Global associations of national economic wealth are more robust with inflammatory bowel diseases than with obesity.

The inflammatory bowel diseases consisting of Crohn’s and ulcerative colitis have expanded into previously low incidence areas of the world. The spread follows the relatively recent pandemic of global obesity. Pathological relations have been proposed between these two diseases. Both inflammatory bowel diseases and obesity originated in wealthier western societies marked by high gross domestic product per capita. The pathogenic influence of national wealth on the inflammatory bowel diseases has been recognized but are less clear with obesity. Parallel correlations of national wealth with obesity would further strengthen relations between these two diseases. Alternatively, diverging relations could suggest that obesity is less dependent on wealth. As such it would supports another earlier hypothesis that obesity depends on adoption of western diet which precedes national acquisition of wealth. Previously ecological modifiers of global disease patterns, including latitude and lactose digestion status have shown different influences on IBD compared with obesity. We evaluate. the influence of the Gross Domestic Product on these two diseases taking into consideration the former’s relationship with ecological markers. Patterns of correlations could suggest contributing mechanisms how these ecological parameters influence some disease distributions. The literature and internet were searched for national rates of obesity, inflammatory bowel diseases, national gross domestic product per capita and national lactase distribution rates. National average latitudes were calculated previously. Pearson correlations were used to compare variables in three regions; global, European and Asian theaters. SAS statistical package was used and statistical significance was accepted at p < 0.05. Globally and in Europe correlations of gross domestic product were moderate and significant r = 0.55 and r = 0.6 respectively with Crohn's disease but weaker with ulcerative colitis. The results were negligible in Asia. Obesity was weakly correlated with gross domestic product globally r = 0.32 and negligible in Europe and Asia. In addition, gross domestic product was moderately correlated with latitude r = 0.6, and inversely with lactase non persistence r = -0.6 both globally and in Europe. This relationship is similar to that with inflammatory bowel diseases, but less related to obesity. Overall results suggest unequal effect of national wealth and industrialization on obesity and inflammatory bowel diseases. It has been suggested that western type diet precedes full industrialization and this could promote obesity.