Our new paper in the Annual Review of Public Health has an immense amount of additional information on how the comparative risk assessment for household air pollution from solid cookfuels (HAP) was done. Indeed,covering over 60 risk factors, the original Lim et al. Lancet article (Dec 2012) had less than 300 words on HAP itself, while ours has more than 30,000 words (with the supplement). >100x more. Of course, we do not attempt to produce the vast array of figures and tables comparing with other risk factors and by age, sex, region, etc.
We found some relatively minor glitches in how the calculations were done during the last hectic weeks before the Lancet article went to press and believe that the ARPH article is a more accurate representation of the estimates that can still be compared across the other risk factors. Unlike the Lancet article, it also incorporates the burden from HAP’s contribution to outdoor air pollution, corrected for overlap as explained. The resulting premature death total is 3.9 million globally for 2010, quite close to the 3.5 directly from HAP plus the implied 0.5 million due to an uncorrected addition of HAP’s contribution to outdoor pollution in the Lancet article.
We also of course could take direct advantage of the publication of some major pieces of the HAP analysis that occurred after the Lancet article.
We also are able to do some sensitivity analysis toward the end of our article that show, for example, that the results are not sensitive to uncertainties in the exposure assessment, but that the ranking of HAP against other risk factors in the poorest countries is quite sensitive to the choice of what risk factors were left out in the main GBD study.
The paper and supplement can be downloaded from my website below can the original Lancet article. Please note that Nigel Bruce and I are co-first authors/k
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Millions Dead: How Do We Know and What Does It Mean? Methods Used in the Comparative Risk Assessment of Household Air Pollution
Kirk R. Smith,1,. Nigel Bruce,2,. Kalpana Balakrishnan,3 Heather Adair-Rohani,1 John Balmes,1,4 ZoNe Chafe,1,5 Mukesh Dherani,2 H. Dean Hosgood,6 Sumi Mehta,7 Daniel Pope,2 Eva Rehfuess,8 and others in the HAP CRA Expert Group
Abstract – In the Comparative Risk Assessment (CRA) done as part of the Global Burden of Disease project (GBD-2010), the global and regional burdens of household air pollution (HAP) due to the use of solid cookfuels, were estimated along with 60+ other risk factors. This article describes how the HAP CRA was framed; how global HAP exposures were modeled; how diseases were judged to have sufficient evidence for inclusion; and how meta-analyses and exposure-response modeling were done to estimate relative risks. We explore relationships with the other air pollution risk factors: ambient air pollution, smoking, and secondhand smoke. We conclude with sensitivity analyses to illustrate some of the major uncertainties and recommendations for future work. We estimate that in 2010 HAP was responsible for 3.9 million premature deaths and ~4.8% of lost healthy life years (DALYs), ranking it highest among environmental risk factors examined and one of the major risk factors of any type globally.
Kirk R. Smith, MPH, PhD
(Professor of Global Environmental Health, University of California, Berkeley)
Fulbright-Nehru Distinguished Chair (Fall/Winter 2013/14)
Centre for Atmospheric Sciences
Indian Institute of Technology-Delhi
Delhi cell: (91) 96-5092-6030 [note new number]
http://ehs.sph.berkeley.edu/krsmith/
