A study was conducted on over 40,000 men and women to observe the connection between fasting plasma glucose levels and cardiovascular disease and all-cause mortality. A U-shaped curve association was examined between the two. Low fasting plasma glucose levels and impaired fasting glucose levels were associated with high mortality. The most important adverse effect of hypoglycemia has been associated with brain damage. As an important fuel of the brain, severely low fasting blood glucose may induce brain damage and dysfunction. Although association does not directly indicate cause and effect, the data suggests that low fasting blood glucose itself may lead to high mortality risk. If results are confirmed, low fasting blood glucose could be a modifiable risk factor in non-diabetics.