Summary: Older adults who live with family members or in larger households are at a decreased risk of developing the worst symptoms of Alzheimer’s disease, a new study reveals.
Source: University of Adelaide
In a global study, researchers in evolutionary medicine at the University of Adelaide have found that people living in larger households are at reduced risk of dying from dementia and could stave off the progression of the disease for longer.
The study published in PLOS ONE today, looked at variables in living standards and conditions for people aged over 60 years from more than 180 countries around the world, to measure the significance of factors such as GDP, urbanization, age, and household size, and found that people living in larger households or with families, fared better than those living alone.
Ph.D. researcher at the University of Adelaide and lead on the project, Wenpeng You, says the correlation between household size and reduced risk of the worst impacts of dementia is quite strong.
“Independent of aging, urbanization, and GDP, we found large households protect against dementia mortality,” Dr. You says.
“It’s a significant finding in informing how we plan care and living services for people as they age, because it shows that human factors—relationships, a sense of connection and purpose, encouragement and praise, meaningful engagement with others—are all quite important in combatting the progress of dementia.”
Dementia is one of the biggest challenges for the health sector in the 21st century, with an estimated cost globally of AU$1.160 trillion.
Emeritus Professor Maciej Henneberg, the senior author of the study, says humans have evolved to live in families and communities.
“We are one of the few species that have adapted over thousands of years to rely on extended family groupings from cooperative breeding, and then evolved alloparental care, until shaped for flourishing in small communities,” Professor Hennenberg says.
“In the stretch back across that evolution, it has really only been a very short period where we have moved away from that. We are actually not well-adapted to the contemporary trends of small families, personal space and individualism.”
He says there are some very practical benefits to living with family or other household residents.
“There are usually regular mealtimes, there is conversation, people to check to see if you have taken your medications, and family members encouraging regular activity,” Professor Hennenberg says.
“That engagement, when it is positive, stimulates the production of oxytocin, often dubbed the happiness hormone, and that has been shown to have a positive effect on physiological wellbeing by protecting cardio-vascular systems associated with vascular dementia and may exert a beneficial slow-down on dementia development.”
Dr. You says while the research does not show a causal link between the incidence of death from dementia and household size, it is clear living in large households is significantly protective against dementia mortality in terms of dementia initiation and deterioration of dementia patients.
“As part of dementia prevention, healthcare practitioners should encourage people to increase their positive interactions with people from their neighborhood, community groups or other engagements, when a traditional large household or family-centered lifestyle is not possible,” he says.
Professor Hennenberg says if there is a take-home message from this research, it is that we have evolved to benefit from meaningful, daily, human connection.
“Without that human connection, we don’t thrive as we should,” he says.
Large household reduces dementia mortality: A cross-sectional data analysis of 183 populations
Large households/families may create more happiness and offer more comprehensive healthcare among the members. We correlated household size to dementia mortality rate at population level for analysing its protecting role against dementia mortality.
This is a retrospective cross-sectional study. Dementia specific mortality rates of the 183 member states of World Health Organization were calculated and matched with the respective country data on household size, Gross Domestic Product (GDP), urban population and ageing. Scatter plots were produced to explore and visualize the correlations between household size and dementia mortality rates. Pearson’s and nonparametric correlations were used to evaluate the strength and direction of the associations between household size and all other variables. Partial correlation of Pearson’s approach was used to identify that household size protects against dementia regardless of the competing effects from ageing, GDP and urbanization. Multiple regression was used to identify significant predictors of dementia mortality.
Household size was in a negative and moderately strong correlation (r = -0.6034, p < 0.001) with dementia mortality. This relationship was confirmed in both Pearson r (r = – 0.524, p<0.001) and nonparametric (rho = -0.579, p < 0.001) analyses. When we controlled for the contribution of ageing, socio-economic status and urban lifestyle in partial correlation analysis, large household was still in inverse and significant correlation to dementia mortality (r = −0.331, p <0.001). This suggested that, statistically, large household protect against dementia mortality regardless of the contributing effects of ageing, socio-economic status and urban lifestyle. Stepwise multiple regression analysis selected large household as the variable having the greatest contribution to dementia mortality with R2 = 0.263 while ageing was placed second increasing R2 to 0.259. GDP and urbanization were removed as having no statistically significant influence on dementia mortality.
While acknowledging ageing, urban lifestyle and greater GDP associated with dementia mortality, this study suggested that, at population level, household size was another risk factor for dementia mortality. As part of dementia prevention, healthcare practitioners should encourage people to increase their positive interactions with persons from their neighbourhood or other fields where large household/family size is hard to achieve.