Global associations of macronutrient supply and asthma disease burden

Objectives Global age-standardized prevalence of asthma has decreased over time, in parallel with which, the gross domestic product (GDP) per capita and nutritional landscapes also changed at a global level. Both socioeconomic status and nutritional factors are critical confounder for asthma, but most studies so far neglected to interrogate their correlations and interactions comprehensively. Hence, we aim to systematically investigate the relationship between nutrient supply, a good proxy of food environment, socioeconomic status and asthma disease burden at a global level over time. Methods Asthma disease burden, macronutrient (protein, carbohydrate and fat) supply and GDP data covering more than 150 countries around the globe from 1990 to 2018 was collated. Various multi-response generalized additive mixed models (GAMMs) were used to analyze the effects of macronutrient supplies and GDP over time on asthma disease burden. Results A model considering the interactions between macronutrient supplies and GDP, with an additive effect of time was favoured. Modelling results showed that carbohydrate supply was most strongly associated with increase of asthma disease burden, while fat supply had an opposite effect, and protein supply conferred less influences. Conclusions Globally, carbohydrate supply seems to play a driving role for asthma disease burden while fat supply might be the opposite. This is supported by previous studies about the amelioration of established asthma by ketogenic diet and might be linked to the diet quality. Further in-depth studies are warranted, which will be critical for future clinical research and practice and public health intervention. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This project is supported by the Norman Ernest Bequest Fund. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors