A recent study published in PLoS ONE assessed the relationship between glaucoma and key dietary nutrients.
Give me some background.
Prior research has associated calcium (CA), magnesium (Mg), and potassium (K) in the diet with glaucoma risk. However, findings have been inconsistent, so the exact relationship is unknown.
Investigators explored this relationship along with the potential connection between glaucoma and:
- Visual field defect (VFD)
Now talk about the study.
For this cross-sectional study, 7,402 people were selected from the National Health and Nutrition Examination Survey (NHANES) database from the years 2005-2008.
To note, this study was based on a survey conducted by the National Center for Health Statistics (NCHS) to evaluate the nutritional status of the U.S. population.
Expand on NHANES.
NHANES collected data through household interviews followed by physical examinations.
The sampling was designed to be stratified and weighted to most accurately represent the U.S. population in order to assess disease prevalence.
After applying exclusion criteria, 6,189 participants were eligible for this study.
All were ≥40 years old and had previously received glaucoma evaluations as part of NHANES.
How was dietary intake determined?
Via the United States Department of Agriculture’s (USDA) automated multiple-pass method (AMPM), which consists of two 24-h dietary recall interviews.
The first interview of patients was conducted in-person; 3 to10 days later, another was conducted by phone call.
A total of 8.11% of the participants had glaucoma, while a statistically significant difference in nutrient intake between participants with and without glaucoma was noted.
After adjusting for glaucoma covariates, it was determined that in patients both with and without hypertension, recommended level Ca consumption was linked with a decreased risk of glaucoma.
For participants without hypertension, K consumption may cause a decrease in the risk for glaucoma.
Did age have significance?
In participants <65 years of age, Ca was associated with a lower glaucoma risk in those with and without hypertension.
A recommended level of K was determined to have protective factors in this age group for those without hypertension, while Mg had these factors for participants with hypertension.
What about VFD?
Only Ca at recommended levels had an association with lower glaucoma risk in those that had VFD.
This being a retrospective study, causal relationships could not be determined. In addition, there was a portion of self-reporting involved, which opens up the possibility of biases.
However, the researchers excluded extreme values, and the size and representative nature of the sample population aids in improving this.