TOPLINE

Obesity class III was associated with significantly increased risk for all-cause and cause-specific mortality in adults younger than 65 years, while minimal differences in mortality risk were observed across obesity classes in adults 65 years and older.

METHODOLOGY

• Researchers analyzed data from the National Health and Nutrition Examination Survey from 1999 to 2018 to compare mortality across BMI obesity classes by age and sex.
• The final analysis included 41,903 adults, who were stratified by sex and into younger (18-64 years) and older (≥ 65 years) groups.
• Participants were categorized by BMI into underweight (< 18.4), normal weight (18.5-24.9), overweight (25-29.9), and obesity class I (30-34.9), class II (35-39.9), and class III (≥ 40).
• Researchers assessed deaths through December 2019, including all-cause mortality and cause-specific mortality from cardiovascular diseases, malignant neoplasms, and non-cardiovascular/non-cancer causes, as well as diabetes-related and hypertension-related mortality.
• Follow-up times were truncated to 200 months, with average follow-up ranging from approximately 64 to 109 months across groups.

TAKEAWAY

• Obesity class III was associated with higher risk for all-cause mortality compared with obesity class I in younger adults (adjusted hazard ratio [HR], 2.1; P < .05). No significant class differences appeared in older adults.
• The risk for cardiovascular mortality was higher for younger men and women with obesity class III vs class I (HR, 2.4-2.6; P < .0001), while no significant differences across obesity classes were observed in older adults.
• The risk for non‑cardiovascular/non‑cancer mortality was higher for younger adults with obesity class III vs class I (P < .05 for both men and women).
• Obesity class II and III (vs class I) were associated with higher risk for diabetes-related mortality in younger adults and in older men (P < .05). Hypertension‑related mortality was significantly higher only in younger women with obesity class III vs class I (P = .01).

IN PRACTICE

"These differences should be considered when designing obesity management strategies, as they highlight the need for more aggressive approaches for these populations," the authors of the study wrote.

SOURCE

The study was led by Amir Yazdanparast, School of Kinesiology and Health Science, York University in Toronto, Canada. It was published online on August 12 in Clinical Obesity.

LIMITATIONS

BMI was measured only once. Researchers could not examine some less common causes of death, because causes were grouped into broader categories. The large number of comparisons may have increased the odds of type I errors.

DISCLOSURES

The study did not report any specific funding. The authors declared no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.