Depression in older men linked to low testosterone

Australian researchers are suggesting that older men who have lower levels of the male sex hormone testosterone in their blood, may be more prone to depression.

Depression affects between 2 percent and 5 percent of the population at any given time, with women more likely to be depressed than men until age 65, when sex differences almost disappear; several studies have suggested that sex hormones might be responsible for this phenomenon.

The researchers believe the hormone may affect levels of key brain chemicals.

Dr. Osvaldo P. Almeida, and colleagues from the University of Western Australia, Perth reached this conclusion after a study of 3,987 men aged 71 to 89 years, between 2001 and 2004.

They found those with the lowest testosterone were three times more likely to be depressed than those with the most and they suspect the hormone may be the culprit.

Experts say that low testosterone reduces mood is not surprising as other research has found that women are more likely to be depressed than men until the age of 65, when the difference between the genders almost disappears.

Each of the participants gave blood samples and took part in tests to determine whether they were depressed, and a total 203 were assessed as being depressed.

They were found to have significantly lower levels of both total testosterone, and free testosterone, which is not bound to proteins.

When the researchers adjusted the data to take into account factors such as educational attainment and body fat levels they found those men whose level of free testosterone was in the bottom 20% were three times more likely to be depressed than those in the top 20%.

The researchers say while more work is needed to confirm their findings the results do present the possibility that treatment to boost testosterone levels in older men may be an effective way to treat depression.

A previous study of 800 men over the age of 50 found that those with low levels of testosterone had a 33% increased risk of death over an 18-year period than those with higher levels and also appeared significantly more likely to have a cluster of risk factors associated with cardiovascular disease and diabetes.

This raises the suspicion that men with low testosterone levels may be prone to depression because they are also more likely to be in poor physical health.

The Australian researchers say this does not fully explain the link, and that some other factor must also be in play.

Testosterone replacement therapy has also been shown to help elderly men with mild Alzheimer's disease and research suggests that levels of testosterone in men of all ages are decreasing.

Experts say there is abundant evidence which shows that testosterone levels are linked to mood but some say caution must be used regarding testosterone therapy, as depression, particularly in elderly people, was often the result of many different, inter-relating factors.

The study was supported by funds from the National Health and Medical Research Council of Australia and is published in the current issue of the Archives of General Psychiatry.