Are thin people weak

Large and fat people have a hard time with atrial fibrillation

UPPSALA. The risk of developing atrial fibrillation is known to be influenced by cardiovascular risk factors such as hypertension, diabetes, obesity or excessive alcohol consumption. However, there are also indications that height and weight influence this risk regardless of the BMI.

A team led by Dr. Kasper Andersen from the University of Uppsala followed up on such information on the basis of Swedish sample data. According to this, particularly tall and heavy people actually carry a particularly high risk of atrial fibrillation (J Intern Med 2017: online December 25).

For its analysis, Andersen's team evaluated information from around 1.1 million Swedish men who were called up for drafts between 1972 and 1995. In addition to weight and size, physical performance was also determined using an ergometer test and the strength of the handle. The latter correlates quite well with the percentage of muscle mass and the cardiovascular risk.

Correlation size and surface

Results of a Swedish study

»Men taller than 185 cm were 2.8 times more likely to develop atrial fibrillation than those under 174 cm.

»Men who weighed over 77 kg were also 2.8 times more likely to develop atrial fibrillation than those of low weight.

»Men with a body surface of over 2 m2 developed atrial fibrillation 3.2 times more often than those with a surface area of ​​less than 1.8 m2 Body surface.

After a median of 26 years, the researchers looked at how often the men - now 44 years old - had atrial fibrillation. To do this, they looked for information in various Swedish patient registries. They found information on hospitalization due to atrial fibrillation in almost 10,000 of the men. Two thirds of them had no other known comorbidities at the time.

The patients with atrial fibrillation were on average 2 cm taller and 3 kg heavier than men without such a disease, and the BMI was half a point higher. The physical performance in the ergometer test was slightly lower at 267 versus 274 watts, but the men who later suffered from atrial fibrillation performed slightly better in terms of grip strength (633 versus 616 Newtons).

Such differences do not seem dramatic at first glance, but if the individual quintiles are considered, an exponential increase in the risk of atrial fibrillation becomes apparent, especially for body size: men taller than 185 cm were 2.8 times more likely to be affected as such under 174 cm.

When the higher weight in taller people was taken into account, the rate was still twice as high. However, further adjustments for the strength of the handle and the performance in the ergometer test had no significant influence on the result. So, regardless of fitness, height seems to increase the risk of atrial fibrillation.

Men weighing over 77 kg were also 2.8 times more likely to develop atrial fibrillation than those with a low weight (less than 62 kg). After taking the size into account, the rate was doubled, but the relationship was further weakened when Andersen's doctors also considered hand grip strength and ergometer tests. The BMI alone was only weakly associated with atrial fibrillation.

Enlarged atrium the problem?

The atrial fibrillation rate was most clearly associated with body surface area. People with a large surface are usually both: particularly tall and particularly fat. As the scientists found, men with a body surface of over 2 m fell ill2 a total of 3.2 times more likely to have atrial fibrillation than those with a surface area of ​​less than 1.8 m2. The strength of the grip and the ergometer performance hardly had any influence.

From a purely mathematical point of view, this results for people with a body surface of 2.4 m2 even an eleven times higher risk of atrial fibrillation. Such people weigh around 100 kg with a height of 2 m and are not even fat with a BMI of 25. People weighing 120 kg and 180 cm tall come across a similar surface, but with a BMI of 37 they are already severely obese.

Andersen's team explains the increased risk of particularly tall and fat people with an enlarged atrium and increased ejection volume. According to the results of many other studies, the risk of developing atrial fibrillation also depends on such factors.