All levels of overweight and obesity tend to persist over time, with severe obesity taking the largest toll on cardiovascular health, according to a new study published in the journal BMC Public Health.
The study authors noted that while obesity is widely recognized as a risk factor for cardiovascular disease, the relationship between body weight changes over time and the risk of cardiovascular disease hasn’t been studied in great depth. So the researchers decided to look at how body-mass index (BMI, a measure of body weight that takes height into account) tended to change over time in people who were overweight or belonged to three different categories of obesity severity. The UK-based study had 264,230 participants, with an average age of 49.5 and an average BMI of 33.8. The participants all belonged, at the beginning of the study, to one of four different BMI categories: overweight (BMI of 25.0 to 29.9), class 1 obesity (30.0 to 34.9), class 2 obesity (35.0 to 39.9), and class 3 obesity (40.0 or greater).
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BMI tends to increase over time
In all four groups, BMI tended to slowly and steadily increase over time, increasing by an average of 1.06 during an average follow-up period of 10.9 years. During this period, study participants with a higher BMI experienced a higher rate of cardiovascular problems. Compared with those in the overweight category, those with class 3 obesity were 3.26 times as likely to experience heart failure (inability to adequately pump blood to meet the body’s needs), 3.31 times as likely to die of cardiovascular causes, and 2.72 times as likely to die of all causes. These relative risk levels were calculated after adjusting for demographic differences between the groups (like income level and race or ethnicity), as well as known cardiovascular risk factors at the beginning of the study other than BMI.
As noted in a press release on the study from Britain’s University of Nottingham, the researchers also found that people in the top two categories of obesity were no more likely than those in the overweight category to have a stroke or coronary artery disease (CAD, the buildup of plaque in the arteries leading to the heart). Greater socioeconomic deprivation (lower income and wealth) was linked to greater severity of obesity within the study group.
The study didn’t look at participants’ diets or physical activity, so it’s unknown what role these factors might play in BMI over time. More research is needed, the study authors emphasized, to understand the role of diet and physical activity in the persistence of overweight or obesity, and whether any medical or public health interventions could have a meaningful impact on these trends.
“Despite widespread efforts to prevent and manage obesity, the majority of adults who are overweight or obese in the general population continue to remain so in the long term,” said study author Barbara Iyen, MBBS PhD MRCGP, in the press release. “More effective policies and weight management interventions are needed urgently to address this increasing burden and associated adverse health outcomes.”
Want to learn more about protecting your heart? Read “Be Heart Smart: Know Your Numbers,” “Does Diabetes Hurt Your Heart?” “Fight Off Heart Disease With These Five Heart-Healthy Foods” and “Lower Your Risk of Heart Disease.”
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