The global burden of dementia is rising. Worldwide, approximately 50 million individuals have dementia and there are nearly 10 million new cases each year, according to the World Health Organization (WHO). Alzheimer’s disease (AD) is the most common type of dementia. In recent years, evidence has shown that modifiable lifestyle behaviours can slow down brain degeneration and cognitive decline associated with AD. GlobalData examined the prevalence of AD in Spain and the ways in which the country’s lifestyle norms may explain its low disease prevalence.
Figure 1 presents the total prevalence of AD in ages 60 years and older in 2021 in Spain, the US and Japan. The data are derived from GlobalData’s Alzheimer’s Disease: Epidemiology Forecast to 2028 report. Japan showed the highest total prevalence of AD, with 23.23% and 11.55% in women and men, respectively. The US showed the second-highest total prevalence rates of AD, with 11.64% in women and 7.66% in men. Spain had the lowest total prevalence of AD out of the three major pharmaceutical markets, with 11.23% and 3.80% in women and men, respectively. These trends raise questions about what might be causing the lower prevalence of AD in Spain.
According to a 2019 article in News Digest, Spain ranked first on a list of the 169 healthiest countries in the world. Spain’s citizens are often commended for their Mediterranean diet, which comprises olive oil, nuts, fish and legumes, as well as less processed meat and baked goods than other countries. Spain’s engagement in a healthy diet can be associated with its lower prevalence of AD. A 2018 study by Berti and colleagues published in the American Academy of Neurology (AAN) showed that the brains of healthy middle-aged people who adopt a Mediterranean diet showed less accumulation of the protein amyloid-β, which is a hallmark of AD, compared with those who did not maintain the diet.
Data on Spanish commuting habits from one of the 28 Union Member State Factsheets on health-enhancing physical activity showed that 37% of the Spanish population engage in walking and cycling to work while 52% drive to work. However, in the US, more than 15% of adults were classified as physically inactive according to state maps of adult physical inactivity from the Centers for Disease Control and Prevention (CDC). Lower physical activity implicates a higher prevalence of dementia in later life.
Japan is among the countries with the highest life expectancy. However, this could also be the driving force of its high dementia prevalence. Japan’s elderly population (ages 65 years and older) comprises 28.7% of the nation’s total population, resulting in a higher prevalence of AD within the population. Another potential cause of the high total prevalence of AD is the increased prevalence of metabolic disorders (such as diabetes), which have also been associated with an increased risk of AD.
More research is needed to better understand the causes of the international differences in AD prevalence. These findings will enable other countries to promote healthier lifestyles, including schemes for cycling to work and healthy eating to buffer against cognitive deficiency with age.