Regional differences in body fat distributions among people with comparable body mass index: a comparison across six German population-based surveys.
INTRODUCTION
The mortality of circulatory diseases of the German population varies considerably across regions. The comparison of the regional distributions of cardiovascular risk factors can provide clues to the reasons for cardiovascular mortality differences. The aim of this study was to determine whether indirect measures of fat distribution within subgroups of comparable body mass indices (BMIs) differ by region in Germany.


METHODS
We included six German population-based epidemiological studies conducted between 1997 and 2006 that included a detailed assessment of anthropometric measures including overall 15 215 people aged 45–74 years. We calculated mean values of BMI, waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR). We estimated mean regional differences of WC, HC, and WHR within narrow ranges of BMI.


RESULTS
BMI distributions across the study populations were very similar. However, body fat distributions as measured by WC within subgroups of similar BMIs differed considerably across regions. For example, among people with a BMI of 24.0–25.9, estimated WCs were on average 3.4 and 6.7 cm higher among men and women in Saxony-Anhalt than among men and women in Bavaria, respectively.


CONCLUSION
We provide evidence that the BMI distributions across six population-based surveys in Germany are very similar and that body fat distributions among people with comparable BMIs show relevant regional differences. Our observed WC differences might contribute to regional cardiovascular disease risk differences in Germany. Our findings may trigger further similar analyses across European populations to explain large area variations of cardiovascular disease burden.