Higher levels of protein hormone associated with lower risk of dementia, Alzheimer's disease

December 15, 2009, JAMA and Archives Journals

Persons with higher levels of leptin, a protein hormone produced by fat cells and involved in the regulation of appetite, may have an associated reduced incidence of Alzheimer disease and dementia, according to a study in the December 16 issue of JAMA.

Previous studies have shown that overweight and in mid-life are associated with poorer cognitive function in the general population and an increased risk of . There has been evidence that leptin exerts additional functions on the brain outside the hypothalamus (a region of the brain that controls body temperature, hunger, and thirst), according to background information in the article.

Wolfgang Lieb, M.D., of the Framingham Heart Study, Framingham, Mass., and colleagues examined the relationship between measurements of plasma leptin concentrations and incidence of dementia and Alzheimer disease (AD). For this study, plasma leptin concentrations were measured in 785 persons without dementia (average age, 79 years; 62 percent female), who were in the original Framingham study group at the 22nd examination cycle (1990-1994). A subsample of 198 dementia-free survivors underwent volumetric brain magnetic resonance imaging (MRI) between 1999 and 2005, approximately 7.7 years after leptin was measured. Two measures of were assessed: total cerebral brain volume and temporal horn (a region of the brain) volume, both of which are markers of early AD pathology and subsequent dementia risk. The researchers conducted follow-up for new cases of dementia and AD until Dec. 2007. During a median (midpoint) follow-up of 8.3 years, 111 participants developed dementia; 89 of them were diagnosed with AD.

The researchers found that higher leptin levels were associated with a lower incidence of all-cause dementia and AD. The incidence of decreased gradually across increasing levels of leptin: a person with a baseline leptin level in the lowest quartile group had a 25 percent risk of developing AD after 12 years of follow-up, whereas the corresponding risk for a person in the top quartile group was only 6 percent.

Higher leptin levels were also associated with higher total cerebral brain volume. Lower temporal horn volume was not significantly related to leptin levels.

"These findings are consistent with recent experimental data indicating that leptin improves memory function in animals through direct effects on the hippocampus and strengthens the evidence that leptin is a hormone with a broad set of actions in the central nervous system. Due to the exploratory character of the present analyses, we did not adjust for multiple comparisons and acknowledge that our findings require confirmation in independent samples," the authors write.

"If our findings are confirmed by others, leptin levels in older adults may serve as one of several possible biomarkers for healthy brain aging and, more importantly, may open new pathways for possible preventive and therapeutic intervention. Further exploration of the molecular and cellular basis for the observed association may expand our understanding of the pathophysiology underlying aging and the development of AD."

More information: JAMA. 2009;302[23]:2565-2572.

Related Stories

Recommended for you

New study offers insights on genetic indicators of COPD risk

January 16, 2018
Researchers have discovered that genetic variations in the anatomy of the lungs could serve as indicators to help identify people who have low, but stable, lung function early in life, and those who are particularly at risk ...

Previous influenza virus exposures enhance susceptibility in another influenza pandemic

January 16, 2018
While past exposure to influenza A viruses often builds immunity to similar, and sometimes different, strains of the virus, Canadian researchers are calling for more attention to exceptions to that rule.

Don't hold your nose and close your mouth when you sneeze, doctors warn

January 15, 2018
Pinching your nose while clamping your mouth shut to contain a forceful sneeze isn't a good idea, warn doctors in the journal BMJ Case Reports.

Surfers three times more likely to have antibiotic-resistant bacteria in guts

January 14, 2018
Regular surfers and bodyboarders are three times more likely to have antibiotic resistant E. coli in their guts than non-surfers, new research has revealed.

New antifungal provides hope in fight against superbugs

January 12, 2018
Microscopic yeast have been wreaking havoc in hospitals around the world—creeping into catheters, ventilator tubes, and IV lines—and causing deadly invasive infection. One culprit species, Candida auris, is resistant ...

Dengue takes low and slow approach to replication

January 11, 2018
A new study reveals how dengue virus manages to reproduce itself in an infected person without triggering the body's normal defenses. Duke researchers report that dengue pulls off this hoax by co-opting a specialized structure ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.