乌鸦传媒

Obesity was tied to a shorter lifespan, and a significantly increased risk of cardiovascular morbidity and mortality compared with normal BMI, researchers reported.

In addition, being overweight (BMI 25.0-29.9) was linked with a significantly increased risk of developing cardiovascular disease (CVD) at an earlier age, according to Sadiya S. Khan, MD, of Northwestern University Feinberg School of Medicine in Chicago, and colleagues.

Men and women of all ages with a higher BMI were found to have both an earlier onset of incident CVD followed by shorter overall survival, they wrote in.

Also, middle-aged men had significantly shorter overall time of survival if they were obese (27.2 years) or morbidly obese (23.4 years), compared to those who were either normal weight (29.1 years) or overweight (29.3 years). Similar findings were reported in middle-aged women, while overweight (31.8 years), obese (29.8 years), or morbidly obese (27.2 years) women had shorter survival time compared to normal weight women (33.2 years).

"In recent years, controversy has grown about the benefits of obesity in patients with cardiovascular disease," Khan explained to 乌鸦传媒. "This was concerning to us as it may have led to detrimental consequences related to confusion about the true adverse effects of obesity and risk of cardiovascular disease."

"We believe the life-course perspective of our study helps shed new light on the fact that participants who were obese had a higher risk of developing cardiovascular disease over follow-up. Further, they developed cardiovascular disease at a younger age and spent more years living with cardiovascular disease despite not living as long," she added.

The analysis pooled data from 10 prospective cohort studies, all of which had a minimum of 10-years follow-up time after initial examination and tracking of cardiovascular events, totaling to 190,672 individual examinations with 3.2 million person-years of follow-up. All individuals were free of CVD at baseline, but with BMI index and CVD outcomes data available.

Stratified into age groups -- young (ages 20-39 years), middle-age (40-59), and older (60-79) -- the highest prevalence of diabetes and hypertension were seen among the older age group. Among all the age groups, the higher proportion of men fell into the overweight category, while women were more likely to be of normal weight.

Among middle-aged men, there were 13,457 incident CVD events total, with the highest percentage attributed to fatal or nonfatal myocardial infarctions. This incidence rate of CVD events increased accordingly with BMI range, with the highest seen in those who were morbidly obese. Compared with men who died due to non-CVD related causes -- the most common of which was cancer -- men who weighed more had a significantly higher rate of experiencing their first CVD event.

When compared to middle-aged men of normal weight, those in higher BMI categories had an increased incidence of CVD:

• Overweight: adjusted competing HR 1.21 (95% CI 1.14-1.28)
• Obese: 1.67 (95% CI 1.55-1.79)
• Morbidly obese: 3.14 (95% CI 2.48-3.97)

Similar event rates were seen among middle-aged women of a higher BMI, as well:

• Overweight: HR 1.32 (95% CI 1.24-1.40)
• Obese 1.85 (95% CI 1.72-1.99)
• Morbidly obese: 2.53 (95% CI 2.20-2.91)

Both men and women had a longer time to first CVD event if they were of normal weight by around 7.5 year and 7.1 years, respectively, when compared with people with morbid obesity.

The researchers noted that the morbidly obese category likely saw the highest rate of CVD events mainly due to a five-fold increase in the incidence of congestive heart failure events. These patterns were also seen in the younger and older age groups.

Although the notion of the "obesity paradox" -- when people with a higher BMI might actually live longer after CVD onset compared to those of normal weight -- has been described in some prior studies, the researchers noted that their findings suggest that "this occurs because of a trend toward earlier onset of disease in individuals who are overweight and obese."

"This false reassurance is akin to the phenomenon of lead-time bias observed in other situations, such as with cancer screening. This is especially important because overweight status has been associated with poorer quality of life, functional impairment, and greater work-related disability," the group wrote.

Study limitations included the use of baseline BMI at index ages without accounting for change in BMI across follow-up, the authors noted.

Khan suggested that future research should focus on "strategies to promote primordial prevention in maintenance of a healthy BMI throughout the lifespan from childhood to adulthood to promote longer, healthier lives."

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