Background: This study measures the burden of chronic diseases associated with being underweight.
Methods: Underweight prevalence in the community was obtained from national survey data, together with hospital use rates for malnourished and non-malnourished persons for diagnoses associated with underweight. Meta-analyses of published literature calculated the following disease-specific relative risks: incidence of underweight-associated disease (UAD), mortality from UAD, and all-cause and disease-specific mortality after hospitalization in underweight persons.