Dementia Rates Declined Over Past 30 Years

The incidence of dementia has declined over the past 3 decades, according to a study published in The New England Journal of Medicine.1

Researchers reviewed the files of patients in the Framingham Heart Study, which has recorded the incidence of dementia since 1975. In the review, 5200 patients at least 60 years old were separated into four study periods based on when they were monitored: late 1970s to early 1980s, late 1980s to early 1990s, late 1990s to early 2000s, and late 2000s to early 2010s.

The 5-year age- and sex-adjusted cumulative hazard rates for development of dementia in the oldest to most recently monitored groups, respectively, were 3.6, 2.8, 2.2, and 2.0 per 100 patients. Compared with the earliest group, incidence of dementia declined by 22%, 38%, and 44%, respectively, in the subsequently monitored groups.

The risk reduction was observed only in patients with at least a high school diploma.

The study authors noted that the prevalence of most vascular risk factors (with the exception of obesity and diabetes) that may lead to stroke, atrial fibrillation, or heart failure decreased over time. Although these cardiovascular conditions are, in turn, risk factors for dementia, the trends in their decline did not completely explain the decrease in the incidence of dementia.

 

1. Satizabal CL, Beiser AS, Chouraki V, et al. Incidence of dementia over three decades in the Framingham Heart Study. N Engl J Med. 2016;374(6):523-532.

Study Found Lower Verbal Memory Scores in Middle-Aged Patients With Prolonged Marijuana Use

Past exposure to marijuana was associated with worse verbal memory in middle age, and longer exposure to marijuana use was linked to worse verbal memory scores, according to a study in JAMA Internal Medicine.1

Researchers measured verbal memory, processing speed, and executive function in nearly 3400 patients whose marijuana use had been tracked for 25 years in the CARDIA study. Of the patients followed in the study, 84% reported past marijuana use, and 12% reported continued use into middle age.

Current marijuana use was associated with worse verbal memory and processing speed; cumulative lifetime exposure was associated with worse verbal memory, processing speed, and executive function. After adjusting for potential confounders, cumulative lifetime exposure to marijuana remained significantly associated with worse verbal memory but not executive function or processing speed.

Worse verbal memory scores were linked to duration of marijuana exposure. For each 5 years of past exposure, verbal memory was significantly lower: half of participants remembered one word fewer from a list of 15 words for every 5 years of use (P = .02).

 

1. Auer R, Vittinghoff E, Yaffe K, et al. Association between lifetime marijuana use and cognitive function in middle age: the Coronary Artery Risk Development in Young Adults (CARDIA) study [published online ahead of print February 1, 2016]. JAMA Intern Med.

 

Depression Risk Linked With Diabetes Duration

Risk of depression in geriatric men was linked with duration of diabetes, according to a study published in Maturitas.1

Researchers reviewed a community-derived sample of nearly 5500 men aged 70 years to 89 years. Patients scoring 7 or more on the Geriatric Depression Scale were categorized as currently depressed; duration of diabetes was self-reported.

Diabetic patients were 1.5 times more likely to have ever reported depression compared with patients without diabetes; those with diabetes were nearly twice as likely as those without diabetes to currently be depressed. The association between duration of diabetes and risk of current depression was J-shaped, with odds ratios of 1.92, 1.56, 2.49, and 3.13 for patients reporting diabetes duration of less than 10, 10 to 19.9, 20 to 29.9, and 30 or more years, respectively.

The study authors noted that, according to structural modeling, frailty mediated some of the association between diabetes duration and depression and was a strong predictor of depression in the sample. n

 

1. Almeida OP, McCaul K, Hankey GJ, et al. Duration of diabetes and its association with depression in later life: the Health In Men Study (HIMS). Maturitas. 2016;86:3-9.

 

 

Section Editor David S. Boyer, MD
• clinical professor of ophthalmology at the University of Southern California Keck School of Medicine, department of ophthalmology, in Los Angeles, Calif.
• member of the Retina Today editorial advisory board
• +1-310-854-6201; vitdoc@aol.com