Belly Fat Warning! WC-d/BMI-d Predicts Health Risks Better Than BMI

According to a new study published in the journal Nutrients, a new metric, WC-d/BMI-d, is proposed to assess health risks. It divides waist circumference (WC) and body mass index (BMI) deciles (rankings within a group) to show fat distribution. A value over 1 indicates more abdominal fat relative to weight, linked to a higher mortality risk even for those with a normal BMI. This association holds true across weight categories and strengthens with age, especially for men. This highlights the importance of considering WC alongside BMI for a more accurate picture of health.

Key Points

1. A New Metric for Obesity Risk: The study proposes WC-d/BMI-d (waist circumference decile divided by body mass index decile) as a way to assess obesity-related health risks. This ratio considers both overall weight (BMI) and fat distribution (WC).

2. WC-d/BMI-d and Mortality Link: The study found a significant association between a higher WC-d/BMI-d and increased risk of death from all causes. This means more abdominal fat relative to overall weight (higher WC-d/BMI-d) is linked to greater mortality risk.

3. Normal BMI Doesn't Equal Low Risk: Importantly, the association between WC-d/BMI-d and mortality was evident even among individuals with a normal BMI. This highlights the importance of considering WC even for those who appear healthy based on BMI alone.

4. WC-d/BMI-d increases with age: The study showed that WC-d/BMI-d tends to increase with age, particularly for men. Around 40 years old seems to be a critical point where waist circumference starts to outpace BMI for many people.

5. Consistent Risk Across BMI Categories: The association of WC-d/BMI-d with mortality risk remained consistent across different weight categories (normal weight, overweight, and obese). This suggests that increased abdominal fat is a risk factor regardless of overall weight.

6. WC-d/BMI-d as a Clinical Tool: The study suggests WC-d/BMI-d could be a valuable tool for doctors to identify individuals at higher risk, especially those with normal BMI but higher WC. This can help with preventative measures and lifestyle changes.

7. Limitations and Future Research: The study acknowledges limitations like its observational nature and single time point data. Future research should explore WC-d/BMI-d in diverse populations, link it to specific health outcomes, and use longitudinal studies to understand how WC and BMI changes impact health risks over time.

Waist Size Matters, Even for Normal Weight: New Metric Predicts Mortality Risk

Carrying excess weight around your middle, even if your overall BMI falls within the "normal" range, can significantly increase your risk of death from all causes. This is the key takeaway from a recent study published in a respected medical journal and based on data from the National Health and Nutrition Examination Survey (NHANES). The study introduces a new metric, WC-d/BMI-d, that combines waist circumference (WC) and body mass index (BMI) to provide a more nuanced picture of obesity-related health risks.

The Problem with BMI:

Traditionally, BMI has been the go-to measure for assessing obesity. It's a simple calculation based on weight and height, but it has limitations. BMI doesn't distinguish between muscle mass and fat, and it doesn't tell you where the fat is located. Research shows that carrying excess fat around your abdomen, also known as visceral fat, is a major risk factor for heart disease, stroke, type 2 diabetes, and other chronic conditions.

Waist Circumference and the Need for a Better Metric:

Waist circumference (WC) is a more accurate measure of abdominal fat. However, using WC alone also has limitations. Standardized cutoffs for healthy WC vary by gender and ethnicity. Additionally, the association of WC with health risks can differ depending on someone's overall weight category (normal, overweight, obese).

Introducing WC-d/BMI-d: A More Precise Measure:

This new study proposes WC-d/BMI-d as a way to address the limitations of both BMI and WC. Here's how it works:

• WC and BMI are each divided into ten categories (deciles) for men and women separately.

• Individuals are assigned a decile based on their WC and BMI measurements.

• WC-d/BMI-d is calculated by dividing the WC decile by the BMI decile.

• A WC-d/BMI-d of 1 indicates someone falls in the same decile for both WC and BMI (proportionate body fat distribution).

• A WC-d/BMI-d greater than 1 suggests a higher WC decile compared to BMI decile (more abdominal fat relative to overall weight).

• A WC-d/BMI-d less than 1 indicates the opposite (less abdominal fat relative to overall weight).

Key Findings of the Study:

• The study found a significant and direct association between WC-d/BMI-d and mortality risk. As the ratio increased (indicating more abdominal fat relative to weight), the risk of death from all causes increased.

• This association held true even after adjusting for factors like age, sex, smoking status, and chronic health conditions.

• Notably, a significant association was observed even among individuals with a normal BMI level. This highlights the importance of considering WC even for those who appear to be a "healthy weight" based on BMI alone.

• The study also revealed that WC-d and BMI-d tend to increase with age, particularly for males. Around 40 years old seems to be a critical turning point where WC outpaces BMI for many individuals.

• Interestingly, the association between WC-d/BMI-d and mortality risk remained consistent across different BMI categories (normal weight, overweight, and obese).

Let's imagine we have two individuals, Sarah and Michael, to understand how WC-d/BMI-d can be high even in normal BMI categories and why it consistently predicts risk across weight groups.

Sarah and Michael: Similar BMI, Different Fat Distribution

• Sarah: Sarah has a BMI of 22, which falls within the "normal" weight range. However, due to a lack of exercise and a diet high in processed foods, she has accumulated more fat around her waist (abdomen). Let's say her WC decile is 8 (a higher decile indicates a larger waist circumference).

• Michael also has a BMI of 22. But unlike Sarah, he maintains a healthy lifestyle with regular exercise and a balanced diet. His fat is more evenly distributed throughout his body, resulting in a lower WC decile, perhaps a 4.

Calculating WC-d/BMI-d

• Sarah: WC decile (8) / BMI decile (let's assume 5 for a normal BMI range) = WC-d/BMI-d of 1.6 (higher than 1, indicating more abdominal fat relative to overall weight)

• Michael: WC decile (4) / BMI decile (5) = WC-d/BMI-d of 0.8 (lower than 1, indicating less prominent abdominal fat)

Why WC-d/BMI-d Matters Across BMI Categories

The study highlights that even though Sarah and Michael have the same BMI (normal weight range), Sarah's WC-d/BMI-d is significantly higher due to her excess abdominal fat. This increased abdominal fat, regardless of overall weight category (normal weight in this case), is associated with higher mortality risk, according to the study.

Why This Result is Consistent Across Weight Groups

The study suggests that WC-d/BMI-d captures the risk associated with abdominal fat distribution, which is a stronger risk factor than overall weight alone. This explains why the association between WC-d and BMI-d and mortality risk was consistent across different BMI categories (normal weight, overweight, and obese) in the study.

Implications for Clinical Practice and Future Research:

This study suggests that WC-d/BMI-d could be a valuable tool for healthcare professionals. It allows for a more individualized assessment of obesity-related health risks, especially for those with a normal BMI but higher WC. Implementing WC-d/BMI-d in clinical practice could help identify individuals who might benefit from lifestyle changes or preventative measures to reduce their risk of chronic diseases.

Journal Reference

Reges, O.; Test, T.; Dicker, D.; Karpati, T. Association of Waist Circumference and Body Mass Index Deciles Ratio with All-Cause Mortality: Findings from the National Health and Nutrition Examination Survey. Nutrients 2024, 16, 961. https://doi.org/10.3390/nu16070961

Related

https://healthnewstrend.com/weight-loss-revolution-sleep-meals-and-the-habits-you-need-to-know-prioritize-sleep-and-limit-snacking

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