BA (Hons) Philosophy, Politics & Economics student, University of Oxford
Urbanisation is occurring rapidly in low- and middle- income countries (LMICs), yet comparatively little is known about the effect urbanisation will have on health in this region.  Of those who have tried to investigate this relationship, similar problems and limitations have emerged ranging from conceptual ambiguity, insufficient data surveillance to a general lack of research.
One of the most pressing limitations within the field is the conceptual ambiguity of ‘health’ and ‘urbanisation’. Given the broadness of these concepts, and the multitude of indicators they may refer to, there is significant heterogeneity between studies regarding how these concepts are measured. For many studies, this meant that meta-analyses could not be conducted.    But even when trying to ascertain the relationship between a more specific outcome, such as diabetes, differing diagnostic criteria can prevent more meaningful comparisons being made. 
Conceptual ambiguity is also an issue with urbanisation – as it appears to be used interchangeably with urbanicity. At present, the bulk of research on urbanisation and health in LMICs has focused upon urbanicity – addressing the question: What is the effect of living in an urban area as opposed to a rural area?  However, this is conceptually distinct from urbanisation – which is the process of change from a rural to an urban area. But even within the narrower question of urbanicity – the measures used to classify regions varies within the literature. 
Insufficient data surveillance
Moving beyond conceptual issues, a secondary issue which researchers face is the lack of granular local- and individual-level data. This is particularly the case with urbanisation, wherein many studies use secondary population data to assess urbanicity.  The issue with this approach however is that fails to consider the intra-national variations in urbanicity. Furthermore, population data means that researchers are not able to disaggregate urbanisation and establish the impact specific processes have on health outcomes.
Analogously, attempts to study specific health outcomes have faced similar issues. Due to many LMICs having poor health data surveillance, many are not able to provide disaggregated data of health outcomes in urban as opposed to rural areas.  In doing so, it limits policy recommendations for local- and individual-level interventions, which can be less resource-intensive than national-level interventions.
Lack of research
But even researchers who can overcome the above limitations are still faced by another problem: a lack of high-quality research. In one survey article, researchers attempted to investigate the relationship between of stunting and nutritional interventions in slums within LMICs.  Even though the researchers searched 32 databases, it was only able to find 15 relevant studies – of those none were deemed to have a low risk of bias, four were of moderate risk and the rest had high overall risk of bias. Ultimately preventing researchers from making concrete conclusions.
In many cases however, it is not simply a case that there is a lack of high-quality research, but there appears to be a lack of research in LMICs in general. This is best seen in a review article on desert sand and air quality, De Logueville (2010) notes how even though one of the most affected regions was West Africa, most of research was conducted in Europe.  Reflecting a general trend of a discontinuity between regions most affected and where research is conducted.
Overall, this blog should have highlighted the current limitations and challenges which exist in this field of research.
 Thondoo, M., 2021. Urban Health in Cities of Low- and Middle- Income Countries – Blog. [online] ISGlobal. Available at: https://www.isglobal.org/en/healthisglobal/-/custom-blog-portlet/la-salud-urbana-en-las-ciudades-de-los-paises-de-ingresos-bajos-y-medios/6113739/0.
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 De Longueville F, Hountondji YC, Henry S, Ozer P. What do we know about effects of desert dust on air quality and human health in West Africa compared to other regions? Sci Total Environ. 2010 Dec 1;409(1):1-8. doi: 10.1016/j.scitotenv.2010.09.025. Epub 2010 Oct 8. PMID: 20934742.