Background: Alcohol and drug use (A&D) and dietary risks are two increasingly important risk factors. This study examines whether there is a relationship between the burden of these risk factors in countries of specific income bands as defined by the World Bank, and the number of primary studies included in Cochrane Systematic Reviews (CSRs) conducted in those countries.

Methods: Data was extracted from primary studies included in CSRs assessing two risk factors as outcomes. For each risk factor, data was obtained on its overall burden in disability-adjusted life years (DALYs) by World Bank Income Levels and examined for a link between DALYs, the number of primary studies and participants.

Results: A total of 1601 studies from 95 CSRs were included. Only 18.3% of the global burden for A&D is in high income-countries (HICs) but they produced 90.5% of primary studies and include 99.5% of participants. Only 14.2% of the dietary risk burden is in HICs but they produced 80.5% of primary studies and included 98.1% of participants.

Conclusions: This study demonstrates the unequal output of research heavily weighted towards HICs. More initiatives with informed contextual understanding are required to address this inequality and promote health research in low and middle-income countries.