India, China, and the US will drive global diabetes burden by 2050, study finds

A sweeping global study finds that India, China, and the US will account for one-third of diabetes deaths and disabilities by 2050, unless urgent action is taken to curb the soaring rise of type 2 diabetes.

Study: Comparative diabetes mellitus burden trends across global, Chinese, US, and Indian populations using GBD 2021 database. Image Credit: Lightspring / Shutterstock

In a recent study published in the journal Scientific Reports, researchers evaluated the trends in diabetes mellitus (DM) globally and in India, China, and the United States (US).

DM is a chronic disease characterized by the inability to adequately synthesize or respond to insulin, leading to abnormally elevated blood glucose levels. Globally, around two million deaths occurred due to DM in 2019. Moreover, chronically elevated blood glucose can cause microangiopathy and macrovascular disease, which may lead to complications like blindness, heart disease, stroke, and renal disease.

DM and related complications pose a substantial psychological and economic burden on families and the community. The prevalence of diabetes has been rapidly increasing in low- and middle-income countries, whose total health expenditure is over 300 times lower than that of high-income countries. These disparities are particularly pronounced in regions with lower socioeconomic development (e.g., India) compared to high-income nations like the US. This inequality highlights the need for cross-country comparative investigations.

Key Study Details

The present study assessed the trends in DM burden worldwide and in the three most populous countries, India, China, and the US, from 1990 to 2021. The researchers obtained incidence and mortality data for type 1 (T1DM) and type 2 DM (T2DM) from the Global Burden of Disease, Injury, and Risk Factors (GBD) 2021 study. A Joinpoint regression model was used to identify inflection points in trends.

Further, the team computed the annual percent change in prevalence rates between inflection points. Moreover, they calculated the age-standardized rates (ASRs) of disability-adjusted life years (DALYs) and deaths using age-period-cohort interaction analysis. Additionally, disease burden was decomposed into different factors, such as epidemiologic change, population size, and population age.

A health inequality analysis was performed to examine health status differences across populations and explore the relationship between factors like age, gender, socioeconomic status, and location and their impact. Notably, the analysis revealed that the burden of T2DM in high Socio-Demographic Index (SDI) regions like the US defied expectations, with higher-than-predicted DALYs relative to national SDI. The burden of diabetes for 2022–50 was predicted using a Bayesian age-period-cohort (BAPC) model.

Findings

Globally, DM had a substantial impact in 2021, with significant variations in morbidity and mortality across countries. India had the highest mortality burden, with more than 331,300 deaths, followed by China and the US, with 178,475 and 74,017 deaths, respectively. India’s mortality rate was over double that of the US and nearly 3.5 times higher than China’s when adjusted for population age (ASR). Consistently, the distribution of DALYs followed a similar trend, with India leading at 13.6 million DALYs, followed by China (11.71 million DALYs) and the US (5.04 million DALYs).

India also had the highest ASRs of deaths and DALYs per 100,000 individuals (31.1 deaths and 1,102 DALYs), followed by the US with 12.64 deaths and 959 DALYs and China with 8.98 deaths and 585 DALYs. In 1990, T1DM and T2DM accounted for 5.9% and 94.1% of deaths and 9.4% and 90.6% of DALYs, respectively. However, in 2021, deaths and DALYs due to T2DM increased to 97.1% and 95.4%, and those due to T1DM reduced to 2.9% and 4.6%, respectively.

Similar trends were observed in the three countries. The ASR of deaths due to T1DM showed a decreasing trend worldwide, with the most significant decline from 2003 to 2011. China saw the steepest drop in T1DM deaths (annual average of −2.62%), attributed to improved healthcare access and traditional medicine (TCM) integration. Likewise, the ASR of DALYs due to T1DM showed a similar pattern, decreasing the highest between 2004 and 2012. Conversely, the global ASR of T2DM deaths increased until 2003 and declined slightly thereafter, and the ASR of T2DM DALYs increased.

In the US, T1DM DALYs paradoxically rose by 0.17% annually (non-significant) despite falling mortality rates (−0.39%), reflecting increasing complications. The T1DM burden was higher in males than in females and in younger populations, especially in the 40–44 age group, whereas the T2DM burden increased with age, peaking in the 65–69 age group, and was slightly lower in females than in males; the three countries followed the global trends. There was a substantial increase of 919,068 deaths worldwide due to DM between 1990 and 2019, with population growth (53.6%) and aging (36.51%) being the primary drivers. Epidemiologic changes (e.g., rising obesity rates) accounted for the remaining 9.89% of deaths.

Future Projections

The BAPC model suggested a progressive decline in T1DM burden globally and in the three countries, with the ASRs of DALYs and deaths predicted to steadily and gradually decline. China’s T1DM burden is projected to continue falling sharply due to sustained policy interventions. By contrast, the global T2DM burden was projected to continue increasing, with an increase in the ASRs of DALYs and deaths. By 2050, global deaths due to T1DM and T2DM were predicted to be 51,837 (a 6.7% increase from 2021) and 3.67 million (a 128.6% increase), respectively. In the US, T2DM DALYs are expected to rise despite falling mortality, driven by complications such as cardiovascular disease and renal failure, which are linked to prolonged hyperglycemia.

Conclusions

In sum, T1DM exhibited a declining trend in global deaths and DALYs, while T2DM showed an increasing trend. India experienced the highest deaths and DALYs, followed by China. India, China, and the US shared about a third of the global diabetes burden, highlighting the need for greater attention from global health institutions for these countries.

Population growth and aging were the major factors driving the burden of diabetes. Notably, projections suggest a continued increase in the burden of T2DM by 2050. The study underscores that tailored strategies are critical: India requires urgent healthcare infrastructure upgrades, China must sustain its T1DM management successes, and the US needs to address rising T2DM complications linked to obesity. Overall, these results warrant the need to increase public awareness of diabetes, address socioeconomic disparities, improve equity in healthcare resource distribution, and implement preventive measures, early screening, and lifestyle interventions to reduce the burden of DM.