Age‐specific prevalence, thyroid dysfunction and depressive symptomatology in adults with down syndrome and dementia

Abstract Two hundred and one adults with Down syndrome (DS) were investigated for differing aspects of clinical dementia. Age‐specific prevalence rates of 9.4% for age range 40–49 years, 36.1% for 50–59 years and 54.5% for 60–69 years were found. Findings associated with increasing severity of dementia were gait deterioration, onset of urinary incontinence, increased muscle tone and onset of seizures. No association was found between thyroid dysfunction or thyroid autoimmunity and dementia. However, depressive symptomatology of depressed mood, weight loss and reduced appetite were associated with dementia. These findings investigating Alzheimer's disease (AD) in adults with DS support findings reported for the non‐learning disability population of an association between age, depressive symptomatology and AD but no association between thyroid dysfunction and AD.