Econstudentlog

A few Cochrane reviews and links

I’ve spent the last few days at my parents’ place and haven’t had much time for blogging due to social obligations. I read The Murder on the Links the day before yesterday and I’ll finish Lord Edgware Dies later today – I’ll probably blog the books tomorrow. For now I’ll just post a few Cochrane reviews and a couple of links:

i. Abstinence-only programs for preventing HIV infection in high-income countries (as defined by the World Bank). (link to the full paper here)

“Abstinence-only programs are widespread and well-funded, particularly in the United States and countries supported by the US President’s Emergency Plan for AIDS Relief. On the premise that sexual abstinence is the best and only way to prevent HIV, abstinence-only interventions aim to prevent, stop, or decrease sexual activity. These programs differ from abstinence-plus designs: abstinence-plus programs promote safer-sex strategies (e.g., condom use) along with sexual abstinence, but abstinence-only programs do not, and instead often highlight the limitations of condom use. An up-to-date review suggests that abstinence-only programs do not affect HIV risk in low-income countries; this review examined the evidence in high-income countries.

This review included thirteen randomized controlled trials comparing abstinence-only programs to various control groups (e.g., “usual care,” no intervention). Although we conducted an extensive international search for trials, all included studies enrolled youth in the US (total baseline enrollment=15,940 participants). Programs were conducted in schools, community centers, and family homes; all were delivered in family units or groups of young people. We could not conduct a meta-analysis because of missing data and variation in program designs. However, findings from the individual trials were remarkably consistent.

Overall, the trials did not indicate that abstinence-only programs can reduce HIV risk as indicated by behavioral outcomes (e.g., unprotected vaginal sex) or biological outcomes (e.g., sexually transmitted infection). Instead, the programs consistently had no effect on participants’ incidence of unprotected vaginal sex, frequency of vaginal sex, number of sex partners, sexual initiation, or condom use.”

ii. Healthcare financing systems for increasing the use of tobacco dependence treatment.

The short version:

“Apart from providing counselling and drug treatment, strategies that reduce or cover the costs of accessing or providing these treatments could help smokers quit.

We found eleven trials, eight of which involve financial interventions directed at smokers and three of which involve financial interventions directed at healthcare providers.

Covering all the costs of smoking cessation treatment for smokers when compared to providing no financial benefits increased the proportion of smokers attempting to quit, using smoking cessation treatments, and succeeding in quitting. Although the absolute differences in quitting were small, the costs per person successfully quitting were low or moderate. Financial incentives directed at healthcare providers did not have an effect on smoking cessation.”

From the paper:

Summary of main results:

With very high to modest levels of consistency, we detected a statistically significant positive effect of full financial interventions targeting smokers with regard to abstinence from smoking compared to provision of no financial intervention at six months follow-up or more (all abstinence measures: RR 2.45, 95% CI 1.17 to 5.12). The effect of full financial interventions was also extended to favourable outcomes on the use of smoking cessation treatments: the pooled effect of full coverage compared with no financial intervention on the use of smoking cessation treatments was highly significant for each treatment type (NRT, bupropion, and behavioural interventions).Despite the observation of multiple favourable effects of full as compared to no financial intervention, when full coverage was compared to partial coverage, results showed no significant effect on smoking cessation or quit attempts. […]

Five studies presented data on cost effectiveness. When full benefit was compared with partial or no benefit, the costs per quitter ranged from $119 to $6,450. [the $6,450 estimate is an outlier in that group; the other estimates are all much lower, at or below $1500/quitter – US] […]

In this review, covering the full cost to smokers of using smoking cessation treatment increased the number of successful quitters, the number of participants making a quit attempt, and the use of smoking cessation treatment when compared with no financial coverage. As the majority of the studies were rated at high or unclear risk of bias in three or more domains, and there was variation between the settings, interventions and participants of the included studies, the results should be interpreted cautiously. The differences in self-reported abstinence rate, number of participants making a quit attempt and use of smoking cessation treatments were modest.”

iii. Psychosocial and pharmacological treatments for deliberate self harm.

“Deliberate self-harm is a major health problem associated with considerable risk of subsequent self-harm, including completed suicide. This systematic review evaluated the effectiveness of various treatments for deliberate self-harm patients in terms of prevention of further suicidal behaviour. […]

Main results:

A total of 23 trials were identified in which repetition of deliberate self-harm was reported as an outcome variable. The trials were classified into 11 categories. The summary odds ratio indicated a trend towards reduced repetition of deliberate self-harm for problem-solving therapy compared with standard aftercare (0.70; 0.45 to 1.11) and for provision of an emergency contact card in addition to standard care compared with standard aftercare alone (0.45; 0.19 to 1.07). The summary odds ratio for trials of intensive aftercare plus outreach compared with standard aftercare was 0.83 (0.61 to 1.14), and for antidepressant treatment compared with placebo was 0.83 (0.47 to 1.48). […]

Authors’ conclusions:

There still remains considerable uncertainty about which forms of psychosocial and physical treatments of self-harm patients are most effective, inclusion of insufficient numbers of patients in trials being the main limiting factor. There is a need for larger trials of treatments associated with trends towards reduced rates of repetition of deliberate self-harm. The results of small single trials which have been associated with statistically significant reductions in repetition must be interpreted with caution and it is desirable that such trials are also replicated.”

A few other links which are not from the Cochrane site:

iv. Plausible indeed!

v. Errors in DCP2 cost-effectiveness estimate for deworming.”Over the past few months, GiveWell has undertaken an in-depth investigation of the cost-effectiveness of deworming, a treatment for parasitic worms that are very common in some parts of the developing world. While our investigation is ongoing, we now believe that one of the key cost-effectiveness estimates for deworming is flawed, and contains several errors that overstate the cost-effectiveness of deworming by a factor of about 100. This finding has implications not just for deworming, but for cost-effectiveness analysis in general: we are now rethinking how we use published cost-effectiveness estimates for which the full calculations and methods are not public. […]we see this case as a general argument for expecting transparency, rather than taking recommendations on trust – no matter how pedigreed the people making the recommendations. Note that the DCP2 was published by the Disease Control Priorities Project, a joint enterprise of The World Bank, the National Institutes of Health, the World Health Organization, and the Population Reference Bureau, which was funded primarily by a $3.5 million grant from the Gates Foundation. The DCP2 chapter on helminth infections, which contains the $3.41/DALY estimate, has 18 authors, including many of the world’s foremost experts on soil-transmitted helminths.”

vi. Evolution, Creationism, Intelligent Design – a Gallup poll from last year. According to that poll a majority of Americans (56%) think creationism should be taught in public school science classes. One of the questions asked were: If the public schools in your community taught the theory of evolution, — that is, the idea that human beings evolved from other species of animals — would you be upset, or not?  A third of the people asked (34%) answered yes to this question. Incidentally in related news it should be noted that in a recent poll of South Korean biology teachers, 40% of them “agreed with the statement that “much of the scientific community doubts if evolution occurs”; and half disagreed that “modern humans are the product of evolutionary processes”.”

In slightly related news, according to an older poll conducted shortly before the turn of the century roughly one in five Americans asked back then didn’t know that the Earth revolves around the Sun. Other countries didn’t do any better:

“Gallup also asked the following basic science question, which has been used to indicate the level of public knowledge in two European countries in recent years: “As far as you know, does the earth revolve around the sun or does the sun revolve around the earth?” In the new poll, about four out of five Americans (79%) correctly respond that the earth revolves around the sun, while 18% say it is the other way around. These results are comparable to those found in Germany when a similar question was asked there in 1996; in response to that poll, 74% of Germans gave the correct answer, while 16% thought the sun revolved around the earth, and 10% said they didn’t know. When the question was asked in Great Britain that same year, 67% answered correctly, 19% answered incorrectly, and 14% didn’t know.”

You do have a potential ‘this is a silly question so I want to mess with the people asking it’-effect lurking in the background, but that’s probably mostly related to people giving the wrong answer deliberately. But even if many of the people asked perhaps gave the wrong answer deliberately, there’s still a substantial number of people answering that they ‘don’t know.’ I found the numbers surprising and I would love to see some updated estimates; a brief googling didn’t turn up anything.

July 28, 2013 - Posted by | data, demographics, evolution, health, medicine, Psychology, religion, studies

5 Comments »

  1. “You do have a potential ‘this is a silly question so I want to mess with the people asking it’-effect lurking in the background…”

    I’m glad you pointed it out. I definitely did not think of that.

    Comment by Miao | July 29, 2013 | Reply

    • You can’t always trust people’s answers when you have survey data; people may lie, exaggerate, etc. (for another example see my response to Plamus’ comment here) ‘Etc.’ may sometimes include interesting effects like the one I mention in the post…

      Comment by US | July 29, 2013 | Reply

  2. On “Evolution, Creationism, Intelligent Design”:

    1) I think (perhaps wrongly) that the popularity and impact of Christianity on Korean society is underappreciated in the West. Excluding Kazakhstan and Russia (and modern Russian Christianity is weird, for lack of a better word), South Korea is the second most Christian country in Asia (after the Philippines), and of the religious Koreans, Protestants and Catholics combined outnumber Buddhists. I have read (anecdata alert!) that Koreans Christians, on average, are way more devoted than comparable self-professed Christians in the West would be. More anecdata: I lived briefly in Queens, New York City, and on the way to the local supermarket used to walk by a massive building that was a Korean church – we are talking “small stadium” kind of massive. A few years later, a friend of mine told me about a female Korean co-worker of hers, whose family (woman, husband, and two teenage sons), would spend every freaking Sunday in church – leave home 7:30am, come back 8:30pm. Turned out they went to the same church in Queens. It’s a 2-hour drive (one way) from where they live in New Jersey to Queens. So, I am not really surprised that Korean biology teachers would bend over backwards to respond the way their religion demands, and try to shoe-horn this nonsense into their scientific education.

    2) As for the US: please, remember that the US educational system is nothing like the European one. The federal government does exercise significant control over schools, but only over those that receive federal subsidies. Thus:
    a) The ones that do not receive subsidies are free to teach whatever they please (including that Jesus rode dinosaurs)
    b) Of the ones who do, a good bit are utter disasters that fail to teach students to read and do basic math, let alone some semblance of modern biology
    c) Home-schooling is a much bigger thing in the US than elsewhere, especially among evangelical Christians
    Being a rabid-eyed libertarian, I think this is a feature and not a bug. Americans are probably objectively less generally educated than peers in Europe and East Asia (US’s linked studies notwithstanding), but I believe having a healthy distrust of government trumps knowing where Vanuatu is on the map.

    Comment by Plamus | August 3, 2013 | Reply

    • Hello Plamus, it is true that Christianity is becoming increasingly popular in South Korea, but it seems like the Catholic + Protestant populations there constitute only 29.2% (http://en.wikipedia.org/wiki/Religion_in_South_Korea), which does not explain why 50% of South Korean biology teachers reject evolution, if we are assuming that religious beliefs are the sole cause of their attitude. Of course, the statistics are almost 10 years old already, and the number of Catholics + Protestants in South Korea could have surged tremendously over the past decade. Anyway, according to the article linked in this blog post, “a survey of trainee teachers in the country concluded that religious belief was not a strong determinant of their acceptance of evolution” — which makes me wonder what else could account for their rejection. Perhaps they just find it repulsive to think that they “descended from monkeys” — it could be a general yuck factor at play.

      Comment by Miao | August 3, 2013 | Reply

    • Re 2) And I’d remind you that there’s no such thing as a ‘European educational system’. Educational systems in Europe vary widely in terms of most variables you could care to think about; teaching language, school starting age, student composition, financing model, degree of tracking, curricula, outcomes, …

      As for schools that “fail to teach students to read and do basic math”, we have plenty of those as well. A recent estimate based on Pisa scores from 2012 found (Danish link) that 55 % of the euphemistically termed ‘bilingual’ students (mostly descendants of non-Westerns) in Copenhagen leave the 9th grade as functional illiterates – the corresponding number for ‘ethnic Danes’ is roughly 1 in 4, although that number also includes some people of non-Western origin (we stop tracking ethnicity after the first generation). I’m a bit skeptical about the methodology applied in the Pisa comparisons, but if you go by those I don’t think there’s much difference between Denmark and the US. Of course the numbers in that link don’t tell you anything about intra-country variance and skewness and it seems logical to assume that variance is higher in countries with larger populations – but as I point out there’s plenty of variance even in small countries like Denmark.

      Comment by US | August 3, 2013 | Reply


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