Waist-Hip Ratio Excels at SCD Risk Prediction in ARIC Cohort

May 10, 2012

May 10, 2012 (Boston, Massachusetts) — The risk of sudden cardiac death (SCD) tied to markers of obesity in a major community-based cohort study climbed faster with increasing waist-to-hip ratio (WHR) compared with two more familiar measures [1]. And for WHR but not for the other two measures — waist circumference and body-mass index (BMI) — the link with SCD was independent of diabetes, coronary disease, heart failure, and hypertension.

Of the three obesity measures, observed Dr Selcuk Adabag (University of Minnesota and VA Medical Center, Minneapolis), lead author of the analysis, WHR may have been more independently predictive of SCD because it "adjusts" for variation in patients' body frames and thereby becomes a more accurate surrogate measure of abdominal obesity.

Dr. Selcuk Adabag

As hip circumference isn't often measured in North America or Europe, while BMI and waist circumference are routinely documented, Adabag told heartwire , the study suggests current practice may fall short for reliably assessing SCD risk based on adiposity.

The analysis from the multicenter Atherosclerosis Risk in Communities (ARIC) study, which Adabag presented here at the Heart Rhythm Society 2012 Scientific Sessions, included 15 156 people (mean age 54 years), of whom 55% were women and, by design, one-fourth African American. The 301 SCD events observed over an average 12.6 years of follow-up were independently adjudicated. All three obesity markers predicted SCD risk regardless of race.

The risk of SCD went up significantly with increasing levels of all three obesity measures in an analysis that controlled for age, sex, race, study center, education level, smoking, and CHD family history. With further adjustment for several markers and comorbidities known to be associated with obesity, WHR emerged as the only independent predictor of SCD risk.

Hazard Ratio (95% CI) for Sudden Cardiac Death Over Mean 12.6 Years in ARIC, by Obesity-Measure Quintiles

Obesity measure

Quintile 3

Quintile 4

Quintile 5

p for trend*

BMI (reference: quintile 2)

25–29.9

30–34.9

>35

 

Model 1

1.13 (0.84–1.51)

1.41 (1.01–1.96)

1.85 (1.22–2.80)

0.005

Model 2

0.88 (0.65–1.19)

0.91 (0.64–1.29)

1.05 (0.69–1.62)

0.84

Waist circumference (reference: quintile 1)

89–96.9 cm (female), 96–100.9 cm (male)

97–106.9 cm (female), 101–107.9 (male)

>107 cm (female), >108 cm (male)

 

Model 1

1.10 (0.8–1.6)

1.22 (0.8–1.8)

1.61 (1.1–2.3)

0.004

Model 2

0.82 (0.6–1.2)

0.78 (0.5–1.1)

0.95 (0.7–1.4)

0.76

Waist-hip ratio (reference: quintile 1)

0.87–0.91 (female), 0.95–0.97 (male)

0.92–0.96 (female), 0.98–1.00 (male)

>0.97 (female), >1.01 (male)

 

Model 1

1.43 (0.94–2.17)

1.97 (1.33–2.92)

2.35 (1.59–3.47)

<0.0001

Model 2

1.09 (0.72–1.65)

1.33 (0.89–1.99)

1.40 (0.94–2.11)

0.009

*trend from quintile 1 to quintile 5

Model 1: Adjusted for age, sex, race, center, education level, smoking status, and CHD family history

Model 2: Further adjusted for diabetes, low-density-lipoprotein levels, hypertension, prevalent CHD, heart failure, and LV hypertrophy

The significant linear relationships between SCD risk and all three indirect measures of obesity in the first multivariate analysis were not surprising, according to Adabag. But, he said, it was unexpected for WHR to emerge alone with further adjustment for diabetes, hypertension, CHD, and heart failure. It suggests that any SCD predictive value to BMI and waist circumference is somehow dependent on development of other disorders.

Apparently, for example, elevated BMI "leads to hypertension, diabetes, and coronary heart disease, which in turn lead to sudden death." But abdominal obesity as measured by WHR, in particular, seems to have a more direct effect on SCD risk.

Adabag discloses receiving research grants from Boston Scientific and Medtronic. None of the other authors had disclosures.

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