BMI's not all
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BMI Isn’t the Only Measure Needed to Predict Mortality Risk
Associations between BMI and mortality have been inconsistent in the past, with some studies showing elevated risk and others finding lower risk for adults who are overweight, the study’s authors wrote in PLOS ONE. And most studies to date have used data from the 1960s through 1990s that predominantly include non-Hispanic White men and women.
To offer additional insight, Aayush Visaria, MD, MPH, analyzed recent health survey data from 1999 through 2018 to extrapolate BMI and found that although being obese was associated with an increased mortality risk, being a healthy weight or overweight had almost no effect on a person’s risk of dying.
“Especially in the overweight range, BMI doesn’t differentiate mortality risk, so I think it’s important to include other measures of adiposity to try to better risk stratify people,” Visaria, of Rutgers Institute of Health in New Jersey, said in an interview with JAMA. He coauthored the study with Soko Setoguchi, MD, DrPH, of Rutgers Robert Wood Johnson Medical School.
The role of BMI as a stand-alone metric for obesity gained new attention in June when the American Medical Association, which publishes JAMA, urged physicians not to use it singularly to assess healthy weight.
The new analysis only examined all-cause mortality, not the association between BMI and risk of cardiovascular disease or diabetes. These diseases, along with hypertension, are the leading causes of premature death in the US, and it is well-established that elevated BMI contributes to these conditions, the authors noted in their study.
What is the relationship between falling off a pole-dancers pole and mortality?
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Waist-Hip Ratio a Stronger Mortality Predictor Than BMI
TOPLINE:
Compared with body mass index (BMI), waist-hip ratio (WHR) had the strongest and most consistent association with all-cause mortality and was the only measurement unaffected by BMI.
METHODOLOGY:
- Cohort study of incident deaths from the UK Biobank (2006-2022), including data from 22 centers across the United Kingdom.
- A total of 387,672 participants were divided into a discovery cohort (n = 337,078) and validation cohort (n = 50,594), with the latter consisting of 25,297 deaths and 2297 controls.
- The discovery cohort was used to derive genetically determined adiposity measures while the validation cohort was used for analyses.
- Exposure-outcome associations were analyzed through observational and mendelian randomization (MR) analyses.
TAKEAWAY:
- In adjusted analysis, a J-shaped association was found for both measured BMI and fat mass index (FMI), whereas the association with WHR was linear (hazard ratio 1.41 per standard deviation (SD) increase).
- There was a significant association between all three adiposity measures and all-cause mortality, with odds ratio 1.29 per SD change in genetically determined BMI (P = 1.44×10−13) 1.45 per SD change in genetically determined FMI, 1.45 (P = 6.27×10−30), and 1.51 per SD change in genetically determined WHR (P = 2.11×10−9).
- Compared with BMI, WHR had the stronger association with all-cause mortality, although it was not significantly stronger than FMI.
- The association of genetically determined BMI and FMI with all-cause mortality varied across quantiles of observed BMI, but WHR did not (P = .04, P = .02, and P = .58, for BMI, FMI, and WHR, respectively).
IN PRACTICE:
"Current World Health Organization recommendations for optimal BMI range are inaccurate across individuals with various body compositions and therefore suboptimal for clinical guidelines."
More on the FMI (Fat-Mass-Index)
