Cholesterol levels in the Caribbean
Medicine is full of examples where we use data collected on one group of people and then apply it more generally across populations, sometimes incorrectly. Some blood pressure lowering medications, for example, we now know work better in certain groups than others, probably for genetic reasons. Blood cholesterol - or more accurately blood lipid levels - is another example. And working in the Caribbean and Latin America, that’s what Rodrigo Carillo has been looking at, as he explains to Chris Smith…
Rodrigo - So we wanted to know what was the most common lipid problem in Latin America and the Caribbean. There are plenty of large scale studies in Europe, US and Asia as well, but in low-middling countries like Latin America and Caribbean, and also in Africa, these sort of quote unquote well-known questions are still unanswered.
Chris - And obviously this is important in terms of a health priority, because if we want to manage disease and anticipate disease risk, and therefore plan ahead appropriately, we need to know these sorts of numbers rather than just assume that what's true in North America or Europe applies also to other countries as well.
Rodrigo - Absolutely. For this kind of thing, we're perhaps still trying to answer the most basic questions. Like how many are we, how many are there? Where are they? There were some smaller studies in some countries, but looking at the region as a whole, we will still need to answer many questions.
Chris - Did the raw material exist for you to study or did you have to literally embark on this from the get go physically drawing blood and looking at people's cholesterol levels to find this out?
Rodrigo - In this work we rely on published data. So we did a systematic review, which in simple terms is looking through every single journal article, scientific papers, and extracting information when they measure lipids or any sort of cholesterol to have information from as many countries as possible.
Chris - So when you amalgamate all of these research studies, how many subjects, how many people do you end up with to consider?
Rodrigo - I think it was about 150,000.
Chris - So big numbers, these, and when you extract the data, are there any obvious trends?
Rodrigo - Low HDL is not very good for your health. And we found out it was the most common trait.
Chris - What about the other risk factors like triglycerides, and also like LDL bad cholesterol that also furs up arteries? What do they show?
Rodrigo - For LDL we also find quite large estimates, quite a large prevalence though it was smaller than for HDL. For triglycerides we also find large numbers and it was interesting to see that triglycerides was a little bit higher in what we call Andean Latin America, which is perhaps Peru, Ecuador, and Valeria. And it could relate with the sorts of diets they have in these countries, which is perhaps most based on carbohydrates.
Chris - To what extent do you think what you're seeing here is just the environment in which people live and perhaps their lifestyle. In other words, I know if for instance, you drink too much alcohol, you depress your HDL good cholesterol. And to what extent is this relevant to a person's ethnicity? Because obviously these areas have also seen a lot of immigration over the years and those people could quite possibly have brought disease risk with them couldn't they? So how do you dissect out if you can, those effects?
Rodrigo - Yeah, it's difficult to do that with this work. Though I think you are right. And lifestyle will have a lot to do with that, but not only lifestyles, but also opportunities to have a better lifestyle, for example, physical activity and also diet. What sort of diet do you have access to? Unfortunately, like you say, you can't differentiate migration between external and internal immigration and sometimes internal immigration coming from rural areas to urban areas - these people do not usually have the highest standards of living. Of course this has implications for the diet they can afford.
Chris - What's your take home messages then from what you've discovered - depressed HDL, some high levels of LDLs and some high levels of triglycerides as well, and some possible associations with diet. What are your take home messages and how should this inform our understanding of heart disease risk in these geographies going forward?
Rodrigo - The take home message is that LDL is important. And many, if not all, clinical guidance target this with pharmacological treatment. And there is lots of evidence of how lipid lowering medications work and do great things for your health. But these medications do not usually work for HDL. So the take home message I think is that we have to work together from a practitioner perspective prescribing medicines, where these are required, but also from the public health perspective, in which we should give people the opportunity to embrace a healthy lifestyle with access to physical activity, with access to adequate diet. And to include both in clinical guidelines, as well as in policies or strategies. Over the last year, there has been a lot of evidence and a lot of work in obesity and in blood pressure, and diabetes, but lipids and cholesterol overall have not been very well paid attention to.