Worldwide relation between the number of McDonald's restaurants and the prevalence of obesity.

In total, 44 countries were included in the present study. This group comprised the 20 most populated countries of the world, the five most populated countries of each continent and a few other countries that were included in a recent nutritional study [3]. The number of McDonald’s restaurants per million inhabitants was calculated for each of these countries (www.mcdonalds.com). Countries were classified according to quartiles of the number of Mac Donald’s restaurants per million inhabitants. The proportion of overweight persons according to each of these quartiles was calculated using World Health Organization data [4]. The correlation between the proportion of overweight individuals and the number of McDonald’s restaurants per million inhabitants was investigated.