sábado, 23 de marzo de 2019

Diabetes in Men

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By Hannah Simmons, B.Sc.Reviewed by Chloe Barnett, BSc

Numerous population studies have revealed that men, compared to women, have twice the risk of getting diabetes between the ages of 34-55. Several studies are currently working to identify why, but so far, they have all been inconclusive.

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Diabetes is characterized by an impairment in glucose metabolism, leading to excessive blood glucose levels. Such high blood sugar levels lead to serious consequences in both men and women, such as neuropathy, kidney disease and heart failure. There are two types of diabetes (type 1 and 2) which affect different groups of people and have different causes, however they are both more prevalent in men.

Why are men at higher risk of type 2 diabetes?

One possible theory behind the increased diabetes risk in men is that they, on average, get diabetes at a lower BMI. Obesity is one of the most important risk factors involved in the development of type 2 diabetes, leading to increased insulin resistance and therefore increased glucose blood levels.

In a recent study by Glasgow University, the BMIs of 51,920 men and 43,137 women were obtained and compared 1 year after diagnosis with type 2 diabetes. This revealed that men were far more at risk of diabetes at a lower BMI, therefore requiring less weight gain to be at the same risk as women. One reason behind this could be that men without diabetes are more insulin resistant than women, so only a small increase in resistance is required for the condition to occur.

Another possible reason behind the increased risk of diabetes in males is that there are a greater number of males with impaired fasting glucose (otherwise known as pre-diabetes). This condition is characterised by increased blood glucose levels which are not high enough to be classed as full diabetes.

Individuals with this condition are far more at risk as their ability to metabolise is already impaired, so they only need a small increase in insulin resistance to develop the full condition. The increased incidence in men is not fully understood, but it may be due to protective hormones in females.

Type 1 diabetes in men

It is not only type 2 which is more common in males. Type 1 diabetes is also more common in Caucasian males than females. This has been explained by the stronger residual function of β-cells in women, possibly also due to hormonal protection, meaning that more insulin can be released and glucose levels can be regulated.

A final reason for the increased risk of diabetes in males is the loss of protective testosterone in a condition called testosterone deficiency. This hormone is important in male development throughout puberty, leading to vital changes such as increased muscle and genital development.

Various studies have recently revealed that males who have a deficiency in this hormone have a greater risk of developing diabetes. This is due to the important role of testosterone in the deposition of fats. It stimulates the formation of subcutaneous fat, which lowers the risk of diabetes (associated with visceral fat).

Loss of this hormone function through aging, however, leads to an increased propensity to develop visceral fat. This means that as males age, they are at a much higher risk of diabetes.

Overall, there are many possible theories behind the increased risk of diabetes in males, such as higher risk at a lower BMI, no protective female hormones to reserve β-cell function and loss of testosterone function in aging.

Men also show additional symptoms associated with diabetes which are not seen in women, such as erectile dysfunction and muscle mass loss (due to testosterone deficiency).

Other diabetes-like conditions are also more common in males, such as Ketosis-prone diabetes; 75% of people with this condition are males, and it is characterised by diabetic ketoacidosis without the other related symptoms of type 1 diabetes.

It is very important that research continues to identify why males are at a greater risk, to aid the search for improved diabetes management strategies and reduce future risk.