Decades of medical data from New Zealand has provided definitive evidence suggesting that infections can increase the likelihood of developing dementia. This study reflects the findings of a population register investigation which spanned over three decades, observing individuals born from 1929 up to 1968 and their health records from 1989 until 2019. It examined over 1.7 million cases where dementia was diagnosed and tracked from a baseline age of 21-60 and used public health records to ascertain information about past infections of the individuals, proceeding to derive a link between the presence of infection and the onset of dementia.
When compared to individuals who didn’t have an infection, those who had experienced some form had an almost threefold increase in dementia risk. The study also demonstrated that dementia diagnoses were possible up to 25-30 years post-infection. These correlations were resilient when taking into account existing physical diseases, mental disorder history, and socioeconomic deprivation. Further critical insights showed a pattern across different types of infections—viral, bacterial, parasitic, etc.—which showed increased risks for various dementia types, including Alzheimer’s and vascular dementia.
This groundbreaking investigation underscores the potential role of infection prevention in reducing neurodegenerative disease prevalence. The dataset used for this study is stored securely on Statistics New Zealand servers and can be accessed by application to Statistics New Zealand. This study was made possible due to support from the National Institute on Aging’s Center to Accelerate Population Research in Alzheimer’s and the Center for Advancing Sociodemographic and Economic Study of Alzheimer’s Disease and Related Dementias. The UK’s Medical Research Council also provided funding assistance.