Global burden and cross-country inequalities of nutritional deficiencies in adults aged 65 years and older, 1990–2021: population-based study using the GBD 2021

Nutritional deficiencies remain significant public health issues in older populations globally. This study evaluates the burden, trends, and cross-country inequalities of four common nutritional deficiencies (protein-energy malnutrition, iodine deficiency, vitamin A deficiency, and dietary iron deficiency) in older adults from 1990 to 2021. Age-standardised prevalence, disability-adjusted life years (DALYs), and average annual percentage changes (AAPCs) of these deficiencies in people aged ≥ 65 years at global, regional, and national levels were estimated from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021. Cross-country inequalities in disease burden were quantified using the slope index and concentration index, standard health equity methods recommended by the World Health Organization. Globally, age-standardised prevalence rates of protein-energy malnutrition increased from 1407.16 per 100 000 population in 1990 to 2015.58 in 2021, with an AAPC of 1.18 (1.08–1.28), showing significant changes in 2015 and 2019, which were turning points in the joinpoint regression. Age-standardised prevalence rates of iodine, vitamin A, and dietary iron deficiencies decreased, with AAPCs of -0.49 (-0.53 to -0.44), -3.24 (-3.27 to -3.20), and − 0.14 (-0.17 to -0.12), respectively. Except for an increase in the DALY rate of vitamin A deficiency (AAPC 0.40), the DALY rates of the other three deficiencies decreased. Inequality in the burden of protein-energy malnutrition and iodine deficiency between high- and low-income countries narrowed, while inequality for vitamin A and dietary iron deficiencies remained stable. Age-standardised DALY rates for all deficiencies decreased as sociodemographic index increased. The global status of nutritional deficiency among older adults has improved since 1990, but the increasing prevalence of protein-energy malnutrition requires attention. Additionally, cross-country health inequalities persist, necessitating more efficient public health measures.