Japanese researchers recently found that poor oral health was linked to memory problems. Now, a separate study conducted at Osaka University Hospital in Japan between April 2013 and March 2016 found that people who skipped brushing their teeth at night have an increased risk of heart failure and heart attacks.

According to The Jerusalem Post, neglecting your teeth at night increases the risk for cardiovascular disease. For the study, researchers enrolled 1,675 hospitalized patients over the age of 20. They were divided into four groups: one group brushed their teeth upon waking and again at night, a second group brushed only in the morning, the third group brushed only at night, and the fourth group practiced no oral hygiene.

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The researchers then evaluated each participant’s age, gender, smoking history, and follow-up results. In addition, four independent investigators examined the dental and medical records of all study participants, says the Express. They focused on oral health, time of toothbrushing, the depth of periodontal pockets and teeth count.

Markers of cardiovascular health including hospitalization for heart failure, arrhythmia, myocardial infarction, angina pectoris, and valvular and aortic diseases requiring surgery were also evaluated.

The results revealed that individuals who only brushed their teeth in the morning had a higher level of heart and blood vessel disease. On the other hand, those who brushed only at night or twice daily had higher survival rates. Smokers, equally common in all four groups, were found to have the highest risk level of disease.

“The findings clearly indicate that brushing in the morning after waking is insufficient and that brushing at night is effective for maintaining good health,” said the researchers, adding brushing in the morning is also important to avoid disease. According to experts, bacteria lingering in the mouth overnight are to blame for diseases that can lead to serious problems.

“Therefore, we suggest that brushing teeth at night is important for lowering cardiovascular risk,” noted the study authors.