A new study from California has raised concerns about the long-term metabolic consequences of COVID-19, revealing that individuals infected with the virus while incarcerated face a persistently higher risk of developing diabetes even months after recovery. The research, posted on the medRxiv preprint server, highlights the urgent need for post-COVID monitoring and targeted healthcare strategies in vulnerable populations.
The study specifically examined diabetes, one of several chronic conditions increasingly observed following COVID-19 infection, reinforcing global concerns surrounding “long COVID.” While the pandemic response has primarily focused on acute illness, mounting evidence suggests that SARS-CoV-2 can leave a lasting physiological impact, contributing to new neurological, cardiovascular, and metabolic disorders. Previous research on post-infection diabetes risk has been limited by underrepresentation of racial and ethnic minorities and challenges in distinguishing new-onset cases from preexisting diabetes.
Researchers analyzed data from 29,470 individuals incarcerated in 31 California state prisons, tracking participants from the start of the pandemic through March 2023. Individuals with known diabetes prior to the pandemic or inadequate baseline health data were excluded to ensure accurate estimates of new diabetes cases. COVID-19 exposure was determined via positive test results, and to focus on long-term risks, participants were only considered exposed beginning 31 days after testing positive.
Over the study period, more than half of the cohort (58.3%) tested positive for COVID-19. Across 15.8 million days of observation before infection and 8.9 million days after infection, researchers identified 690 diabetes diagnoses in the uninfected period and 429 diagnoses following infection. This corresponded to crude incidence rates of 15.9 per 1,000 person-years among the uninfected and 17.6 per 1,000 person-years among those infected. After adjusting for demographic and clinical factors, COVID-19 infection was associated with a 17% higher rate of developing diabetes, a risk that persisted for at least two years post-infection.
The study projected that if all individuals in the cohort had contracted COVID-19, the two-year cumulative risk of diabetes would have increased to 3.2%, compared with 2.7% if none were infected. Sensitivity analyses confirmed the robustness of these findings, though statistical significance weakened when early post-infection periods were included.
These findings align with broader research on COVID-19’s long-term impact in the general population. Studies of millions of individuals have shown that COVID-19 can result in persistent symptoms such as cognitive impairment, memory deficits, loss of smell or taste, fatigue, and hair loss. Severe infections are also linked to higher risks of cardiovascular events, pulmonary fibrosis, and ongoing cardiopulmonary dysfunction months or even years after recovery. In pregnant women, COVID-19 infection has been associated with higher odds of preeclampsia, preterm birth, stillbirth, and cesarean delivery, with risks further elevated in moderate to severe cases. Cohort studies indicate increased rates of fetal distress, low birth weight, and ICU admission among infected pregnancies.
The present study adds to a growing body of evidence demonstrating that COVID-19’s impact extends well beyond the acute infection phase. The increased risk of developing diabetes among formerly incarcerated individuals highlights the virus’s potential to trigger long-term metabolic complications, particularly in vulnerable populations. Coupled with data on persistent neurological, cardiovascular, and reproductive risks, these findings emphasize the importance of ongoing surveillance, targeted healthcare interventions, and long-term follow-up for all individuals recovering from COVID-19. Addressing these post-infection health challenges will be critical in mitigating the broader consequences of the pandemic.
Reference
- Goldhaber-Fiebert JD, Phillips SC, Lucas KD, Jacobsen DA, Studdert DM. COVID-19 Increases the Rate of Incident Diabetes: A Case-Control Cohort Time-to-Event Study. medRxiv, 2025.
- O’Mahoney LL, Routen A, Gillies C, et al. The risk of Long Covid symptoms: a systematic review and meta-analysis of controlled studies. Nat Commun. 2025 May 7;16(1):4249.
- Niebauer JH, Ahmet I, Sarah S, et al. Eur Heart J Qual Care Clin Outcomes. 2025 May 30:qcaf035.