Homocysteine is an amino acid that has attracted an increasing level of attention since studies linked it to health issues such as dementia, Alzheimer’s, and cardiovascular disease. Studies exploring a link between homocysteine levels and obstructive sleep apnea (OSA) have reached mixed conclusions — and this led researchers to perform a meta-analysis that was published in BioMed Research International in 2017.
Researchers analyzed 10 studies involving 773 participants to investigate the association between OSA and homocysteine levels. Just over half of all participants were OSA patients; the remainder served as controls.
Each study examined the sleep of participants using polysomnography and divided participants into groups based on their apnea-hypopnea index (AHI) scores. The studies did not include participants who were receiving CPAP treatment or who reported health complications such as heart disease or stroke.
Researchers found that increased homocysteine levels were observed in individuals with OSA compared to those without the sleep disorder — and this finding was more pronounced in those with more severe OSA.
These findings led the authors of the meta-analysis to determine that elevated homocysteine levels may contribute to severe health complications, such as coronary heart disease and stroke, among individuals with OSA.
Why is homocysteine associated with OSA?
The pauses in breathing and reduced blood-oxygen levels associated with OSA can lead to frequent arousals and trigger the body’s inflammatory response. As pointed out by the authors of the meta-analysis, the consequent increase in oxidative stress can lead to higher levels of homocysteine in the blood.
Researchers also investigated whether there was a relationship between AHI scores and body mass index (BMI) scores and homocysteine levels in those with OSA. They found that those with AHI scores of 30 and above had significantly higher homocysteine levels than those with lower AHI scores. They determined that BMI had no relationship to homocysteine levels in OSA patients.
Although this study suggested that homocysteine levels were higher in those with OSA compared to those without the sleep disorder, more research is needed before we can conclude that homocysteine levels are able to predict OSA severity — yet it does appear to be clear that there is a close and significant association between homocysteine levels and OSA.
How to reduce homocysteine levels
A study published in 2004 found that smoking, excessive coffee consumption, and alcohol abuse can increase homocysteine levels — while endurance exercise and fruit consumption can decrease them.
Nutrition and exercise help the body metabolize homocysteine and keep levels in check. (One study found that exercise training reduced homocysteine levels by 12 percent.)
Vitamin B6, folic acid and vitamin B12 also appear to reduce homocysteine levels — vegans and vegetarians may be at a greater risk for higher homocysteine levels compared to meat eaters since these diets tend to supply less vitamin B12.
A meta-analysis published in 2014 concluded that CPAP treatment significantly reduced homocysteine levels in those with obstructive sleep apnea hypopnea syndrome after just three months of therapy.
Seek medical advice
You should speak with your doctor if you have any concerns about OSA or your homocysteine levels. Although not conducted as part of routine bloodwork, your doctor can order a blood test to determine whether you need to take steps to reduce the amount of homocysteine in your blood.