New research from a study recently published in Ophthalmic Research measured the association between Vitamin B1 consumption and the prevalence of late age-related macular degeneration (AMD) in the United States.
Give me some background first.
Oral supplements with key dietary components are well established prophylactic treatments to delay the development of AMD into intermediate or late stages.
Nutrients significantly associated with a decreased risk of late AMD include:
- Carotenoids (lutein, zeaxanthin, and β-carotene)
- Vitamins (vitamins A, B6, B9, C)
- Minerals (magnesium, copper)
How does vitamin B1 relate?
Vitamin B1—also known as thiamin—has robust antioxidant properties.
Considering that oxidative stress is a key mechanism in the pathogenesis of AMD, investigators behind this study sought to clarify the vitamin’s potential impact in reducing the risk of AMD.
Of note, previous research (i.e., the Age-Related Eye Disease Studies (AREDS 1 and 2) and Alienor Study) reported no association between Vitamin B1 intake and the risk of late AMD.
Now, talk about the study.
In this cross-sectional study, researchers analyzed data from the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2008.
The NHANES, conducted by the Centers for Disease Control (CDC), examines a nationally representative sample of around 5,000 people each year.
It combines interviews on demographic, socioeconomic, dietary, and health-related questions and physical examinations with medical, dental, and physiological measurements.
How did they measure the relationship between vitamin B1 and AMD?
From 2005-2008, NHANES participants aged 40 years and older underwent fundus photographs.
Logistic regression models were used to evaluate the link between self-reported vitamin B1 intake levels and late AMD (measured with fundus photography).
Findings?
In total, 5,107 people aged 40 years and above were included in the study.
Investigators observed that higher levels of vitamin B1 intake were statistically associated with lower rates of late AMD, suggesting that dietary consumption of vitamin B1 was lower in participants with late AMD.
Tell me more.
This association was reported across all logistic regression models:
- Unadjusted model
- Odds ratio (OR) 0.40 (95% confidence interval [CI] 0.26-0.62)
- Adjusted model
- OR 0.53 (95% CI 0.29-0.94)
- Adjusted for age, sex, race, marriage, education, and total energy intake
- Fully-adjusted model
- OR 0.55 (95% CI 0.31-0.99)
- Included covariates above plus body mass index (BMI), alcohol consumption, smoking status, and various systemic diseases
There was no association between Vitamin B1 intake levels and early AMD across all models.
Expert opinion?
According to the study authors, “By inhibiting oxidative stress, vitamin B1 plays its vital role in slowing down the development of AMD, especially for late AMD.”
Limitations?
Due to the cross-sectional nature of this study, it was not possible to establish a causal connection between vitamin B1 intake levels and late AMD.
Additionally, as mentioned earlier, these findings differ from previous research (AREDS and Alienor study), which may have a higher level of proof because they were a multicenter randomized clinical trial and cohort study, respectively.
Take home.
These findings indicate that higher Vitamin B1 consumption levels were associated with a lower prevalence of late AMD in the US.
Next steps?
Additional multi-center randomized clinical trials are warranted to further elucidate the longitudinal and causal relationship between Vitamin B1 consumption and late AMD.