Sometimes Less Is More

Letters to the Editor regarding the article Differences in Anthropometric Measures Based on Sex, Age, and Health Status Findings From the German National Cohort (NAKO) by Michael J. Stein, M.Sc., Dr. oec.-troph. Beate Fischer, et al. in issue 7/2024

The German National Cohort (NAKO) health study is set in 18 sites in Germany. It is funded with a total of €400 million, has a response rate or 17%, and aims to examine the most widespread diseases. This is a worthwhile approach (1). However, we have doubts, whether this issue can be realized by applying the selected anthropometric parameters.

Measuring hip circumference is a complicated parameter to determine (2). This might be the reason that only 7 out of 18 study sites perform this measurement (drop-out rate about 76%). Nevertheless, correlation coefficients are calculated, not indicating, which sample sizes and which study groups are included into the calculations.

For several years, it has been common practice to transform anthropometric measurements into index factors. The most commonly used indices—body mass index (BMI), waist to height ratio (WHtR), waist to hip ratio (WHR)—are surrogate markers for estimating fat mass as a health risk. The validity of these and other indices has been discussed in detail (2, 3). Hardly any index reaches AUC values (area under curve) >0.70. This is an order of magnitude that is unable to deliver further insight or sustainable information on individual patients (3).

As a consequence of this fact bioelectrical impedance analysis (BIA) became part of the present study.

It is therefore all the more surprising that the very BIA data to assess body fat are not presented in the article (1). Instead, associations between health status and subcutaneous adipose tissue (SAT) measurements are shown, which – for example – persist on a level of 1.9 cm, although the body fat percentage increases from 21.3% to 29.1% (men).

DOI: 10.3238/arztebl.m2024.0140

Prof. Dr. med. Nicolaus Dahlmann

stringID, Institute for Biometry and Nutrition, Hamburg

Prof. Dr. med. Dietrich Klingmüller

Endokrinologie, Diabetologie und Stoffwechselmedizin,
Universitätsklinik Bonn

Conflict of interest statement

ND is the founder and managing director of Start-up stringID and the proprietor of the website www.dahlmann-body-analysis.de.

DK declares that no conflict of interest exists.

References

1. Stein MJ, Fischer B, Bohmann P, et al.: Differences in anthropometric measures based on sex, age, and health status: findings from the German National Cohort (NAKO). Dtsch Arztebl Int 2024; 121: 207–13

2. Schneider HJ, Friedrich N, Klotsche J, et al.: The predictive value of different measures of obesity for incident cardiovascular events and mortality. J Clin Endocrinol Metab 2010; 95: 1777–85

3. Dahlmann N, Klingmüller D: A new anthropometric model for body composition estimation in the assessment of metabolic risk factors of obese women. Arch Intern Med Res 2023; 06. www.fortunejournals.com/articles/a-new-anthropometric-model-for-body-composition-estimation-in-the-assessment-of-metabolic-risk-factors-of-obese-women.html (last accessed on 9 August 2024)