Calcium is a crucial mineral for numerous physiological processes, primarily bone health. Inadequate calcium intake, often due to socioeconomic factors and dietary habits, is linked to various diseases including osteoporosis, cardiovascular issues, and colorectal cancer. While a previous study estimated global calcium deficiency risk, comprehensive country-specific data and recent prevalence and temporal trends were lacking. This study aimed to address this gap by utilizing the GBD 2019 dataset to provide a detailed analysis of DLC prevalence and associated disease burden globally, regionally, and nationally, considering factors such as age, sex, and sociodemographic index (SDI). Understanding the epidemiology of DLC is crucial for public health interventions and nutritional policy development, particularly in low- and middle-income countries where the burden may be highest.

Existing literature highlights the critical role of calcium in various bodily functions and the association between inadequate calcium intake and several health problems. Studies have shown links between low calcium intake and osteoporosis, cardiovascular diseases, increased body fat mass, and colorectal cancer. The impact of socioeconomic factors on calcium intake is also well-documented, with lower intakes frequently observed in low-income populations due to limited access to calcium-rich foods and dietary diversity. A previous study estimated the global risk of dietary calcium deficiency, but lacked detailed country-level data and the most recent prevalence estimates. This research addresses this gap by focusing on the most recent GBD data.

This cross-sectional study employed data from the GBD 2019 study, a comprehensive global disease burden analysis that estimates the prevalence and burden of various diseases and risk factors. DLC was defined as an average daily calcium consumption below 1.06-1.1 g. The prevalence of DLC was measured using summary exposure value (SEV), a risk-weighted prevalence. The disease burden, specifically for DLC-induced colorectal cancer, was measured as disability-adjusted life years (DALYs). Sociodemographic index (SDI) was used to account for socioeconomic factors. Bayesian meta-regression in DisMod-MR 2.1 was used for estimation. Age-standardized rates (ASR) of SEV and DALY were calculated. Spearman's rank correlation analyzed the association between SEV, DALY and SDI. Estimated annual percentage change (EAPC) assessed temporal trends from 1990 to 2019. All analyses were performed using R software.

From 1990 to 2019, the global age-standardized SEV for DLC decreased (EAPC -0.47). However, increases were observed in Oceania and several countries including the United Arab Emirates, New Zealand, Japan, and France. In 2019, the global age-standardized SEV was 46% (95% UI, 35.9–60.3%), higher in males than females. Regions with high DLC prevalence included Central Sub-Saharan Africa, Southeast Asia, and Oceania. The global DALYs for DLC-induced colorectal cancer in 2019 were 3.14 million (95% UI, 2.25–4.26 million), with an age-standardized rate of 38.2 per 100,000 (95% UI, 27.2–51.8). Globally, the age-standardized DALY rate remained relatively unchanged, but increased in over 80 countries, primarily in Asia, Africa, and South America. Strong negative correlations were found between SDI and both SEV (ρ = -0.823, P < 0.001) and DALY (ρ = -0.433, P < 0.001). Prevalence decreased with age, while DALY rates increased with age, peaking around 90 years. Males consistently showed higher SEV and DALY rates than females.

This study demonstrates a global decline in DLC prevalence but a persistent and concerning burden of DLC-induced colorectal cancer, particularly in specific regions and populations. The findings highlight the significant influence of socioeconomic status, with low-SDI countries experiencing disproportionately high prevalence and burden. The higher prevalence and burden in males compared to females warrant further investigation into potential underlying factors beyond dietary intake differences. The discrepancy between decreasing prevalence and increasing DALYs with age highlights the age-related nature of colorectal cancer. Future research should expand the scope of DLC-associated diseases beyond colorectal cancer for a more complete understanding of the health impact. The observed increases in DLC prevalence in some high-income countries also require attention.

The global prevalence of DLC has decreased, but the burden of DLC-induced colorectal cancer remains high and is increasing in many countries, particularly those with low SDI and among males. Interventions focusing on improving dietary calcium intake, especially in low-SDI countries and among vulnerable groups, are crucial to reduce the associated health burden. Future research should focus on expanding the analysis to include all DLC-related diseases and address data limitations.

This study has some limitations. First, the disease burden was estimated only for DLC-induced colorectal cancer, underestimating the total burden. Second, data were only available for individuals aged 30 years and older. Third, the study relies on GBD 2019 data, which may have inherent limitations regarding data quality and accuracy, especially in countries with limited data availability. These limitations necessitate cautious interpretation of the findings and further investigation.