Couples' Shared Lives Linked to Increased Dementia Risk, Study Finds

A significant study conducted in Taiwan indicates that the risk of developing dementia may be higher for individuals if their spouse has been diagnosed with the condition. This finding arises from decades of research demonstrating that partners can often experience similar health issues, including obesity and heart disease. This particular study suggests that dementia might also fall into this category, although it clarifies that the condition is not contagious.

The research examined health records of nearly one million married individuals who were part of Taiwan's national health insurance programme between 1998 and 2022. It specifically focused on over 190,000 individuals whose spouses had recently been diagnosed with dementia, comparing their health outcomes with more than 760,000 individuals whose partners did not have the disease. For adequate comparison, participants were matched based on age, gender, income, and geographic location.

Despite factoring in various elements including existing medical conditions and healthcare utilisation, a clear trend emerged: individuals were more likely to receive a dementia diagnosis if their spouse had already been diagnosed with it.

Statistics from the study revealed that women whose partners developed dementia had a 74 per cent increased relative risk of receiving a similar diagnosis. For men, this increase stood at 69 per cent. Specifically, over a five-year span, approximately 6.5 per cent of women whose spouses had dementia were diagnosed themselves, compared to 3.7 per cent among those whose partners did not. For men, 9.2 per cent developed dementia if their spouse had the condition, while the figure was 5.8 per cent for those without a partner diagnosed.

In more relatable terms, the extra risk linked to a spouse's diagnosis translates to roughly three additional cases of dementia for every 100 people over a five-year period.

However, it is essential to clarify that the study does not imply that dementia can spread between couples. Rather, researchers propose that partners often share inherent risk factors before dementia comes into play. Common characteristics, such as educational backgrounds, income levels, and dietary habits, lead to what is known as assortative mating, where individuals typically partner with those who have similar traits.

Furthermore, years of living in close proximity can cultivate overlapping experiences—sharing meals, environments, and daily routines—which over time may influence cognitive health.

Another contributing factor may be the stress associated with caregiving, as looking after a partner with dementia can be physically and emotionally taxing. Caregivers frequently face disrupted sleep and social isolation, alongside diminished opportunities for exercise and balanced nutrition. Previous studies have linked these lifestyle changes with poorer cognitive health.

The researchers also noted that aspects like oral health and the gut microbiome are under investigation in relation to brain ageing, but these were not specifically addressed in this study.

The key takeaway from this research is the importance of maintaining overall health in mitigating dementia risk. According to the World Health Organisation, several lifestyle choices can help lower the risk of cognitive decline, including regular exercise, a balanced diet, and sufficient sleep. These beneficial habits extend far beyond brain health, positively impacting heart health and overall wellbeing.

Experts caution, however, that the responsibility for healthy living should not fall solely on individuals. Socioeconomic factors, access to healthcare, educational opportunities, and safe exercise environments also play crucial roles in shaping health behaviours.

Ultimately, this study underlines a vital point: the lives of couples often become intimately intertwined over time. They share responsibilities, routines, and emotionally significant moments. It is perhaps expected that their health trajectories might reflect shared experiences.