The treatments have leveled off cholesterol and blood pressure levels in adults over 40 with and without obesity, according to a study

As always, The Lancet has published another excellent article based on a large database of nearly one million adults in developed industrialized countries. However, this data should be used with caution, as it comes from observational studies with large populations, which can establish relationships but never causality. We must always remember this.

The study is interesting because it analyzes data on body mass index, blood pressure, and cholesterol levels from this population. In practical terms, I would highlight that over time we have become more aware that people with obesity have a high cardiovascular risk. This is evidenced by the higher prevalence of cardiovascular events and comorbidity associated with obesity, such as hypertension, high cholesterol, and diabetes.

We have increasingly better therapeutic tools that can bring blood pressure and cholesterol levels in people with and without obesity back to the same level. However, we must be cautious with this message because we know that people with obesity have a high cardiovascular risk, which is why they are being treated for hypertension and cholesterol. But the cardiovascular risk doesn't disappear; it remains. This study failed to include diabetes, low-grade chronic inflammation, and cancer. Obesity is a much greater risk factor than hypertension and cholesterol alone.

The study is very good, of high quality, and the news is positive: we are increasingly better at treating high blood pressure and cholesterol, and this could lead to a reduction in the cardiovascular risk associated with obesity in adults. However, we must emphasize that obesity has not become benign or controllable, because treating obesity means treating the root cause of the problem, and the root cause is metabolic and adiposopathy. It's not just about treating the consequences of obesity. Furthermore, this study overlooks many of the more than 200 complications associated with metabolic syndrome, which is a cardio-renal condition linked to obesity, such as diabetes, fatty liver disease, kidney disease, cancer, and sleep problems.

Obesity remains a major clinical problem. Treating obesity means addressing each and every cardiovascular risk factor, from its metabolic origin, without neglecting any of them. It's a treatment we call comprehensive, and we must be aware that it's crucial to address the root cause and prevent it in its early stages.

My headline would be that time is of the essence when treating obesity and its cardiovascular complications; time is of the essence for prevention and for initiating the correct treatment for this chronic and complex disease.

It is a fairly robust and ambitious study in terms of scale: it combines data from nearly one million people in seven countries over more than three decades, something unusual in this type of research. The methodology is well explained, and we commend the authors for their honesty in acknowledging several of their own limitations.

The main finding—that the blood pressure and cholesterol levels of older adults with obesity are increasingly similar to those of people of normal weight, thanks in large part to increased medication use—is consistent with what we already knew about the advancement of pharmacological treatment in recent decades. It is not an unexpected finding, but it does provide a useful quantification of the phenomenon.

However, caution is advised, as the study only measures two of the many mechanisms by which obesity influences health (blood pressure and cholesterol); it does not analyze inflammation, insulin resistance, diabetes, joint problems, or some types of cancer, which are also linked to excess weight. Furthermore, this improvement is only observed in people over 40: in young people with obesity, the metabolic risk remains significantly higher than in those of normal weight.

[Regarding potential limitations] The study uses BMI (Body Mass Index) to define obesity, but health professionals have long pointed out that this measure is insufficient to assess the true risk induced by obesity: it does not distinguish between fat and muscle, nor does it indicate where that fat accumulates (which is clinically the most important factor), and the study also does not include any data on the participants' diets. This means we cannot know for sure how much of the observed improvement is actually due to the medications and how much to other unmeasured factors.

In addition, they use the same BMI thresholds to classify obesity in all countries, even though it is known that, for the same BMI, Asian populations tend to have more body fat and a higher cardiometabolic risk than Western populations. This may make it difficult to fairly compare the results between different countries, such as Japan and the United States. In fact, cases of severe obesity in the Asian countries included in the study are so rare (less than 2-3% of the population) that many of these estimates had to be excluded or are unreliable. Furthermore, a potential survival bias is likely (people with severe obesity and poorer metabolic health die earlier and are not surveyed in their later years), adding uncertainty to this specific part of the study. Therefore, in the group of older adults with obesity in general, some of the observed improvement could be due to a selection effect: people who reach advanced ages with obesity and a poorer metabolic profile are more likely to have died earlier, so the survivors who enter the study might be biased towards the healthiest within that group.

Another potential limitation is that the study only records whether or not the person is taking medication, but not the intensity or type of treatment. This makes the estimates of improvement approximate, not a direct causal link. The use of other possible statistical tests to estimate the impact of different drugs could have been considered, among other possible suggestions.

Finally, the article does not detail how many people each country contributes to the overall results. That is, it indicates the total sample size used, but without specifying the representation from each country, it is difficult to assess whether the findings are dominated by one or two countries with larger samples (such as the US or England). While it is true that the appendices contain additional information on BMI ranges and age groups, etc., it would be advisable to include this information in the main article for optimal reading and evaluation.

In conclusion:

These results could be good news regarding the control of blood pressure and cholesterol in older adults with obesity thanks to medical treatment, but they cannot be considered a sign that obesity is no longer a health problem, and the results should be read with these methodological nuances in mind.

What do you think of the article overall? Is it of good quality?

“This article presents a sound design for a retrospective study and is of good quality. Suffice it to say that it presents a sample size of almost one million patients, 110 surveys, and data from various countries on different continents. It is a study that covers the period from 1990 to 2024, which gives it a very broad time frame; therefore, its conclusions can be supported by the sample size without any problem.”

How does it fit with the existing evidence, and what implications might it have? Could it suggest that, with treatment, obesity is no longer a clear risk factor?

“This study doesn't offer any scientific discoveries that common sense couldn't already explain. It's logical that obese patients treated with lipid-lowering and antihypertensive drugs tend to experience a decrease in their blood pressure and lipid levels. If these results didn't follow this pattern, we would be applying ineffective pharmacological treatments and misleading the patient.

However, I think it's very important to extrapolate these results from different perspectives. On the one hand, regarding obesity: I don't believe it sends the message that obesity isn't a risk factor for many comorbidities; on the contrary, it clearly introduces this in the article's content. What is important is that it makes us reflect and helps us understand that those of us who live in industrialized countries have an effective healthcare system that cares about our well-being, which we often fail to appreciate, with access to medical treatments, specifically in our country, that are practically free. In other words, obese people in industrialized countries with available medical treatments have better quality of life and they will probably live longer. This idea is definitely worth taking to heart, to appreciate how far we've come, where we'll go, and how essential it is to sustain our system.”

Are there any significant limitations to consider?

“No, the study is well done. A comparison with developing countries would be welcome, but I suppose that would be the subject of another article.”