New publication: Ambient air pollution and non-communicable respiratory illness in sub-Saharan Africa: a systematic review of the literature
New publication from our Air Pollution and Health team out today in BMC Environmental Health:
Aerosol pollutants are known to raise the risk of development of non-communicable respiratory diseases (NCRDs) such as asthma, chronic bronchitis, chronic obstructive pulmonary disease, and allergic rhinitis. Sub-Saharan Africa’s rapid pace of urbanization, economic expansion, and population growth raise concerns of increasing incidence of NCRDs. This research characterizes the state of research on pollution and NCRDs in the 46 countries of Sub-Saharan Africa (SSA). This research systematically reviewed the literature on studies of asthma; chronic bronchitis; allergic rhinitis; and air pollutants such as particulate matter, ozone, NOx, and sulfuric oxide.
We searched three major databases (PubMed, Web of Science, and Scopus) using the key words “asthma”, “chronic bronchitis”, “allergic rhinitis”, and “COPD” with “carbon monoxide (CO)”, “sulfuric oxide (SO)”, “ozone (O3)”, “nitrogen dioxide (NO2)”, and “particulate matter (PM)”, restricting the search to the 46 countries that comprise SSA. Only papers published in scholarly journals with a defined health outcome in individuals and which tested associations with explicitly measured or modelled air exposures were considered for inclusion. All candidate papers were entered into a database for review.
We found a total of 362 unique research papers in the initial search of the three databases. Among these, 14 met the inclusion criteria. These papers comprised studies from just five countries. Nine papers were from South Africa; two from Malawi; and one each from Ghana, Namibia, and Nigeria. Most studies were cross-sectional. Exposures to ambient air pollutants were measured using spectrometry and chromatography. Some studies created composite measures of air pollution using a range of data layers. NCRD outcomes were measured by self-reported health status and measures of lung function (spirometry). Populations of interest were primarily schoolchildren, though a few studies focused on secondary school students and adults.
The paucity of research on NCRDs and ambient air pollutant exposures is pronounced within the African continent. While capacity to measure air quality in SSA is high, studies targeting NCRDs should work to draw attention to questions of outdoor air pollution and health. As the climate changes and SSA economies expand and countries urbanize, these questions will become increasingly important.”
New publication: “Long-Term PM2.5 Exposure Is Associated with Symptoms of Acute Respiratory Infections among Children under Five Years of Age in Kenya, 2014”
In early December, I was asked to submit a paper to a special issue on “Air pollution and health in Africa and the African Diaspora” which is great! But the deadline was Dec 31st, which is absolutely crazy. I pulled an amazing team together and somehow we made the deadline and now, here we are…. published!
Here’s the “video abstract.”
Introduction: Short-term exposures to air pollutants such as particulate matter (PM) have been associated with increased risk for symptoms of acute respiratory infections (ARIs). Less well understood is how long-term exposures to fine PM (PM2.5 ) might increase risk of ARIs and their symptoms. This research uses georeferenced Demographic Health Survey (DHS) data from Kenya (2014) along with a remote sensing based raster of PM2.5 concentrations to test associations between PM2.5 exposure and ARI symptoms in children for up to 12 monthly lags. Methods: Predicted PM2.5 concentrations were extracted from raster of monthly averages for latitude/longitude locations of survey clusters. These data and other environmental and demographic data were used in a logistic regression model of ARI symptoms within a distributed lag nonlinear modeling framework (DLNM) to test lag associations of PM2.5 exposure with binary presence/absence of ARI symptoms in the previous two weeks. Results: Out of 7036 children under five for whom data were available, 46.8% reported ARI symptoms in the previous two weeks. Exposure to PM2.5 within the same month and as an average for the previous 12 months was 18.31 and 22.1 µg/m3, respectively, far in excess of guidelines set by the World Health Organization. One-year average PM2.5 exposure was higher for children who experienced ARI symptoms compared with children who did not (22.4 vs. 21.8 µg/m3, p < 0.0001.) Logistic regression models using the DLNM framework indicated that while PM exposure was not significantly associated with ARI symptoms for early lags, exposure to high concentrations of PM2.5 (90th percentile) was associated with elevated odds for ARI symptoms along a gradient of lag exposure time even when controlling for age, sex, types of cooking fuels, and precipitation. Conclusions: Long-term exposure to high concentrations of PM2.5 may increase risk for acute respiratory problems in small children. However, more work should be carried out to increase capacity to accurately measure air pollutants in emerging economies such as Kenya.
Brucellosis: My New Bacterial Tenant
For those keeping up, you may remember that I spent the summer in Kenya, working with a team extracting blood samples from camels, cows, goats and sheep. We were in contact with all of these animals on almost a daily basis. We weren’t wearing any protection at all, but it’s inconceivable to wear a full hazmat suit while taking blood from goats in a Maasai community. You’d get laughed out of town.
My days right now are running in a fairly predictable pattern. I wake up, feel pretty good, eat breakfast and drink some coffee. At about 10-11 a.m. I begin to feel dizzy, sweat somewhat, a low grade fever kicks in and a horrible taste develops in my mouth. My peripheral vision is limited and I have trouble focusing on distant objects. It gets progressively worse throughout the day, but improves before dinner. After dinner, I feel worse than before. I’m positive that the brunt of the physical symptoms are associated with anemia. It’s like a low grade malaria.
The psychological effects are fascinating. Again, in the morning, I feel fine. As the day progresses, I am less and less able to string coherent sentences together (not that I’m good at it in the best of times), lose thoughts in mid sentence and can’t remember important vocabulary words. I’m stuck in an existential funk where the thought of tomorrow is dark, I’ve forgotten the past and the present isn’t all that meaningful. I often find myself staring into space and time passes quickly.
Though I have no other negative physical effects and am able to leave the house and move around, I’m finding this incredibly debilitating. Even writing this blog post is a challenge.
From the pathogen’s standpoint, this situation is ideal. It doesn’t immediately kill the host, and the bacteria tends to incubate in cells so that it can avoid the body’s immune response. If I were a herd animal, eating and defecating in the same space, I would be able to transmit for, conceivably, the rest of my life. The low grade anemia keeps the animal mobile, yet impedes its ability to evade predators, allowing transmission to occur from herbivorous ungulates to carnivorous animals.
Again, because the bacteria hides out in cells, it’s a bear to kill. I have two months of two types of antibiotics to look forward to, both with different schedules and dietary requirements. One causes awful nightmares (doxycycline).
If left untreated brucellosis can include abscesses in the joints, spinal problems, blindness and inflammation of the testicles. It is anecdotally associated with elevated rates of suicide in veterinarians. I’m wondering how much chronic brucellosis there is in pastoralist communities in Sub-Saharan Africa. The burden must be quite severe.
This is going to be rough, but it’s better than a lifetime of these symptoms. I’m certainly finding this scientifically interesting, though I will be happy to have it gone for good.
Thoughts on Environmentalism and an Anthrocentric World
I think that rather than ask whether humans are “more important than other species,” we have to explore the human-nature dichotomy itself. Unfortunateley, discussions on environmental issues seem to start from an assumption that one exists. These discussions, which put humans at odds with nature, generally lose me on three points (though, again, this is not my field of expertise):
1) The intense focus on large mammals. If we are going to convince ourselves that “nature’s” needs are more important than our own (or simply worth considering) we have to eliminate the idea of a hierarchy of species and consider all living things as equally important. It often seems that conversations become less holistic and more mammal-centric. Given that we are mammals and hard wired to like cute and furry things (particularly those small and weak), this is to be expected. However, the urge to protect things like ourselves makes it impossible for humans to objectively rank the importance of living things.
How often do you hear about people screaming to save snakes? Perhaps it happens and I just don’t hear about it. Clearly, big furry animals are an easy sell.
2) The idea that “species” are distinct entities, the number of which needs to be maximized at any cost. Preserving more species is seen as a goal, when in fact, the word itself is not uncontroversial. “Species” is a rough and artificial concept created by humans to assist in our understanding of the world. Even scientists can’t agree on what a species is, given that the situation that determines how a species is defined differs by type of animal and context (and history).
Take the Zebra, which comes in three main flavors, though I’ll focus on two. The Grevy zebra is Equus grevyi and the plains zebra is Equus quagga, different “species” by classification, but able to breed with one another and create offspring which are able to reproduce. The two “species” are distinct from one another only in superficial morphological features (stripes and size) and behavior.
Gravy’s, though genetically indistinct from plains zebras, are listed as endangered, which gives them certain benefits and allows Kenya (for example) to legally restrict grazing for Maasai goat herders, with the support of international groups. It’s a simplistic example, but it makes little sense to me to ask that humans make sacrifices based on a flawed concept of what makes a “species.” It also makes little sense to create policy which impacts the lives of Africans based on a false paradigm created by 19th century Europeans (“Gravy” was a French President). Yet, here we are.
An aside, but I often think that people really believe that “species,” particularly large mammals, are individuals with distinct personalities and collective thought patterns. From the animals’ standpoint, extinction isn’t an issue. Rhinos don’t hold regular meetings and worry collectively about extinction. Individual rhinos are merely concerned with eating enough grass and mating when necessary.
3) The concept that nature is a fragile and static entity which would be ultimately benefit from our non-existence. This stems from traditional dichotomies of “man” and “nature” where man operates in his (male) world and nature operates in an entirely separate and unchanged sphere. In the West, this goes all the way back to Genesis. It is a simplistic and useless concept and does more harm than good.
Nature is a dynamic and constantly changing system of which we are one part. We create nature “reserves” which are thought to “preserve” the “natural” state of “nature” but even these are artificial, human constructed spaces, as we have dictated the location and killed all our large wildlife. We approach them are “preserves”, but forget that we have altered the system (by, for example killing the wolves or cutting all the pine trees in Michigan). Thus, arguing for the “preservation” of nature is somewhat disingenuous, since even by advocating for what part of nature needs to be preserved, we are writing its rules.
The question of whether the world would be better or worse off without us is fairly moot since humans are defining the terms of “better” and “worse.” Moreover, from the German cockroach’s (Blattella germanica) standpoint or the Black rat (Rattus rattus), humans could be considered a great thing as we tend to migrate and take our pests with us. If it could, Plasmodium falciparum should worship us like a God, since it wouldn’t exist without us.
I don’t see man as separate from nature. For better or for worse, we are a part of it. But after we have run our course, the world will go on without us. “Nature,” however it may be defined, has shown itself to be a tough beast in the past. Even if the entire planet became desertized (is that a word?), life would continue to exist. One day, with or without us, all life on Earth will cease to exist.
The most salient questions should revolve around how our environmental impacts affect our long term survival for humans. Focusing on our own needs is the only sustainable strategy (though I despise the word).
“Monsanto Protection Act”: Liberal Outrage or Herd Behavior?
First, there is no such thing as a “Monsanto Protection Act” anymore than there is any such thing as “Obamacare.” This is a term created by the item’s opponents to rile up opposition, rather than foster critical analysis. I think that Liberals should be well aware of the political problems associated with demonizing and reductionist labeling of things they don’t like.
Second, though Presidents can veto any bill that comes across his desk, the veto of appropriations bills are rare, and have often been overridden by Congress in the past. It may be a shock to liberals, but Presidents aren’t kings. Conservatives often don’t seem to understand the three branches of Government. Liberals often appear to understand it even less.
Third, there was hardly “no debate.” A Google search will reveal that discussions of this particular item go back at least to June of 2012 and the “Famer’s Assurance Provision” as it is correctly known is part of another Ag Appropriations bill which passed last year. Anyone who tells you this is new, is either lying, or doesn’t know what they are talking about. (Even Snopes took this on.)
Fourth, there is no evidence (that I’m aware of) that GMO’s, which are already in our food supply, are having deleterious effects on human health or the environment. There have been some studies on mouse models that I know of, but it appears that no one can really agree on what a “GMO” really is. Until we can nail that down, and have more informed discussion of which GMOs are “bad” and which are “good”, I don’t think that screaming about GMO’s is any more productive than poorly informed discussion of complex issues such as climate change.
I’m not trying to suggest that there are no effects of “GMOs” whatever they may be. I am saying that lefties are accepting that there are broad effects without question and are relying on less-than-scientific and politically motivated sources such as Salon and the Huffington Post to inform them. That’s a very, very dangerous position to take.
Fifth, I think we should all know by now that rightists use issues like this to weaken Democratic Presidencies. I was of the opinion that much of the furor over controversial portions of the 2012 NDAA bill was stoked by right wingers hoping for a Achilles heel in the 2012 Obama campaign. When we buy into this type of sensationalist reporting without examining the evidence, we play right into their hands.
Sixth, well, I had a sixth, but lost it. But back to GMO’s: It’s interesting that discussions of GMO’s in Sub-Saharan Africa are opposite of what we hear in the US. People view the American and European opposition to GMOs, some of which have the potential to increase food yield while minimizing inputs, as an infringement on developing countries’ rights of self determination. It’s easy to dismiss their concerns as uninformed. However, people and policy makers in developing countries face competing issues of immediate economic needs and broad environmental concerns. Lots of things seem obvious to us, but then we have most of our basic needs already met.
I mean this not as a defense of the Farmer’s Assurance Provision or anything else having to do with GMO’s (so chill out). The endless (and perhaps deserved) vilification of Monsanto has reached a point where examination of the facts is secondary to screaming like a blithering idiot. To me, this is dangerous. When we reduce ourselves to merely accepting positions without criticism, we allow ourselves to be manipulated by just about anything. Not everyone has the time to read all that is required to create a truly informed and reasoned opinion on all subjects, I realize. Striving toward obtaining as much information as is reasonable, however, and acting critically should be a priority for everyone, however.
Liberals are the smart ones. We can do better.
Food Prices and Conflict in Sub-Saharan Africa
I’ve written before on the link between unrest in South Africa and the problem of rising food prices. Looking at the plot of the right, it’s not hard to notice the similarities in the series of conflict events post 2005 to food prices as estimated by the FAO’s Food Price Index (FPI).
I began to wonder whether some of the recent rise in conflict events is somehow related to rising food commodity prices. Having found a correlation in South Africa, it’s not out of the realm of possibility.
I calculated the cross correlations between the FPI and conflict events and found that the FPI was predictive of conflict, but that conflict was not predictive of FPI. This was similar to what I found in South Africa.
Plotting the FPI against the number of monthly conflict events, I found something interesting. It appears that the two are mostly unrelated until the FPI reaches a threshold of approximately 200, then the number of monthly events shoots up. It is interesting to note that in other research, 210 was the assumed maximum price that households would absorb before taking to the streets.
I’ve repeatedly written on the problem of stock market speculation in food commodities as a cause for rising volatility in world food prices. I won’t beat this into the ground again. However, results such as these indicate that the problem of rising and volatile food prices is not just an economic problem, but also a problem of human health and welfare.
Kenya Day 4: Reflections on fish and global capitalism
Lake Victoria is a rich source of Nile Perch and Tilapia. Both fish are recent introductions to the lake. The Nile Perch, as a top predator, is associated with extensive ecological damage to the Lake’s ecosystem. Extensive fishing of the Nile Perch has led to a decrease in size, and the comeback of several types of local fish fauna.
Local fisherman on hand made boats use crudely fabricated nets to pull a few fish out of the water, they then sell either whole fish or smoked chunks to dealers. Dealers in turn sell the fish to processors, who then sell the fish to European, American and Japanese distributors. The distributors sell the fish to large supermarkets, who, of course, sell the fish to you and me.
Where the fish may bring as much as $20 a kilo in giants such as Whole Foods, a local fisherman can expect approximately $1.00, but the price is set by the world market and also subject to the whims of dealers. Without a union, fishermen have little means to negotiate prices.
As the lure of quick and plentiful cash is hard to resist, local fisherman have abandoned traditional fishing practices to enter the cash economy. This, of course, in itself is not a bad thing, but the money often gets spent on alcohol and prostitutes, rather than school and health fees for children. The nutritional profile of Lake communities suffers, and children are malnourished in an area that brings nearly $500 million dollars in revenue to Kenya.
Worse yet, ready cash creates a new market for sex work and positions are easily filled by poor women from the rural areas with no other options. The result is that the fish trade, and its destabilizing effect on families, is fueling HIV transmission here. Up 40% of people in any community along Lake Victoria may be HIV positive.
The trade has brought people from the inland areas to Lake Victoria, which has led to displacement of indigenous populations. Displacement has serious implications for security and livelihoods but in this area of intense malaria transmission, displacement and encroachment both impacts human health. The movement of populations has changed the genetic profile of local communities. Millennia of interactions between locals and parasite had led to at least some minimal level of genetic balance, which may have been disrupted by the introduction of new humans not acclimated to local strains of the parasite which causes malaria. This present added risks of serious disease.
Now, anyone who reads this blog knows that I am pro-economic development, pro-market and see no merit in suggesting that developing countries uselessly stick to old, antiquated and oppressive ways. No matter how nostalgic we may be for an idyllic past that may or may not have ever existed, the reality is that economic development in many cultural contexts has extended human life expectancy, reduced infant mortality, freed women to not be treated as cattle and reduced the subjugation of social minorities. But being pro-development means that one must support, err, development, which is only occurring slowly here.
The fishing communities suffer for a number of macro level factors.
- The nature of global economic disparities means that the government cannot step in and help negotiate fair prices for fish. The producers live entirely at the mercy of the market. The government would probably not be successful in artificially raising prices, but could help reduce price volatility by negotiating a yearly floor.
- There is no reliable means of taxing earnings to make sure that money is invested in schools and infrastructure (instead of alcohol). Say what one will about taxation, but the truth is that without it, power lines and roads don’t get built.
- The economy here is insufficiently diversified. The entire economy relies on fish, that developed countries may or may not buy. There is sadly little agriculture here, almost no tourism and, like just about all African countries, no manufacturing. A concentrated economy like that along Lake Victoria, could easily bust overnight.
All of these things, however, are challenges that all developing countries are facing. The economy along Lake Victoria is hardly an exception, but the mechanism are at least somewhat more obvious.
Kenya Day 3: Malaria Journal
Called “hearsay ethnography,” it makes ethnographers out of non-professional folks who are already embedded within the community. To date, it has been used in understanding the cultural understanding of HIV in Malawi.
We are turning local young people into anthropologists.
Through this technique, we can minimize the observer effect, i.e. the problem of influencing the data collection environment by being the odd, linguistically challenged white people of ambiguous intent. The writers have to write in English, in a manner assumed to be understood by educated folks, which presents problems of its own, but it’s a somewhat more flexible methodology.
It’s a valuable tool for medical anthropology. Through this study, we hope to begin to understand how people in this area conceptualize malaria, malaria treatment and health delivery.
I hired these guys last May, the money ran out, and I thought that the project was just a bust. To my surprise and delight, the data collectors are still writing in their journals and I was finally able to see the results.
Here’s a sample:
I attended the funeral of a child below five years old at Kamyeri. There were so many people who attended irrespective of their age or gender. The discussion about malaria broke out when the child’s father was narrating the cause of her death. He said that many people may think that his daughter had been bewitched but according to him, her death was as a result of his wife’s negligence.
He went on saying that he wasn’t at home when he received the news about her daughter’s illness. He told his wife to take the child to the hospital. However, he arrived home after two days to find out that the child had not been taken to hospital and have not received any kind of medication. He rushed her to the hospital but it was too late because the child died dew hours after the doctor had confirmed that she had serious malaria.
He went on saying if she would have diagnosed early enough, maybe she could have not died.
He added that before someone make or jump to any conclusions about the cause of any illness, he/she should go to the hospital and get tested in order to know the real cause of a disease he/she must be suffering from.
Then an old woman who was just in front of me said that she had informed the child’s mother to take to her the child so that she could treat her through “frito” and “suro.” ”Frito” means a method in which powder traditional herbs are administered to a patient through snifting, while “suro” means a method in which herbs in a powdered form is put on small cuts made using a knife. However, the woman did not turn up instead she went to a preacher to seek divine healing.
The old woman continued saying that the shivering and headache could have been treated using traditional herbs.