In the News: Drug-Disease Interaction; Omega-3s & Depression; Anthocyanins & Endothelial Function

Statins Linked to Increased Cataract Risk

Following a Canadian analysis published last year, a second, large-scale retrospective study has also implicated statin use as increasing cataract risk (1).

The study matched nearly 7,000 statin users with non-users in a propensity score-matched analysis of roughly 45,000 people in a military healthcare system. Statin users in the propensity matched meta-analysis showed a risk increase of 9%. The risk of developing cataracts was 29% higher in statin users when the researchers looked at all patients with no comorbidities at baseline. The results were consistent regardless of the duration of statin use – 2, 4, or 6 years.

Propensity score analysis is a statistical matching technique used to balance two non-equivalent groups and reduce bias due to confounding variables. Observational studies of statins and cataracts have been conflicting, with some reporting increased risk and others a beneficial effect. The use of propensity matching to try to eliminate baseline confounding is seen as an important tool to help resolve divergent findings about this potential drug-disease interaction.

EPA / DHA & Symptoms of Depression

Higher intake of omega-3 fatty acids is associated with a significant 49% reduction in risk of elevated depressive symptoms in women, according to a new study (2) led by a National Institutes of Aging Aresearcher. A similar pattern was seen for the lowest ratio of highly unsaturated omega-3 (EPA & DHA) to highly unsaturated omega-6.

The investigators assessed whether there was a relationship between omega-3 consumption and elevated depressive symptoms (a score of ≥16 on the Center for Epidemiologic Studies Depression Scale) in over 1700 adults aged 30-65 residing in Baltimore City, MD. Elevated symptoms of depression were seen in 26% of women and 18% of men. Evidence that depressive symptoms are inversely related to omega-3 fatty acids is growing among US adults, and the results of this study support a protective effect of the omega-3s against these symptoms, at least in women.

Three mechanisms were proposed by the researchers to explain the findings. The first involves the serotonergic neurotransmitter system, which is regulated by the omega-3s. The second, called the “macrophage theory of depression”, involves inflammatory responses. EPA, which can form of anti-inflammatory compounds, is proposed as a prophylaxis against depression and omega-6 fat as a promoter. The third mechanism involves impaired phospholipid metabolism and fatty acid-related signal transduction.

Anthocyanins Support Endothelial Function

Epidemiologic studies suggest that increased consumption of anthocyanins (a type of flavonoid found in blueberries, bilberries and grapes) lowers the risk of cardiovascular disease, the most common cause of mortality among men and women. The results of a new randomized, controlled, crossover trial suggest that anthocyanins may improve circulatory function in healthy men (3). German and British collaborators investigated the effect of blueberry flavonoids on endothelial function. They assessed the effects of various doses of anthocyanins on flow-mediated dilation, a measure of vessel elasticity.

The effective doses of anthocyanins identified are equivalent to those found in 3 ½ to 8 ½ oz. of blueberries. Flow mediated dilation increased significantly after an hour, and again at 6 hours. The results suggest that regular consumption of anthocyanins supports cardiovascular health by promoting endothelial function.

References

1. Leuschen J et al. Association of statin use with cataracts: a propensity score-matched analysis. JAMA Ophthalmol, published online September 19, 2013.
2. Beydoun MA et al. Omega-3 Fatty Acid Intakes Are Inversely Related to Elevated Depressive Symptoms among United States Women. J Nutr Sep 4, 2013 [Epub ahead of print].
3. Rodriguez-Mateos A et al. Intake and time dependence of blueberry flavonoid-induced improvements in vascular function: A randomized, controlled, double-blind, crossover intervention study with mechanistic insights into biological activity. Am J Clin Nutr, Epub Sept 4, 2013.