Study suggests late adolescent risk factors for young-onset dementia

A study of Swedish men suggests nine risk factors, most of which can be traced to adolescence, account for most cases of young-onset dementia (YOD) diagnosed before the age of 65 years, according to a report published by JAMA Internal Medicine.

Dementia is a major public health concern that affects an estimated 35.6 million people worldwide. The cost and disability associated with dementia are expected to increase in the next 40 years, affecting more than 115 million people by 2050, Peter Nordstr?m, Ph.D, of Umeå University, Sweden, and colleagues write in the study background.

The study included 488,484 Swedish men conscripted for mandatory military service from September 1969 through December 1979 with an average age of 18 years.

"Young-onset dementia (YOD), that is, dementia diagnosed before 65 years of age, has been related to genetic mutations in affected families. The identification of other risk factors could improve the understanding of this heterogeneous group of syndromes," the study notes.

During a median follow-up of 37 years, 487 men were diagnosed as having YOD at a median age of 54 years. Significant risk factors for YOD included alcohol intoxication (hazard ratio [HR], 4.82); stroke (HR, 2.96); use of antipsychotics (HR, 2.75); depression (HR, 1.89); father's dementia (HR, 1.65); drug intoxication other than alcohol (HR, 1.54); low cognitive function at conscription (HR, 1.26); low height at conscription (HR, 1.16); and high systolic blood pressure at conscription (HR, 0.90), according to the results.

"Collectively, these factors accounted for 68 percent of the YOD cases identified," the authors comment.

The results also indicate that men with at least two of the nine risk factors and in the lowest third of overall cognitive function had a 20-fold increased risk of YOD during follow-up.

"In this nationwide cohort, nine independent risk factors were identified that accounted for most cases of YOD in men. These risk factors were multiplicative, most were potentially modifiable, and most could be traced to adolescence, suggesting excellent opportunities for early prevention," the study concludes.