Differences in height and body mass index (BMI) between European nations have a genetic basis, suggests a paper published online this week in Nature Genetics. The study may also explain why people from northern European countries tend on average to be taller and thinner than other Europeans.
Many human traits, including height and BMI, vary between people from different regions, but the relative roles of genes and the environment in shaping these regional differences were previously unknown.
Matthew Robinson, Peter Visscher and colleagues studied height and BMI differences in 9,416 people from 14 European countries, using data from genome-wide association studies (GWAS). They found that historic natural selection on both height and BMI has created genetic differences among different countries. On average, 24% of the genetic variation in height and 8% of the genetic variation in BMI could be explained by regional genetic differences.
The authors showed that a greater frequency of height-increasing genes was strongly correlated with more BMI-reducing genes, suggesting that tall nations are more genetically likely also to be slim. The findings also suggest that, while genetic variation between countries provides an explanation for differences in national height, environmental factors, such as diet, are the main driver of national BMI.