Persistent Calcium Inadequacy in Korean Adults over 20 Years: Analysis of the 1998–2018 Korea National Health and Nutrition Examination Survey

Calcium inadequacy in Asian populations has been well documented, but whether it has improved over time remains uncertain. We analyzed dietary calcium intake and its association with osteoporosis prevalence over a 20-year period in 48,653 adults (21,932 men and 26,721 women, aged 19 years and older) in Korea, using data from the first to the seventh Korea National Health and Nutrition Examination Survey (1998-2018). Over the past 20 years, Korean adults consistently fell short of the recommended dietary calcium intake, with women and older adults particularly affected, typically consuming only 40-80% of the recommended levels. The 30-49 age group had the highest calcium intake (497-568 mg/day), while those aged 75+ had the lowest (319-457 mg/day). A significant inverse relationship was found between calcium intake and osteoporosis risk, with lower calcium intake associated with higher odds of developing osteoporosis, as determined by both physician diagnoses and bone mineral density measurements (<i>p</i> < 0.001). Notably, over the past 20 years, 68-70% of dietary calcium consistently came from plant-based foods. This study strongly emphasizes the urgent need to enhance calcium-rich food availability and implement targeted interventions to increase calcium intake among those most affected by inadequacy, particularly the elderly and women. Further research with recent data would be valuable for understanding current intake levels and evolving nutritional needs.