Cooking For Life interview with Kirk Smith

Headline numbers from the Global Burden of Disease study

Pr Kirk R Smith, Professor of Global Environment Health, Berkeley The Global Burden of Disease is a huge effort, covering a vast range of issues. Out of the seven papers, the one that most concerns you is the one on risk factors. The study measured over 60 of these. The most important statistic in the study is the DALYs, but it’s premature mortality statistics that resonate most with a wider public. **Global DALYS from household air pollution: 107 million (available also by sex, age, and 21 regions of the world). For males the number is 60 million. It is higher for males because males have a higher background disease rate than women, because they have higher rats of heart disease, cancer, etc. BUT women are at higher risk. HAP is an important risk factor because it exacerbates existing disease conditions. Comparative figures: DALYs from outdoor air pollution: 75 million DALYs from water and sanitation: 21 million. This is a very striking result, how low this figure is. **Household air pollution is the second most important risk factor for women and girls after high blood pressure. Comparing this figure to the 2000 study or the 1990 GBD studies, while we have done the recalculation with the 1990 study, is probably not a good figure to use, because of the tremendous advances in the 2010 study. Best to just refer to the 2010 figures alone. Global DALYs for other risk factors: child and maternal malnutrition, 166 million; tobacco, 156 million; alcohol and drug use, 154 million; all occupational hazards, 62 million; physical inactivity, 69 million. Global DALYs for other environmental risk factors: radon, 2 million; lead, 14 million **Household air pollution is now the single biggest environmental risk factor.  **Premature mortality from household air pollution: 3.5 million total, 1.6 million women. **Another important subtlety is the figure on second-hand cooking smoke. The GBD shows that it accounts for 16% of total outdoor air pollution (analogy with second-hand tobacco smoke, which causes 600,000 deaths). **That means total premature mortality from household air pollution is 4.0 million, factoring in 500,000 deaths from second-hand cooking smoke. **The main reason why the figure of premature mortality from HAP is now 4.0 million versus around 2.0 previously, is because we have more information this time on other diseases that we didn’t have before from indoor air pollution, including cataracts and heart disease. Because heart disease is such an important cause worldwide, it really bumped up the numbers. Previously, the diseases that we had good information on from the health literature was mostly pneumonia, COPD, and lung cancer. **Also, we have much better evidence of the effects of HAP on men. At the same time, the rates of background pneumonia for children has gone done, from 1.0 million previously to 500,000 in the 2010 GBD study. **What’s changed in this 4.0 million figure is that the effects are much higher for adults due to better information on lung cancer, heart disease, and chronic lung disease. It’s not really an increase, we just have better estimates. **Also, this time around we were able to focus the data more on cooking fuel exclusively, and it does not count the impact  (I am going to ask Kirk to explain this a bit more). In the 2010 GBD study, the figures do not count the impact from heating with wood or coal. The 4.0 million is not really an increase, it is just better estimates. QUOTE: Personally, the idea that one billion more could convert to clean cooking fuels is doable” (Kirk includes elec and gas and the whole set of solutions, including rice cookers an water pots in this explanation)   *Buried in the GBD study – is strong evidence from chimney smoke. It’s not really possible to get the health benefits (when there is smoke going up the chimney). You need to get a reduction in household air pollution of 90% to 95%, and that’s only possible with gas.   **25% to 30% of all outdoor air pollution in India is due to household air pollution. **Messages on clean fuels from the GBD: -You need to get a really clean environment before you can reap the health benefits and the only way to get this is with clean fuels -60% of the world’s population is able to do this – we just have to apply these lessons to the other 40% of households, which means tackling the poverty issues.