The analysis included 16 studies. In terms of different types of fast food consumption, hamburger intake was most prominently associated with allergic diseases in a dose-dependent manner, irrespective of consumers' income.

The authors note that poor quality diet is likely to contribute to the development and progression of asthma and wheeze via multiple mechanisms. "Additional studies are needed to confirm the relationships seen in this analysis, however, and to identify potential causal associations between the consumption of fast food and allergic diseases," said senior author Dr. Gang Wang, of West China Hospital, Sichuan University.