Low income may be linked to a significantly increased risk of all-cause mortality in younger adults, results of a study published in JAMA Network Open showed.

According to a nationwide cohort study conducted in South Korea, socioeconomic disparities significantly affect mortality outcomes in individuals with type 2 diabetes, with the greatest impact observed among young adults aged 20-39 years.

“The incidence and prevalence of type 2 diabetes in young individuals is increasing worldwide. Patients with early-onset type 2 diabetes have poor glycemic control and a high risk of diabetic complications,” Ji Yoon Kim, MD, PhD, from the department of internal medicine at Korea University College of Medicine in Seoul, and colleagues wrote. “While this is partly due to the biological characteristics of early-onset type 2 diabetes, it is also influenced by behavioral factors. Therefore, the effect of socioeconomic status on health outcomes may be more pronounced in these individuals.”

The study included 1,240,780 individuals aged 20-79 years. The adjusted hazard ratio for all-cause mortality in low-income versus high-income participants was 2.88 (95% CI, 2.25-3.69) for those aged 20-39 years, 1.90 (95% CI, 1.81-2.00) for those aged 40-59 years, and 1.26 (95% CI, 1.23-1.29) for those aged 60-79 years.

According to the researchers, although previous studies established a general link between low income and increased mortality risk, this study is among the first to explore how these associations differ by age in patients with type 2 diabetes. The researchers analyzed all-cause, cardiovascular, and cancer mortality using logistic regression and Cox proportional hazard models, categorizing income into three levels based on health insurance premiums.

The cohort included 604,975 patients with type 2 diabetes and 635,805 age- and sex-matched controls without diabetes, followed from 2008 to 2019. Among those with diabetes, the mean age was 56.9 years and men accounted for 50.5% of participants. The findings showed that low income not only elevated mortality risk among patients with diabetes but also contributed to disparities compared with the nondiabetic control group, further emphasizing the compound effect of financial and health vulnerabilities.

The researchers found that adjusted odds ratios for all-cause mortality were significantly higher in type 2 diabetes subgroups compared with controls without diabetes: 1.47 (95% CI, 1.44-1.50) for high-income, 1.79 (95% CI, 1.75-1.83) for middle-income, and 2.03 (95% CI, 1.99-2.08) for low-income groups. Among participants with type 2 diabetes, the low-income subgroup had an adjusted hazard ratio of 1.35 (95% CI, 1.32-1.38) compared with the high-income subgroup; a similar pattern was observed for cardiovascular and cancer-specific mortality.

According to the study, behavioral and clinical profiles revealed disparities among income groups. Current smoking was least prevalent in the high-income diabetes subgroup, whereas alcohol abstinence was most common in the low-income group. The prevalence of regular exercise was highest in the high-income type 2 diabetes subgroup. Patients with diabetes showed higher rates of hypertension, dyslipidemia, atherosclerotic cardiovascular disease, and cancer history compared with nondiabetic controls. The high-income diabetes subgroup had greater use of antidiabetic, antihypertensive, and lipid-lowering medications, whereas clinic visits were more frequent in the low-income type 2 diabetes subgroup.

In addition to all-cause mortality, income disparities were particularly prevalent in cardiovascular-related deaths among younger individuals, according to the study. Compared with type 2 diabetes, the influence of income on cancer-related mortality was less evident across all age groups.

According to the researchers, the overall results of the study suggest that diabetes-related management and health policies must focus on younger adult populations with type 2 diabetes.

“This provides epidemiologic evidence of the need for health care policies targeting young people with type 2 diabetes,” the researchers wrote. “More efforts at the social and national level should be made to reduce the disparities in health outcomes according to socioeconomic status among young adults with type 2 diabetes.”

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Disclosures:  No authors declared financial ties to drugmakers.

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