Continuing Deccan Traps dating — appears to demonstrate that massive volcanism was a significant and perhaps major cause — of the Cretaceous-Paleogene extinction

© 2014 Peter Free

Citation — to study

Blair Schoene, Kyle M. Samperton, Michael P. Eddy, Gerta Keller, Thierry Adatte, Samuel A. Bowring, Syed F. R. Khadri, and Brian Gertsch, U-Pb geochronology of the Deccan Traps and relation to the end-Cretaceous mass extinction, Science (via Science Express), DOI: 10.1126/science.aaa0118 (11 December 2014)

Citation — to press release

Morgan Kelly, New, tighter timeline confirms ancient volcanism aligned with dinosaurs’ extinction, Princeton University (18 December 2014)

Continuing from where I left off — here, here and here

In regard to the causes of the Cretaceous-Paleogene boundary extinction event:

The Chicxulub asteroid impact (Mexico) and the eruption of the massive Deccan volcanic province (India) are two proposed causes of the end-Cretaceous mass extinction, which includes the demise of nonavian dinosaurs.

Despite widespread acceptance of the impact hypothesis, the lack of a high-resolution eruption timeline for the Deccan basalts has prevented full assessment of their relationship to the mass extinction.

Here we apply U-Pb [uranium-lead] zircon geochronology to Deccan rocks and show that the main phase of eruptions initiated ~250,000 years before the Cretaceous-Paleogene boundary and that >1.1 million km3 of basalt erupted in ~750,000 years.

Our results are consistent with the hypothesis that the Deccan Traps contributed to the latest Cretaceous environmental change and biologic turnover that culminated in the marine and terrestrial mass extinctions.

© 2014 Blair Schoene, Kyle M. Samperton, Michael P. Eddy, Gerta Keller, Thierry Adatte, Samuel A. Bowring, Syed F. R. Khadri, and Brian Gertsch, U-Pb geochronology of the Deccan Traps and relation to the end-Cretaceous mass extinction, Science (via Science Express), DOI: 10.1126/science.aaa0118 (11 December 2014) (at Abstract) (paragraph split)

The interesting methodological twist

From the press release:

Schoene and his co-authors gauged the age of petrified lava flows known as basalt by comparing the existing ratio of uranium to lead given the known rate at which uranium decays over time.

The uranium and lead were found in tiny grains — less than a half-millimeter in size — of the mineral zircon. Zircon is widely considered Earth’s best “time capsule” because it contains a lot of uranium and no lead when it crystallizes, but it is scarce in basalts that cooled quickly.

The researchers took the unusual approach of looking for zircon in volcanic ash that had been trapped between lava flows, as well as within thick basalt flows where lava would have cooled more slowly.

© 2014 Morgan Kelly, New, tighter timeline confirms ancient volcanism aligned with dinosaurs’ extinction, Princeton University (18 December 2014) (paragraph split)

More to do, of course

Again, from Morgan Kelly:

Vincent Courtillot, a geophysicist . . . said that the paper is important and “provides a significant improvement on the absolute dating of the Deccan Traps.”

Courtillot, who is familiar with the Princeton work but had no role in it, led a team that reported in the Journal of Geophysical Research in 2009 that Deccan volcanism occurred in three phases, the second and largest of which coincides with the K-Pg mass extinction.

The Princeton researchers also plan to test the three-phases hypothesis, Schoene said. Their data already suggests that the second and third phase might be a single period of eruptions bridged by smaller, “pulse” eruptions, he said.

© 2014 Morgan Kelly, New, tighter timeline confirms ancient volcanism aligned with dinosaurs’ extinction, Princeton University (18 December 2014) (extracts)

Caveat

Even with the apparent narrowing of the Deccan volcanism’s time relationship to the extinction window, 250,000 years before the boundary layer was presumably formed is a long time.

Yet, one member of the team makes a good dynamics-based counter-argument:

Existing models of the environmental effects of the Deccan eruptions used timelines two to three times longer than what the researchers found, which underestimated the eruptions’ ecological fallout, [Gerta] Keller explained.

The amount of carbon dioxide and sulfur dioxide the volcanoes poured out would have produced, respectively, a long-term warming and short-term cooling of the oceans and land, and resulted in highly acidic bodies of water, she said.

Because these gases dissipate somewhat quickly, however, a timeline of millions of years understates the volcanoes’ environmental repercussions, while a time frame of hundreds of thousands of years — particularly if the eruptions never truly stopped — provides a stronger correlation.

The new work confirms past work by placing the largest Deccan eruptions nearer the K-Pg extinction, but shows a much shorter time frame of just 250,000 years, Keller said.

“These results have significantly strengthened the case for volcanism as the primary cause for the mass extinction, as well as for the observed rapid climate changes and ocean acidification” . . . .

© 2014 Morgan Kelly, New, tighter timeline confirms ancient volcanism aligned with dinosaurs’ extinction, Princeton University (18 December 2014) (paragraphs split)

The moral? — Good thinking, increasing plausibility

However, given the huge chunks of time and what I assume is a somewhat impressionistically dated paleontological record, I am not yet convinced that we will be able to distribute persuasive degrees of extinction causation between Chicxulub and the Traps.

 

Poorly thought out computer models can lead us astray — for example, ebola is not randomly transmitted, as previous transmission models reportedly assumed

© 2014 Peter Free

Citation — to study

Samuel V. Scarpino, Atila Iamarino, Chad Wells, Dan Yamin, Martial Ndeffo-Mbah, Natasha S. Wenzel, Spencer J. Fox, Tolbert Nyenswah, Frederick L. Altice, Alison P. Galvani, Lauren Ancel Meyers, and Jeffrey P. Townsend, Epidemiological and viral genomic sequence analysis of the 2014 Ebola outbreak reveals clustered transmission, Clinical Infectious Diseases, DOI: 10.1093/cid/ciu1131 (15 December 2014)

Citation — to press release

Ziba Kashef, Yale researchers reveal Ebola virus spreads in social clusters, Yale University (16 December 2014)

If Yale’s press release is accurate, it makes one wonder how scientifically dumb we can get

From Yale University:

Prior studies of Ebola transmission were based on models that assumed the spread of infection occurred between random pairs of individuals.

However, because transmission of the virus happens most often in hospitals, households, and funeral settings, Yale researchers, and an international team of co-authors, investigated the possibility of clustered transmission, or spread between individuals in small social groups.

For their analysis, the researchers reviewed both genomic and epidemiological data from the current outbreak in Sierra Leone. They found evidence of significant social clustering.

“Clustered transmission means that when you have an individual who has the disease and they transmit it to another individual, the next transmission is likely to be to someone who the first individual knew,” said Jeffrey Townsend, principal investigator . . . .

“It’s all happening within little small social networks.”

Researchers were also able to estimate that for every Ebola case reported, fewer than one went unreported. This estimate, that up to 70% of cases were not reported, is significantly lower than previous estimates.

“For Sierra Leone, underreporting is lower than some more speculative estimates that ran as high as 250%,” Townsend noted.

These findings underscore the importance of rapid contact tracing and quarantine of symptomatic individuals, which can be highly effective among these clustered groups.

© 2014 Ziba Kashef, Yale researchers reveal Ebola virus spreads in social clusters, Yale University (16 December 2014) (paragraphs split, underline added)

Well, duh

We have known for some time that ebola is transmitted by contact. And further that ebola is most often transmitted by families and from patient to medical worker.

So, why would ebola virus transmission modelers presume (a) random transmission between (b) people who don’t know each other?

Caveat

It is possible, of course, that Yale exaggerated the ignorance of existing ebola transmission models and accordingly drew unwarranted attention to its allegedly revising work.

The moral? — Provided that Yale’s statement about the ignorance of past ebola computer-generated projections is correct — then, a bunch of mathematically inclined folk had previously ignored data that we already had . . .

. . .  thereby illustrating my point that masking ignorance behind the camouflage of mathematical precision doesn’t get us anywhere useful.

A British Medical Journal study and companion editorial take aim — at exaggerations and misstatements of medical fact — from investigators, academic institutions, and the press

© 2014 Peter Free

Citation — to study

Petroc Sumner, Solveiga Vivian-Griffiths, Jacky Boivin, Andy Williams, Christos A Venetis, Aimée Davies, Jack Ogden, Leanne Whelan, Bethan Hughes, Bethan Dalton, Fred Boy, and Christopher D Chambers, The association between exaggeration in health related science news and academic press releases: retrospective observational study, British Medical Journal [BMJ] 349:g7465, DOI: 10.1136/bmj.g7015 (10 December 2014)

Citation — to editorial

Ben Goldacre, Preventing bad reporting on health research, British Medical Journal [BMJ] 349:g7465, DOI: 10.1136/bmj.g7465 (10 December 2014)

One of my peeves is now apparently shared by the British Medical Journal

Researchers, academic institutions and the press all frequently mislead the public with exaggerations and misstatements of fact and causation:

Although it is common to blame media outlets and their journalists for news perceived as exaggerated, sensationalised, or alarmist, our principle findings were that most of the inflation detected in our study did not occur de novo in the media but was already present in the text of the press releases produced by academics and their establishments.

Among biomedical and health related press releases issued by Russell Group universities [see here] in 2011, 33% to 40% contained exaggerated statements compared with the corresponding peer reviewed journal articles.

Moreover, when press releases contained exaggeration it was likely that the news would too . . . 58% for advice, 81% for causal claims, and 86% for inference to humans . . .

but

when press releases did not contain exaggeration, rates of exaggeration in news were only 17%, 18%, and 10%, respectively.

Therefore the odds of exaggerated news were substantially higher when the press releases issued by the academic institutions were exaggerated . . . odds ratios 6.5 [medical advice], 20 [causal claims], and 56 [inference to humans], respectively. . . .

Petroc Sumner, Solveiga Vivian-Griffiths, Jacky Boivin, Andy Williams, Christos A Venetis, Aimée Davies, Jack Ogden, Leanne Whelan, Bethan Hughes, Bethan Dalton, Fred Boy, and Christopher D Chambers, The association between exaggeration in health related science news and academic press releases: retrospective observational study, British Medical Journal [BMJ] 349:g7465, DOI: 10.1136/bmj.g7015 (10 December 2014) (at 1st paragraph under Discussion (paragraph split, underlines added)

How did the research team discover this?

Ben Goldacre explained that:

Sumner and colleagues identified all 462 press releases on health research from 20 leading UK universities over one year. They traced 668 associated news stories and the original academic papers . . . .

[T]hey assessed the press releases and the news articles for exaggeration, defined as claims going beyond those in the peer reviewed paper.

[T]he authors’ structured appraisal focused on three areas: making causal claims from correlational findings in observational data, making inference about humans from studies on other animals, and giving direct advice to readers about behaviour change.

If a news story claimed a new treatment for humans, for example, but the study was on mice—and the academic paper made no claim about humans—then did the exaggeration first appear in the press release, or the newspaper article?

© 2014 Ben Goldacre, Preventing bad reporting on health research, British Medical Journal [BMJ] 349:g7465, DOI: 10.1136/bmj.g7465 (10 December 2014) (extracts)

The academic institution’s initial presentation apparently makes a big difference downstream

Presumably because most reporters are not scientifically confident — or perhaps because some do not think at all:

For main news statements about correlational results, 39% . . . were more strongly deterministic than those present in the associated journal article. The odds of exaggerated statements in news was 20 times higher . . . when press release statements were exaggerated . . . than when they were not . . . .

For non-human studies, 47% of news contained inflated inference to humans. The odds of exaggeration in news was 56 times higher . . . when press release statements were exaggerated . . . than when they were not . . . .

© 2014 Petroc Sumner, Solveiga Vivian-Griffiths, Jacky Boivin, Andy Williams, Christos A Venetis, Aimée Davies, Jack Ogden, Leanne Whelan, Bethan Hughes, Bethan Dalton, Fred Boy, and Christopher D Chambers, The association between exaggeration in health related science news and academic press releases: retrospective observational study, British Medical Journal [BMJ] 349:g7465, DOI: 10.1136/bmj.g7015 (10 December 2014) (at last 2 paragraphs under section entitled, “Association of news exaggeration with press release exaggeration”) (extracts)

Team’s reasonable assumptions about the nature of exaggeration

Understandably:

[W]e assume that pressure to publish means that most journal articles already contain the highest level (at least) of justifiable inference and advice; if further inflation occurs in a press release, it is thus likely to go beyond what a consensus of scientific opinion would find acceptable.

Consistent with this interpretation, a preliminary survey (see supplementary section SI12 and figure S2) revealed that a surprising number of scientists were willing to say that their press releases were exaggerated (relative to their own judgment of what was scientifically justified).

Furthermore, given the imperfections of peer review, many journal articles may contain statements that are already exaggerated relative to a consensus of scientific opinion, or at least spun to emphasise positive findings,and thus our measured level of within university exaggeration is likely to underestimate the extent of the problem.

© 2014 Petroc Sumner, Solveiga Vivian-Griffiths, Jacky Boivin, Andy Williams, Christos A Venetis, Aimée Davies, Jack Ogden, Leanne Whelan, Bethan Hughes, Bethan Dalton, Fred Boy, and Christopher D Chambers, The association between exaggeration in health related science news and academic press releases: retrospective observational study, British Medical Journal [BMJ] 349:g7465, DOI: 10.1136/bmj.g7015 (10 December 2014) (at last 2 paragraphs under section entitled, “Association of news exaggeration with press release exaggeration”) (extracts)

“Yeah, I lied and I’m darn proud of it!”

In writing BrainiYak, it is rare for me to come across a scientific paper that appears to underemphasize the nature of its findings. Publication pressure, narcissistic self-promotion, and the weight of anticipated profit all run the other way:

It is important that these results are not perceived as simply shifting the blame from one group of non-scientists (journalists) to another (press officers).

Most press releases issued by universities are drafted in dialogue between scientists and press officers and are not released without the approval of scientists (and confirmed in our survey, see supplementary section SI12), and thus most of the responsibility for exaggeration must lie with the scientific authors.

The blame—if it can be meaningfully apportioned—lies mainly with the increasing culture of university competition and self promotion, interacting with the increasing pressures on journalists to do more with less time.

© 2014 Petroc Sumner, Solveiga Vivian-Griffiths, Jacky Boivin, Andy Williams, Christos A Venetis, Aimée Davies, Jack Ogden, Leanne Whelan, Bethan Hughes, Bethan Dalton, Fred Boy, and Christopher D Chambers, The association between exaggeration in health related science news and academic press releases: retrospective observational study, British Medical Journal [BMJ] 349:g7465, DOI: 10.1136/bmj.g7015 (10 December 2014) (at 1st paragraph under section entitled, “Implications for practice”) (extracts)

The laughable lapse of scientific integrity in original investigators that the research team recorded in its Supplement

To wit, at S112:

Scientist doublethink

Whilst instigating the main study, we performed an online survey of scientists’ attitudes toward science in the media, and their experiences with PR [press releases]. We advertised the survey via the Guardian, the BBSRC, and social media.

The sample is self-selected and likely biased towards pre-existing interest in the topic of science news and by the subject area distribution in our advertising routes. As expected, the respondents (N=248) blamed journalists more than any other party for misreporting in science news.

However, 79% of scientists who had PRs about their work reported involvement with those PRs, and despite this involvement, 32% acknowledged that their PRs were exaggerated (Figure S2).

Thus it appears that some scientists do have awareness that PRs are a source of misreporting, but as a group we appear to engage in doublethink – colluding in producing exaggerated PRs but mainly blaming the media for the shortcomings of science news.

© 2014 Petroc Sumner, Solveiga Vivian-Griffiths, Jacky Boivin, Andy Williams, Christos A Venetis, Aimée Davies, Jack Ogden, Leanne Whelan, Bethan Hughes, Bethan Dalton, Fred Boy, and Christopher D Chambers, The association between exaggeration in health related science news and academic press releases: retrospective observational study, British Medical Journal [BMJ] 349:g7465, DOI: 10.1136/bmj.g7015 (10 December 2014) (at Data Supplement link to PDF section entitled, “Supplementary Information, S112.Scientist doublethink”) (paragraph split, underlines added)

The moral? — Modernity’s twin soul diseases of Ratbag Capitalism and Narcissism roll confidently along

It was inevitable that science and medicine become victims. We are professionally no better than who we are.

Phthalates exposure during the third trimester of pregnancy — appears to associate with lower IQ in presumably natally affected children — by about 7 points, measured at age seven

© 2014 Peter Free

Citation — to study

Pam Factor-Litvak, Beverly Insel, Antonia M. Calafat, Xinhua Liu, Frederica Perera, Virginia A. Rauh, and Robin M. Whyatt, Persistent Associations between Maternal Prenatal Exposure to Phthalates on Child IQ at Age 7 Years, PLoS ONE 9(12): e114003, DOI :10.1371/journal.pone.0114003 (10 December 2014)

Citation — to press release

Timothy S. Paul, Exposure During Pregnancy to Common Household Chemicals Associated with Substantial Drop in Child IQ, Mailman School of Public Health at Columbia University (10 December 2014)

This environmental association with household phthalates should give us pause

From the intelligently written, logically developed press release — (if only there could be more like this one):

Children exposed during pregnancy to elevated levels of two common chemicals found in the home—di-n-butyl phthalate (DnBP) and di-isobutyl phthalate (DiBP)—had an IQ score, on average, more than six points lower than children exposed at lower levels, according to researchers at Columbia University’s Mailman School of Public Health.

DnBP and DiBP are found in a wide variety of consumer products, from dryer sheets to vinyl fabrics to personal care products like lipstick, hairspray, and nail polish, even some soaps.

Since 2009, several phthalates have been banned from children’s toys and other childcare articles in the United States.

However, no steps have been taken to protect the developing fetus by alerting pregnant women to potential exposures. In the U.S., phthalates are rarely listed as ingredients on products in which they are used.

Researchers followed 328 New York City women and their children from low-income communities. They assessed the women’s exposure to four phthalates—DnBP, DiBP, di-2-ethylhexyl phthalate, and diethyl phthalate—in the third trimester of pregnancy by measuring levels of the chemicals’ metabolites in urine. Children were given IQ tests at age 7.

Children of mothers exposed during pregnancy to the highest 25 percent of concentrations of DnBP and DiBP had IQs 6.6 and 7.6 points lower, respectively, than children of mothers exposed to the lowest 25 percent of concentrations after controlling for factors like maternal IQ, maternal education, and quality of the home environment that are known to influence child IQ scores.

The association was also seen for specific aspects of IQ, such as perceptual reasoning, working memory, and processing speed. The researchers found no associations between the other two phthalates and child IQ.

The range of phthalate metabolite exposures measured in the mothers was not unusual: it was within what the Centers for Disease Control and Prevention observed in a national sample.

© 2014 Timothy S. Paul, Exposure During Pregnancy to Common Household Chemicals Associated with Substantial Drop in Child IQ, Mailman School of Public Health at Columbia University (10 December 2014)

Do seven IQ points matter?

Very probably, especially given the team’s associated checks of the two phthalates’ effects on:

child processing speed, perceptual reasoning and working memory . . . and child verbal comprehension . . . .

© 2014 Pam Factor-Litvak, Beverly Insel, Antonia M. Calafat, Xinhua Liu, Frederica Perera, Virginia A. Rauh, and Robin M. Whyatt, Persistent Associations between Maternal Prenatal Exposure to Phthalates on Child IQ at Age 7 Years, PLoS ONE 9(12): e114003, DOI :10.1371/journal.pone.0114003 (10 December 2014) (at Abstract)

Meaning that:

“The magnitude of these IQ differences is troubling,” says senior author Robin Whyatt, DrPH . . . .

“A six- or seven-point decline in IQ may have substantial consequences for academic achievement and occupational potential.”

© 2014 Timothy S. Paul, Exposure During Pregnancy to Common Household Chemicals Associated with Substantial Drop in Child IQ, Mailman School of Public Health at Columbia University (10 December 2014)

Caveats

Obviously, there is a lot that go wrong with a study like this — from (among many other things):

(i) unseen variables,

(ii) erratic personal physiological characteristics with potential impact on excreted metabolites,

(iii) unrecognized variability in lab results,

(iv) the arguably questionable accuracy of tools that purport to assess “smarts” in 3 and 7 year olds

to

(v) the questionable statistical validity of inferences made from such a small sample size — which was apparently further divided in at least one aspect of the study, so as to try to distinguish between effects on IQ between the two culprit phthalates.

And so on.

All of which may explain the inconsistent results from previous studies of the same phenomenon — see the 3rd paragraph under Discussion in the team’s paper.

That said — the team thoughtfully documented the strengths and weaknesses of their scientific protocol and their reasoning in regard to it

I extract from the paper at some length to demonstrate how scientifically minded people think, when doing research with numerous interrelated and potentially confounding variables:

Our study has a number of strengths.

First it is a prospective evaluation with assessment of exposure to phthalates not only in the prenatal period, but also at ages 3 and 5 years. It is noteworthy that our associations were primarily limited to prenatal concentrations of phthalate metabolites, with some additional associations seen for age 3 exposures, suggesting that there are critical periods of exposure related to adverse cognitive outcomes.

Second, although our sample size was likely not sufficient to estimate sex-specific associations, we did observe several sex specific differences in associations. This is important given that many of the purported mechanisms for these associations are linked to brain concentrations of sex hormones.

However, there are also some limitations. We are unable to identify specific times during pregnancy when phthalates could be related to outcomes as urine was only collected from the pregnant women in the third trimester.

Because phthalates have a half- life of approximately 12 hours, single, spot urine measures do not reflect long term exposure.

We evaluated reproducibility of these urine measures in a sample of 48 women who had repeat urine measures during the third trimester; the ICCs were 0.77 for MBzP, 0.65 for mono-n-butyl phthalate (MnBP), and 0.60 for monoisobutyl phthalate (MiBP) and ranged from 0.27 to 0.42 for the DEHP metabolites, indicating moderate reliability over a short time span.

Strictly speaking, therefore, our results should be specific to phthalate exposure during the third trimester.

Restriction of the study sample to inner-city African American and Hispanics reduces the generalizability of the results, but likely also minimized residual confounding by socioeconomic status and race.

We note that we also controlled for a variety of factor known to be associated with child IQ, namely maternal IQ, race/ethnic group, alcohol use during pregnancy, maternal education, marital status, other contaminants and HOME score.

Birth weight, another predictor of child IQ, did not change the estimated associations between any phthalate metabolite and IQ.

Further work in other ethnic and socioeconomic populations would be needed to generalize these results.

We also measured a limited number of phthalate metabolites and thus cannot infer our results to other phthalates.

We also could not evaluate the associations between phthalate exposure and school performance as these data are not available.

Finally, there may be some measurement error in the categorization of phthalates exposure based on urinary metabolite concentrations because the correlations between measures of the same metabolite over relatively short intervals were moderate to low [9].

Given the observational nature of this study, we cannot conclude a causal relationship between late prenatal exposure to certain phthalates and reductions in IQ.

Nevertheless, we have now observed consistent associations between exposure and outcomes measured at two time-points, one in the preschool years and one in the early school years, suggesting the results are not spurious and appear to be persistent.

© 2014 Pam Factor-Litvak, Beverly Insel, Antonia M. Calafat, Xinhua Liu, Frederica Perera, Virginia A. Rauh, and Robin M. Whyatt, Persistent Associations between Maternal Prenatal Exposure to Phthalates on Child IQ at Age 7 Years, PLoS ONE 9(12): e114003, DOI :10.1371/journal.pone.0114003 (10 December 2014) (at 6th and 7th paragraphs under Discussion) (extracts)

The moral? — We should be worried

Europe’s interest in the Precautionary Principle is not wild-eyed Luddite-ism. Studies are increasingly finding worrisome ways in which human contributions to the environment are hanging around to cause us (and it) apparently significant trouble.

Three validated computer simulation models — indicate that providing post mammography ultrasounds for dense tissue breasts — is likely to be too expensive and arguably too harmful — when balanced against — (a) preventing only 0.36 cancer deaths per 1,000 women screened — and — (b) the unnecessary extra 354 biopsies per 1,000 women screened

© 2014 Peter Free

Citation — to simulations study

Brian L. Sprague, Natasha K. Stout, Clyde Schechter, Nicolien T. van Ravesteyn, Mucahit Cevik, Oguzhan Alagoz, Christoph I. Lee, Jeroen J. van den Broek, Diana L. Miglioretti, Jeanne S. Mandelblatt, Harry J. de Koning, Karla Kerlikowske, Constance D. Lehman, and Anna N. A. Tosteson, Benefits, Harms, and Cost-Effectiveness of Supplemental Ultrasonography Screening for Women With Dense Breasts, Annals of Internal Medicine, DOI:10.7326/M14-0692 (online first, 09 December 2014)

Another “what to do” breast cancer screening conundrum for women

From the abstract:

Many states have laws requiring mammography facilities to tell women with dense breasts and a negative screening mammography result to discuss supplemental screening tests with their providers.

The most readily available supplemental screening method is ultrasonography, but little is known about its effectiveness.

Design: Comparative modeling with 3 validated [see here] simulation models.

Data Sources: Surveillance, Epidemiology, and End Results Program; Breast Cancer Surveillance Consortium; and medical literature.

Target Population: Contemporary cohort of women eligible for routine screening.

Time Horizon: Lifetime.

Perspective: Payer.

Intervention: Supplemental ultrasonography screening for women with dense breasts after a negative screening mammography result.

Outcome Measures: Breast cancer deaths averted, quality-adjusted life-years (QALYs) gained, biopsies recommended after a false-positive ultrasonography result, and costs.

Results . . .  Supplemental ultrasonography screening after a negative mammography result for women aged 50 to 74 years with heterogeneously or extremely dense breasts averted 0.36 additional breast cancer deaths . . . gained 1.7 QALYs . . . and resulted in 354 biopsy recommendations after a false-positive ultrasonography result . . . per 1000 women with dense breasts compared with biennial screening by mammography alone.

The cost-effectiveness ratio was $325 000 per QALY gained . . . .

Supplemental ultrasonography screening for only women with extremely dense breasts cost $246 000 per QALY gained . . . .

Conclusion: Supplemental ultrasonography screening for women with dense breasts would substantially increase costs while producing relatively small benefits.

©  2014 Brian L. Sprague, Natasha K. Stout, Clyde Schechter, Nicolien T. van Ravesteyn, Mucahit Cevik, Oguzhan Alagoz, Christoph I. Lee, Jeroen J. van den Broek, Diana L. Miglioretti, Jeanne S. Mandelblatt, Harry J. de Koning, Karla Kerlikowske, Constance D. Lehman, and Anna N. A. Tosteson, Benefits, Harms, and Cost-Effectiveness of Supplemental Ultrasonography Screening for Women With Dense Breasts, Annals of Internal Medicine, DOI:10.7326/M14-0692 (online first, 09 December 2014) (at Abstract) (extracts)

This modeled study is unlikely to change established clinical practice or law

I have addressed (a) the complexities of breast cancer screening and (b) the tensions that exist between medical realities and competing patient and physician perspectives, here.

This is a topic in which all the psychic momentum goes toward doing what one can, even if it makes little “hard eyed” financial or statistical sense. Probably the only way to implement reductions in screening is for payers to do it. We can all imagine how popular that decision would be.

The moral? — Worthy study — but without more, unlikely to change practice

Breast cancer is such a commonly fearsome thing that patients and their physicians will continue to be likely to do whatever they can — no matter how slimly effective — to detect it early.