Recent papers of interest, week 31

Some recent catch-up reading that’s caught my eye; all HIV stuff it turns out, and as a bonus, all freely accessible:

  • How important are viral introductions vs. local transmission for sustaining an epidemic in rural Uganda?  In Rakai, it seems, pretty important.  I really liked how the authors triangulate spatial, phylogenetic and mathematical modelling approaches to build a solid narrative. And the topic seems really important in the context of targeting key subpopulations within generalized epidemics – something that is rising up the prevention agenda, apparently/hopefully. The primary author also has some recent work (presented at CROI this year) on which partner brings HIV into stable couples; an area in desperate need of good data.
  • Unconditional cash to caregivers of children affects age of sexual debut, but not other risk behaviours, in Kenya. This study starts to get at which behaviours are, and are not, driven by economic factors – as opposed to cultural or other norms.  I would have liked to have seen data on marriage age too, but since that doesn’t typically happen while the child is within the home, perhaps that’s too distant an outcome.
  • A review of some heterogeneities in infection dynamics that provoked some thoughts, although not about modelling, which is the nominal reason for the piece.  Notably, the authors highlight that there may well be heterogeneity in susceptibility, which will practically act to fragment sexual transmission networks as less-susceptibles act more like recovered individuals.  And that alloimmunity to a partner’s expressed antigens may mean that infection risk from an ongoing partner recently infected may be less than expected, while that from a new partner with a chronic infection may be higher than expected (due to no acquired alloimmunity). I must admit this is my first introduction to alloimmunity – it looks like there’s a whole world of research out there on this, with some interesting paradoxical results. Happy reading.

Titanic-like gradients

In the world of social determinants there is one teaching tool that bests all others.  Deaths on the Titanic were highly skewed towards men and those in the lower classes.  This is an excellent point from which to begin to present information on the manner in which health is patterned by social processes, and disproportionately affects some groups within society.

In recent days there has been a certain amount of publicity surrounding a new paper (gated version, ungated version) by Mikael Elinder and Oscar Erixson at Uppsala University that looks in detail at survival in 18 maritime disasters between 1852 and 2011.  The authors’ goal was to look at gender differences in survival and how this might be linked to social norms.  Their headline result is that women have poorer survival rates than men (by about 20%), although things have been improving over time.  Sadly, as John Timmer at ArsTechnica notes

before we conclude that chivalry was dead and [is now] seeing a revival, we’ll caution you that it may be just that more women now learn how to swim.

My interest, however, is on the social side of things, and here two items jump out at me.

1. First, the authors make the following assertion in the final sentence of their abstract:

Taken together, our findings show that human behavior in life-and-death situations is best captured by the expression “every man for himself.”

However, both Timmer’s commentary and the article itself seem to gainsay this by noting that in cases where the Captain issues the order “Women and children first”, the female survival penalty is roughly halved.  For me, this points to the importance of social control in addition to social norms.   The authors even note elsewhere in their piece:

it seems as if it is the policy of the captain, rather than the moral sentiments of men, that determines whether women are given preferential treatment in shipwrecks.

2. Second, only a minority of ships contain information on class of passenger and the authors look at this only as a footnote.  But, it does appear that being in 1st class was protective relative to being in 2nd or 3rd class overall (there were 7 ships with class info: 3 significantly positive results, 1 significantly negative).  So it does seem that the SDoH classes can keep using this example for now at least.

H/T to Marginal Revolution for drawing me to the paper.

Taking the health impact of economic factors seriously

If (or when) I tire of reading trite articles linking exposure A to outcome B while avoiding even a consideration of context or history, I turn to the International Journal of Health Services.  It is not the best-known journal around, and there are very few quick fixes and takeaway messages.  There are certainly no ‘What this study adds’ boxes à la BMJ stable.  Thank goodness.  The journal provides provocative and deep analysis of the current political and economic system and how it affects health.  Under the editorship of Vincent Navarro the journal has focused on critiquing the mainstream, and while I do not always agree with the views expressed, I always gain something from reading.

For example, the most recent issue contains at least four articles that are now high on my to-read pile.

  1. Nadine Nowatzki takes us down the well-worn path of the cross-national relationship between income inequality and mortality/life expectancy.  She focuses on wealth inequality (perhaps a more insidious form than income, since it is longer-lasting) and finds that while the overall pattern looks similar to that for income inequality, the ordering of nations differs.  Her discussion looks at a range of explanations, including social capital and redistributive policies across classes and the lifecourse.
  2. Carles Muntaner and colleagues continue to consider income inequality, explicitly engaging with Richard Wilkinson and Kate Pickett’s The Spirit Level.  They note that Wilkinson and Pickett focus on psychosocial explanations for the ill-health associated with greater inequality, and go on to challenge the authors on this.  Muntaner et al. prefer to focus on materialist explanations, specifically those which arise from social class in the form of exploitation (cf Erik O Wright), and this leads them to urge greater intervention in the economic structure of societies to improve health.
  3. Gavin Mooney moves us to more conceptual ground.  Mooney’s name is one I know from the Health Economics world, where he has been a careful and trenchant critic of the focus on efficiency over equity in that field.  Now it appears he has a new book out, focusing more on political economy and the impact of neoliberalism on health, and for which this paper is a taster.  The core of his argument (and please note I haven’t read the paper thoroughly yet) appears to be that the WHO and the Breton-Woods institutions (World Bank, IMF) have been co-opted into the global neoliberalist focus on individual rights over communitarian needs and approaches.  And that this has had serious negative effects on health.  Certainly an argument worth engaging with.
  4. Claudio Schuftan considers the links between poverty and broader human rights violations, not so much the direct links but rather the common causes.  She identifies the neoliberal governmental framework, religion and man-made disasters at the fulcrum of the system, driving the failure to implement UN (and other) conventions protecting rights and subsequent powerlessness and resignation amongst the powerless.  These then cascade into numerous direct causes of rights violations, but I’ll leave those for you to read about.  It’s certainly a strongly argued vision of the way the world works, and works to harm the most vulnerable.   This paper in particular, I would like to see linked up with Sen/Nussbaum’s capabilities approach.

All of which adds up to uncomfortable, but (indeed perhaps therefore) important, but never dull, reading.

Papers of the Week: 25/2012

Clearly much water (23 weeks worth, apparently) has passed under the bridge since I last posted on new papers crossing my rss/email desk.  So here are the latest batch:

  1. I am more than a little fascinated by the interplay of race, SES, gender and any other stratifier you can mention in determining infection risks.  And in the field of STIs, I appear not to be the only one.  One angle on this is to look at multiple low-power identities and see how they interact.  For example, here‘s a paper that focuses on the intersection of race/ethnicity and sexual orientation.  Risks definitely rise with multiple minority statuses, but the pattern is non-simple and varies by sex.  It’s never as simple as you’d think.
  2. More on concurrent partnerships in Africa.  A recent study found no association between (self-reported) concurrent partnerships and HIV incidence in rural South Africa and while it is generally accepted that concurrency can theoretically drive an HIV epidemic, empirical evidence remains scant that it does so.  One reason for this may be that while concurrency is risky, its prevalence is low.  This idea is supported by a paper out of Malawi from last year which finds that concurrency is long-lasting when it occurs, but that it occurs infrequently (only in 9% of the sample).  Lots more evidence is needed on this, but these are the right questions to be asking.
  3. This one is only “new to me”. Dynamic models of sexual relationships (and other contact networks, I think that sexual networks are simpler than most) need to be a big new field in ID Epi.  If that’s going to happen we (public health people) are going to need to read lots of network analysis stuff (aside: here‘s an intro from Nick Christakis and collaborator Kirsten P Smith (meta-aside: Smith’s disseration from Penn looks really interesting – international comparisons of STI rates, but I can’t see it published yet).  If you want more theoretical details, James Moody – one of the key people behind the Add Health network work mentioned in the above article – wrote a paper in Social Forces a decade ago, which outlines things nicely.  Beach reading, if I ever made it to the beach.  And enjoyed reading once there.

Next time I’ll try and make these papers a little more up-to-date, but this’ll have to do for now.

Papers of the Week: 01/2012

I’ll keep this brief, since I should be doing far less useful things than posting while on holiday.  But here are three that caught my eye:

1. Qualitative research on sexual relationships is so important in interpretting sexual behaviours.  Especially partner types, as discussed here by Noar and colleagues.  I do note that many examples of this type of study focus on minorities (often by sexual preference or race/ethnicity).  One day I should probably look at the variation in findings by such factors, but I’m lazy when it comes to meta-analyses or just pulling together whole literatures.

2. I often find interesting, but not immediately useful, stuff in the Milbank Quarterly.  The latest edition has a piece using the Earned Income Tax Credit as an IV to measure the impact of income change on health status (both self-reported) at the individual level.  Larrimore finds a correlation in levels between income and health status, but not an effect in changes (i.e. more income to better health).  As the author notes, etiologic period is key here, and these effects are short-run, but it’s always good to be reminded that correlation and causation are very different things.

3.  And finally a quickie – state inequality is associated with a higher familial burden for children with special healthcare needs in the USA.  Not shocking, but another brick in the evidential wall that unequal states are less supportive than others.

NB.  As ever, I haven’t read these papers in detail and cannot vouch for them – they are just the abstracts/titles that caught my eye this week.

Potentially interesting papers: Week 51 2011

I had expected this week to be quiet, what with the upcoming festive season and all, but I was pleasantly surprised to find a few titbits to look over and decide ‘yes, I should definitely read this some time soon’.   Therefore, without further ado,  I present:

1.  A simple, yet elegant, study of the interplay of individual and national income in determining who volunteers to be tested for HIV (this paper has been around for a year or so it seems).  It looks like the positive income gradient seen within countries (more income = more testing) is less pronounced in richer countries.  The analysis uses individual income in within-country quintiles, which makes interpretation difficult.  As the authors suggest, one way to look at things is to see this as evidence for the need to focus on poorer people in poor countries.  Another angle would be to see this as evidence that there may be a positive but decreasing slope to the overall relationship internationally – i.e. there is a positive relationship up to some income threshold internationally, and then the relationship levels out.  Which would suggest that focus needs to be on poor people everywhere.  Either way, food for thought.

2. A recent paper on drinking and STI acquisition in the US has me thinking about the causal relationships around sex and drugs (and rock and roll) again.  The paper finds various alcohol-related activities in adolescence linked to various risky behaviours (non-condom use) and self-reported STIs in early adulthood.   The temporality of this relationship is clear, but the almost syndemic nature of the package of behaviours that goes with alcohol and sex – can I call it a lifestyle without implying too much or too little agency? – makes me loath to attribute any direct causal effect from the alcohol to the sex/STI.  Not that the authors of this piece are claiming this, but I remain very unclear on how we might make an impact on STIs through interventions on adolescent behavioural patterns.  Of course, this may just be me banging my ‘social epi’ drum, so you may wish to let me bang it in peace.

3. Here’s something from another field that interests me greatly, but I have never had the time to get into deeply enough.  This is a nice conceptual effort to link human and pathogen behaviour together in an Ordinary Differential Equations setup to consider the mitigating/conflagratory effects of the former on the later in studies of dynamic disease spread.  It doesn’t look too technical for the non-mathematicians amongst us, so might be worth a skim for thought-provocation, if nothing else.

Potentially interesting papers: Week 50 2011

This week I have three possibilities to tantalize you with, one of which I am immediately set against, but feel I should read.

1. This piece in AIDS Care worries me for two surface reasons.  First, the abstract suggests that it is a quantitative analysis of DHS data being published in AIDS Care, a journal I usually turn to for depth and richness, not number crunching.  But I would never write something off based only on this.  Of more concern is the line “Contrary to the public health literature, women of high SES were also vulnerable to HIV risk”.  I am pretty there is a large literature highlighting this relationship already, which leads me to question the level of background research conducted.

2. A reminder that prevention interventions are acutely context-dependent.

3. I find it strange/disturbing how infrequently we consider the disease context of a community in measuring risk factors for HIV across large areas.  This paper from Zimbabwe, via UNC Chapel Hill, is a nice reminder of the importance of cross-level interactions.

Disclaimer. These posts are based on my reading of titles and abstracts, and all papers may be of much greater/lesser interest/quality than I have concluded based on reading 200 words or fewer.