University of Otago researchers have uncovered an unexpected benefit from a widely prescribed medication for type 2 diabetes. Their systematic review of studies involving more than two million patients shows that metformin use is associated with a significant reduction in prostate cancer risk among men with the condition. This finding emerges from work led by Associate Professor Yoram Barak in the Department of Psychological Medicine and adds to growing evidence of the drug’s broader effects on healthspan.
The study, published in Rejuvenation Research, analysed literature from the past decade covering 2.25 million individuals with type 2 diabetes who were taking metformin. Researchers expected to confirm established benefits such as lower rates of cardiovascular disease and dementia. The prostate cancer association came as a surprise and represents the first conclusive link of its kind in this context.
Metformin has long served as a first-line treatment for type 2 diabetes in New Zealand and globally. It helps control blood glucose levels by improving insulin sensitivity and reducing glucose production in the liver. Beyond its primary role, the medication has attracted interest for potential anti-ageing properties. The Otago team’s review reinforces this interest while highlighting a specific protective effect against prostate cancer, one of the most common cancers among New Zealand men.
New Zealand faces rising rates of both type 2 diabetes and prostate cancer. Data from the Ministry of Health indicate that diabetes prevalence has increased steadily, particularly among Māori and Pacific populations. Prostate cancer remains a leading cause of cancer-related death for men. Any intervention that could reduce incidence or progression therefore carries substantial public health value. The Otago findings suggest metformin could form part of a more integrated approach to managing multiple age-related conditions in male patients.
The research team conducted a comprehensive literature review rather than a new clinical trial. They examined existing cohort studies and meta-analyses that tracked health outcomes in large populations of metformin users. Senior author Associate Professor Yoram Barak noted that while the cardiovascular and cognitive benefits aligned with prior expectations, the cancer reduction stood out. “The role of metformin in reducing cancer rates has been proposed prior to this project, but never in relation to prostate cancer,” he stated. The analysis found a statistically significant association with lower prostate cancer incidence and related mortality.
Other age-associated cancers showed inconclusive results, underscoring the need for further targeted investigation. The team emphasised that these findings apply specifically to men already diagnosed with type 2 diabetes. Extending recommendations to non-diabetic individuals would require additional large-scale trials, which remain costly and logistically complex.
University of Otago’s Department of Psychological Medicine provided the institutional home for this interdisciplinary project. The work draws on expertise spanning psychiatry, epidemiology, and public health. Such collaborations exemplify how New Zealand universities foster cross-disciplinary research that addresses real-world health challenges. The university’s location in Dunedin, with strong ties to the Southern District Health Board and community health providers, supports translational research that moves from literature synthesis to potential clinical application.
Funding for this type of review often comes through competitive grants from the Health Research Council of New Zealand. Success in securing such support reflects the university’s strong track record in health sciences. For early-career researchers and PhD candidates, projects like this offer valuable experience in systematic review methodology, data synthesis, and publication in peer-reviewed journals.
Prostate cancer screening and prevention strategies in New Zealand continue to evolve. The Otago study adds a pharmacological dimension that could complement existing approaches such as PSA testing and lifestyle interventions. Associate Professor Barak suggested that metformin should become a standard consideration in type 2 diabetes management for male patients. This recommendation aligns with broader efforts by New Zealand’s health sector to optimise medication use for multiple benefits.
Implementation would involve general practitioners and endocrinologists discussing the additional potential advantage during routine diabetes care. Patient education materials from organisations such as the Prostate Cancer Foundation of New Zealand could incorporate these findings once further validation occurs. The study also highlights the importance of ongoing pharmacovigilance and real-world evidence generation within the New Zealand health system.
New Zealand’s ageing population presents both opportunities and pressures for higher education institutions. The World Health Organization projects that the country will meet the definition of an ageing society by the late 2030s. Research into interventions that improve healthspan, such as the metformin review, directly supports national goals of healthy ageing. University of Otago researchers explicitly connect their work to this demographic shift, advocating for increased investment in senolytic and related fields.
Senolytic research focuses on clearing senescent cells that accumulate with age and contribute to chronic disease. Metformin’s potential role in this area opens avenues for collaboration between psychological medicine, gerontology, and oncology departments across New Zealand universities. These partnerships strengthen the research ecosystem and create training opportunities for postgraduate students interested in translational health sciences.
International interest in metformin’s pleiotropic effects continues to grow. The Otago publication adds a New Zealand perspective to global discussions and may encourage larger trials in other jurisdictions, as suggested by the research team. Such visibility enhances the international reputation of New Zealand higher education and can attract collaborative funding and visiting scholars.
Universities New Zealand and Education New Zealand actively promote the country’s research strengths to international partners. Findings like these contribute to narratives around innovation in health and ageing research, supporting student recruitment and academic mobility programmes.
Challenges remain in translating observational associations into clinical guidelines. Confounding factors in diabetes populations, variations in metformin dosing, and differences in prostate cancer screening practices across studies require careful interpretation. The Otago team acknowledged these limitations while calling for targeted prospective research. Future work could explore dose-response relationships, interactions with other medications, and effects in diverse ethnic groups within New Zealand.
PhD students and postdoctoral researchers at institutions such as the University of Otago, University of Auckland, and Massey University could pursue related projects examining metformin in local cohorts or modelling cost-effectiveness for the New Zealand health system. These opportunities align with national priorities identified in the Tertiary Education Strategy.
The study also raises questions about equitable access to medications with multiple benefits. Māori and Pacific communities experience higher diabetes prevalence and prostate cancer mortality. Ensuring that any expanded use of metformin reaches these populations equitably will require culturally appropriate implementation strategies developed in partnership with iwi and community health providers. University-led research can play a role in co-designing such approaches.
Academic staff interested in health equity research may find fertile ground for projects that combine epidemiological analysis with community engagement. Funding bodies increasingly prioritise research with demonstrated impact on underserved populations, creating alignment between institutional goals and national health objectives.
Looking ahead, the Otago findings contribute to a growing body of evidence supporting metformin’s role beyond glycaemic control. While not a standalone solution for prostate cancer prevention, the drug represents a low-cost, well-tolerated option that could be integrated into existing diabetes care pathways. Continued monitoring through New Zealand’s health data systems will help clarify long-term outcomes.
Higher education institutions in New Zealand are well positioned to lead follow-up studies. Strong data linkage capabilities through Statistics New Zealand and the Integrated Data Infrastructure provide unique resources for population-level research. Academics and students can leverage these assets to generate further insights into medication effects across the life course.
Photo by Joshua Bayliss on Unsplash
The University of Otago continues to demonstrate leadership in health research that addresses both local and global challenges. This latest contribution underscores the value of systematic reviews in identifying unexpected benefits from established therapies. As New Zealand’s higher education sector navigates funding pressures and demographic change, research outputs with clear public health relevance strengthen the case for sustained investment in university-based inquiry.
Readers interested in academic positions or research opportunities in New Zealand health sciences can explore current openings through established university job platforms. The intersection of diabetes management, cancer prevention, and ageing research offers promising pathways for emerging scholars.
