Obesity Shown to Adversely Influence Heart Health Prior to Symptom Onset

From a 4-decade evaluation of adults classified as being at a stable normal weight, considered to be at a stable overweight level, or having stable obesity, individuals who fell into the 2 latter categories had higher levels of cardiac troponin I, a biomarker known to indicate cardiac injury, including heart failure. Persons with long-standing obesity also had a greater chance of cardiac injury, even in the absence of symptoms, according to study findings from Norway published in Journal of Internal Medicine.

“Although obesity is associated with subclinical myocardial injury as quantified by concentrations of cardiac troponin T,” the authors wrote, “whether lifetime excess weight history is associated with increased concentrations of cardiac troponin I and how indices of abdominal adiposity and glycemic dysregulation affect these associations remain unclear.”

A high-sensitivity assay gauged cardiac troponin I levels among 9739 Trøndelag Health Study participants at their fourth study visit. For this study—the largest population-based cohort in Norway—the cohort was evaluated at an overall 4 participant visits: visit 1 took place between 1984 and 1986; visit 2, 1995 and 1997; visit 3, 2006 and 2008, and visit 4, 2017 and 2019. Body mass index (BMI) results from visits 1 and 4 were also compared. A majority of participants were women (59%), and the final median study age, as indicated at visit 4, was 68.7 (range, 52.6-101) years.

An overall 84.1% of the entire study cohort had detectable cardiac troponin I levels, with the median (interquartile range) measurement being 2.5 (1.5-4.5) ng/L. These levels were evaluated using nonfasting serum samples collected during the period of visit 4.

The greatest associated risk of adverse cardiac outcomes was seen among those classified into the stable obesity category, who had a 70% greater risk of elevated cardiac troponin I at visit 4 (odds ratio [OR], 1.70; 95% CI, 1.33-2.17). These individuals also more often had hypertension and diabetes. Participants in the stable overweight group also had an increased risk, albeit to a lesser degree at 27% (OR, 1.27; 95% CI, 1.09-1.47; P < .001).

In addition, compared with those who maintained a normal weight over the 40 years of the study, the stable obesity group had a 22% greater risk of higher concentrations of cardiac troponin I (95% CI, 14.1%-29.9%; P < .001), despite the fewest study participants (9.9%) being classified into this group. Most of the entire study group (47.8%) was categorized as having a stable normal weight.

Findings were not influenced by dysregulated glucose metabolism or abdominal obesity, the authors highlighted. However, “BMI and body weight at study visit 4 exhibited comparable associations with subclinical myocardial injury, and more strongly so than body fat mass and visceral fat area,” they added.

In addition to heart failure and coronary artery disease, long-term obesity has been linked to greater risks for stroke, peripheral artery disease, and sudden cardiac death and has been shown to have independent associations with hypertension, diabetes, inflammation, and dyslipidemia. Meanwhile, previous research has shown a link between elevated cardiac troponin I and most cardiovascular conditions.

Together, obesity and having a high cardiac troponin I measure combine to especially increase the risk of heart failure.

“Our data support a direct detrimental effect of long-standing obesity on cardiovascular health,” the authors concluded.

Still, because of study limitations that include lack of a retrospective biomarker analysis, the cardiac troponin I assay used having low analytical precision, recall bias, lack of myocardial imaging, and most study participants being of European Caucasian ethnicity, the results may not be generalizable to a wider population. Additional study is needed.

Reference

Lyngbakken MN, de Lemos JA, Hveem K, Røsjø H, Omland Torbjørn. Lifetime obesity trends are associated with subclinical myocardial injury: the Trøndelag Health Study. J Intern Med. Published online October 19, 2021. doi:10.1111/joim.13391