For anyone suffering a mid-life crisis, and maybe contemplating ditching some of their responsibilities in favour of fun, new research suggests you pause before indulging in health compromising vice during this period.
According to new research published in the BMJ, maintaining good health and limiting the development of chronic disease during this life stage may bode well for dementia prevention through the rest of one’s life.
In a longitudinal study that observed 10,000 British men and women since 1985-88, researchers from Université de Paris, France followed a group aged 35 to 55 over 30s to see if multi-morbidity – that is, the presence of multiple chronic health conditions – increased participants risk for the onset of the neurological condition.
“To our knowledge, this study is the first to use a longitudinal framework to examine the association of multimorbidity with the risk of dementia on such a large scale,” the researchers write.
They discovered that those who sustained two or more conditions by their mid-50s, including high blood pressure, diabetes, coronary heart disease, depression, and chronic lung disease (COPD), were much more likely to develop dementia later in life than healthier participants.
Interestingly, the risk was still higher when compared to participants who eventually developed multiple chronic conditions later in life, suggesting that attention to good health in our younger years pays dividends over the long run.
“Multimorbidity, particularly when onset is in midlife rather than late life, has a robust association with subsequent dementia,” researchers concluded.
In fact, after taking account of a range of factors including age, sex, ethnicity, education, diet and lifestyle behaviours, multimorbidity at age 55 was associated with a 2.4-fold higher risk of dementia (1.56 per 1000 person years) compared with disease-free participants.
This association weakened progressively with older age at onset of multimorbidity.
For example at age 65, onset of multimorbidity before age 55 was associated with a 2.5-fold higher risk of dementia (3.86 per 1,000 person years) compared with a 1.5-fold higher risk (1.85 per 1,000 person years) in those with onset of multimorbidity between age 60 and 65.
In other words, for every five year younger age at onset of multimorbidity up to age 70, the risk of dementia was 18 per cent higher.
When the researchers examined more severe multimorbidity (defined as three or more chronic conditions), the importance of younger age of onset of multimorbidity for the risk of dementia was further accentuated.
Compared with people with no or one chronic condition, those with three or more chronic conditions at age 55 had a nearly fivefold higher risk of dementia, whereas the risk was 1.7-fold higher when onset of multimorbidity was at age 70.
This is an observational study, so can’t establish cause, and the researchers point to some limitations, such as possible misclassification of some dementia cases, and the fact that study participants are likely to be healthier than the general population.
However, this was a large study with more than 30 years of follow-up, and results were similar after further analyses using death as the outcome measure, which the researchers say increases confidence in their findings on dementia.
“Given the lack of effective treatment for dementia and its personal and societal implications, finding targets for prevention of dementia is imperative,” they write.
“These findings highlight the role of prevention and management of chronic diseases over the course of adulthood to mitigate adverse outcomes in old age.”