quality of life domains were missing from the EQ-5D questionnaire. This paper focuses on the aspects of health that people identified as being missing, using a content analysis framework. There were 436 respondents, about half of whom reported being in a 11111 EQ-5D state. 41% of participants considered the EQ-5D questionnaire to be missing some important aspect of health. The authors identified 22 (!) different themes and attached people’s responses to these themes. Sensory deprivation and mental health were the two biggies, with many more responses than other themes. 50 people referred to vision, hearing or other sensory loss. 29 referred to mental health generally while 28 referred to specific mental health problems. This study constitutes a guide for future research and for the development of the EQ-5D and other classification systems. Obviously, the objective of the EQ-5D is not to reflect all domains. And it may be that the public’s suggestions – verbatim, at least – aren’t sensible. 10 people stated ‘cancer’, for example. But the importance of mental health and sensory deprivation in describing the evaluative space does warrant further investigation.

Re-thinking ‘The different perspectives that can be used when eliciting preferences in health’. Health Economics [PubMed] Published 21st March 2017

Pedantry is a virtue when it comes to valuing health states, which is why you’ll often find me banging on about the need for clarity. And why I like this paper. The authors look at a 2003 article by Dolan and co that outlined the different perspectives that health preference researchers ought to be using (though notably aren’t) when presenting elicitation questions to respondents. Dolan and co defined 6 perspectives along two dimensions: preferences (personal, social and socially-inclusive personal) and context (ex ante and ex post). This paper presents the argument that Dolan and co’s framework is incomplete. The authors throw new questions into the mix regarding who the user of treatment is, who the payer is and who is assessing the value, as well as introducing consideration of the timing of illness and the nature of risk. This gives rise to a total of 23 different perspectives along the dimensions of preferences (personal, social, socially-inclusive personal, non-use and proxy) and context (4 ex ante and 1 ex post). This new classification makes important distinctions between different perspectives, and health preference researchers really ought to heed its advice. However, I still think it’s limited. As I described in a recent blog post and discussed at a recent HESG meeting, I think the way we talk about ex ante and ex post in this context is very confused. In fact, this paper demonstrates the problem nicely. The authors first discuss the ex post context, the focus being on the value of ‘treatment’ (an event). Then the paper moves on to the ex ante context, and the discussion relates to ‘illness’ (a state). The problem is that health state valuation exercises aren’t (explicitly) about valuing treatments – or illnesses – but about valuing health states in relation to other health states. ‘Ex ante’ means making judgements about something before an event, and ‘ex post’ means to do so after it. But we’re trying to conduct health state valuation, not health event valuation. May the pedantry continue.

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Sam Watson’s journal round-up for 9th January 2017

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

Non-separable time preferences, novelty consumption and body weight: Theory and evidence from the East German transition to capitalism. Journal of Health Economics [PubMed] [RePEc] Published January 2017

Obesity is an ever growing (excuse the pun) problem associated with numerous health risks including diabetes and hypertension. It was recently reported that eight in ten middle-aged Britons are overweight or exercise too little. A strong correlation between economic development and obesity rates has been widely observed both over time within the same countries and between countries across the world. One potential explanation for this correlation is innovation of novel food products that are often energy dense and of little nutritional benefit. However, exploring this hypothesis is difficult as over the long time horizons associated with changing consumer habits and economic development, a multitude of confounding factors also change. This paper attempts to delve into this question making use of the natural experiment of German reunification in 1989. After the fall of the Berlin Wall a wave of products previously available in West Germany became available to East Germans, almost overnight. The paper provides a nice in depth theoretical model, which is then linked to data and an empirical analysis to provide a comprehensive study of the effect of novel food products in both the short and medium terms. At first glance the effect of reunification on diet habits and weight gain appear fairly substantial both in absolute and relative terms, and these results appear robust and well-founded, theoretically speaking. A question that remains in my mind are whether preferences in this case are endogenous or state dependent, a question that has important implications for policy. Similarly, did reunification reveal East German preferences for fast food and the like, or were those preferences changed as a result of the significant cultural shift? Sadly, this last question is unanswerable, but affects whether we can interpret these results as causal – a thought I shall expand upon in an upcoming blog post.

Ontology, methodological individualism, and the foundations of the social sciences. Journal of Economic Literature [RePEc] Published December 2016

It is not often that we feature philosophically themed papers. But, I am a keen proponent of keeping abreast of advances in our understanding of what exactly it is we are doing day to day. Are we actually producing knowledge of the real world? This review essay discusses the book The Ant Trap by Brian Epstein. Epstein argues that social scientists must get the social ontology right in order to generate knowledge of the social world. A view I think it would be hard to disagree with. But, he argues, economists have not got the social ontology right. In particular, economists are of the belief that social facts are built out of individual people, much like an ant colony is built of ants (hence the title), when in fact a less anthropocentric view should be adopted. In this essay, Robert Sugden argues that Epstein’s arguments against ontological individualism – that social facts are reducible to the actions of individuals – are unconvincing, particularly given Epstein’s apparent lack of insight into what social scientists actually do. Epstein also developed an ontological model for social facts on the basis of work by John Searle, a model which Sugden finds to be overly ambitious and ultimately unsuccessful. There is not enough space here to flesh out any of the arguments, needless to say it is an interesting debate, and one which may or may not make a difference to the methods we use, depending on who you agree with.

Heterogeneity in smokers’ responses to tobacco control policies. Health Economics [PubMedPublished 4th January 2016

In an ideal world, public health policy with regards to drugs and alcohol would be designed to minimise harm. However, it is often the case that policy is concerned with reducing the prevalence of use, rather than harm. Prevalence reducing policies, such as a Pigouvian tax, reduce overall use but only among those with the most elastic demand, who are also likely to be those whose use leads to the least harm. In this light, this study assesses the heterogeneity of tobacco users’ responses to tobacco control policies. Using quantile regression techniques, Erik Nesson finds that the effects of tobacco taxes are most pronounced in those who consume lower numbers of cigarettes, as we might expect. This is certainly not the first study to look at this (e.g. here and here), but reproduction of research findings is an essential part of the scientific process, and this study certainly provides further robust evidence to show that taxes alone may not be the optimum harm reduction strategy.

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Sam Watson’s journal round-up for 19th September 2016

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

Health losses at the end of life: a Bayesian mixed beta regression approach. Journal of the Royal Statistical Society Series A Published 2nd September 2016

The growth in healthcare expenditure is and has long been a concern for policy makers worldwide. Many factors contribute to this increase, for example it may be a consequence of economic growth, but perhaps the most widely cited determinant is an ageing population. A growing literature is questioning the simplicity of this assumption though: is it age per se that leads to increased healthcare costs or is it proximity to death? This study presents a new analysis of this question. More specifically, the authors propose that the observed decline in health related quality of life (HRQoL) associated with age is due to the increased age-specific mortality and the lower HRQoL associated with being close to death, and not age itself. The implication of this is that increased longevity is unlikely to have a large effect on overall healthcare expenditure. To examine this empirically the authors use longitudinal data on HRQoL from 356 individuals over 16 years. Issues such as the skewness of the outcome measure and it being bounded between zero and one, along with the correlation within individuals over time and the relationship between the mean and variance are accommodated using a Bayesian beta regression. Estimation using MCMC methods provides great flexibility in terms of complex models that may be intractable using classical maximum likelihood methods, and the inclusion of previous evidence through the prior reduces uncertainty that may arise due to smaller sample sizes. A wide range of sensitivity analyses are also conducted. The authors’ key finding is that when time to death is included as a variable the effect of age is almost negligible. This journal round-up author’s interest in Bayesian methods has grown exponentially over the last few years and most of his analyses are now in the Bayesian paradigm. Articles such as this demonstrate the power and flexibility of such methods and, importantly, they show how the emphasis is on the estimation problem rather than arbitrary hypothesis testing and estimation of p-values.

Group-based microfinance for collective empowerment: a systematic review of health impacts. Bulletin of the World Health Organisation Published September 2016

Microfinance initiatives have become a popular method to promote development and a sizable empirical literature has grown around it. Indeed, the 2006 Nobel Peace Prize was awarded to a Bangladeshi microfinance program. Many microfinance schemes are founded on the principle of collective empowerment by providing capital to support female autonomy and entrepreneurship. As such, there is an increasing interest in whether these schemes can also improve health. However, the enthusiasm for microfinance initiatives is often said to outstrip evidence of their effectiveness. This systematic review considers the evidence for whether microfinance can improve health. The studies identified in this review provided evidence that microfinance schemes can reduce maternal and infant mortality, improve sexual health, and in some cases lower interpersonal violence. However, even in the higher quality studies, there was potential for bias and unfortunately publication bias was not assessed. Nevertheless, such a review of the effectiveness of microfinance has been long overdue.

The impact of changing economic conditions on overweight risk among children in California from 2008 to 2012. Journal of Epidemiology and Community Health [PubMedPublished September 2016

The relationship between economic conditions and population health has emerged into a huge research area in the last 20 years. We’ve previously discussed it in a number of blog posts. As the literature grows and understanding and knowledge expand, research moves from generalities to specifics. This article explores whether childhood obesity was affected by changing economic conditions during the last recession using a huge dataset of over 1.7 million children. The proportion of children who are obese is larger among low socioeconomic status groups than higher status groups, so it may be expected that a worsening of economic conditions, measured here as unemployment, would lead to an increase in childhood obesity. However, the authors theorise that the association is ambiguous, citing the typical economic argument that through income and substitution effects households may both change their consumption patterns and the amount of time devoted to health promoting activities, which could either improve or worsen health. Using an individual and county level fixed-effects linear probability model (the justification for using the linear probability model over a perhaps more appropriate nonlinear model is not given), a one percentage point increase (around 10-15% relative increase) in the county level unemployment rate is estimated to lead to a 1.4 percentage point increase in the risk of being obese (around 4% increase in risk). Of course, the results are statistically significant. The results seem reasonable, but I’m left struggling to interpret them properly having had the same issue with an aggregate treatment and individual level outcomes previously. The results are consistent with the idea that the increase in obesity occurred among individuals whose families increased their income over the period, for example. Simpson’s paradox often rears its head in the economic conditions and health literature, as we have previously seen with infant health.

Photo credit: Antony Theobald (CC BY-NC-ND 2.0)