(NewsNation) — Those tossing and turning throughout their early midlife years may be more susceptible to dementia as they age, researchers found. The new study, published Wednesday in the journal Neurology, analyzed 589 people's brain scans for a connection between sleep quality in people in their 40s and their brain age later in life. Researchers found a "dose-response relationship" between the two factors, with those who reported more poor sleep characteristics at 40 showing an advanced brain age in MRIs obtained 15 years later. Poor sleep characteristics include: Bad sleep quality Difficulty initiating sleep Difficulty maintaining sleep Early morning awakening Daytime sleepiness Patients who reported two or three characteristics had a brain age that was 1.6 years older than people who only reported one characteristic, which made up roughly 70% of the pool. However, those with more than three characteristics — around 8% — showed a brain age 2.6 years older than their counterparts. When will the next COVID, flu surge start? Experts weigh in “Sleep problems have been linked in previous research to poor thinking and memory skills later in life, putting people at higher risk for dementia,” study author Dr. Clémence Cavaillès told MedPage Today. “Our study which used brain scans to determine participants’ brain age, suggests that poor sleep is linked to nearly three years of additional brain aging as early as middle age.” "Advanced brain aging is associated with cognitive decline and Alzheimer's-related atrophy patterns," Cavaillès added. "Therefore, poor sleep may be an important target for early interventions aimed at preventing neurocognitive decline, even before amyloid and tau accumulation begins." The researchers used CARDIA, a long-term federal study of cardiovascular disease, to obtain baseline data. As the characteristics were self-reported, study leads acknowledged that some people's sleep data could have been misreported.